Conference vmszoo::rc

    
    Well, as reported in another note, my dreams came true when I
    transferred to a new group and the old group gave me an
    Ultra-Sport 40 kit as a parting gift!

    I brought the unopened kit to the DECRCM meeting on Tuesday
    and opened it on live TV in front of a live audience. The
    general reaction was that it is a superior kit. Many parts
    are pre-cut and pre-punched. The Leading and trailing edges
    are shaped from a single piece of balsa, grooved for rib
    placement, and you just cut them apart.

    I'll be glad to add more commentary when I actually get started
    building the kit, which may be a few months. Meanwhile, I got
    varied input at the meeting and would like your collective
    wisdom on a couple decisions I need to make.

    1. Engine - I was planning to use my trusty OS .45FSR, which is
    the size engine the plane is intended for. There is an option for
    a 70 four-stroke. However, the "go vertical" lobby (actualy
    nearing a majority of the folks!) strongly encouraged me to go for
    a 91 Surpass. This decision is going to be even harder if Charlie
    Watt does what he intends and buys himself an Ultra-Sport and puts
    his 91 Surpass in it. It will be hard for me to fly with Charlie
    if he can significantlyout-perform me with the same plane. The 91
    Surpass weights about 10 oz more than the 45FSR, but is rated at
    only 15-20% more power. So, the questions are: a. Is it crazy to
    put a 91 Surpass in a 40-size sport plane, and b. Does anybody
    have an OS .91 Surpass for sale?

    2. Finishing - I'm seriously considering glass and paint. I've
    never painted a model before, I'm a die-hard Monokote user. What
    are the pros and cons of going glass and paint?

    3. Any other advise?

    Dave Hughes

	Well, Dave (Hughes), did you get that beast built and flown yet? I'm
	seriously considering getting one and would like to hear comments 
	from anyone who has experience with it. Tower has a "special" ($10
	off) on the combo with a OS .46 SF/ABC. I'm looking for a plane with
	sort of pattern-like qualities, something I could use to train for 
	pattern type flying.

	Dave

One of the guy's in the Ware club has one with a K&B 60 in it. It screams 
through the air. The tower deal sounds like a nice combo. The plane will do 
everything and is very "crisp" in doing it.

I got some stick time in on one a couple of weekends ago and promptly went home 
and put my Super Tigre 60 into the Sharp (which flew monday at lunch). I got the 
speed but the balance was off (lateral - now fixed) due to a big muffler so I'm 
hoping for similar performance (without the building time).

If I had the time to build one, I would.

    Mine's still in the box. I have no plans for it until next winter.
    I'll probably build the Unic-20 first. I'm waiting for Charlie
    Watt to get his and put that 91-Surpass in it to convince me to
    stick with my 45FSR. 
    
    I intend the Ultra-sport to be my first paint job, and I'm gonna
    do the retracts too. 
    
    I guess I'm glad we've got winter after all. The Desert Rat has to
    waste his off-season in the pool, since his shop is uninhabitable.
    I got a nice little electric heater that makes my shop nice and
    comfy. Want to borrow it, Al?
    
    Dave

    There is a construction review of the Ultrasport in this months
    Model Airplane News.
    
    
    Tom

    Dave W,
    	I decided to build the Ultra-Sport as well.  I saw the review that
    Tom T mentioned and I plan to also use the YS45 and tuned pipe that I
    now have on my U-NIC.  It should have excellent performance and fly
    very well.  I sort of wish it was a 60 size but Them's the Breaks.  I
    don't plan to put the 91 Surpass in it as Dave Hughes suggested.  I
    would have if it was a 60 size plane though.
    
    I'll probably wait until fall to start building.
    
    Charlie
    

Re:-.1

Good, then we'll have at least two people building an Ultrasport this winter.
Maybe Dave Hughes will take his out of the box too.

Tower Hobbies has a special on the Ultrasport packaged with the OS .46 SF for
about $190. I'm also thinking of putting a pipe on it for a little extra zip.
I welcome any suggestions on the best way to add a pipe, what kind to buy,
etc.

By the way Charlie, are you going to install retracts?

Dave

	I finally got started on my Ultra Sport 40 now that the cooler weather
	has arrived. I'm already pretty impressed with the kit. The instruction
	book is probably the best I've seen yet, and there's an extensive 
	section at the end on fine tuning the airplane. It has tips for
	correcting problems that I didn't even know could exist.

