Conference vmszoo::rc

    
    	 Mill a slot in the con rod to improve cooling or give
    Perry Automotive a call and ask if they sell a hopped up
    con rod for the engine.  They are the originatord of the
    slot idea. Also don't forget to order a header pipe when
    you order your tuned pipe. If noise isn't a problem run
    a Nitro pipe instead of a muffled tuned pipe.
    
         Buy a second .19 fox. You may need the spare parts.
    
    
    						Tom

    I will probably be fun work ...
    
    other thoughts came to mind: 
    	- what about glow plugs (like ther are long and short ones).?7
        - should one attmpt tp play carb jets & needles ??

I believe what you are wanting to do could end up being a disappointment. The
Fox configuration that you outline is a speed configuration not a torque
configuration hence you will be swinging a small prop. The problem as I see it
is unless the model is very clean (aerodynamically) you will lose too much
power in drag from the prop wash over the air frame. Also consider the size of
the frontal area of model and the area of the prop disk, you could find that
the majority of the prop disk is blanked by the fuselage and therefore very
inefficient. 

If you want to tune up an engine start with a .40 size it is a lot easier to 
work with that the smaller sizes. Try getting an OS 46VF, it is a front intake 
rear exhaust and is easily adapted to rear intake by swapping the front housing 
with one from the OS 40VRP. You can add a tuned pipe for more gooooooo. 

John

    re .-1... Very good point.. 
    
    If you define "speed configuration" as high RPM & low torque, that
    is not quite what I would like
    
    A few more details about the FOX .19 : The cylinder head can be
    rotated to provide for RHS exhaust, LHS exhaust or rear exhaust..
    
    Btw, I was give a number of some 38 oz/inch as probable torque I
    would get out of this. I don't know if this is good or not. 
    
    Now, I plan to run the engine without mods an some form of dynamometer
    to get a reference torque curve. (Torque vs RPM)
    
    Then I am looking to find out the critical factors that will affect
    RPM and/or torque. If any factor interact with an other factor,
    I'd like to know that too. That way I can use experimental design
    techniques (such as Taguchi technique) to  study the factors and
    then optimize.
    
    The objective of the exercice is to raise torque & RPM as much as
    possible. Then I plan to work on which prop config will develop
    most power. Rough equation is 
    
        ((prop diameter - fuselage diameter) * prop pitch * RPM) = NUMBER
    
      NUMBER is volume of cylinder of air moved by prop. Biggest number
    should a fair measure of power.
    
    Sure I could get an bigger engine. But then I  would loose some
    of the intent of the exercise: Find out as much as I can about 
    what can affect engine performance and see you far I can take my
    current power plant. If I decide I want more power, then I can
    use th knowledge gained here on a bigger engine.
    
    lastly: I can understand front intake, rear exhaust. Now is rear
    intake, rear exhaust a reasonable config and aht does it buy me?
    
    md
    
    
       

>    A few more details about the FOX .19 : The cylinder head can be
>    rotated to provide for RHS exhaust, LHS exhaust or rear exhaust..
    
If you can turn the head 90 degrees then won't the cooling fins be 
wrong for a plane?

              _!_
Bye        ----O----
Kay R. Fisher / \
 
==============================================================

    no.. the cylinder is in two parts: the head & the body. 4 screws
    hold everything to the crank body. One just removes the screws,
    litfs the head off, rotates the cylinder body as needed, reseat
    the head re-screw everything. This scheme offers the intersting
    possiblity of configuring a front carb-front exhaust engine...:-)
    
    md

    re .-1 and front-carb/fron exhaust: a possiblity for turbocharging
    maybe ?? Has anyone tried that ??

Re: 93.4 What will rear intake buy me.

Rear intake is better that front intake for many reasons.

1) The fuel air mixture has less distance to travel as the induction is by a 
   disk or drum valve on the back plate. This keeps the mixture cooler and more 
   gas volume is passed to the combustion chamber.

2) With the front intake as the gas passes down the crank shaft it slows down 
   due to the drag in the shaft.

3) With the front intake there is a limit to the size of induction passage, if 
   you go to big you weaken the crank shaft, there is virtually no limitation on 
   the rear intake configuration.

4) The rear intake configuration blast's the mixture up to the bottom end 
   bearings and the piston underside improving lubrication and cooling.

There are many more but thats all that comes to mind at this time.

Re: 93.7 Turbo charging.

I think on the size of engines we use the drag on the turbine would be too
great and insufficient boost would be gained from the compressor. The turbo 
would probably be spinning at 60,000+ RPM and small bearings would be very 
inefficient. An interesting idea if somebody has the time and inclination to 
experiment.

Last night I ran up the Six Million Dollar Eaglet for the first
time since the crash.  The OS .25 sounded real good, but it looks
like I'll be in for more fun and games with the tank...

Funny thing, we have two other Eaglets at the club, with OS .25s
in them and the stock tank installation that run full tanks
regularly.  I've modified the heck out of the nose and still
cannot get a full tank run after more than a year of trying. 

But, my question. After the crash I took the OS apart, even
though I know you shouldn't, and cleaned it.  Last night while I
was running it there was a different sound.  Now, its been 6
weeks of flying gliders since I've heard that engine, or any
other for that matter, so I could be wrong...but it sounded like
the crankshaft was rubbing on something.

When I got home I dismounted the engine and checked the front
bearing for play. With the prop on it felt about right.  So I
pulled the back of the case.  The con rod slips very freely on
the wrist pin and crank pin and there are light score marks
on the case back.  There is no play on the wrist and crank pin
bearings, they just slip back and forth freely.  So it looks like
the con rod is slipping to the back of the wrist pin and rubbing
against the case back.  Is this normal?

That's one fine engine.

    John,
    
    The con-rod rubbing the backplate is quite normal...in time you'll
    see a perfect circle burnished on the face of the backplate.  However,
    I'd be very watchful of excessive scraping noise since, as a rule,
    you can't really hear the rubbing that's taking place.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

>>When I got home I dismounted the engine and checked the front
>>bearing for play. With the prop on it felt about right.  So I
>>pulled the back of the case.  The con rod slips very freely on
>>the wrist pin and crank pin and there are light score marks
>>on the case back.  There is no play on the wrist and crank pin
>>bearings, they just slip back and forth freely.  So it looks like
>>the con rod is slipping to the back of the wrist pin and rubbing
>>against the case back.  Is this normal?

    Yes that's normal, especially if you use an electric starter.  It
    won't rub when the engine is running since the prop is pulling it
    away from the backplate.  The scraping is one of the disadvantages
    of using an electric starter.
    
    I'd look closer at the bearing, since it could cause the sound you
    describe.  There could be some corrosion on the balls or races -
    especially if you didn't get the raw fuel out of the engine for a
    while after the crash.
    
    Bill
    

I brought the engine in because I'm going to stop by my model
junkie Phlyin Phil on the way home and see what he thinks.  But
I did try to wiggle the bearing from side to side and there's no
play, only a front-back play of about 1/32" with the prop on, and
about 1/16" with the prop off.  Sounds like I'm worrying about
nothing though I'd never noticed it before.

So, from your last two replies, I guess that its normal for that
con rod to slip back and forth during operation.   It was very
quiet out there last nite, so I'm not surprised that I heard the
rubbing.  Very quiet, and cold, and dark.

Thanks for the feedback. 

        Re:< Note 93.12 by SSDEVO::TAVARES "Oh yeah, life goes on..." >

                A shot bearing usually feels a tad rough when you turn it
        over slowly, like  there's  fine  sand in it, or the balls aren't
        quite round.  It's  amazing  how  long  you  can  keep running an
        engine with a show crank case bearing.  I wouldn't try to use one
        with a bad bearing on either end of the connecting rod.
                      _ 
                     / |
        |  _====____/==|
        |-/____________|
        |    |        o \
             O           \ 
                          O
         Hang in there! o_|_
                          |
             Anker      \_|_/

    
    Re: .-1  - exactly!  And for a while the bearing won't feel loose
    either.  I wouldn't stop flying immediately if this is the problem
    but I would replace the bearing when I got a chance (during the
    building season if you have one).  The new bearing should only be
    10 or 15 bucks I would think.
    
    Bill
    

OK. Thanks for the advice, I'll watch that bearing.  As of now it
seems ok.

    Is this OS25 an FP or FSR?  If it's an fp, it doesn't have ball
    bearings on the crank.  THe FP engines have lots of crankshaft end
    play that's perfectly normal.  The FSR's don't.  If you disassembled
    the engine, make sure that you got the sleeve back right.  If the
    ports in the sleeve are not lined up with the ports in the case,
    you will have problems with the engine not running right.  If there
    is any doubt get someone to look at it for you.  THe other thing
    to check for (Al had this problem) is a bent crankshaft if you had
    a hard crash.  
    
    Charlie
    

Now that you mention it, it is an FP.  Its 1972-vintage, but I
bought it unused in 1984.  I am positive I reassembled it
correctly.

After the crash I called Phylin Phil in a panic because I though
the case had been damaged.  Turned out that it was only the
contour change on the outside of the case where the transfer port
is.  With all the dirt and fretting, it looked like a stress
bulge.  This is why I disassembled it completely; I wanted to
verify for myself that the bulge was indeed the transfer port,
and I pulled the sleeve to be sure.  I was very careful, and I
did it knowing that it wasn't the right thing to do because it
disturbs the wear-in of the engine.

I was most concerned about bending the crank, since the
Eaglet hit the ground pretty hard, but it ran without vibration,
so I'm sure no real harm's done. 

Last month in Model Builder Eloy Marez showed a picture of this
engine and praised it as being the best engine he'd ever owned.
I can agree with this, it has been a very dependable engine, even
with all the other "bad luck" I've had with engines in general.

I wonder if I don't have a bent crank in my OS H60FGR in the Aeromaster.
The last two times I ran it there was a lot of vibration and I just
checked the prop again last night and it is in balance.

Is there an easy way to confirm the crank?
If it is bent will I need some special tool to pull
bearings out to remove it?

Anyone ever send their engine to Clarance Lee for maintenance?

Al - are you still running that crankshaft straightening service?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

    I sent a head to Clarence Lee to have a helicoil put in the 
    thing and I sent it out second day air.  I had it back in
    6 days.  I couldn't believe the rapid response.  I would rate
    the service 4 stars.

		________
	 /	  __|__  
	=========[_____\>
	/	__|___|__/  BREAK A BLADE,
			    Ken    	

    Kay,
    
    A simple, not terribly accurate but adequate, means of checking
    for a bent crank is to block the airplane up with the thrust-line
    reasonably parallel to the work-surface.  Then place virtually any
    object at either side of the fuse such that the prop lines up with
    it at the 90-degree from vertical position.  Now, simply rotate
    the prop through from blade-to-blade checking the position of each
    tip as it passes the 90-degree reference point previously established 
    (BTW, this is best performed with the glo-plug removed).
    
    The _best_ way, of course, is to remove the crank, set it up in
    a lathe and check for trueness, end-to-end, using a dial-indicator.
    If found to be bent, this is the place and time to straighten it
    as well.
    
    Yeah, I could probably still straighten a crank fer' ya' using lathe
    and tools in the plant's machine shop but you'd be better served
    to replace the crank with a new one or send it to a professional
    as Ken mentions in .-1.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    Hi Y'all....I have a question or two, now that I have been forced
    to rip into my engine this past weekend!
    
    	I have a Royal .40 which I bought used, and have run twice before.
    First time was on a test stand, and it ran ok for the small amount
    of time I ran it.  Second time was a couple of weeks ago, with Ken
    Soutiere.  We entered the symptoms on this network of how it would
    not respond properly to throttle inputs.  Anyway, I took the Carb
    apart after the test flight with Ken, and found a piece of fuel
    tank plastic on the needle valve, and assumed my problems were over.
    	This weekend I tried to start it again to check it out, and
    believe I caused another problem. I had it running for a moment
    or two, and it would keep stalling.  Then finally, the starter would
    not turn it over anymore.  It would spin part way, but not through
    TDC.  I took it apart and found two disturbing things.
    	1)  The connecting rod is shaped like this:
    
    			       -| |-
    				/ /
    			       | |
    			       | |
    			      -| |-
    	The angle is not that severe of course, but you get the drift.
    The ends seem to be parallel still, with the rod being bent between.
    My theory is I caused a hydraulic lock somehow by fooling with the
    needle valve, and bent the thing.  Does anyone else think this is
    the cause?
    
    	2)  The second problem is that the piston does not slide freely
    through the entire length of the sleeve.  The sleeve seems to be
    the ABC type, and the piston is freemoving up till the last few
    millimeters of travel..then it sticks tight as a drum!  (This is
    slightly _Below_ the top of its actual travel, according to the
    cylinder wall scuff marks.)
    
    	Does anyone have any suggestions?  I should also tell you that
    I will be ordering some parts from Royal anyway, due to the fact
    that I lost one of the wrist-pin "c" clips while trying to replace
    it!  Durnit, those things are _small_!!  Will I need to replace
    the rod, sleeve, and piston, or just the rod and sleeve?
    	
    	Oh yes, one other question...does anyone have Royal's address?
    
    	Thanks,
    
    	Brian
    

    
    	Thanks!!!  That is rather interesting about the taper in the
    cylinder....I wonder why they do that?
    
    	Again, thanks....I'll put Royal's response here if it is
    worthwhile.
    	
    	Brian
    

    
    	Ok, thats what I had thought as the only possible explanation
    too.  Now, for the real kicker...if I "force" the piston to the
    top of the scuff marked area of the sleeve, the piston is stuck
    so tight it has to be removed with the full pressure of my thumb
    pushing down.  Does this fit with the "minimal" taper description,
    or is there something else happening here?
    	I will be calling Royal today from home, due to the dreaded
    cold/flu virus.  I'll let y'all know what they say.
    
    	Thanks, Mr. Snowman!  (Gee, sounds like that old song, Mr.
    Postman!)
    
    	Brian
    

    It's normal with ABC engines to have a very tight fit at the top.
    It shouldn't be scuffed up though.  The taper is to compensate for
    thermal expansion, I think.  ABC engines rely on a gas tight fit
    while running.  The piston and sleeve both expand at different rates
    so it actually can loosen up when it is running.  The real problem
    with a new one can be lack of sufficient lubrication during breakin.
    You must run it rich and not let it sieze up.  The piston and sleeve
    wear in during breakin and the thing gets looser.  It's very easy
    to bend a rod if you force an ABC engine through compression without
    sufficient lubrication.  That may be what happened to yours.  I
    had a new Supertigre 61 that I ran in last summer and it was so
    tight that it would squeek when you flipped it over at the top of
    the stroke.  It took a good deal of running to get it to the point
    where it didn't start to sieze up when I leaned it out.  By the
    way, I think that ABC engines are more trouble than they're worth
    for sport flying.  A ringed engine is much more tolerant to abuse
    and easier to start when hot.
    
