Conference vmszoo::rc

    
    Eric , 
    	I don't see any reason why the mixing switch would have caused
    the problem that you had . What caught my eye is the freq. you said
    that your radio was on , ch. 77 ! This is a surface only freq. area
    for r/c cars and boats and even with them , the freq.'s are still
    in even increments , eg: 74 ,76, 78, 80.... and so on . It may be
    that new freq.'s are also available for these too , therefore the
    reason for the odd freq. but I can't say . How about more info on
    your radio and actual freq. in mhz . Anyone else out there with
    some input on this ??
    
    
    	Carl

    Carl,
    
    The frequency is 35.060 MHz. I hope I am correct in saying this is
    channel 77. I was using 4 standard servos. Receiver is the 107N I
    think. After drying the Rx etc I tried flicking the mixing switch along
    with the elev / ail / rudder - nothing out of the normal happens just
    some nice mixing. 
    
    I noticed while fitting the gear that the servos 'rattled' around
    when I touched the engine with a metal object. The engine control
    is bowden cable with a metal clasp on both ends. This noise
    dissappeared after installation. All the other controls except for
    the ailerons which use torque rods are again wire cable inside
    a plastic tube. The rudder / elev. control lines will be running
    nearly parallel to the aerial. 
    
    Thanks,
    
    Eric();
   

    
    		Don't overlook pilot error.... Even good pilots make
    mistakes. I have seen more "radio hits" that were actually stalls.
    How much time elapsed from the problem to crash. All tests of new
    setings should be done at high altitude to allow plenty of time
    to recover. If the plane crashes in less that 15 secs. I would vote
    for a stall without sufficient time to recover. Once a plane stalls
    the controls are very ineffective until airspeed is regained.
    

    re .-1
    
    Jonathan had nearly done a complete circle so it wasn't up very long a
    minute at the outside and about 200+ feet up. The idea of a stall did
    cross my mind. Further along the lines of a stall I had to change from
    a 10x7 to an 11x6 to get a little more momentum. It just would not get
    up off the ground with the smaller prop (I think a 60 might have been a
    better choice of engine). There was an improvement with the larger
    prop. But the climb out was nothing compared to a Yamamoto. 
    
    The prop being driven by a Super Tiger Sport 40. 
    
    Weight is around 7lb. 

    Back to the mixing ... The model was climbing gradually at a good speed
    when the mixing switch was changed (This may have given it a sudden bit
    of elev or rudder provoking a nasty stall). Total control was lost at
    this point. Jonathan shouting that he had lost control. 
    
    Eric();

    Eric,
    
    Obviously, you're one of our UK amigos, based on the frequency you
    stated.  Therefore, disregard anything previously said regarding
    surface vehicle vs. aircraft frequencies. I'm unaware what (if any)
    scheme may exist in the UK to try to separate the two user groups.
    
    As to your immediate problem, I also fly a "G" series Futaba in
    the ol' Yeller Peril (Bucker Jungmeister) so I'm familiar with the
    mixing switch you refer to; it's a 3-position switch with the center
    position being neutral and the two extreme positions being ail/rud
    and elev/rud (I think that's right).  To begin with, regular readers
    of notes know well my LOW opinion of mixing switches, rates, etc.,
    particularly when these bells/whistles are MISinterpreted by the
    novice flier as "training aids."  But, I'll not launch into another
    on the subject diatribe; suffice to say, however, that this particular 
    switch has been dubbed the 'suicide switch' hereabouts...and for good
    reason.
    
    I've witnessed the following scenario at least three times and have
    heard of it happening many more times:  model flies normally enough
    until it becomes slow/approaching stall speed (unfortunately, this
    situation normally occurs at landing or takeoff where altitude is
    low to boot); suddenly, the plane snap rollss (I believe you Brits call
    it flick-roll) on its back and begins spinning in; if the pilot
    has presence of mind to get off the elevator to allow airspeed to
    build up, the instant he applies elevator to raise the nose, the
    snap immediately reoccurs and the plane resumes its earthward spin;
    the cycle repeats as many times as the pilot tries to break the
    spin, limited, of course, by how much/little altitude he has to
    work with.
    