	The die cutting is superb. The ply parts literally fell right out of
	the sheet, and so far the fit of the pieces has been quite good. The
	balsa sheets for the ribs varied widely in density, so I had to sort
	them to balance the wings (maybe too picky).

	So far, I've got the tail pieces built and sanded, and the wing halves
	are built and just need to be joined. Fuse is next. I plan to build
	the taildragger option, no retracts.

	My first preference for an engine was the OS .46SF, but nothing is 
	available from OS these days. I will probably pick up a Magnum Pro .45
	from Fisher RC, looks like a good buy at $77.

	Still haven't come up with a color scheme yet.

	Dave

    

>	has arrived. I'm already pretty impressed with the kit. The instruction
>	book is probably the best I've seen yet, and there's an extensive 
>	section at the end on fine tuning the airplane. It has tips for
>	correcting problems that I didn't even know could exist.

Dave - if it isn't copyrighted - perhaps you could re-type it into
our tuning note.  We keep hearing how good the new Great Planes tuning
guide is.

>	Still haven't come up with a color scheme yet.

How about a "Sky Blue" bottom and a "Grass Green" top :-)

Remember when Eric made a pilot look like himself for his last plane.
Yours should be easier - no glasses (and less hair) :-)

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

>>> Remember when Eric made a pilot look like himself for his last plane.
>>> Yours should be easier - no glasses (and less hair) :-)

Yeah, a bare ping-pong ball should look just right...

    Careful. You might need to tint the canope to avoid too much glare and
    a strobe effect during rolls ;^)

    I persume the Ultra Sport 60 is close enough to the 40 that I can ask
    some questions in this note and not start a new one.
    
    Christmas came early this year and I've been working on my 60 for about
    a week.  Vertical Stab is done and I'm just finishing up the horiz
    stab.  My question is what to do with the stab tips.  The instructions
    don't say anything about it and the pictures and drawings aren't clear. 
    The elevator is sanded to a taper.  Are the stab tips left to 3/8 inch
    at the tip or are they also sanded down to match the taper on the
    elevator.
    
    As far as my plans for this bird.  Engine will be an OS 60 2 stroke. 
    Will have nose gear instead of the tail dragger version and will have
    fixed gear, no retracts.  I will probably Ultracoat it in silver and
    blue.  My wife is expecting in June so I WILL complete it by then.
    
    Any other hints before I get to far into it?  I'm still waiting for a
    wing jig from Tower so I will probably start on the fuse next.
    
    Oh yes, the cockpit is large enough for my favorite pilot, Barbie,
    though she will need some rather radical surgery.  Time to start
    browsing Toys R Us for an outfit.
    
    Loren

    Loren,
    
    Sandem' to a taper....If you're running the block wing tips which the
    40 has...hollow both tips as much as possible.  Be sure to check the
    balance of the wing before covering.  
    
    Lastly....hope you enjoy yours as much as I do mine.
    
    John

About wing balance...

I had weighed all the ribs (BIG differences in weight between sheets) and mixed
them so they would be about equal for both wing halves. After gluing them in,
Charlie Watt suggested (too late) that I put all the heavy ones in the left wing
to compensate for the engine hanging out to the right. Later on in the wing
building instructions, they have you hollow out ONLY the right wingtip for the
same reason.

I really don't know how much you have to compensate. I also wonder how sensitive 
the plane is to such a weight imbalance. Maybe it makes a difference when 
executing precision pattern maneuvers.

    
    	Walt, to answer your question it does make a difference.  If
    your really try to trim this plane to consistent manuaver you will
    find that you will be hunting for a trim that will give you good
    inside and outside loops without having to compensate with ailerons
    during the manuaver. 
    	Today the wing balance rule in pattern is balance the wing and
    then rebalance the wing and fuse as a unit.  This is probably due
    to the fact that in most pattern designs today the engine tuned
    pipe run down the center line.  For your application I think balancing
    once with the fuse a one unit will be OK.
    
    Hints..
    
    	If the wing isn't fully sheeted per design, consider sheeting
    it.  Consider putting the bigest engine you can fit into the plane.
    