    Charlie
    

    Brian,
    In the cold weather, the ABC engine will even be more difficult
    to turn over when it is cold.  I have an ABC in one of my choppers,
    and when it is cold (45-50) I cannot turn it over with my heavy
    duty Sullivan starter and starter battery.  I have to use the 
    car battery.  That is with an engine that has had many hours of
    run time over the past two years.  However, I suspect that a
    combination of tight fit and hydro-lock is what did your connecting
    rod in.

		________
	 /	  __|__  
	=========[_____\>
	/	__|___|__/  BREAK A BLADE,
			    Ken    	

    Brian,
    
    	If your limited in your experience ask Royal if they have a
    repair center and if YES then send the entire engine back. Let 
    them quote the cost of repairs prior to any repair. 
    
    
    Tom

    
    	Thanks all.  I called Royal yesterday and the guy there (Dan)
    said there is in fact a taper of 2 thousanths of an inch, through
    the sleeve.  He also said that it would probably be cheaper and
    smarter for me to send the whole thing back for a check-up, due
    to the fact they would be able to tell exactly what it needed, and
    not be "shotgunning" as I would be.  Very good salesman, and that
    is said without taking away from the fact he was speaking the truth!
    	He said if I sent it back with the complaints listed on paper,
    they would repair whatever was necessary and test run it to verify
    all was ok after repair.  He also said that they would "run it in"
    if need be, to eliminate the need for me to do it!
    	End result?  I have the engine here with me, and it will be
    going out by UPS this afternoon.  Thanks everyone!!
    
    		Brian
    

    
    	Well, how about an update, someone asks!??  Ok, Yesterday I
    called Royal and asked what they found on the engine.  (I had been
    in Florida for a week, and figured they couldn't reach me when they
    called.)  The guy I had originally called said "there is no .40
    size engine on my shelf.  Must be I sent it back already."
    	So, I asked what about the charge?  He said either they put
    it on my card, or there was nothing wrong and there would be no
    charge.  (Originally he had said that the labor charge was $8.00)
    	I got home last night and found my engine there waiting, and
    read the slip inside the box.  It said:
    	"Replaced Con Rod and "O" rings.  Test ran to 12,400 rpm. Good
    idle and transition, no other problems found.  Do not overprime
    and use an engine starter - you will bend the con rod.  You will
    void the warranty.
    
    	Charge - $0.00!!!
    	I couldn't believe it!  I am going to send these people a letter
    of thanks.....I'd also like to send the guy a gift certificate for
    dinner or something...according to the part prices, I was looking
    at about $15-20. for a minimum cost, and they did it for free.!
    
    	I think I like dealing with Royal!
    
    	Thanks for the help all....you saved me some bucks, and headaches!
    
    	Brian
    

    I have a friend who has a Merco 61 engine with twin plugs. He bought
    it second hand. Finally he had to change a plug and found that the
    threads for the plugs were stripped. He is getting an engineering
    shop to put in some threaded sleeves for the plugs. 
    
    Anyone ever seen or used one of these twin plug engines ? I was
    surprised to see two plugs on the head - a bit of an overkill.
    
    In case he needs to get a new head do you know of anywhere that
    sells parts for these beasts ?

    
    Regards,
    
    Eric();
    

    Eric,
    
    Twin plugs, like on the Merco, the old Fox .59 and O.S. .80 were
    an attempt, in the days before efficient carburetors, to achieve
    more reliable idling and mid-range performance.  The success of
    this ploy is arguable but I had an O.S. .80 in a Flite-Glas Mustang
    back when and, though the engine was generally a dog, prone to
    overheating, you could definitely hear/feel the difference in peak
    RPM when the second plug was lit upon starting.  
    
    Boy, if you can't find parts for the English-built Merco there in
    the UK, I couldn't guess where you might find them.  There were helicoil
    type devices available to repair this problem though it's been a
    looooong time since I've seen them advertised and I can't recall
    mfgr.'s name(s) or anything else pertinent to them at the moment.
    The approach yer' taking is probably the best/most expedient available
    to you at the moment.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    > Boy, if you can't find parts for the English-built Merco there in
    > the UK, I couldn't guess where you might find them.  There were helicoil

    Excuse my ignorance - I didn't realise it was an English manufactured
    engine !
    
    Regards,
    
    Eric();

    The main dealer fro MERCO in the states was ROYAL PRODUCTS of Denver,
    and later, Bill Kessler of BK Products in the Denver area. They
    might have left over parts.
    
    Don

    Since I landed in the river some time ago I have been trying to
    get a spare for my OS90 4-stoke. When it hit the water the engine
    was pushed back and the carb mounting snapped.
    
    The part is the rear end cover - it has the carb bracket on it, sinks
    into the rear of the engine and held with 4 bolts. I have been waiting
    nearly two months for the part from England but there seems to be a
    problem with spares for this (relatively new) engine. I was wondering
    if someone stateside could check on availablity of the part and
    possibly get it for me. I would expect that OS spares are easier to get
    in the states. I was told that the part was in the $10-15 region. 
    
    Regards,
    
    Eric();
    
    PS: The plant here is shutting down for two weeks holidays. But
    I will try and get in and read any replies. 

    Again, if this is not the right place, feel free to move it.
    
    The following is a list of several engines and their associated
    shaft thread sizes.
    
    	MAKE			SIZE			SHAFT
    ----------------------------------------------------------
    
    ENYA			.19 TO .80		7X1MM
    
    ENYA			1.20			8X1MM
    
    FOX				.19 TO .45		1/4X28
    
    FOX				.60 TO 1.20		5/16X24
    
    HB				ALL SIZES		1/4X28
    
    HP				.21 TO .61		1/4X28
    
    HP				1.20			5/16X24
    
    IRVING			ALL SIZES		1/4X28
    
    K & B			.19 TO .61		1/4X28
    
    OS				.20			6X1MM
    
    OS				.21 TO .50		1/4X28
    
    OS				.60 TO 1.20		5/16X24
    
    ROSSI			.60 TO .90		8X1.25MM
    
    SUPERTIGER			.19 TO .60		1/4X28
    
    SUPERTIGER			.61 TO .90		5/16X24
    
    SATIO			.30 TO .60		6X1MM
    
    SATIO			.90			7X1MM
    
    SATIO			1.20			8X1.25MM
    
    WEBRA			.28 TO .61		1/4X28
    
    WEBRA			.80 TO .90		8X1.25MM
    

>< Note 93.37 by RVAX::SMITH >
>                     -< List of Engine shaft thread sizes >-

With one addition by Kay R. Fisher

    Again, if this is not the right place, feel free to move it.
    
    The following is a list of several engines and their associated
    shaft thread sizes.
    
    	MAKE			SIZE			SHAFT
    ----------------------------------------------------------
    
    ENYA			.19 TO .80		7X1MM
    
    ENYA			1.20			8X1MM
    
    FOX				.19 TO .45		1/4X28
    
    FOX				.60 TO 1.20		5/16X24
    
    HB				ALL SIZES		1/4X28
    
    HP				.21 TO .61		1/4X28
    
    HP				1.20			5/16X24
    
    IRVING			ALL SIZES		1/4X28
    
    K & B			.19 TO .61		1/4X28
    
    Old K&B Veco    .61             5/16X24

    OS				.20			6X1MM
    
    OS				.21 TO .50		1/4X28
    
    OS				.60 TO 1.20		5/16X24
    
    ROSSI			.60 TO .90		8X1.25MM
    
    SUPERTIGER			.19 TO .60		1/4X28
    
    SUPERTIGER			.61 TO .90		5/16X24
    
    SATIO			.30 TO .60		6X1MM
    
    SATIO			.90			7X1MM
    
    SATIO			1.20			8X1.25MM
    
    WEBRA			.28 TO .61		1/4X28
    
    WEBRA			.80 TO .90		8X1.25MM
    

    REF .33
    Eric,
    I don't have the address here handy, but Clarence Lee in California
    does replacement threads using helicoils for the glow plugs.  I
    had my Webra done three or four years ago and have had no problems
    since.  I believe you are in England, so you may want to look for
    someone local, but if not, I think that Clarence Lee's address is
    listed in the notesfile somewhere.  Good luck.
    
    Ken
    

	I'm having some real frustrating and weird engine problems maybe
someone can help with. I'll give you as much info as possible and try to
keep it all cronilogical.

	The engine is an OS 40 SF. I got it used, so I have no idea how the
breakin was done. I was told it had about 20/25 flights on it. Taking the
head off, it looks new. It's on a Train-Air 40 and I'm running a 10X6 wooden 
prop. (Zinger).

	The first time out at the field, I got together with Charlie Watt
and we fired it up. The engine will idle like a charm but at full throttle,
with the engine leaned out to near max RPM, it will suddenly die. It did
this a few times with various settings (needle valve). The first thing we
did was to change the glow plug. Same results. The engine would run for
aprox. 10 to 15 seconds at max RPM and then sign off. Charlie thought
something must be putting the glow plug out at high RPM. Thought my fuel
(red max 15%) may be contaminated. Tried a tank full of his fuel (red max
12%) and the engine ran like a top. At this point, we thought we had the
problem licked. Bad fuel.

	I bought a jug of red max 12% and the engine ran fine ON THE GROUND.
Started with one or two flips, idled fine, lean it out, hold the plane
straight up, and everything was normal. Take off and the engine would die
anywhere from 30 seconds to a couple of minutes into the flight. Run the
engine rich, and it would run better, and sometimes even go through the
whole tank, but usually quit somewhere along the line. Got Eric Henderson
involved and he said the tank was too low. Went over to Eric's house and
got the tank up to the proper level. Actually, it's about a quarter inch
low. Eric made sure the tank set up was perfect (clunk, vent line etc)
Went back out to the field, did a little tuning, and the engine ran
absolutely perfect. It never ran so good. Everyone figured we had the problem
licked.

	Went back out to the field 4 days later (yesterday) and the first
5 or 6 flights were great. Then subsequent flights got progressively worse.
The engine would run richer and richer. Most of the time, there was at least
a 10 to 15 minute break between flights. Eventually I was back to the same 
old problem. The engine runs fine on the ground, but quits
on takeoff. Ran it rich one time and the engine didn't quit, but wasn't
performing either. This bothers me because I shouldn't have to run rich
all the time just to keep the engine running. I should say that as the day
went on, the fuel was getting near the bottom of the jug. However, I tried
a tank full of Charlie's fuel and although the engine ran, it still needed to
be run rich to keep going. The only thing we didn't do yesterday was try
another glow plug. Considering you could lean out to max RPM and let it sit
there and run out of fuel with no problems, I don't think it was the glow
plug. Only on climb out after takeoff would it quit. Or, if I just flew around
in circles, it would eventually load up and die. I became intimate with 
numerous bushes yesterday that I'd rather not see again.

	I should also state that I've left out some of the more obvious things
to check. When Eric got on it, he was very thourough. Things like making sure
there are no pressure leaks, that the fuel line isn't crimped, fuel filters
aren't clogged, etc.

	Any ideas?????????

Regards,

Steve

    Steve, I am assuming that your running pressure off of the muffler.
    
    Obviously something changed. Granted as a day goes on the temp and
    humidity change and this can lead to problems but I think you again
    need to check all of the bases. 
    
     Check seal of muffler to head, nipple to muffler and tube from
    nipple to tank. Check plug in tank to verify it's tight. Check clunk
    to make sure it not wrapped up at the front of the tank. Check tube
    from outlet of tank to carb nipple. If you have an electric pump
    take the draw tube out of the fuel bottle, cut the line and install
    a fuel filter. Install a second filter after the fuel pump as close
    to the takn hook up as possible. 
    
    NOW THROW AWAY THE FUEL FILTER ATTACHED TO THE AIRPLANES FUEL TANK.
    
    Attach the filler tube to the tank and a secont tube from the muffler
    pressure line back to the gallon fuel bottle. Turn on the electric
    pump and run it far a good length of time. This will serve to clean
    out the tank in the plane and put all of the crud into the gallon
    fuel bottle. BUT you have two fuel filters in line at two different
    points so the fuel entering the planes' tank will be clean.
    
    Before you shut off the pumo crimp the muffler line and see if there
    are and leaks. Leaks mean trouble.
    
    Take the highspeed needle valve and screw it in noting how many
    turns. now remove the high speed needle vavle and hook up the fuel
    pump to the carb nipple and waste some fuel but this will clean
    out the nipple section of the carb. Open the carb barrel to full
    abd this will clean out that part of the carb. 
    
    Try and get your hands on a rossi #5 glow plug. This is a cold
    plug and will be insurance to and heating problems you might have.
    
    Now reinstall the high speed needle valve and reset to MFG spec.
    Fill the tank and try it.
    
    
    Tom

    
    	Wild shots:
    
    	Is the needle valve loose enough to lose it's adjustment in
    	flight due to vibration ?
    
    	Have you tried and equivalent needle valve in place of that one ?
    
    	

This sounds like the problem I had when I first fired up my OS
.25 in the Eaglet.  I chased that one around and around (check my
entries in This Sport Ain't Easy for a diatribe on frustration)
for several months.  Finally I replaced the fuel tank, for
absolutely no reason, and the engine has been running excellently
since; in fact its been a haven in a sea of bad luck with this
damn sport...but I digress.

My K&B .20 did something like this too.  I sent it back to the
factory twice, both times they replaced the entire top end.  This
last time, I got it back a few weeks ago and installed it in Son
of Quick Stick, it has behaved magnificiently.  I've been waiting
to see if it lasts before posting a public apology to K&B.  The
sack cloth and ashes are coming in the mail.  I think that in the
case of the K&B they made some design changes to it; the piston
at TDC is not nearly as tight, in fact the squeak is gone
entirely.  Also I think they've improved the little ring gasket
on the head.

I have two personal theories on this -- if its in the engine, I
think the root cause is a crankcase leak that comes on when the
engine heats up.  Otherwise its the fickle gods of RC flying
getting their Dues Paid Up Front.  Don't sacrifice your eldest
son, it didn't work, and the kid was no great loss anyway.  