    Invariably, the pilot "thinks" he had a radio problem where, in
    reality, it was the 'suicide switch' that did him in...he had control
    throughout but the switch sabotaged him.  How? by inadvertently
    (or ill-advisedly) moving the mixing switch to the elevator/rudder
    position.  Think about it; what controls do you apply if you want
    to 'deliberately' do a snap/flick roll?  You raise the nose slightly
    then kick in full up elevator and [usually left] rudder.  This can
    be performed at [depending upon the aircrat's capabilities] any
    airspeed but is _particularly_ effective at low speeds.
    
    So let's think back to the scenario I described above: the plane
    was slow, the pilot applied up elevator (perhaps in a turn or just
    to correct altitude, attitude or rate of climb/descent) and the
    airplane snapped into a spin...why? BECAUSE THE RUDDER WAS ALSO
    APPLIED DUE TO THE COUPLING/MIXING.  If he had time, altitude or
    the presence of mind to release the elevator, the spin was broken
    but every attempt to raise the nose simply caused the same problem
    all over again AND THE SUICIDE SWITCH CRASHED THE MODEL!!
    
    Now, I can't say with certainty that this absolutely happened to
    you, but it certainly sounds like an excellent probability,
    particularly when you say the wrong mix position was accidentally
    selected just prior to the crash.  Are you absolutely positive that
    the switch was returned to the neutral position before the crash?????
    
    On my Futaba "G" Tx, I've tightened a wheel-collar onto the
    mixing/coupling switch lever such that it CANNOT be moved out of
    the neutral position, deliberately or by accident and I strongly
    advise all beginner pilots to do likewise, at least until such time
    as enough experienced has been attained to safely utilize it.  ABOVE
    ALL, DO NOT think of all these trick bells and whistles available
    on today's radios as training aids.  Quite the contrary, they can
    be the unwary pilots undoing and should only be experimented with
    AFTER a moderate amount of experienced has been gained.
    aids

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

    Al,
    
    That was interesting. You mentioned elevator/rudder coupling and
    described how it can cause snap-rolls at low speeds. What's the scoop
    on aileron/rudder coupling? That is the only coupling available on my
    TX, so I am interested. You could point me to a previous note, too...
    
    ajai

Al,

I think what you said describes, to a near perfect fit, what could have
happened. 

I can't agree more on 'bells & whistles' as a no no for beginners. I
don't use it and had adjusted the mixing for a minimal effect. The pilot
decided that it would help on take off. I haven't got exact details on what the
pilot did during the 'stall / snap/roll' but you can guess what I was thinking
& saying and worse still what reception I would get on arriving back home with
the plane re-kitted - WP's (wife point) back in the red zone... I think I will
have to finish off the patio to get some back.

The switch was set to the non-suicide position within a couple of seconds ie
back to the neutral center position. But still no cigar - it continued to
spiral down. As regards the dual rates I adjusted (several months ago) the pots
inside the back cover so that they have zero effect - its so easy to hit them
and I am no ready for them yet.

I will check tonight what effect the elev/rud mixing will have with the full
throws of the ail/rud/elev. 

Your idea of a '..collar' on the mixing switch sounds what I should do to my Tx
if I can build up the ego & confidence to continue with the transmitter /
receiver. Its not easy the next time around. I got hold of a Yamamoto after the
crash and had a couple of good flights with it -  it helped get me back on
track and dig my ego out of the ground.

Small correction to location. We are in the West of Ireland - Galway. 

Thanks for the replies so far guys - invaluable. 

Eric();

    Ajai,
    
    I'm sorry but I'm not sure where to point you on the discussion(s)
    that occured previously on this subject.  I'm sure some were in
    Ramblin' but couldn't say they were confined to a particular subject.
    
    As I intimated in .5, I'm not a big fan of ANY of the mix/couple/rate
    switch bells/whistles though I concede there are many within and
    without this notesfile whose abilities I respect that disagree with
    me.  I _do_ think, however, that I can get a concession from the
    majority of camps on this issue that these features should NOT be
    treated lightly by the tyro aviator and I continue to maintain that
    it is a grave mistake to treat any of them as "Training Aids."  
    