    Tom

    I don't have the manual with me but I do recall wording to the effect
    that carving out one wing tip IS to compensate for the engine and
    muffler weight.  From this discussion then I assume the procedure is to
    build the plane up to the point of covering it and then balance it with
    the all the necessary components mounted.
    
    Another question: All of my previous kits have been Goldberg.  Their
    procedure for attaching the wing together seems pretty solid. 
    Basically, two pieces of ply epoxied to the spars and the fiberglass
    tape for added strength.  Also, the wing mounting dowel is sunk
    directly into a block of wood in the wing.  The GP precedures are
    similar but don't appear as extensive or solid.  I'm sure it probably ok 
    but I have nightmares of going into a dive and having the body reach the
    ground before the wings.  Comments.
    
    Loren

    I'm building the US60 but I'll stick my stuff here anyway since there
    should be no major construction differences.  My tail feathers are done
    and my wing is built, joined, and glassed in the center section.  I
    started the fuse and it is about half built.  So far, the construction
    has gone well and I am happy with the kit quality.  The balsa does vary
    in weight and hardness more than I would like.  One of my leading edge
    wing sheeting pieces cracked when I went to bend it in place even after
    I soaked it with amonia/water.  I replaced it with a lighter piece.  I
    plan to go with fixed gear - taildragger and an OS91 Surpass.  I don't
    agree with Tom about fully sheeting the wing, but I agree with him that
    lateral balance is important if you want a well behaved airplane.  I
    always try to build the engine head side of the wing light rather than
    have to add weight to the other side late in the assembly process.  I
    do the final balance with everything installed but before covering.
    
    Charlie
    

Re: .17

I agree that the procedure for attaching the wings with the ply joiner is a bit
questionable. I did it their way simply because I hadn't read ahead to see what 
was coming. I would have prefered to join the wings BEFORE sheeting the center
section so that a C clamp could be used to fix the joiner to the spars. But...
we'll see how strong it is!

Time to glass the wing center section, fuse is next.

Dave

Don't worry about the GP center section method. If you build a Great Planes kit
as spec'd out it will be plenty strong enough. Do glass the center section if it
isn't called out specifically, but other than that don't worry.

The difference between GP and Goldberg kits is not that the GP variety are week.
In my humble opinion, the Goldberg are significantly over-engineered. This isn't
a problem, but does account for the difference. What I can't figure out is why
Goldberg offers wing kits for their planes and not fuse kits. I've dorked my
Cub twice now hard enough to split the fuse and remove the firewall with no
damage whatsoever to the wing.

Randy

    	I have built and flown three different sized Super Sportsters by
    Great Planes and I can attest to the strength of their wing joining
    methods.  The UltraSport actually is overkill compared to the Super
    Sportsters.  The Super Sportsters have no ply joiners at all!  You 
    build the two wing halves completely, butt join them together, and
    glass them.  The larger planes use heavier cloth, but still no joiner. 
    I have hundreds of flights on these planes and I've seen other
    Sportsters withstand severe crashes without wing center section
    failure.  This is conclusive proof that you don't need the heavy ply
    joiners that lots of kits use.  (Assuming you glass the center section.
    I have seen other planes have wing failures and they almost always
    occur at the edge of the center section sheeting and not at the center.
    A properly built UltraSport wing will not fail at the center!
    
    Charlie
    
    
    P. S.  My UltraSport 60 is comming along well.  I have the wing
    completed except for the aileron servos (one for each aileron).  The
    fuse is about half built.  I am about to add the engine mount and
    turtle deck.
    
    

    I'm considering either a SS40 or a US40.  Does the US40 tend to be tail
    heavy like the SS40?  Are there any other contrasts between the two
    planes that would be worth knowing?  I have a Super tiger S45 I plan to
    use.  It's an old engine but with little time on it.  I assume it will
    be enough power.  Comments?

    My choice is the US40.  I have one and it actually came out nose heavy.
    I'm running the OS.46.  It seems to fly faster and more stable than the
    SS40.  I would consider the US40 over the SS40 in the way it's built
    also.  SS's build up to be heavier planes, slight overkill for
    strenght.
    