    RE. .41 and .42
    
    	Tom, thanks for the info, but that's all the obvious stuff I
    left out. That's all been done.
    
    	.42     I havn't tried a new needle valve yet, but the one there
    now is tight.
    
    	One other thing I had considered is that the carb/needle valve
    adjustments are off just enough so that when the engine "unloads",
    in the air, it's too lean and starves itself. BUT, when you set it rich, it
    "stays" rich and doesn't lean out in the air like you would expect
    if this was the case. This has several people totally baffled.
    
    Steve

    Steve, my OS SF .40 once had a problem where the needle valve would
    unscrew slowly due to vibration. I suggest that once you set your
    needle valve you very carefully note it's position. After a flight
    check to determine if the location has changed. The fix was to replace
    the little spring, or perhaps a drop of zap. Mine would rotate on the
    smooth barrel assembly on the needle assembly. 
    
    
    						Dave
    

    Steve, I also have an OS .40 FP and have had similar problems(maybe
    not quite as bad), but I put a larger diameter fuel line over the
    tank to carb line AND the same thing on the tank to muffler line.
    It seems there was some air leakage and this stopped it.
    
    Just a 3/16" to 1/4" piece over the fuel line at the nipple.
    
    Another thing to consider, remove the needle, cut about a 3/8" piece
    of fuel line, slip it over the needle and screw it back into the carb.
    I was getting some air leakage at that point and the fuel line fix
    cured it.
    
    Chuck

Steve, 

My first thought is that possibly the mid range may be too rich causing needle 
to be set too lean on the top end. The other things I would look for first are 
foaming in the tank from a badly packed tank of a small hole in the fuel line 
inside the tank.

Toms suggestion on he plug is a good one as it will change the apparent 
compression of the engine and confirm that the compression  has not been 
drastically altered (screwed up).

* When the engine quits does it just stop DEAD; or does is slow, stutter and 
then stop over a few seconds.

* What color is the residue of the fuel; is it clear and clean or burnt and 
discoloured.

* What does the plug look like. Is the element clean and shinning or cloudy and 
distorted.

It appears you have covered most bases already.

John

    Re. last few
    
    	Dave....I'll check the needle valve for movement the next time
    		it stay's up long enough. Seriously, it's something
    		I havn't checked yet and I will.
    
    	Chuck...I'll give it a try. I'll try anything. Anyone got any
    		heavy duty rubber bands???????
    	
    	John....I think the settings are probably the problem. What
    		I would question is why they would change (settings)
    		that much over about 10 flights. The previous two days
    		were great. To answer your questions......when the engine
    		quits, it quits dead. Just drops right off like the
    		glow plug got shot out of the head. The fuel is clear
    		and not burnt. I did have it set to lean Saturday and
    		the fuel residue was black and burnt. I corrected that
    		and it was clear Tuesday. The current plug has been
    		in there for the last 10 or so flights. So, I havn't
    		looked at it. Previous ones I've taken out during similar
    		diagnostic attempts looked fine. New plugs didn't help.
    		One of the things I checked on Tuesday was to make sure
    		the clunk hadn't turned forward (after a couple of bush
    		landings). I didn't notice and foaming. I can try a
    		colder plug, but checks at the field by people like
    		Charlie and Eric didn't turn up any apparent over heating
    		problems.
    
    Steve
    

    Guys,
    	This is a strange one.  I've been running engines for mucho years
    and I have never seen one that behaves like this one.  It have perfect
    compression, and it runs strong on the ground with the plug warmer
    attached.  It never quits with the ni-starter on but with it off, if
    you start rich and go toward lean at full throttle, just as it starts
    to 2-cycle, it signs off like there's water in the fuel putting out the
    plug.  I'm sure that something is getting on the plug.  The plug looks
    fine and we've tried several new ones.  I'm wondering whether there is
    some sort of vibration problem going on like a resonance in the engine
    mount/ plane that causes some sort of problem at full throttle.  The
    behavior is just like bad fuel but Steve has tried other fuel that was
    running fine in other people's planes.  Yesterday, it was running fine
    on the ground, nose up and all, but when he took off, it would go sour
    and quit shortly afterward.  I don't blame Steve for being frustrated
    with this one.  Flying is much more fun than tinkering with engines.

    It might be the taper of the high speed needle valve. If you have
    and FP around that runs well compare the two. The needles taper
    can cause some problems making the click adjustments to critical.
    
    
    Tom

Maybe it really is the fuel.

You said that first it was fuel then you changed and
it ran great then a few days later it wouldn't work
again.  Running OK on the plug but not off can be fuel.

How do you store your fuel?  Could it be that your storage
method is not air tight?

One thing is for sure - if you keep at it you will find the
problem and we all want to hear what the final cure is!

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

    Steve, OS has a 2 year warranty on its engines. If you have the sales
    slip, (or can get it) send it in to OS once you have given up. I have
    my trusty ole .40 SF that you can borrow if that puts you down.
    
    
    
    
    
    						Dave
    

    
    Steve,
    This may be one of the "obvious" things you've already done, but have
    you taken the carb apart and thoroughly flushed it out, replaced the
    fuel line and filter, and even the fuel tank?
    
    The evidence really seems to point to a contamination problem, and a
    tiny piece of plastic floating around near the needle valve would be
    the perfect thing to cause the problems you describe.  It could be so
    small (and clear) that you'd never see it.  It could even be a small
    shaving from the end of the fuel tubing from when you stuck the tubing
    on the carb nipple.  It just floats around in there for a while, even
    several flights, until it happens to get caught up near the needle and
    starve the fuel.  Or, it can restrict the fuel flow slightly, causing
     the engine to lean out unpredictably and forcing you to set it rich
    to compensate.  And since it stays inside the carb, nothing you do
    with the fuel lines/tank/filter will help until the carb is completely
    flushed out.
    
    I find it hard to believe you can't recreate the problem on the ground.
    Try running a few full tanks of fuel through the engine on the ground,
    changing the attitude of the plane around to simulate normal flight.
    That should cause it to quit if it were going to in the air, unless the
    problem has to do with the loading on the prop (which seems unlikely).
    
    Once you can recreate it on the ground I would immediately try cleaning
    out the carb completely, and try a new fuel tank and tubing and filter.
    
    I remember someone having almost identical symptoms as yours, and he
    had gotten a tiny plastic shaving (from when he installed his fuel
    tank) in the needle valve area.  Hope this helps - good luck,
    
    Bill

    My father has a K&B .40 that had a similar problem.  Set it up on the
    ground, lean it out, but leave it a bt rich, fly it up and it stalls.

    The problem ultimately turned out to be a burr stuck in the spray bar,
    just on the other side of the needle valve.  I found it by trying to
    richen his motor until it'de die.  It wouldn't.  Even with the needle
    valve out so far fuel was leaking past the threads.  We replaced the
    spray bar and needle assembly and fixed the problem.

    RE. .53
    
    	Thanks Bill. What have I got to loose. I'll start from scratch
    tonight. The tank is new, but I will make sure it's completely flushed
    out. I will replace all of the tubing inside and outside. I will
    flush out the carb, I will make sure all fittings are tight, I will
    make sure head and back plate are tight, I'll give it a message,
    I'll give it a back rub, I'll even give it a bl**job if it'll run
    right.
    
    	With no offense meant to our Polish flying friends, did anyone
    hear about the single seat plane that crashed into a Polish cemetary?
    
    
    
    
    
    
    
    
    
    
    
    
    
    So far they've recovered 157 bodies.
    
    
    Steve

    
    All I can say is good luck, Steve.  Eric mentioned off-line that you
    and he had done much of that already, which I figured would be the
    case.  I just hope it's a case of something stuck in there, like the
    burr that Randy mentioned.  Let's hope you won't have to go to some
    of the extremes you mentioned!!!
    
    By the way, did you say that you are using an in-line fuel filter?
    What kind?
    
    Bill

RE : previous...

This may help but then I might be spelling out the obvious - anyway good
luck with the prob. It was happening on my Super Tiger S40 - worst still 2
needles (Low and High speed). I found that if I leaned out my engine and
held it verticaly the following could happen - 

    If the muffler inlet to the tank (inside the tank) was in the fuel (tank 
    full) I was loosing the exhaust back pressure and the engine leaned out 
    further and died.

    On the otherhand if the exhaust inlet wasn't in the fuel it ran fine.

So I would move the muffler inlet pipe inside the tank to the highest point or
as far forward as possible. Thus reducing my eng problem. Since the effective
fuel delivery pressure is at its minimum in a climb (at either idle or full
throttle).

A bit on pressures...

Working out the pressures that are involved may help a bit. These figures are
rough estimates but you can see what I am getting at. I guess if one went over
the top they could measure the pressures for the engines in question. The
effect of pressure differences can have different effects depending on tank
position. In a pusher model the direct opposite of this below happens. And for
the aerobatic plane with a C of G mounted tank the problem is greater, also the
larger the engine the greater the differences. 

So its a 'get that tank kissing the engine' position that is best !

Lets say that :
                                                test values
------------------------------------------------------------------------
    H   - distance from clunk to carb.          = 5"
    V   - carb venturi suck.                    = 5"
    Mi  - muffler pressure at idle.             = 1"
    Mf  - muffler pressure at full throttle.    = 5"

On the level you have no H (if clunk and carb in line) so

    Pressure    = V + Mi                        = 6"
    or          = V + Mf                        = 10"

In a climb the H is negative so

    Pressure    = V - H + Mi                    = 1"
    or          = V - H + Mf                    = 5"

And in a dive

    Pressure    = V + H + Mi                    = 11"
    or          = V + H + Mf                    = 15"

So a loop puts the engine through the full pressure cycle. The variation is
enough to make setting up needle valves a real pain. Then again a pump +
regulator can give a more ideal response.

Regards,

Eric();

    OK, since we've got so many "Engine Wizards" with their thinking
    caps on, here's another engine problem for y'all...

    Last night, I tried to get an old K&B .40 running.  I bought it used
    at an auction last fall and I never tried to get it running before
    last night.  

    I mounted the engine on a Super Sportster that hasn't flown since
    last summer.  At the time, the plane had a different engine on it
    that ran fine.  I am assuming the tank and fuel lines are still OK. 
    I did check for leaks and blocked lines.  Everything seems just fine
    with the tank and lines.

    Here's the problem:  It's very tough to start (even with a starter)
    and the only way to get it running is to turn out the needle valve
    about 5 or 6 turns (VERY rich).  Then when the engine starts (at
    full throttle), it barely runs since it's so rich.  As I begin to
    lean out the engine, the RPMs begin to pick up but before it even
    gets close to the point of 2-stroking, it slows down and dies.

    I just remembered one more piece of information: about 6 months ago,
    I took off the backplate to inspect for rust (I didn't see any). 
    When I removed the backplate, I assumed it was symetrical and didn't
    pay attention to which side was up.  However, when I replaced it, I
    noticed the inside was machined in a "D" shape.  In other words, it
    was round with a flat spot on it.  Which way should the flat spot
    go?  Hmmm... come to think of it there were TWO flat spots - the
    smaller one appeared to be for piston clearance while the larger one
    I guessed was for fuel/air flow.  

    Also, one more question.  The carb on this engine is one like I've
    never seen before.  I think it's a Perry carb, but I'm not sure. 
    Where the needle valve screws into the carb, there's a copper (or
    brass?) wheel that appears to be some sort of adjustment.  There is
    a slot in the top of is that is used to determine how much you've
    turned it and the symbols "+" and "-" stamped on it.  Does anyone
    have any idea what this is for?  Is it low speed idle?

    [ Before you say: "Junk it and buy an O.S."; I'd like to say I agree
    but the budget doesn't allow it right now.  As soon as I get some
    $$$, I _will_ buy a new O.S. ... ]

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    
    Dan,
    
    I also have a 10 year old K&B .40.....it DOES have a perry carb.
    I beleive the slotted wheel is the idle mixture, the needle valve
    controls the top end. I'm just about to put the engine on a Falcon
    56.
    Unfortunately, the backplate has me puzzled, too. I took mine off
    without noting the position. Venturing a guess...the inside of the
    plate also has a flat spot....flat spot up for rod/crank clearance?
    My engine ran many years ago on a Sig Kadet (circa 1977/78), and
    I NEVER had any problem with it. It always turned over with <three
    flips of the prop (I was in high school and couldn't afford luxuries
    like and electric starter ) ....I hope it still does.
    
    Doug

    
    Dan...
    Maybe i should be a little more clear (I am doing this from memory)..
    the LARGE flat spot goes up. Mine is reasonably easy to flip, It
    should not be tight. I believe that the piston does NOT have a
    ring...the piston fits in a sleeve in the head. Is the sleeve scored
    or smooth on the inside? Make sure that the sleeve is oriented
    correctly. I'll go home and check mine, and post something Tuesday
    (unless some other K&B buff can enlighten us sooner). 

>    Last night, I tried to get an old K&B .40 running.  I bought it used
>    at an auction last fall and I never tried to get it running before
>    last night.  

Gee I sold one at the Salisbury Auction last summer for $20.
I wanted $40 but I would have taken $0.05

>    Here's the problem:  It's very tough to start (even with a starter)
>    and the only way to get it running is to turn out the needle valve
>    about 5 or 6 turns (VERY rich).  Then when the engine starts (at
>    full throttle), it barely runs since it's so rich.  As I begin to
>    lean out the engine, the RPMs begin to pick up but before it even
>    gets close to the point of 2-stroking, it slows down and dies.

Sure sounds like the one I had - maybe who ever bought it sold it again.

Mine had a problem sucking air around the carb.  The slot for the
idle screw was so sloppy that the carb was sucking air from that whole
general area.

Recently I talked to K&B on the phone (for a different problem on a different
engine) and they will sell you a new carb for your .40 for about $20 retail.
Probably cheaper thru Toms Hobby Korner.

>    [ Before you say: "Junk it and buy an O.S."; I'd like to say I agree

Why don't you consider an electric plane - perhaps a electro-streak :-)

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

    Well, at lunch time I took the engine to the flying field and
    Charlie Watt was there.  (As I had hoped he would be.)  After
    spending a few minutes trying to get it to run, we decided to take
    it off the plane and take it apart.