    Many noters have argued that coupling aileron and rudder helps them
    in the learning environment, however, I contend that this merely
    provides a crutch that must [sometimes painfully] be UNlearned later...
    if _never_ unlearned, the dependence upon the crutch will stifle
    or severely limit the pilots ability to progress and become _really_
    proficient.                                          
    
    Coupled ail/rud may be of some miniscule benefit while airbore but
    my contention, based upon experience, is that it frequently does
    more harm than good, creating rathing that curing troubles around
    the ground at altitudes where trouble can be ill afforded.
    
    Beyond these statements, I'll not try to persuade you in any direction
    regarding mixers/rates but will advise you to comply with whatever
    a competent instructor recommends and is comfortable with.  I will
    continue, however, to advance the notion that all the gingerbread
    available to us today is nice enough and has some application in
    specific situations but should be experimented with carefully and
    only AFTER the basic "stick and rudder" skills have been mastered..

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

                My experience,  personal  unfortunately, is that once you
        get into a  stall/spin  situation  your nerves get so high strung
        that you overcontrol, which in itself causes new stalls.
        
                This reminds me of  my  first Aeromaster, which I decided
        to build as my fourth  plane  after a PT-20, a Trainer 40, and an
        ACE 4x40 bipe.  All these planes were extremely benign and simply
        could not be forced into getting you  into  trouble.    Well, the
        Aeromaster did, and I had a whole rash  of  "radio hits", which I
        ultimately learned were snaps caused by too early takeoffs  (this
        is  where  the  Aeromaster really will punish you, early in  this
        file  you  will find my "wounded goose" note), but also snaps  on
        landings.  What  was  especially  disturbing was exactly what you
        found.  It would snap,  I  would recover, and then the darn thing
        would snap again right away, ad  infinitum, or rather hard ground
        collisium.  I still have the remains  sitting  in  my basement to
        remind me to be a little bit humble.
        
                      _ 
                     / |
        |  _====____/==|
        |-/____________|
        |    |        o \
             O           \ 
                          O
         Hang in there! o_|_
                          |
             Anker      \_|_/

    
    I have another theory that could be all wet (sorry :-)) but should
    be easy to check out.  I'm pretty sure there is a switch to reverse
    the aileron/rudder coupling on the FGK.   So, it is possible to have
    the rudder control backwards when you use just the rudder stick but ok
    when you use the coupling (aileron stick).  Did you do a pre-flight check
    and make sure that the rudder stick and aileron stick (with coupling) both
    moved the rudder in the same direction?  It's a wild guess, but a
    plane with reversed rudder would sure be out-of-control after you
    disabled the coupling!
    
    Bill

>    be easy to check out.  I'm pretty sure there is a switch to reverse
>    the aileron/rudder coupling on the FGK.   So, it is possible to have
    
Bill - there is no such switch on the FGK.  On the Cirrus version of the
same radio it is possible (and documented) to adjust the pot thru zero and
achieve negative aileron/rudder coupling - but there is no way on the FGK.

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

    
    RE: .-1  Hmmm, I coulda sworn there was a servo reversing switch for
    	     coupling on the FGK.  I must be thinking about the
    	     Airtronics.  Thanks for the correction.
    
    	     Bill

    There is a reversing switch for the coupling.  I used the aileron
    rudder coupling on mine but I took the back off and cut the wire that
    gave the rudder/elevator coupling so that this function was permanently
    disabled.  I knew I never wanted to accidentaly have this mode.  I
    think that Futaba was crazy to have both functions available on an
    external switch.  All reasonable transmitters put this switch with the
    reversing switches so that the type of coupling is selected only at
    setup and not while flying.  Ergonomics?  By the way, I think aileron/
    rudder coupling is ok but not necessary.  I had to unlearn this
    function after about a year of flying always using coupling for
    takeoffs and landings.  I never had a crash caused by coupling but it
    may have delayed my learning to use rudder properly.
    
    Charlie
    

    re .-1
    
    Sounds like a good idea - cutting the wire.
    
    
    
    Eric();

    
>>    There is a reversing switch for the coupling.
    
    I thought so!!  I keep forgetting to check my FGK.  Kay, what makes
    you say there isn't a reversing switch for coupling on the FGK????
    I have the 7 channel version, is that what you were talking about?
    