    John

    I guess I would agree with John that the US40 comes out lighter than
    the SS40 but the SS40 flies about the same except in knife edge.  The
    US fuse was designed to knife edge and the SS was not.  I've flown the
    US40 with an ASP 40 for power and it was adequate.  I'd go with the
    46FS in either plane.  I'd say the SS40 is easier to build because it
    has stringers for the turtle deck and a straight wing where as the US
    has a tapered wing and a sheeted turtle deck.  The rest of the
    construction is very similar.  Instructions are GREAT for both of them.
    Keep it light and use a good engine and you will have a great flying
    plane.
    
    Charlie
    

	Finally finished my Ultrasport 40 this weekend, thanks to the
	dreary weather. I built it as a tail dragger, threw a Magnum Pro
	.45 on the front, and installed a simple 4 channel radio. The
	color scheme is black with red accents on the top surfaces and
	fuse sides. 

	I took it to the Westboro field Monday evening and enlisted the
	help of Charlie and Eric to look it over. It looked fine, but we
	soon found some hidden problems, the worst of which was a pinched
	fuel line. Access to the fuel tank compartment is only from the
	back, so you can't see a blasted thing once you start stuffing
	the tank in. With a lot of help from Eric, we successfully
	rerouted the plumbing and got it back in. I had also failed to
	tighten the muffler screws and prop nut sufficiently, and the
	glow plug wasn't tightened at all. Little things.

	We ran the engine for maybe 5 minutes, not slobbering rich but
	not lean either. For those of you who buy one of these engines,
	be advised that the idle mixture screw comes from the factory
	about two full turns too rich. 

	I had just enough daylight to get in one flight. It flew
	beautifully! As I was taking off, the plane lifted before I even
	advanced the throttle fully, and went up smooth as could be. It
	needed several clicks of trim on aileron and elevator, but nothing
	drastic. 

	Once it was trimmed out, I pretty much flew a pattern around the
	field to get used to it. God, it's smooth, like on rails! I'm
	also not used to the speed; a Skooter is the fastest plane I've
	flown with any regularity. This thing covered sky much faster
	than I'm used to; gonna have to change my perceptions a bit.
	Tried a couple loops and one roll, and they were nice and
	straight, the roll right on axis. I had set the control throws at
	the full rate distances suggested in the manual, and it felt just
	about right.

	The landing was easily controlled, although I misjudged its sink
	rate and almost put it in the grass. I guess I overcompensated
	for the long glide these planes reportedly have.
	
	Once the engine breaks in, I'll try some lower altitude stuff,
	stall turns, etc. to see how balanced it is. If the first flight
	is any indication, I think I'm going to like this plane!
	
	Dave
	
	PS: The duck in the cockpit enjoyed the ride, but commented that
	the landing didn't measure up to duck standards.

    Great. Glad to hear it's finally in the air. I guess it's fortunate
    you remembered to tighten down the engine mount bolts, and the wing
    bolt's.
    
    If it flies anything like Charlie's, I'm sure you'll love it. Now I
    have to get the Stryker done. Then we can go out with the Stryker, an
    US40, US60, and Eric's Dalotel and put on one hell of an aerobatic's
    demo. OR......we could start something new and do COMBAT with pattern
    planes.
    
    Steve

    I finally started to built my Ultra Sport 60 I purchased some time
    agao. Unfortunatelly I starting building BEFORE I read through this
    note. 
    The first thing I did was to finish the tail feathers. And my
    experience with SS60 told me, to enlighten the tail as much as
    possible. So I cut big holes in the elevator and rudder and put some
    diagonal ribs is. Saved me 1.5 ounces. Not bad, I thought. Right until 
    now I read that the US come out noseheavy !  But still, I put in a HB61 PDP with
    tuned pipe underneath, adding not too much weight to the nose as a 
    90 4-stroke would. Hopefully the right decision. 
    I'll built it as in tail dragger configuration. 
    Fuselage is half done, engine mounted already. The next step will be
    the wings. Before I'm gonna to make too many mistakes, any hint is very
    much appreciated.
    Look forward to retire the good ol' (lead slead-) KNIFE-edge.....
    
    (Wonder what I should do with this WEBRA 61 long stroke sweetheart......)
    
    
    Bernd

I managed to get my kit open this weekend. I recieved it as a present for 
Christmas so I was starting to get "comments" and was fearful about next 
year being an underwear and tie holiday 8^)

I completed the tail feathers and one wing panel before the end of saturday
and then got side tracked. I'll be using retracts and a ST.75 in mine. I'm 
also considering using two aileron servos (still in the center section) and 
mixing them as flaperons.