    I won't bore you with the details.  Here's a summary of what Charlie
    found: 
        - The piston and sleave walls are scored causing there to be
          very little compression.  Thus, it doesn't run too good... 
        - the rear bearing is totally shot and needs to be replaced 
          (this is currently doesn't bother the engine however)

    Basically, I need to trash this engine since it'd cost more to fix
    it than it's worth.  It looks like the SS 40 will have to stay
    grounded unless I can come up with enough money to get another
    engine.  (I might be able to swing this if I can convince the "other
    half" that I really, really, _need_ a new engine...  :-)

    By the way - after Charlie looked at the backplate carefully we
    decided that there is only one way it can go on.  The small flat
    spot goes up and is there for piston clearance.  The larger flatspot
    goes on the left side of the engine and is for the fuel port (as I
    had guessed before).  WARNING - this may be different for "your" K&B
    .40.  (ie, "Your mileage may vary...")

    Thanks to all for the help and information on the Perry Carb.  All
    seem to agree that the wheel is the idle mixture and is VERY
    sensitive.  In other words, the full range of travel from "too rich"
    to "too lean" is only 5 or 10 degrees.  (VERY small amount...)

    RE: .60  My K&B .40 DOES have a ring on the piston.  I assume that
    over the years K&B has also made engines without rings.

    RE: .61  Kay - I was hoping you'd reply to this note.  Unlike you
    however, I am going to call a junk engine "Junk" and dump it.  
    Oh wait a minute - maybe I should keep the engine and spend 3000
    hours building a nice scale biplane for it...   :-)

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    Maybe some progress........Last Friday night I went over to Dave
    Hartwell's house and we (he) opened up the 40SF. The first thing
    we found out is that it isn't a 40, it's a 46SF. It was advertised
    as a 40 when i bought it, and I never looked at it any differently.
    
    Once apart we did find rust in the engine. Not bad, but it will
    deffinately have to go back once the flying season is over. Still,
    nothing to cause the current problems. Also took the carb apart,
    and found nothing there.
    
    Saturday, I went out to CMRCM and met up with Eric. He was still
    cursing and fiddling and fiddling and cursing his Webra but eventually
    got that running not half bad. Then we went to work on mine. One
    of the biggest accomplishments was that we were able to re-create
    the problem on the ground. Eric got the engine all set up, meaning
    low end adjustments and needle adjustments to where the engine would
    scream. Hold it up and it would still scream. But....what we did
    this time was take the plane and taxi it around for a couple of
    minutes. High speed, low speed, spin it around in circles, goose
    it several times, etc. Then Eric held it and I gunned it. DEAD.
    Because we were standing right next to it, we discovered that contrary
    to previous thoughts, the engine was not leaning out and dieing,
    it was loading up and dieing. STILL TOO RICH. Eric leaned out the
    low end as much as he could. Litterally maybe 5 degrees from killing
    the engine. After that it screamed on the ground AND in the air.
    I put three flights in with no problems. I went out again yesterday,
    and put 6 more in with little or no problems. The only problems
    I had yesterday, was when the needle wasn't set right. After Friday,
    I marked the needle valve and low end adjustment screw to see if
    they were moving. There not. The only other thing I'm doing is running
    15% fuel rather than 12%. So far, it seems to be running fine. I
    will be going out this afternoon (I took today off) and flying
    somemore. So, we'll see what today brings.
    
    I think that basically, the settings on this engine are VERY CRITICAL
    both on the low end and needle adjustments. I noticed yesterday
    that a variance of 1 click on the needle would cause the engine
    to run differently. I mean noticeably different. There is also about
    a 16th or maybe even a 32nd of an inch of play in the carb rotor.
    Probably a weak spring. This makes it tricky to adjust on the ground
    because everytime you push in the low end adjustment screw to turn
    it, just pushing in changes things. I don't know if this is moving
    in and out in the air though. Maybe a new needle valve and new carb
    are the next things to try. But, so far, the engine is running and
    the only problems have been my own not getting the needle setting
    right. If I can get six or seven flights in today and the engine
    continues to run well, then I'll be convinced that the main problem
    was the low end adjustment. Also, with the settings being as critical
    as they are, maybe it needs the 15% to burn that much leaner and
    hotter to keep the engine cleared out. I'll post another update
    tomorrow.
    
    Steve

Re: Note 93.63 by RVAX::SMITH >>>

Steve,

>    I think that basically, the settings on this engine are VERY CRITICAL
>    both on the low end and needle adjustments. I noticed yesterday
>    that a variance of 1 click on the needle would cause the engine

You might improve this by running a little hotter plug.

>    to run differently. I mean noticeably different. There is also about
>    a 16th or maybe even a 32nd of an inch of play in the carb rotor.
>    Probably a weak spring. This makes it tricky to adjust on the ground
>    because everytime you push in the low end adjustment screw to turn
>    it, just pushing in changes things. I don't know if this is moving
>    in and out in the air though. Maybe a new needle valve and new carb

Every engine does this to some extent. The problem adjusting the mid range 
screw can be helped by having the throttle open a little while adjusting. The 
carb rotor can move in the air it your throttle linkage is too ridged or does 
not move in a straight line with the throttle arm. I use a bowden cable linkage 
to prevent this happening, rigid enough to move the throttle but flexible enough 
to allow a free movement of the throttle arm over it's cam.

Don't change the throttle/rotor because of this. it's quite normal.

Glad to hear you have got the problem beaten.

John

    Well, I think I can finally consider the problem solved. I was out
    this afternoon (too late to see the space shuttle...aka Eric's new
    high powered Panic) But I put in 4 more flights and the engine purred
    like a kiten. After the first flight which was a little rich, I
    adjusted the needle one more time and didn't touch it the rest of
    the afternoon. She never even coughed. I think the problem was three
    fold.
    
    	1. Low end wasn't set lean enough
    
    	2. We thought it was leaning out and quitting, when it was still
    	   too rich.
    
    	3. I'm now running 15% Byrons fuel which the engine seems to
     	   like. According to Eric, Byrons has less of an oil content
    	   than say RedMax. Just for kicks, I'll try a tank of 15% Red
    	   Max and see what happens.
    
    All in all, it starts with one or two flips and keeps on ticking.
    The only question I have now is how can you tell, besides just knowing,
    what plugs run hotter than others.
    
    Thanks to all for your inputs.
    
    Steve

While this topic is semi-warm, I'd like to ask about something
that's puzzled me for a long time.

When I'm hand-starting a cranky engine, sometimes I'll get a
short teaser run out of it -- you know how that goes.  If you get
two or three of these, the engine warms up a little.  Then it
gets real nasty and doesn't do anything.  So I think that maybe
its dry and I squirt a little fuel down the carb.  When I go to
flip it again, I notice the compression has dropped off -- I've
had it drop off to be virtually non-existent.  So I panic,
thinking I've blown an engine.  But in about a minute of sitting
the compression returns to normal and eventually the engine
starts and runs fine.

I'm pretty sure this happens to all of us; I've experienced it
with all my engines at one time or another.  What's the reason
for this?

    
    John,
    What kind of engine?  I'd say there is a different answer for
    each.  If it's a 4-stroker, the most likely cause is one of the
    valve seats or a stuck valve.  If it's a 2-stroker without rings
    (like any ABC engine, it might be that the raw fuel
    cools the piston quickly and causes it to contract, momentarily
    loosing compression until the cylinder cools too.  If it's a
    ringed engine, like an FSR,  I would think that loss of compression
    indicates a problem with the engine, unless uneven contraction during
    rapid cooling could also cause the same problem with rings.
    
    I've had an OS 25 FP in a super sportster that has MANY flights on it
    over three seasons.  I can't remember if the FP has rings or not
    (memory seems to say no) but I can't recall ever losing compression,
    hot or cold.  But I don't think I've ever primed a hot engine to start
    it.
    
    Now if you want to talk about 4-strokers losing compression, I've seen
    that happen MANY times!
    
    Bill

Naw, none of that sophisticated rings and 4-stroke stuff -- all
my engines are sleeved.  I think you hit it with the fuel cooling
the piston.  The K&B (10 flights and still behaving itself) will
actually crackle and hiss when the fuel is squirted in, even
though its relatively cool on the outside.  I'll accept your
answer.

    K&B's do have a nasty tendency of hanging up the ring.
    
    
    Tom

  Well this seems to be as good a place as any to put this.....



  Last night I was working on my J3 Cub and found that the only real way
to mount my ASP .61 in it is to have it inverted.  If it is upright the 
cylinder head sticks up about 3 inches in front of the windshield.  Sideways
either requires chopping the bottom out of the fuse or poking a hole in 
the windshield for the muffler.  Inverted is perfect!  The entire engine
fits inside the cowl and the muffler runs along the lower left side of the
cabin.

  Now my questions:  Is it likely that I will need a glow plug warmer to keep
the inverted engine running?  If so, what should I use for a power source?
Where can I find a connector?  Would I still need my ni-starter?



		Jim

    Jim,
    
    properly installed (including fuel system, i.e tank height, etc) and
    properly adjusted, you shouldn't _require_ a plug warmer...I've NEVER
    used one.  An inverted engine _will_ require you to learn a new
    starting technique but, once learned, you'll have no more starting
    difficulty than anyone else.
    
    Your fuel tank centerline should be slightly below, yes _below_ 
    needle-valve height in an inverted installation; this is to prevent
    undue fuel siphoning/engine flooding.  To start, I always begine with a
    dry engine, throttle and throttle trim to full low.  Then, I connect
    the starter-battery and flip the engine 'til it fires.  At this point,
    I move the trim to flight position and open the throttle 2-3 clicks and
    the engine, invariably, starts on the very next flip.  If you choose to
    use an electric starter, leave the trim in flight position but do
    everything else and apply the starter in short bursts...continued
    cranking _can_ flood the engine.
    
    It's inevitable you'll flood the engine occasionally.  In these
    instances, remove the plug and apply the starter for a short burst to
    blow out all the excess fuel.  Blow the fuel out of the plug element
    and reinstall...the engine will likely start on the first flip. 
    
    Special procedures:  1. Never fuel the plane 'til ready to fly (to
    			    prevent siphoning/flooding.
    			 2. After a flight, open the throttle to full and 
    			    turn the prop slowly to top-dead-center (max
    			    compression point), rocking the prop back-and-
    			    forth 'til it "sticks."  This seals off the
    			    porting to prevent flooding.  The wide-open carb
                            helps to simply dump any fuel as may find its
    			    way to the carb on the ground.
    
    After all this, I'll add that a plug warmer actuated by a microswitch
    at low throttle is certainly a good enhancement to reliability BUT it's
    not a panacea; if the engine isn't properly adjusted to begin with, the
    system won't necessarily cure all the problems you may encounter.  I
    hazard to say that, if you've already got problems, you'll probably
    _still_ have them after installing a plug-warmer.  Ironically, for the
    warmer system to provide maximum benefit, you must _first_ adjust the
    engine to the extent that it really doesn't _need_ the system...if you
    REQUIRE such a system, I guarantee you have a bad engine, poor
    installation, bad carb/adjustment or all the preceding.
      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    
    If it were a 4-stroker you might have trouble idling inverted but
    the 2-stroker should be fine.  By the way, have you considered
    side-mounting with a pitts-style muffler?
    
    Bill

    Good thought, Bill,
    
    In fact, that'd be my preferred mounting scheme for a J3 Cub or any
    aircraft with a similar nose arrangement.  There's no doubt whatever
    that a side-mounted engine is superior in running/handling to inverted
    and the Pitts-style muffler could probably be mostly hidden in the cowl
    with only the two stacks protruding from the bottom...a ver functional
    and attractive arrangement.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

  Thanks Al, Bill, and Eric 


  Tonight I will look into both alternate ways of mounting the engine.  I
am a bit concerned with engine noise and if I am going to replace the 
'muffler' with something else I would prefer to get something that is actually
going to act as a silencer, not just a diverter.  Last years Tower cat. (the
one I keep here at work) lists the Tatone manifolds for around $16.00. The
latest ad in RCM lists a Snufler for $17.99.  So if I can make it work with
an off-set mounting I will.  If I can't then your starting procedures will
sure come in handy Al!

  By the way...are there any other bolt-on muffler replacements that I could
consider?


	Thanks again,
			Jim

	P.S. Did anyone see the Super Kadet on page 111 of November issue
of RCM?  The thing is HUGE!!!!!  It is a 2X scale version of the Kadet Sr.
with a 13 foot wing and a 10 foot fuse!  The stringers and longerons are
made from 1/4" x 1/2" and 3/4" sq. pine!

  	Maybe this should be my next plane after the 1/4 scale L4 !!  8^}

    
    As I recall, Charlie Watt's .60 with pitts muffler _was_ quite loud.
    Al (or anyone else), do you know of something better than the Tatone that
    has baffles?  I expect to have the same challenge with the same engine
    in the near future and would be willing to spend some extra $$$ to quiet
    things down.
    
    Bill

    exhaust systems are a pain.
    
    yet another possibility is to use a jtec in-cowl muffler.  this by
    itself is awful loud but you can use exhaust extension(s) to a
    second silencing device which may be under or even in the fuse itself.
    there are some problems tho, like most jtecs come with 2 exits instead
    of 1 so you gotta plug 1 and maybe have backpressure problems or have
    2 extensions to ? or plug one and use an oversized extension on the
    other or...
    
    my cap21 has an enya 45cx inverted and runs/starts great.  muffler is
    a jtec with 2 straight extensions down.  much too loud for even me tho.
    
    my p47 has a bully upright with a jtec muffler and those flexible-
    metal jtec exhaust extensions (they are slick).  its loud too but
    just right for a warbird.  this setup works great except that the
    muffler (if you can call it that) is so close to the cowl that the
    paint on the outside of the cowl sometimes discolors from heat.
    
    another potential problem with the jtec (or tatone, same diff) is that
    you might not be able to get a sharp enough radius in the extension
    tubing to suite ya.
    
    kevin
    

    Jim,
    	I agree with Eric about trying to get the engine off of inverted by
    as much as is reasonable and still get the muffler to clear.  This will
    help prevent raw fuel from snuffing out the glow plug.  I have a Davis
    pitts style muffler on my Supertigre 61 equipped Cap 21 and it is very
    quiet and very Expensive.  It is much nicer than a Snuffler but about
    twice the price.  Most 61's are pretty loud with stock mufflers and the
    ASP is no exception.  You will probably be flying at half throttle
    anyway.  Be careful when using a starter on an inverted engine because
    it is easy to 'hydro lock' it.  If it floods and gets a pool of fuel in
    the cylinder, you can bend the con-rod with a starter because the
    piston can't compress the fuel.  I've seen this happen on Ducted Fan
    engines that are inverted.  Most DF's that are inverted get started
    upright on a stand. (wheels up in the air)  It's difficult to do this
    with a cub.  If you follow Al's starting advice, you should have no
    problems.
    
    Charlie
    

  Well, I tried experimenting with different engine positions on the Cub over
the weekend and here are my conclusions:

  * The engine can not be in any sort up upright position because the fuel
tank would have to sit on top of the front deck in front of the windshield.
This is simply to get the tank and needle valve in alignment.

  * Straight sideways mounting is out because the muffler doesn't fit.

  * Mounting towards the inverted (9:00 to 6:00 on the clock- looking head-on
at the plane) won't work because of the muffler.

  * 6:00 - 4:00 works (muffler gets pretty close to the windshield in the 4:00
position).

  * 6:00 fits perfectly.

  
  Considering I don't want to spend $30.00+ dollars on a new muffler, will 
mounting the engine in the 4:00 position really make that much of a difference?


		Jim

>>* The engine can not be in any sort up upright position because the fuel
>>tank would have to sit on top of the front deck in front of the windshield.
>>This is simply to get the tank and needle valve in alignment.

    Could be resolved with fuel pump but I don't think you want the
    extra complexity and a cylinder head sticking up in front of the
    windshield anyhow.
    
>>* Straight sideways mounting is out because the muffler doesn't fit.

    Sounds like Charlie's expensive Davis Pitts muffler would do the trick here.
    
>>Considering I don't want to spend $30.00+ dollars on a new muffler, will 
>>mounting the engine in the 4:00 position really make that much of a difference?
    
    C'mon Jim, do the "right" thing and put a Davis Pitts muffler on that
    Cub, and side-mount the engine!  It'll be quiet, less fussy to start,
    and easier to get at the glo plug.  If I can't talk you into that, I'd
    say the inverted-mount is your only other option and you will just have
    to heed Al/Charlie/other's advice with this config and live with glo-glop
    down the side of your nice fuse, a big ugly muffler sticking out the side,
    .... (laying it on thick now)
    
    Bill
    

>    C'mon Jim, do the "right" thing and put a Davis Pitts muffler on that
>    Cub, and side-mount the engine!  It'll be quiet, less fussy to start,
>    and easier to get at the glo plug.  If I can't talk you into that, I'd
>    say the inverted-mount is your only other option and you will just have
>    to heed Al/Charlie/other's advice with this config and live with glo-glop
>    down the side of your nice fuse, a big ugly muffler sticking out the side,
>    .... (laying it on thick now)
>    
>    Bill


   Ok...ok...let me think about this!  I suppose it doesn't cost anything
to check prices.  Who sells the Davis mufflers and what are they listing for?


		Jim
    

  WOW!  I just got off the phone with Mr. Davis of Davis Diesel, and wow..
can he talk....and talk.....and talk....and......!

  A quick call for a catalog turned into a 40 min. conversation!

  Well some of the things he told me were:

	o He is not impressed with the ASP engines.  He said a lot of his
	  friends that have tried them were not very happy with them.
	  He said the .40 had the same basic casting as the O.S. but that
	  is about where the similarities ended.  He doesn't have much info
	  on the .61.

	o He doesn't trust any fuel manufacturers that haven't been making
	  fuel for at least a million years.  He likes K&B, SIG...but 
	  had to bite his tongue when I mentioned that I was using Byron fuel.
	  He feels that syn. lubes. are crap.  Give him good old castor.
	  There should be about 20% castor in a fuel mix.

	o As for the Pitts style muffler: You shouldn't use more than 5%
	  nitro with one.  The muffler increases pressure in the tank and
	  acts sort of like a fuel pump.  The muffler also returns some of
	  the heat back to the engine which improves the idle and reduces
	  the need for higher nitro content.  The price of the Pitts muffler
	  for the .61 is $41.95, but it will fit anything from a .40 to a .75
	  which makes it interchangeable and re-usable.

	o The best mag. is RC Scale.

	o Graupner makes the best props.

	o When I do my 1/4 scale L4 one option to holding the wings on is to
	  replace the hex nuts that bolt the wings on with hook screws and
	  rubber bands.  This reduces the chance of serious damage if a wing
	  catches the ground (won't rip the fuse apart).

	o If you use the regular nylon bolts 1/4 x ??, drill them out the
	  long way to insure they break before the wing blocks tear out.

	o Always use an air filter on your engine.

	
   Well...you get the idea that he was talkative 8^)...but a nice guy.

   I did remember to ask for a catalog!


   Jim


(Please note that all of the above comments, preferences are Mr. Davis' so 
don't flame me if you disagree!!  8^)

    hey jim,
    
    the trick of using rubber bands to hold the 1/4 scale l4
    wings to the fuse is a great idea.  the dowels that slide
    into the fuse bear all the weight anyways.  i just might
    retrofit my cub cuz inserting those 4 screws from within
    the cabin is a royal pain.  now if i hold the struts on
    with wingnuts...
    
    it don't surprise me that mr davis likes srcm mag since
    mr goyer takes every opportunity to praise davis diesel
    products.  i used 1 of his diesel heads once - it wasnt so
    hot i thot.
    
    bring the catalog to next decrcm meeting if you remember.
    kevin

    Jim,
    	I think that Davis is mostly BS.  I had a long talk with him a
    while back and he bends your ear as long as you will let him.  I have
    heard from others that have experience with him that he is somewhat of
    a Ripoff.  His prices are way high in my book, but his mufflers are
    good quality.  I have a Pitts Style one on my Cap 21 and it is very
    quiet.  If it were half the price, it would be a good deal and I would
    use one on all of my engines.  I can't justify $45 for a muffler to go
    on an engine that costs only twice that much.  However, his is the only
    good Pitts Style muffler for a 61 that I know of.  I tried a Slimline
    and it was LOUD!!!!  I felt terrible making that much noise so I paid
    the $$ for Davis'.  By the way, Jim, I spent quite a while pondering
    the same problem with the Cap 21.  I couldn't mount the engine upright
    or sideways with the standard muffler and I wasn't crazy about mounting
    it inverted.  The Pitts style muffler was the only reasonable answer to
    my problem.
    
    Charlie
    

  Well the way it looks right now is I am going to go with the 
'sorta-kinda-almost-but-not-quite-inverted' mounting and purchase a 
Snuffler for under $20.  I just can't see spending over $40 for the Pitts 
muffler when looks are secondary to functionality on this model.  I will 
worry about looks with the L4.  I will use care and Al's instructions for
the starting of the motor.

  My thanks to everyone for their input.


		Jim

   Here is an update for anyone who was at the last fun fly at Crow Island.

   I spent the entire day trying to get my ASP .61 to run properly.  It would
either run at full speed (after adjusting the carb) or at idle (after 
completely re-adjusting the carb) but not both.

   Charlie did manage to get one abbreviated flight on the Cub to prove that
it would actually fly.  The engine leaned out and quit though so Charlie did
his usual expert dead-stick landing.

   After a few days of fiddling with the carb I decided to give it to
Charlie so he could compare it with ASP .61.  What he found was the hole
in the spray bar is about 50% smaller on my carb than his!  It would appear
that there is not a great quality control check on these engines.

  Yesterday I called World Engines and told them about my problem and they
said to send them the carb and they would replace it.  Charlie said I could
borrow his carb if I had to send mine back (the alternative was Xacto knife
surgery - yucko!), so I will probably take him up on his offer.

  So...maybe I can get the Cub in the air by Thanksgiving.



		Jim


	P.S.  Next time I have to buy an inexpensive engine I will
	      probably go with Super Tigre.  They have a .60 for
	      only $95.00, just $10.00 more than I paid for the pain
	      in the ASP!

  On the back cover of the March '90 Model Aviation there is an
advertisement for the ASP engines.  The ad states that the ASP engines are
using a new carburetor design.  Looking at the picture, it appears to have
2 needle valves. One on either side of the carb.

  My question is: What is this other needle adjustment?  Is it the idle
set?  My .61 has a screw that you have to use a screw driver on.  Does this
new setup simply replace that screw with an easy to adjust valve?


			Jim

    Jim, Pretty sure the answer is Yes. Some new Supertiger carbs are
    done this way. Just a different way to adjust the low speed
    needle valve.
    
    Tom

    re:- -1
    
    I have a SuperTigre with the twin needle. The extra one helps the
    transition from low to high speeds. I think they are more trouble than
    they are worth but I haven't really used it to the full. Anyone else
    got an opinion on this ?
    
    Regards,
    
    Eric();
    

    Unless it's something entirely new (which I doubt), the extra needle
    represents out-of-date carburetor technology; most of the earliest
    carbs utilized the second needle (for idle mixture adjust) after they
    moved away from the even earlier air-bleed types.  These were a
    definite improvement over the air-bleeds but, compared with today's
    carbs, represent a step backward in technology which, quite frankly,
    I'd kinda' expect in a cheaper line of engines.  There's nothing
    inherently wrong with this style of carb, they're just more fiddly to
    get properly adjusted.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

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    The following note is a PostScript (tm) file that is a reprint of a   
                                                                          
    "TWO-STROKE TROUBLESHOOTING CHART"  it is reprinted without permission
    from the AMA National Newsletter.                                     
                                                                          
    I suggest that we all make a few copies and paste one to our flight   
    box, one to the wall above our engine test stand, one above our       
    workbench and one next to our terminal.                               
                                                                          
    Most of the things are common sense, some are not.  But in a          
    frustrating situation, anything that jump starts your mind is a big   
    help.                                                                 
                                                                          
    To print this file to a PostScript (tm) printer (LPS40 or LN03R)      
                                                                          
        Notes> extract/noheader 2_stroke.ps 93.92                              
        Notes> $ print 2_stroke.ps/param=data=post/que=your_queue_name    
                                                                          
    Enjoy!                                                                
    jeff                                                                  

    Hi,

    Well I have just got a new OS46SF-ABC, well I have been using it now for
    about a month. My problem has just sort of surfaced within the last four or
    so flying sesions. The problem: I am getting, what I think is, more than the
    normal share of black oily flow (sort of intermittent) back throught the
    pressure feed and into the tank - contaminating the fuel - goes a horrible
    grey color. It is effecting the performance of the engine. It tends to lean
    out and die occasionally. 

    So far I have put a filter in the pressure line but this was pointless - the
    flow went right through it.

    Next I cleaned out the carb - this produced no noticable change.

    Next I took the engine apart and cleaned it completely. Apart from the
    piston top being blackened there was no obvious damage or wear from dirt etc
    inside. This worked for a few days the engine ran like a champ. 

    Last night it started to develope the really black flow into the tank again,
    with the engine attempting to die or drop revs. I took the silencer off and
    cleaned out the oily deposit - not the usual sort of dry black deposit but
    very oily. I wondered if the cone shapped baffle was holding the normal
    exhaust inside or letting it build up. The pressure outlet is high on the
    side of the exhaust and not low where it could act as a drain for all to
    exit. The silencer is not loose and neither is the carb or engine mounting
    itself -  it looks more like oil either not enough or possibly too lean -
    needle is around 1/2 to 2/3 turns out. Could it be running to hot ?

    What I suspect is oil content but I have used this fuel for a long time now
    with no problems.

    Flair Fuel (Yellow spot):    5% nitromethane, 15% oil, 80% methanol.

    The engine was run in according to the manufacturers recommendations and  it
    gradually came up to top performance. I had a lot of flights on the engine
    before the problem started.

    So, having not found any notes on the above, anyone got any ideas ? I expect
    that it is a simple problem but then the obvious is not always obvious.

    Regards,


    Eric();

    First guess is that your running the engine too lean. It overheats
    and starts burning the oil. You should also notice that the fuel
    residue on the airplane is also black. The OSSF46 I had, when it
    started to overheat, would start dropping in RPM and "sounding"
    rich. With the throttle full open, I would only get about a quarter
    to a half's worth of power.
    
    The way I ended up setting the engine was to peak it, then back
    the needle off (rich) about 3 clicks. That usually did the trick.
    
    Steve

	Yes, the needle has been gradually needed to be turned in more and 
	more. I have, as you said, turned it out a few clicks, but I don't get
	full power. Do you think that it will build up if I leave it a 
	bit rich ? Any other solution , possibly a prop change ? (using a 10x8 
	or 10x7 at the moment)

	Eric();

    Eric,
    
    	I don't think the prop is a problem. I was running a 10x6, but
    someone else I know is running a 12x8. Remember that the engine
    will "unload" once it's in the air and lean out somewhat. So setting
    it up a little rich on the ground is ok.
    
    Steve

	Yes, I am pretty sure that it is running too lean since I 
	wasn't reducing the neddle setting to a bit rich on the ground
	and so it was leaning out far too much in the air. I will be
	out this evening from a few hours and will see how it runs with 
	a richer setting. Lets hope any possible damage is minor.

	Thanks for the replies guys.


	Eric();												

    Eric, if you weren't so sure that the muffler/silencer were tight, I'd
    have suggested that you read the comment by Al Casey still to be found
    at 239.722.  The last paragraph seems to be applicable.
    
    Alton

	Yes the silencer it really tightly and firmly attached.
	My G40 Super Tiger was always a rubbing at the joint - due
	to greater slop in hole sizes etc. No I am going to try the
	richer running approach and see how I get on. Will put a reply
	in here when I get some answers - hopefully over the weekend.
	For the first time we are having some great weather - 23-26 degrees
	C.

	Regards,

	Eric();

    Eric,
    	The dark stuff sounds like aluminum, a sign of wear.  This is the
    result of lean running, usually removing material from the piston wrist
    pin holes.  I have noticed that the 40 and 46SF are harder to adjust
    correctly than most 2-strokes probably due to the more effective
    muffler.  The change in sound from lean to ok to rich is not as obvious
    as it is with an unbaffled muffler.  I went through two pistons in my
    OS40 FSR due to lean running.  I had an exhaust extension on the
    muffler that seemed to cause the engine to lean out in the air.  I
    would set it rich on the ground and have it go lean.  I removed the
    extension and the adjustment problem went away.  I now know that if I
    see aluminum in the exhaust, I've got a problem.  A loose muffler will
    do the same thing with the wear being at the exhaust port/muffler
    interface.  In general the color of the residue that comes out should
    be a light brown color if you are using castor based fuel.  Some
    buildup on the piston is normal and should be removed if it gets
    substantial since it changes the compression ratio.
    
    Try running it richer and check your tank height.
    
    Charlie
    

    Eric,
    
    	It's been 10 days since your last reply. How's the engine running?

	Yes I was holding out - so that I could read the name off the new
	fuel that I picked up but everytime I forget to _READ_ the label,
	anyhow...