I'm surprised that it's comes out nose heavy. It's probably from all those 
people lightening the tail instinctively 8^)

I love the few flights I've had on other people's and look forward to cranking
mine around the sky.

    If you would put one of those lightweight 2-strokers in you might wish 
    you'd had lightened the tail feathers :-)
    I still believe it's always advantageous to be as light as possible at
    the tailfeathers if you won't give up the needed strength. 
    
    I'll soon reply as well another "start" - hopefully
    

    I'd like to see how your flaperons work out. My US40 just has ailerons,
    and it's real challenging to land sometimes because it just doesn't
    want to come down. Even a modest amount of flap might help steepen the
    approach angle.
    
    Dave
    

Charlie talked me out of the flaperons but into using dual servos for the 
ailerons so I'll probably try them anyway.

I'm also considering the landing gear brakes like the pattern guys are 
using. I think making the plane "dirtier" will be more effective than the 
flaps.

    Charlie is real conservative when it comes to trying both flaperons and 
    ailerons as flaps. Something to do with an Airtronics radio in his UNIC
    I think!.
    
    Steve Smith, Dan Snow and I have used them a lot. We,  I think I can 
    safely say we, have had good results with them. 
    
    Flaperons help in all aspects of flight. They are good on take-off 
    because they lift the wing. This better than the tail having to rotate 
    downwards to get a positive angle of attack for the wing to work and
    achieve lift-off. They also produce much tighter loops. On landing they
    allow a stretched "flair".
    
    When deployed as flaps the two ailerons allow much slower flying.
    Unfortunately this is at the expense of reduced effectiveness. I usually 
    mix in rudder with the "land" switch to help in this department.
    
    
    "Non-flap" landing option.
    
    A neat trick is to select 15 degrees of negative flap. i.e. both the
    aiilerons go up together a preset amount. This forces the pilot to
    hold in some UP to keep the plane level. This creates good dgrag. 
    A nose high attitude can be maintained that both slows the plane down 
    and allows height to be lost without noticeable speed gain. I used this
    extensively on the UNIC and have just dialed it in for the C-6. The
    advantage of "up" flaps is that it gives the wing has washout to permit
    slower more stable flying. It also keeps the ailerons remaining effective.
    
    
    Regards,
    
    E. - See y'all in a week....Wonder if it has rained in Canada - Nope
         but it will as soon as we get there :-).

    I second Eric's comments. I always have elevator/flap and flaperons
    mixed in.
    
    Flaperons work well for increasing decent angle without gaining speed,
    or if you hold in up elevator to compensate for the "pitch down" will
    slow you down quickly.
    
    Just beware that with flaperons, aileron effectiveness pretty much goes
    away (depending on how much you use) and you HAVE to mix in rudder with
    the ailerons to maintain control.
    
    Elevator flap mix, where the ailerons go up and down with the elevator
    is great for getting off the ground quickly and making tighter loops.
    In a glider application, it also helps keep the nose up during those
    nice "flat" thermal turns. However the "best" use I've found for them
    is extending your glide. There have been several times I've gone dead
    stick and normally would not have made the field. When it looks like
    I'm going to come up short, I switch in the elevator/flap mix and make
    the field every time. 
    
    Negative flap works well also. Pushing the wing down causes you to have
    to hold in up elevator to maintain a normal glide path. This creates
    drag and helps slow you down. It also helps on very windy days where
    the air is turbulent near the ground. Negative flap seems to "push" the
    plane down through the rough air and negate some of the girations you
    normally go through.
    
    Here's another use I read about but havn't tried yet (are you listening
    Jim Reith?????). On all out fun fly machines, one of the problems is
    getting the thing down. They float so much that alot of time is lost
    getting back down to the ground. What you do to overcome that is switch
    in negative flaperons. You program the radio so that when you activate
    the mix, both ailerons go UP a preset amount. This is the normal ON
    position. This will effectively kill your forward airspeed and drop the
    plane out of the sky. The neat thing is, when you feed in up elevator
    to flair, the ailerons come DOWN the way they should, giving you your
    forward airspeed back for a normal flair.

    Reviving an old thread..
    
    I'm down to the end of the build cycle on my US60/OS91 Surpass, and I
    have a few questions I'd appreciate any input on.
    