	Well, I ran the engine slightly richer and I have eliminated that
	really black flow. The fuel exhaust residue is back to the normal
	light colour. 

	Thanks for all the advice. 

	I have just got some new fuel - I can't remember its name but its 
	imported from the US - you will probably recognise it's colour - it
	would hit you in the dark - liminous pink. Anyone use it - then there 
	could be a number of pink fuels Hhhhmmmm. Before a bright  (glow) spark
	says "were you using this fuel & getting the black residue" the answer
	is no. I just got some as I was going low and this is sold locally, well
	about a hours drive away. I thought I would try it and see.

	I normally use 5%, and got a couple of gallons, but I also decided to go
	for a gallon on 15% to see what the difference was/is, yea more engine 
	wear. I will read the appropriate topics for more on that before 
	soliciting any replys to the nitro content of fuel.

	Eric();

I have a Webra .61 Blackhead that is 18 years young and back then they realized 
that the carbs were too sensitive to be adjusted so they made a carb (Perry) 
that had a significantly longer taper to the needle (one turn = a couple of 
clicks on the old one). My problem is that with the superb pressure I'm getting 
from my SoundMaster muffler, I can't close the needle valve enough! I need some 
way to regulate/limit the pressure to the tank. I thought I had seen some 
suggestions in here about using the retract limiters but can't find the section 
of notes. I don't need a lot but it would be nice if I could break into a 2 
cycle vertically on the ground (it's REAL close now) I'll let you know if it 
leans out enough in the air after lunch...

    Re: .102, Eric,
    
    The "bright pink" fuel you picked up could very well be Omega, the all
    castor equivalent of Cool Power (which is green).  Of course, the color
    of any fuel is completely meaningless except for product identification, 
    and just about every color known to man is used by one mfgr. or another
    but the bright pink, at least here in the U.S., is unique to Omega.
    
    Omega is a very popular fuel in my whereabouts as it provides the
    maximum heat protective ability due to its castor lubricant.  If heat
    is a concern, like in a tightly cowled sport or [especially] scale
    bird, or if you merely want the extra heat protective margine afforded
    by castor, Omega is a good bet.  The one slight payback is the typically
    gooier, stickier exhaust residue left on the plane and the associated
    clean up problems.  Also, castor tends to bake onto the cylinder head
    and, if not cleaned off regularly, will build into a thick brown
    coating that reduces cooling efficiency of the cylinder and head fins.  
    We used to call thusly affected engines "Pot-roast Specials."
    
    I, personally, prefer 10% Cool Power which is an identical blend to
    Omega except it uses synthetic lubricants.  These synthetics do not
    have as wide a temperature tolerance range as castor but are more than
    acceptable for normal use and _will_ provide heat protection in all but
    the most extreme of overly lean, i.e. HOT situations.  Plus, it's 
    significantly easier to wipe off at clean-up time.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    Re: .103, Jim,
    
    I'm not sure I can agree with yer' assessment of the stock Webra .61
    Blackhead carb.  I have two of these wonderful mills (which were state
    of the art in their [pre-schnuerle] day): one is perhaps 20-years old
    and still runs great; the other is about 6-years old and has less than
    an hour total time on it.  I never had the slightest difficulty setting
    up the stock Webra carb and found it to operate just fine in any/all
    situations...muffler pressure was always used.
    
    Now, I've _never_ been a fan of the Perry carb; in my humble opinion, a
    lot of exaggerated claims were made for it, simply to sell after-market
    carbs to folks who really didn't need them.  True, they _may_ arguably
    have been a little easier to adjust but that's about the only good
    thing I could ever say about them.  I LOATHE AND DETEST the fact that
    they never put a needle valve extension on the Perry carb, making it
    extremely difficult AND DANGEROUS to adjust with just that little stub
    sticking out.  But, you didn't ask for my opinion of the carb so let's
    get back to yer' problem.
    
    If the muffler is _really_ putting out so much pressure that the
    Perry's needle can't effectively control fuel flow, you only have a
    coupla' alternatives: 1.) reduce the pressure somehow, i.e. use a
    smaller inside-diameter pressure nipple and/or smaller I.D. fuel line
    from nipple to tank and/or retract air restrictor (I think Bob Dively
    sells these) or, somehow bleed some of the pressure from the tank.  2.)
    If none of these produce the required effect, you may have to buy a new
    Perry pump-carb that is intended to handle the higher fuel pressures
    produced by running a fuel pump.  
    
    Orrrrrrrrr, if you still have the stock carb, put it back on and give it 
    another try.  I'll bet that, with the added experience you've gained, 
    you'll be able to set it up just fine and I'd be amazed if it didn't 
    handle the muffler pressure just fine.  As I said earlier, I ALWAYS ran
    muffler pressure with my Blackhead (and everything else since muffler
    pressure first came out) and NEVER had the first problem...that ol'
    Webra loved it!  BTW, I may someday do a large Westland Whirlwind or a
    Bristol Beaufighter with twin Blackheads and they _will_ be equipped with 
    the stock Webra Dyna-mix carbs.  That's how much I trust and respect
    them.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

I didn't say I believed what I quoted, just that I replaced the carb for that 
reason. My second reason was that the pressed on control arm came "unpressed".
I'm running the stock carb on my .40 (which is the same as the .61 carb) and 
have had good success with it recently (with the smaller soundmaster muffler).
Other than the Control arm problem, I've got the carb and could retry it in the
near future. I'll be playing with it over the next few weeks but might have to 
swap out the engine in the short term for a Super Tigre .60 for a fun-fly the 
1st weekend in June.

More after the maiden Panic flight at lunch (I'm out the door)

Jim

	RE: .104

	Al,

	I rang home and yea its Omega. They are rather careful with
	all those warnings on the label. Allthough recently I did read
	in RCM&E that methonal is absorbed by the body and can cause/contribute
	to heart attacks - I sort of guessed.

	Cleanest engine I have see to date was a pressurised "air" engine 
	no methonal/nitro/oil etc - just air) recently reviewed in one of 
	the mags - never seen them before. But it looked cool !

	Eric();

I've been having trouble the last few weeks with my OS .40FP
quitting either on takeoff or shortly into the flight.  Since
I've had trouble with fuel I changed from the Nalgene (plastic
bottle used by campers) bottle in my field box to a metal can,
but it didn't fix the problem.

But while fooling with it last weekend, the pressure line to the
tank accidently fell off and the engine picked up speed and ran
great. So, on general principles I went home and cleaned the
engine and tank. 

The engine was fine, but when got to the tank, I did find
something interesting.  For a long time now I've had the practice
of putting right angle bends where the lines exit the tank, so
the carb and pressure lines approach the tank at approximate
right angles.  This was because the smaller planes didn't have
space for the lines to go in straight.  Well, whaddaya know, the
right angle bend on the pressure line had a clogged spot...I use
a K&S bender, the line wasn't kinked, it was clogged at the sharp
bend.

ATTENTION WIZARDS: Why did the engine pick up speed when the
pressure line was removed?  You could say that it was because the
back pressure was removed from the muffler...but when the tank's
under pressure doesn't that cause a back pressure too?  I think
the clogged line did allow a little air to enter, but not enough
to pressurize the tank.

I sure hope it cures the problem, I'm tired of deadsticks.  I did
find a cheering thought in all of this: nobody said my engine was
too small!

I'm going to "borrow" the carb off the .40 (same part number) and give it a try 
the next flying session. I couldn't get the engine running "right" and I find it
hard to believe that this engine can't handle a 7lb plane. I'm going to enjoy 
this Panic but I've got to get my engine humming to take the most advantage of 
it.

More next session.

    Re: .-1, Jim,
    
    For what it's worth, my old, high-time Webra spent its last tour of
    duty (over 13-years worth) in an Ugly-Stik which, over the years,
    numerous repairs and no fewer than 3 rebuild/repaint jobs, became
    verrrrry heavy.  Starting out at around 6 1/2 lb's, the Stik's girth
    increased to over 9 lb's.  Add to this a pair of Gee Bee floats and
    associated hardware and you have a plane that tops 10 lb's and, guess
    what, that ol' Blackhead .61 pulled it just fine having plenty of top
    end and very reasonable vertical performance.  If you can get it
    running up to its potential, a 7 lb. Panic should be a piece of cake
    for it.  Hope the carb change does the trick yer' ya'...good luck!!
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

re: my note .109.  I ran the engine last nite and the problem of
the engine picking up speed after pulling the pressure line has
dissappeared.  But there is still another problem.

It starts easily and runs just fine until the battery is removed,
then it dies -- and its not the plug, it does the identical thing
for 3 plugs.  When I start it at idle and get it to run, as the
throttle is advanced to full open it dies immediately or shortly
after full power -- it will run ok if the battery is left on.
There are no bubbles in the line and no blubbering before it
dies; it dies cleanly.  Also, if you pull the pressure, it runs
better at full throttle (though not dependably), but dies at idle
-- exactly what would be expected without pressure.

The engine has about 45 minutes running time, and I checked my
books on engine breakin, they all say that the engine should be
running ok from about the third tank.  Does this sound like a
break-in problem though?  I tried to richen up the mixture to get
it to run, but it didn't seem to change its behavior; I also
leaned it up and it acted the same.  I am reluctant to blame the
problem on fuel, and I am confident that the tank/engine is
installed correctly.  Other than that its just fine :-); who else
could possibly have trouble with an OS .40FP?

    Re: .-1, John,
    
    Don't you have a local engine wizard up there who could give you a hand
    getting the engine properly set up?  That's what you _really_ need... you 
    probably just have some very minor thing wrong but can't see it.
    
    Assuming everything else is OK as you indicate, lemme' ask a couple
    things:  What kinda' plug are you using? (It almost sounds like the
    fire's going out at high RPM.)  I've had similar problems when the
    entire problem was caused by a flaky plug...it'd start just fine but
    ran ragged as hell, nearly causing the ol' Yeller' Preil to crash when
    it sagged badly just after takeoff.  The plug lit just fine and looked
    OK but, replacing it cured the problem instantly...of course, by then
    I'd stirred up all the carb adjustments trying to sort things out and
    had to readjust the carb before flying.  What brand fuel and what nitro 
    content are you using??
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

Lemme tell you Al, I've gone through the local engine
wizards...since I don't have anything kind to say, I'll just shut
up.

The three plugs I used are a mix of K&B and Fox.  One of them was
brand new when I broke in the engine.  The fuel is Magnum, which
is made in Denver, and is the standard brand Phil sells.  I have
heard mixed reports on the stuff, but its mostly with regard to
its lower power output in vertical performance...nothing that
looks like this problem.  

Think I'll buy a new plug tonite and give that a try -- I have a
tendency to hang onto a plug simply because it lights, but that's
a long shot.

The real concern I have here is, can it possibly be that the
engine is not fully broken in yet?  Its one of the new ABC
.40FP's.  There may be as much as an hour on it; I've put the
equivalent of about 5 tanks thru it.

John,

To answer your last question first, as far as I know you're the only one to
have so much trouble with an OS40 FP. Now to give you credit I think you got
one of the new ABC versions so that could be adding to your problems.

I've broken in 2 .40FPs and never had a lick of trouble. From the playing with
your engine we did on Sunday I'd guess that its broken in fine. It ran strong
and cool at full throttle when we pulled the pressure so I'd guess that
breakin is not the problem.

If it dies when you pull the juice I'd definitely guess its the plug. Get in
the habit of throwing old plugs away! I've had several that would lite, but
would not run the engine. Remember it requires the initial heat of the
electricity and an ongoing catalytic reaction between the fuel and the nichrome
to keep the wire hot. I suspect that a plug that will glow but won't run has
some problem sustaining the catalytic reaction due to fouling of the nichrome.

I've got a bench stand that we can use to run the engine and eliminate all 
non-engine related variables from the equation if you're interested.

Let me know,
Randy

OK, so be it.  Randy, I think I'll stay with the engine in the
plane for at least this week till I check out a new plug and try
some other things.  If I continue to have trouble I'll take you
up on the bench stand.  The one I have is a little light for a
.40.

  John,

  Did you mention wether the engine is mounted upright, inverted, sideways?
If it's inverted then you could be getting too much fuel onto the plug and
snuffing it out.  Leaving the glow driver attached would keep it hot.


  Jim  (just curious)

Its upright.  In one of my books they mentioned that ABC engines
shouldn't be run too rich after the first couple of times.
Apparently the ABC engines use a taper fit at the top of the
piston and the sleeve, similar to the K&B sportsters.  If you run
them too rich, they never wear in because they don't get the
speed necessary to wear in a good fit.  This could be one of my
problems since I did go cautious and ran 3 or so tanks before I
even started cranking on the needle.  

Also, the OS manual gives a troubleshooting chart where one of
the items under "engine stops at high speed" is to adjust the
idle stop position for higher RPM.  I absolutely fail to see the
relationship between idle speed and high speed running, but I had
adjusted the idle mixture and speed for a nice slow idle, so I'm
going to try to diddle this a bit and see what happens.

And of course, there's the glow plug to be changed...

This weekend I put the OS .40 FP on the test stand and duplicated
my problem with disgusting accuracy.  As soon as you pull the
heater off the engine stops cold.  If you keep the heater on and
turn it down (from the power panel) it will keep running until it
hits a certain spot and then it shuts off cold. The fuel is not
the problem, more on that later.

BUT...I've been thinking.  Now, 93.39 and the replies thereafter
handle a very similar problem.  Also, I've had a similar trouble
with the K&B .20.  All these engines are ABC, and here's what I
suspect.  

The ABC engines run with a higher compression, both due to the
superior seal at top end from the cylinder taper, and because the
nature of the chrome-brass fitting keeps compression constant
through the heat range.  This is a good thing as far as normal
running is concerned, but what happens when you get a lean run is
that the glow plug goes bad very quickly.  This can be
temporarily fixed with a higher nitro fuel, or some random
adjustment to the fuel system, such as raising the fuel tank.

Bottom line though is that the plug is bad.  Replacing the plug
with a brand new one AND richening the mixture is the real fix.
Moral: Always run an ABC rich, and be very careful of getting the
idle mixture too lean.

Randy Oswald is going to have a go at the engine next week.  I've
thrown a brand new Fox plug into the box so he can test this
idea, along with general tinkering.  We'll see.