    - The wing fillets (the next step) are a bit daunting. Sanding so tight
    along the wing/fuse cranny looks like a pain. Any suggestions on the
    best way (material/tools/technique) to form these two suckers? I'm
    concerned that simply using lite filler won't be strong enough, but
    making the whole fillet from soft balsa looks like a royal pain as
    well...
    
    - Also on the fillets: these are formed prior to placing silicon or
    foam seating tape on the fuse/wing joint. Do you end up with a gap
    between the underside of the fillets and the wing surface once the
    silicon or tape is installed, or does the fit remain tight?
    
    - Before I fabricated the nose, I took a  l o n g  look at various
    vibration damping mounts, but none of them looked like a good fit
    without changing the nose moment significantly (I've heard that the
    US60's are nose-heavy enough with the 91 Surpass and the soft mounts all
    looked like I'd need another inch or more length in the nose). 
    
    So when I built up the nose, I stuck a 1/8" ply shim between the OS
    mount and the firewall, and I allowed a bit more wiggle room between
    the spinner and the nose ring (1/8" instead of the 1/32" spec'd). 
    
    I'm planning on replacing the ply with a like thickess of rubber, then
    boring out the bolt holes in the mount to accomodate silicon tubing 
    around the mounting bolts, and then using rubber washers backed with 
    metal washers on the bolt heads, thus forming a "home-brew" soft mount
    of sorts. Any thoughts on this? Any ideas on the hardness of the
    rubber for this application?
    
    - Any special techniques on attaching the canopy, or did everyone 
    stick to GP's instructions on this?
    
    - I went with DB retracts on beefed-up mounts (I can thank Andy for the
    education on this ;^) and while this was the singularly biggest
    struggle to perfect, they're in solid and appear to work great. I did 
    go with the DB lite treaded tires, and bumped them to 2 3/4" instead of 
    the 2 1/2" spec'd (every little bit helps on grass, eh?). 
    
    I mounted some lite balsa on the gear box covers and sanded them to 
    match the wing surface to try to clean up the air in that area. The 
    (probably anal)  question is whether there's any aerodynamic point 
    in making gear covers for the major portion of the wheels - and if so, 
    how the heck do you attach them to the piano wire? Is this worth the
    effort or should I skip it? (I'm leaning heavily towards skipping it
    unless the paypack is significant).
    
    - Lastly, anybody want to provide the dry weight on a similarly
    configured US60/US91 w/mechanical gear, separate aileron servos, and
    film covering? I'm making every effort towards balancing weight against
    survivability, but I'd love to know where I stand (not that I can do 
    much about it at this point ;^)
    
    Thanks mucho! (and Happy New year!)
    
    /dave

    
    
      Dave,
    
           Here are suggestions on a couple of the items:
    
          1. Wing fillets: Make them out of lite-spackle. Wrap a layer of
    Saran Wrap aroung the wing where it meets the fuselage. Then bolt the
    wing to the fuselage and form a fillet out of spackle. The saran wrap
    will prevent the spackle from bonding to the wing and at the same time
    will match the fillet to the wing with minimum gap. If you using foam
    wing tape, you can attach it to the fuselage before performing
    the above process
    
         2. Gear doors: Forget them. No Pattern flyers use them on their
     retracts, and trust me, if they made ANY difference, we would
     ALL have them. If you look in the dictionary under ANAL, you will
     see a picture of a pattern flyer! :)
    
         3. Don't know what the instructions say for fitting the canopy,
    but I recommend using RC56? Do NOT allow ANY CA to come in contact with
    the canopy, or you will have a ruined, cloudy canopy.
    
                                     Hope this helps,
    

    I sent Dave mail offline with basically the same suggestions.
    
    Should I be worried that Dan and I think alike????????
    
    It's down right SCARY if you ask me!!!!!!!!!!!!    8^)
    
    Pretty soon he'll have me flying like him and pulling UP one and a half
    turns through 3 rolls.........8^) 8^) 8^)
    
    Come to think of it, I already did that too at Glenn. Now I'm REALLY
    worried.......8^)

    Watch out Dave. Before you know it you'll be flying Choppers instyead
    of finishing up your UltraSport...hmmm... is THAT what caused it...

    
     No coincidence Steve, we were just corrupted by the same individual!
    