In the meanwhile I've installed the Fox .36 in the plane and
after some cussing and fuming got two good flights using the same
fuel.  Its really quite a remarkable engine, though tricky to
adjust as reported previously.  I'm going to let it run a while
and then touch up the idle needle valve as it has a distinct lean
spot in mid-range.  What surprised me is the way it pulls the PT
--- I was getting off the ground in about half the roll of the OS
and it was definitely pulling better in the air.

Al:  This does not contradict your assessment of Fox engines:
it is true that they are touchy.  I was lucky to have someone
with a Fox come over just before I was going to stomp the whole
thing into matchsticks and he applied a little sanity to the
situation.  The key is to run the idle needle nearly all the way
out, till its just standing on the last catch or so.  Then adjust
the top end valve, then go back to idle and run the idle valve in
till the engine is slightly lean, then go back and set the top
end valve slightly rich.  That'll get you into the ballpark.

    Re: .-1, John,
    
    Of course, it's very true that one lean run _can_ and often does ruin a
    glo-plug.  However, I've not found an ABC engine to be any more
    sensitive to this than a ringed engine.  I have to run my O.S. .61FSR/
    ABC at it's peak output every flight to get any kind of reasonable
    performance from the ol' Yeller' Peril and, occasionally, I get it
    tweaked too tight to the point of noticeable sagging when the nose is
    raised during a maneuver.  I merely throttle back a tad, set up and
    land, richen the setting a tad and I'm home free.  Seldom (if ever) has
    this situation cost me a plug...certainly no moreso than my ringed
    engines.
    
    If yer' theory concerning yer' personal engines is true, all I can
    think is that you must _really_ be setting them lean; to the point of
    cooking things.  Since this syndrome seems to follow you from
    engine-to-engine, I'm forced to think there must be something(?) wrong
    with the way you install and/or run yer' engines.  Please don't take
    offense...I'm not trying to run you down; just trying to understand
    what it is that causes you all this grief and, if possible, help you to
    discover the solution.  What you suggest in .-1 might be true but it
    seems awfully thin to this here cowboy.  There just _has_ to be some
    common thread to all the troubles you have with virtually every engine
    you try.
    
    I wouldn't be too hasty to write off fuel as a possiblility,
    particularly if you've been running the same stuff in essentially all
    yer' engines as _there's_ a common thread that just _might_ deserve
    closer scrutiny.  If yer' running some brand-x, no-name,locally-brewed,
    bargain-basement fuel, let me try to convince you to use it to kill
    weeds in the driveway and try some recognized brand-name GOOD fuel. 
    You just might be surprised at the difference.  Get a brand new, FRESH,
    gallon of Cool-Power, Omega, Bryons, REd-Max or whatever fuel...10%
    nitro should surfice though 15% might be better for those smaller
    engines at yer' altitude.  If this doesn't provide any appreciable
    difference in performance, I'll stop harping about fuel but we gotta'
    look at the most common factors, one at a time 'til we've either
    eliminated them all or discovered the problem.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

Thanks, Al.  I'm going to test this idea with Randy next week,
but it fits all the situations I've experienced in the last 3
years.  The plug now in the Fox, btw, is one that didn't run in the
OS -- I think the higher compression makes it more critical to
have a clean plug.  Every time my problems have come immediately
after break-in when I've maxed out the engine for RPMs and
experienced at least 1 hot run.  Of course, with the K&B that's
not hard to do...

With the OS it happened on the run that an instructor leaned it out
with me standing nervously by...I would've waited another tank or
two, but by the time I thought of saying something it was too
late. The plug in the OS now is a Fox Miracle Plug, it ran one
full leaned out tank and hasn't worked since.

I've been using Magnum 10%, a fuel that has been very successful
up here.  However, I too am suspicious of it and will buy some
Byron's next time, actually in a week or two.  I was mentioning
to Ivan when he helped me Sunday that I was thinking about going
to 15% and he said that he runs Tower's 5% up here, even in his
ducted fans (thought he hasn't been successful with DF up here).
I'd like to throw in with someone on their next order for case of
Tower's, but I want to try the Byron's first.

I'll follow up on this, and I will post a tabulation of the after
run procedures as promised.

    Just out of curiosity, what and how much are you using for
    after run oil???????
    
    Steve

As I said in 289.44, its been my practice to flood the engine
with WD40...

I've stopped doing that and, because I don't feel good about
putting the plane away without some strokes, I've restrained
myself to squirting a little Marvel into the intake and turning
the engine over a few times by hand.

Though, if right was right it would probably be best if I did
nothing.  Remembering that its relatively dry up here, unlike the
mosquito-infested, humid swamp that you folks live in :-).

Re: Note 93.120 by 8713::TAVARES "Stay Low, Keep Moving" 

Hi John, 

Al covered most of the points pretty well as usual but his point on good fuel
cannot be stressed enough. You MUST have a good quality fuel if you expect good
runs. Few backyard mixes will have quality consistently. I think I mentioned it
before that I used to own a fuel mixing business. A typical batch of fuel was
70+ US galls. Mixing was with air agitators and measurement was within .5% of
specification. This was regularly tested in a lab. For a back yard mix to
obtain that accuracy on say a 5 gal mix with 20% oil, the oil would have to be
measured to .005 of a gallon; with castor oil that is next to impossible. 

I would like to comment on some points of your note John:- 

< my problem with disgusting accuracy.  As soon as you pull the
< heater off the engine stops cold.  If you keep the heater on and
< turn it down (from the power panel) it will keep running until it
< hits a certain spot and then it shuts off cold. The fuel is not
< the problem, more on that later.

This is classic symptoms of a too cold plug. The fix is to change to a hotter 
plug; or, use more nitro; or, increase the engine compression.

< The ABC engines run with a higher compression, both due to the
< superior seal at top end from the cylinder taper, and because the
< nature of the chrome-brass fitting keeps compression constant
< through the heat range.  This is a good thing as far as normal

ABC and ringed engines operating under the same conditions require the same
compression for optimum performance. Compression is not dependent on the ABC or
ring configuration. Compression is a factor of the fuel and the heat of the
plug. Simply stated the plug temperature effects the timing of the engine, the
hotter the plug the more advanced the timing, the colder the more retarded the
timing. The fuel composition changes the flashpoint that spontaneous combustion
occurs and the mixture burns. Note I say burn not explode as detonation or that
sound like frying eggs is when the fuel explodes and actually does damage to
the engine. If you are running an engine at altitude (say above 2,000ft) you
are running under different conditions than the engine was designed. Try using
a plug one range hotter to compensate for the decreased atmospheric pressure.
If you have access to a machine shop reduce the head volume sufficiently to
allow you to add 2 X .002" shims under the head and maintain the deck height
(approx .015" but check the original) and the volume (depends on the
displacement). With both shims in you will be ok at sea level. By removing 1
shim you will adjust the compression for 2-3,000' altitude, removing the second
will take you up another 2-3,000'. To some extent it is a bit of trial and
error but thats a starting point. 

< Moral: Always run an ABC rich, and be very careful of getting the
< idle mixture too lean.

Always run any engine a tad on the rich side, no more; no less for an ABC.

John

Thanks for your input, John.  I was thinking of the ABC
compression issue with relation to my lapped piston engines -- I
don't own any ringed engines, yet.

On the fuel, Magnum is made up here in Denver, and is widely used
at our field.  I feel like a traitor to Phlyin' Phil because I
have to buy Byron's at a competing shop, and on the smallest of
excuses...Honestly, I think I'm grasping at straws on the above
two ideas, but I can't think of anything else that is consistent
with all cases of the behavior I've observed.

On the hotter plug, yes, that's a solution.  Thanks for telling
me since I didn't know whether to buy a hotter one or a colder
one!  Anyway, with *ANY* other engine in the world, *ANY OTHER
ONE* than the OS .40FP I would concede that maybe I should try a
higher nitro mix or a hotter plug.

But this engine is the most dependable, bullet-proof, machine on
the market, and they are a dime a dozen up here.  Nobody else is
having this problem, with the exception of Chuck Baldridge who
has similar flying habits to myself (he takes a long time to go
through a gallon), and he cured his problem with new fuel and a
new plug.

No, I gotta point the finger at myself, I'm doing something
wrong.  I predict that Randy will put the new plug in and the
engine will run like a top.  I'm so confident of this that I'm
not sending the engine back to the warranty center despite the
warranty running out this weekend.

    John,
    
    If memory serves, in the recent discussion on after-run products/
    techniques, wasn't it established that Marvel Mystery Oil _does_ tend
    to damage/ruin plugs?  Maybe that's yer' plug-eatin' culprit?!
    
    I go along with yer' supposition that maybe you should just _do_nothing_
    in the after-run category for awhile until you have this problem sorted
    out.  As you said, the extreme dryness of our part of the country makes
    rust virtually unheard of out here anyway.  I'm hear to swear to you
    that I have *_NEVER_*, not ever, used any kind of after-run product or
    technique in any engine I've owned (and we're talking _dozens_) since I
    first started gas-modelling back about 1954 and I've *_NEVER*_, repeat,
    NEVER had an engine damaged from rust!  Now, I _DO_ drain the fuel tank
    after every flying session and I hang my fuselages nose-up so any
    residual fuel or whatever drains harmlessly to the backplate (plus, the
    clunk in yer' tank stays stretched out nice and straight with no chance
    of doubling itself up during storage) and this may help but I hardly
    call it an after-run procedure.  Still, engine problems are almost non-
    existant for me so I must be doing something right.
    
    When storing an engine, I clean it up good, inside and out, then fill
    it to excess with Sears Turbine Oil (a _highly_ penetrating oil),
    Hoppe's Gun Oil, Fordham Flex-Shaft Oil or equivalent.  Then, I turn
    the engine over _many_ revolutions 'til I'm satisfied the oil has found
    its way into every nook and cranny and place it into an _unsealed_
    plastic bag, then put it back into its original box.  I've had engines
    in storage as long as 10-years that were returned to service and fired
    right up immediately. 
    
    But, other than the simple steps described earlier and keepint the carb
    covered at all times when not in use, I do nothing exotic or unique at
    the field or after a session.  Maybe you should give this a try but I
    must say up front that I can't guarantee yer' personal results so you 
    should probably pull the backplate frequently in the beginning to assure 
    yer'self that no rust's forming...if not, yer' home free.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

   Al, 

   I use Mystery oil after every session and my current plug has around 130
flights on it!  I'm not stingy with the oil either.  Maybe I just got a good
plug!  It's a K&B.


                       Jim

    
    Last Wednesday, Charlie Watt, Dave Hughes and myself went down to
    the CMRCM field and had the place to our selves. I put in 3 flights
    on the WOT-4 when the engine started acting funny. The rear bearing
    was getting rather noisy and while running the engine prior to another
    flight, it stopped abruptly while idleing.
    
    It didn't seize, but was still loud. I figured I'd better take it
    home and see what was what. Later that night, I took the engine
    appart with some phone help from the Evil one and when I first saw
    the rear bearing, my first thought was HALF THE BEARINGS ARE GONE.
    In actuality, they were all there, but the bearing retaining ring
    had failed and they were all bunched up on one side. When I applied
    a little pressure to the center on the bearing, the whole thing
    fell appart. Fortunately, a careful inspection of the engine revealed
    no further damage.
    
    I was able to get a new front bearing locally, but will have to
    order the rear bearing. Tower carries them, so I'll have the engine
    back together in a few days. Unfortunately, it will be the same
    LOW QUALITY bearing that was originally in there, but at least it
    will be running.
    
    Like so many other RC parts, this bearing is apparently specially
    made (there is not a number on it anyplace) and the size is just
    that much off that bearing houses don't carry them, nor in this
    case, could they even find it listed anyplace in the books. So,
    your stuck going back to the manufacturer.
    
    Oh well, what are ya gonna do.
    
    Steve

Speaking of parts...I just want to follow up on the metric screw
mystery.  As stated in a earlier note, it turns out that the
pitch of the screw is 0.6mm versus 0.5mm for virtually every
metric screw sold in this country.  My machinist friend checked
through the professional outlets and could not find the correct
pitch screw.  Looks like the Japanese engine mfrs -- OS and the
others, have done a good one on us.

My OS .40 has one of the muffler mounting screws wrecked already
-- how come nobody else is complaining about this?  I have the
right tools, and I'm very careful with the way I tighten the
screws, I even use some silicon rubber on the end of the screw to
keep it in place, and still I damage the screws.  I cut a slot in
the bad screw head, but because it has the hole in the center
where the crosspoint used to go, its a less than satisfactory
solution.  Gonna order some new ones from Phlyin' Phil.

I'm open to ideas, or sources of bargain screws.  As noted
earlier, one house in Denver has them for a buck a pop...thats
right folks, $1.00 each!

    I had the same problem with my OS-40FSR muffler after a couple of
    3 point landings (main gear + muffler!).  I could not find replacement
    screws for it, unless I bought a whole new muffler!
    
    So, I took out my trusty tap and die set and bored out the holes to
    a useful american size, like 6-32.  Hex head screws are easy to find
    now!
    
    cheers,
    jeff
    

    Jeff,
    
    Ya' took the words right out'a my mouth.  I've been wondering what 
    the flap about metric screw sizes was all about when it's so simple to
    simply retap the holes to a good ol' American SAE thread.  On my O.S.
    .60FSR and .61FSR-ABC, I retapped the muffler holes to 6-32 and, since
    the existing hole was close to the tap drill size, I didn't even bother
    to redrill the holes...just went right in with the tap.  With ~200
    flights on the MiG-3 and probably over twice that number onthe Yeller'
    Peril, I've yet to have a muffler bolt even loosen up, let alone lose
    one altogether.  
    
    I wouldn't hesitate to do this on any threaded hole in the engine or to
    recommend the procedure though there is an important caveat to consider:
    WORK SLOWLY AND BE EXTREMELY CAUTIOUS as, if you break a tap off in the
    hole, yer' absolutely dead!!  Unless enough of the tap protrudes from
    the hole to get ahold of firmly enough to back out the stuck tap (which is 
    seldom the case), no power in heaven or on earth will extricate it!! 
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

I've had bad results with simply running the 6/32 tap down the
existing hole.  The threads do not cinch up tight, and I've had
bad problems with them vibrating loose or stripping out.  If the
solution was that easy I'd have solved the problem long ago
because its the first thing I tried.

Actually, according to the machinist, the 5/50 thread is much
closer to the existing hole.  If you try to bore out the existing
holes to the 6/32 tap drill size you risk not leaving enough
metal around the hole, especially in the muffler "ears" on the
side of the engine case.

Al, I don't know how you do it...must be blessed by the Desert
Rat Gods, because I sure ain't.  And I'm not very particular
either, I mean I'm not being a perfectionist, its just that these
things I complain about flat are not working, period.