    
    
     

    As Steve was kind enough to email me some very helpful answers to my
    questions posed a few replies back, I thought it might be helpful to
    post it herein for anyone that follows in my balsa dust (so to speak),
    so it'll apeear as the next reply to this thread.
    
    I've gotten the US60/OS91 all assembled and most of the final sanding
    done - just putting the last touches to the leading edges to get their
    profiles to match up, filling dings, and working my way down the
    sandpaper grit size route.. I ended up doing the wing fillets using as much
    soft balsa as I could fit within the fillet area for strength, roughed
    the shape in, then used Micro-Fill to smooth in the detail. They came
    out pretty decent - not award winning for sure but they'll do the job.
    
    Before I did the fillets I spent a long time working the wing saddle to
    set the correct wing incidence (I sprang for a pair of the Robart
    meters which between a Tower sale and a couple of discount coupons came
    in under $15 each) and in the process discovered about 1.5 degrees of
    washin on one wing(!) - the one I built before discovering that my
    worksurface had a major bow. I took the water/ammonia route (70/30
    mix) wetting down the sheeting, cranked the wing back where it belonged
    with a kluge of shims, weights, and clamps, then let it dry overnite.
    
    Next morning at first light I rushed in and beheld a perfectly trued
    wing (phew!). Major bullet dodged... The incidence is now dead-nuts 0
    degrees on both sides - twin meters sure make this easier...
    
    After the fillets the tail feathers were next - the Robart meters  (on
    a newly leveled bench) made this pretty simple. Then I reloaded all of
    the mechanical/electrical/fuel bits, stuffed the radio and battery pack
    as far to the rear of the servo bay as they'd go, attached the wing and
    commensed the static balancing.
    
    The lateral balance was a piece of cake - I needed only 18 grams to
    dial that in and counter the right-side mounted engine & silencer. Of
    course in the process of rigging up a balancing jig I dinged a cap
    strip and put a goodly divot in a wing tip (Waahh!)...
    
    I should buy stock in NHP soon!
    
    Then I went for the CG - and I was prepared for the worst here - the
    OS91 with the OS custom mount seems like a ton of bricks hanging on the
    nose and I figured I'd need many ounces of weight at the tail to get
    close. I had made concessions to this in advance - mounted the servos
    as far to the rear as possible (almost 3" to the rear of spec), went to
    lightweight tires on the retracts, etc. 
    
    And it's paid off, as with the foamed-and-bagged battery and receiver
    at the very rear  (above the servos) it only takes 10 grams to hit the
    rear of the planned CG. I figure once the plane is covered, I probably
    won't need the ballast - and in fact I'll likely have to move the
    battery forward a bit  - but I've got plenty of room in that direction
    (like around a foot or more!)
    
    I can't tell what the all-up weight is - it's somewhere between 6 and 7
    pounds according to the bathroom scale technique. I wonder if the
    postmaster would mind weighing the two chunks for me?
    
    Now I'm battling hangar rash - I don't want to cover this bird until I
    can haul it's arse to a CMRCM meeting and have some grizzled veterans
    give it a going over - and it seems everytime I lay my hands on the
    balsa I either find (or cause) another ding! Hopefully we won't get
    creamed by another blizzard on Feb 5th, 'cuz if this sucker doesn't get
    some mildly protective covering and take up safer residence hanging
    from the ceiling, things could get ugly ;^) 
    
    Not to mention that my son wants us to get started on the pair of
    Gremlin kits that we got from Jim and the US60 is taking up the whole
    workbench...
    
    Ah, such problems...
    
    btw: The Futaba 8UA that'll run this bird (and its hangar mates) is
    turning out to be a kick-buttski radio. I'm still ascending the
    learning curve (Windows 95 was a cakewalk compared to this!) but 
    I've gotten everything setup except for the (5) P-mixers (still going
    to school on those ;^) As my sons say, "It's freakin' cool!" 
    
    Cheers! (and pray for decent driving conditions on the 5th!)
    
    /dave (sanding, sanding, sanding...)

From:	SNAX::SMITH        "Steve Smith Integrated System Services 225-4341"  2-JAN-1996 08:44:16.18
To:	ESB02::TATOSIAN
CC:	SMITH
Subj:	Some answers to your building questions

Hi Dave,

	Looks like you've been busy the last couple of months. We're having
a show and tell on winter projects at the meeting next Monday so why don't
you bring it in. Sometimes it's a little easier to explain things when you
can point to the plane itself.