Guys, if you feel yourself blessed, go ahead and run the "good
ol'" 6/32 tap down the hole, but beware from the Colorado Herald
of Doom, you're risking a bigger mess than what you started out
with.  Again, I've been there.

Re:  Al's note -.2 use WD40 or similar, even kero to lubricate the tap. It helps 
stop the tap binding.

John

    Re: .145, John T.,
    
    Beats me, I'm as baffled at the problems you experience as you are at
    my success and solutions.
    
    You could well be right regarding the hole-size in the O.S. .40; being
    a smaller engine with smaller exhaust stack, it could very well use a
    smaller stock screw and, therefore, require a smaller SAE equivalent.
    All I know is that I was faced with the [similar] problem of attaching
    the manifold for the scale exhaust system on the MiG-3 to the O.S..60FSR's 
    stack and had no screws/bolts to do it with (I'd traded for the [brand
    new] engine and didn't get a muffler/hardware with it...didn't want or
    need it anyway).  Like you, I ran into trouble trying to determine the
    metric size of the hole and finally said "Ta' H*ll with it, I'll tap
    th' sucker for an SAE thread."  I used the shanks of my drill bits to
    test for the snuggest fit in the hole, then mic'ed the bit and compared
    the resulting measurement with my tap/drill chart.  As memory serves,
    the hole measured so close to the recommended 6-32 tap-drill that,
    redrilling would have served no purpose except to remove more needed
    material.  So, I carefully, and as precisely as possible, ran the 6-32
    tap directly into the hole using plenty of oil as I went.  The result
    was an essentially perfect set of 6-32 threads where the old metrics
    had been.
    
    I've had no problem tightening the bolts _tight_ and lockwashers and just 
    a drop of Loc-Tite have kept 'em that way.  As I said, I've _never_
    had them even loosen in hundreds of flights.  Based on this experience
    and the scarcity of the stock metric screws, I didn't even consider
    using the stock hardware on the .61FSR-ABC in the Yeller' Peril...I
    discarded it immediately, tapped out the holes and went with the 
    (plentiful) 6-32 bolts right off the bat.
    
    I _DO_, however, agree with your echo of my caution to do this with the
    utmost of care or, as you say, you can make a terrible mess for yer'self!
    If not familiar with using a tap or the least bit uncomfortable with
    this procedure, I suggest that you DO NOT use it.
						 __
	      			|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    What makes an engine slow to reach low idle. In other words, when
    you throttle back, the RPM'S will drop right off, but the last few
    hundred RPM'S gradually bleed off. Sometimes you have to "blip"
    the throttle to get it down to where you have low idle set.
    
    There is no binding in the linkage that I can find.
    
    Steve

    How do you cool down an engine??
    
    I have an OS.35 with an unknown history.  I had a lot of problems
    setting the engine up, and found that the needle valve assembly had
    been damaged.  After replacing it, the engine runs much more
    consistently, but still VERY hot (too hat to touch; smoking).
    
    OK, I have the throttle wide open, I find max rpms, then I richen it
    until it gurgles and dies.  Restart.   Find a point inbetween and let
    it run for awhile.  Shut it down.  And it is smoking!  The plane is 
    covered with residue, so I believe I am running it rich enough...
    
    important facts:
    
    	Engine mounted inverted
    	New fuel system (tank and tubing) makes no difference
    	Fuel is towards the end of a gallon of 15% red max
    	plug is a Fox R/C long (with bar).  Towers plug doesn't run worth
    		anything.
    
    What can/should I do??  Should I try 10% fuel? Should I use a short
    plug (or an extra washer under the long?) to reduce compression?
    Other suggestions??
    
    thanks,
    jeff
    

Re: Note 93.148  

>    What makes an engine slow to reach low idle. In other words, when
>    you throttle back, the RPM'S will drop right off, but the last few
>    hundred RPM'S gradually bleed off. Sometimes you have to "blip"
>    the throttle to get it down to where you have low idle set.
    
>    There is no binding in the linkage that I can find.
    
Steve

Normaly there is two things that cause the problem; one you have already 
checked is a sticky linkage, however what about a sticky barrel in the carb. 
Have you checked that the linkage does not force the barrel in the carb to have 
lateral movement, it if a common error in setup. The other possibility is a 
midrange adjustment set too rich.

Re Note 93.149 

Jeff
 
Is the engine cowled? if it is make sure you have plenty of air going in to the 
cowel and allow even mode air to come out. If the engine is not cowled I would 
look for tightness, a glazed liner, or run a smaller prop. A heavy load 
increases the heat.

There are other things that will cause overheating but that is worth a first 
run at the problem.

John

Last spring I was whining about not being able to get parts for my "Vintage"
Webra engines. I was having problems getting the .61 to run reasonable and 
needed a few things to get one of my .20's going again. When I got the engines, 
MRC was the US distributor. Currently Hobby Lobby is distributing them. I called 
Hobby Lobby and they directed me to Bill's in E. Longmeadow MA. The people at 
Bill's spent over an hour with me and an unknown amount of time talking to the 
order takers at Hobby Lobby (but we don't show that part number, sir) I ordered 
the parts with the Webra numbers and the Hobby Lobby people couldn't find them 
because they had assigned their own part numbers to everything. The few things 
they found by description came through in bags with the Webra part numbers on 
them ;^) Then Hartmut Klingenberg offers to get them locally in Germany and ship 
them over. 

I want to publicly thank Hartmut for getting a sizable order of parts for me. He
ordered the stuff through his hobby dealer and shipped it over with Bill Lewis 
and Tony Prentakis before recieving my money. It was a large amount and I 
appreciate the effort and trust of a person I've only had contact through this 
notesfile with. I've now got the parts and Hartmut has recieved his money. It's 
wonderful that there is still some trust and cooperation in the world.

Hartmut, Bill, and Tony, thank you very much.

Now where did I put those P-38 plans for my newly rebuilt .20's ;^)

    hello
    
         Question,looking at the tower hobbies tower talk,they show
    a O.S 46 sf-s control line engine for $95.00 they also sell
    a R.C O.S 46 sf for $135.00.Is that the same engine? and can
    i put a O.S carb off my worn out o.s 46 sf abc on the control line
    engine?
    
                                          P.M
      

    The other difference is probably no muffler on the control line model.
    I don't know if the casting is the same for the carb, but I bet it is.
    
    
    Charlie
    

    Thanks Charlie  
      
         I didn,t think about mufflers
    
                                              Paul
    

    I'd like to get some information about the Super Tigre S.75
    
    Are there any owneres out there that wouldn't mind a few questions via
    Email?
    
    Jim Reith (IMOKAY::REITH)

Send mail to PIKES::OSWALD

I have an OS .40 FP and there seemes to be no compression.  I brought it back to
the hobbie shop where I bought it.  They said that it was run too lean and it
needed a new piston and sleeve.  Now they replaced the piston and sleeve and
there is still no compression.  He said he wanted to play around with it and 
see if he could figure it out.  Well It's been about 4 months now and he still
hasn't figured out the problem.  Does anyone have any idea what the problem 
could be.

The original problem was that it would not stay running.

Thanks
Hogie.

    Could you let us know whats been looked at so far?  How old is the
    engine?  How was it used?
    This will help allot on what may be wrong.
    
    John

    Make sure that the glow plug seal has not failed.  I've had fox
    glowplugs blow the seal many times and kill the compression.
    
    Charlie
    

The engine was used on a PT40 for 2 years.  It never ran correct.  It would 
always die in flight.  But it always had compression.  Someone at the field
in Burlington adjusted the engine for me and thats when I started having these
problems.  Thats when I think the engine was run too lean.  The glow plug is 
new and works fine on another engine.  The engine had never crashed or got
damaged in any way other than being run too lean.

Any other ideas would be greatly appreciated.


Hogie

    You may have cooked/blown a gasket somewhere. Can you tell where the
    compression leak is coming from? Try putting some 3-in-1 oil in it and
    cranking it over. You really need to bring it to one of the local
    fields for someone to look at it in person.

    Its very hard to diagnose a problem as such over a notesfile. I find it
    hard to believe that you could have wasted ths engine with a lean run
    or two to the point where no compression is left. If its an older FP40
    then it probably has a ring. The only way to determine what the problem
    is to disasemble it. An person experianced with engines will be able to
    tell rather quickly where the problem lies. Where do you live/work?
    perhaps you can get together with one of us some night and we could
    take a look at it..  I live in work in Boxboro MA. and would be happy
    to lend you a hand...
    
    
    
    							Dave
    

    Tahnks for all your help.  After the piston and sleeve was put in,  Thy had
not run the engine (The Hobbie Shop).  I took the engine home and ran Two thanks
of fuel thruogh it and the compression was fine.

Thank's 
Hogie

    RE -1:
    	The ring was probably stuck a little. (If it had one.)  Running it
    may have freed it up.  I've seen this happen several times with OS40's.
    
    Charlie
    

    
    Hi all wizards,
    
    I have a problem with my OS 30. It does not go past mid-range what ever
    I do on the adjusment or tank location or nitro %. Something like that
    happened to me years ago and it whas the piston sleave that whas
    mounted incorrectly. Is there any other reason why this could happen.
    
    Jacques
    
    P.S. I'm going to check the sleave tonight.
    
    
    

    
    Me again with the OS 30 problem. I think I find the problem. Yesterday
    I dismantled the engine to find that the piston is one of those that
    has an off-centered protrusion to seperate burned gas from unburned fuel
    Well the protrusion was toward the exaust instead of the intake. I turn
    it around and will try it tonight. (weather permitting)
    
    Jacques
    

    
    
    	Recently I've been running an OS 108  2 stroke engine.  At times
    I hear a rattling when the engine is running.  I've checked everything
    to make sure nothing is loose.  I've gone so far as to disassemble
    the engine to check the bearings.  Everythings OK!!  So I think the
    engine is suffering predetonation. Pinging.  I can't remember what
    is the cure. More nitro,Less nitro, Head gasket? what??
    
    
    Tom

    I have a couple of questions.  Firstly does anyone know if there is a
    difference between the FS91 and FS91 SURPASS carbs ? I replaced one a
    while back for the Surpass but I was looking at the old carb last night
    and noticed that the hole the needle screws into is larger on the
    current carb. This means that the needle has to be screwed in more to
    achieve the same setting. Any ideas ? 
    
    Second topic. A friend of mine has an OS46SF ABC and the crankshaft is
    quite loose. Unusual ? I know its not a problem since the drive washer
    holds all in place. I never came across this before as most crankshafts
    are tightly held by the bearings. Any comments ?
    
    Third topic. I thought it a bit unusual to see the slit in the above
    engines carb to be pointing down towards the crankshaft. Most engines I
    have seen have the slit in the carb pointing outwards. I used to have
    one of these super engines but can't recall the details. All said the
    slit position can't be changed on the carb.
    
    Eric.

    The bearings are shot in your friend's OS46SF if there is any noticable
    play in the crankshaft.  If there's enough play, the case is junk also.
    
    The slit in the spray bar should point down toward the crankshaft on
    any engines I've worked with.  It rotates on some with the throttle.
    
    I didn't know that there was an FS91 and a FS91Surpass.  There was a
    FS90 before the Surpass that was quite different.  
    
    Charlie
    

    Charlie,
    
    >>The bearings are shot in your friend's OS46SF if there is any noticable
    >>play in the crankshaft.  If there's enough play, the case is junk also.
    
    There appears to be no play as regards the bearings themselves - they
    appear to be in order. It is just that when he stripped it down the
    other night it all it took to get the crankshaft out was a slight push
    with his hand. Reinserting it was as easy. The bearings are firm in the
    crankcase by the way. My experiences of taking crankshafts out is quite
    different. 
    
    >>The slit in the spray bar should point down toward the crankshaft on
    >> any engines I've worked with.  It rotates on some with the throttle.
    
    I agree now, must have got mixed up somewhere - maybe on the super
    tigers. I had a look at the FS01 carb and they are the same.
    
    
    >> I didn't know that there was an FS91 and a FS91Surpass.  There was a
    >> FS90 before the Surpass that was quite different.  
    
    Typo, yes I meant the FS90. After this correction is there a
    distinguishing factor between the carbs ?
    
    Eric.

    Eric,
    	I'm not really sure about the FS90 carb since I never owned one.
    There are two different taper needles available for the carb on the 91.
    I'd say if it fits it should work fine.  These are simple carbs.  One
    problem with them seems to be the main needle seat.  Some of them are
    such that you can't close the needle all the way before it bottoms out
    other than at the seat.  Mine runs less than half a turn from bottoming
    out - which is ok I guess.  I like needles with long taper for finer
    adjustment.  Maybe someone out there has the OS carb book.  Our local
    hobby shop guy has it and I've figured out carb issues from it several
    times.  You could check with your local guy and see if he has it.  It's
    very complete.
    
    It sounds like your friend has a crank / bearing fit that's not as
    tight as most.  It's probably ok if it's a tight slip fit.  You don't
    want any movement between the bearing inner races and the crank.  It's
    normally a slight interference fit but we're talking .0002 inches or
    so.  Look for evidence of wear on the crank bearing surfaces.  If they
    look good, then it's ok.  I've had some cranks that came out easily and
    some that required enough push that you trash the bearings.
    
    Charlie
    

    Well, I couldn't find my notes on the problems with the Enya 1.20
    from my Junkers...  
    
    Brief recap - Never ran right.  All kinds of folks tried their hands at
    it and could not get it to go.
    
    Earlier this fall, I sent it back to Altech to get them to fix it.  A
    few weeks later, they call and said "are you sure you want us to bench
    run this...  There is a $15 charge".  I said YES, and let me know 
    if you have the same problems that I did.  They said that they would 
    put it in the queue...
    
    Well, Jim's problems with the OS 1.08 got me thinking that I hadn't
    heard from Enya/Altech in awhile.  So I called them up...
    
    They can't get it to run right either!!  YEA!!
    
    the technician was out, so I don't know what they are thinking yet, but
    at least all of us have been vindicated, it really is the engine!
    
    More as I know it!
    
    cheers,
    jeff
    

    
      Jeff,
    
         Glad to hear they are having problems too! Makes me feel a bit
    better, although I STILL would have liked to see the Junkers fly with
    the new engine :) ( Maybe after repairs?)
    
         It will be VERY interesting to see what, if anything, they find
    to be the problem.
    
         The cause of this one is almost as mysterious as the US AIR crash!