	I'll try and answer some of your questions anyway.

WING FILLETS....

	Some people may argue this point, but for the most part, wing fillets
	are "dress up" as opposed to being functional. Therefore, the amount
	of sanding you do is in direct proportion to what kind of "looks"
	your willing to settle for. It's really not that tough and I would
	suggest putting them on as they make the wing seat a little larger
	and provide some additional support for the wing. I'd just take some
	half inch triangle stock, put some "slices" in the top edge to allow
	it to bend where necessary, glue it on so that it extends slightly
	below the wing seat, then sand the bottom to match the curve of the
	wing/wing seat, fill the "slices" with light filler, lightly sand,
	and your done. One evening to put them on.

	As an alternative, they "do" sell ready made wing fillets that are
	a vinyl/plastic type material. The only problem is that covering won't
	stick to it, and paint tends to chip off over time. To attach the
	ready made fillets, attach the wing to the fuse with wax paper between
	the fuse and wing. Lay the fillet in place and stick on with zap. The
	wax paper prevents any leaks/spills from glueing the fillet to the wing.

	Once you have the fillets attached, cover the wing center section with
	handy wrap. Put a generous bead of silicone along the entire wing seat
	and attach the wing. Let dry over night. Remove the wing, trim excess
	silicone, and apply baby power to the wing seat so that the silicone
	is no longer sticky. The only "gap" you'll see is any place the wing
	didn't match the wing seat perfectly. Otherwise, the "gap" will be
	filled in with the silicone.

SOFT MOUNTS.......

	Your system sounds ok although I question the need for the 1/8 inch
	rubber "pad". You would probably be better off making the ply shim
	permenant to gain added strength for the added weight and vibration
	of the 91 4 stroke. Otherwise, your basically building a home brew
	version of the typical soft mount and it should work fine. In fact,
	other people have done the same already. On the hardness of the
	rubber washers, if you were to rate softest to hardest as 0 to
	100, I'd shoot for something around 75%. The system your building
	works more toward preventing "transmitted" vibration as opposed to
	totally isolating the motor. Remember what your shooting for is a
	compromise between vibration dampening and still having an engine that
	is solidly mounted. An engine that vibrates too much (meaning shakes
	back and forth because of the rubber mounts) creates it's own set of
	problems. I've tried using rubber mounts on 60's and could never
	keep the muffler attached. The engine kept shaking it loose.

CANOPY ATTACHMENT.....

	Not too many tricks here. Basically use RC56 glue and use GP'S
	instructions.

RETRACTS...........

	Nothing wrong with beefing up the mounting system as Andy can attest
	too. Also a VERY good idea to bump the wheel size to 2.75. Not only
	will it "roll" better, but the larget wheels will absorb more ground
	induced shock/vibration.

	Don't bother trying to clean up the rest of the retract cutouts. It
	will have no effect on aerodynamics and will be MUCH more of a pain
	in the butt than it's worth. Espically flying off of grass most of
	the time.

DRY WEIGHT.......

	The difference in flying weight between what you end up with and what's
	advertised should only be the difference between the extra weight of
	the 91 versus a typical 60, and any additional weight added due to
	"beefing up" measures. I "think" the advertised weight for the US60
	is something like 5.5 to 6.5 pounds depending on how it's built and
	what's put in it. Hopefully, you'll finish up in the 6.5 area. The
	plane will be perfectly flyable at 7 pounds but over 6.5, all your
	really doing is increasing wing loading with no benefit to the added
	weight.

	Keep in mind that the US60 with the 91 4 stroke is going to be a
	ROCKET SHIP even at 7 pounds. Harvey has one that he has trouble
	flying because it get's too far out to quickly for him to keep up
	with. You'll definately want to get the feel of this bird slowly and
	have an instructor standing by until you are comfortable.

	One more point on balancing. You will still want to balance the plane
	per the instructions and your right, it probably will be nose heavy.
	You should plan now (if you havn't already) on putting at least the
	elevator servo and RX battery pack in the fuse behind the wing.
	Otherwise, you'll have to add weight to the tail to get it to balance
	and you don't need any more weight with this setup.

	Any more questions, let me know.

Steve