    I agree with the comments about poor design, putting coupling and
    mixing on the same switch.  Unreal!
    
    Bill

>>>    There is a reversing switch for the coupling.
>    
>    I thought so!!  I keep forgetting to check my FGK.  Kay, what makes
>    you say there isn't a reversing switch for coupling on the FGK????
>    I have the 7 channel version, is that what you were talking about?

Where?  I think we may be mixing old and new Futaba's here.  I noticed when
I was in Phoenix that Al Casey's FGK looked alot different in the reverse
switch area than mine did and even his Aileron/Rudder Coupling switch was
different - I had to special order a larger than normal wheel collar to
cover the switch - his was the thin switch.  If I misled someone I'm sorry.
I plan to look at mine again tonight.

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

>>>>    There is a reversing switch for the coupling.
>>    
>>    I thought so!!  I keep forgetting to check my FGK.  Kay, what makes
>>    you say there isn't a reversing switch for coupling on the FGK????
>>    I have the 7 channel version, is that what you were talking about?
>
>Where?  I think we may be mixing old and new Futaba's here.  I noticed when
>I was in Phoenix that Al Casey's FGK looked a lot different in the reverse
>switch area than mine did and even his Aileron/Rudder Coupling switch was
>different - I had to special order a larger than normal wheel collar to
>cover the switch - his was the thin switch.  If I misled someone I'm sorry.
>I plan to look at mine again tonight.

Well I looked.  My FGK Futaba 7 channel FM has no reversing switch for 
coupling.  There is a 7 switch DIP for servo reversing and it is
1 switch per channel.  However there are two pots for adjusting the
Aileron Rudder Coupling and you can go thru zero so the functionality
is there as you state and the procedure is documented in the manual.

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

    
    Well I finally looked too, and you are absolutely right.  The Airtronics
    CS7P has a reversing switch for mixing but the Futaba FGK is done by
    trimpot thru zero.  Charlie must have been thinking of the Airtronics
    too.  Sorry for the confusion.
    
    Bill

    I got hit, or so I thought. I spent 2 hours yesterday hoping to
    fly but each time I went up I got hit (or so I thought). Yesterday
    at the drop zone was a bad day. Just before I started to Kougar
    on takeoff. Paul ??? with his brand new 60 size plane lost control
    on a low pass. He was straight and level when the plane went left
    and down hard. I then took off came around to the same general area
    that Paul crashed in. Next thing I know my plane is verring left.
    It was almost upside down before I regained control for a short
    while. Lost control again, Cut the throttle, ran toward the plane
    which is about 100 feet away. No response on throttle, still wide
    open. Throttle finally cut back and I dumped it in the tall grass
    as fast as I could. Only damage was a bent nose gear. All this
    happened on a Futaba 5UAP 1024 dual conversion RX. Failsafe did
    not appear to work. Specualtion runs wild. The scanner does not
    show any interference. Three planes have been hit, the first before
    I got there was a aeromaster that was destroyed. Some specualte
    that the aeromaster was pilot error but others swear that it was
    a radio glitch. Bob Glorioso states that he was geeting hit on
    saturday with his seamaster. At one point plane climbed 400-500
    feet on it's own. Other people also talk of elevator glitches.
    Sundays problem of the day, including mine was planes going left
    with no control. Other people echo that they have had minor glitches
    they can;t explain. Scanner still shows nothing. I wait an hour
    range check and up I go. Controls go dead (not failsafe) controls
    come back. I land without incident. More speculation about chan
    20 causing problem if somebody at other field (crow Island) was
    on channel 20. I did not think this was the case as I was not
    going into failsafe. Plus I think that a dual conv. RX is NOT prone
    to TV4 & chan 20 problems. I later start my plane again. While
    playing with the throttle I notice that it does not always move
    with the stick. At times it hesitates. This happens for a while
    then stops. To make a long story short I went home and removed the
    RX. All connections are tight. By tapping on the RX and playing
    with the sticks I notice that the servos hesitate from time to
    time. Yep radio problem all right. The RX is intermittent. Just
    goes to show you... This radio is only < 6 months old. Its the best
    RX that Futaba makes (R129DP) but it still can fail.
    
    Now that was my problem, what about the other stuff???
    
    
    						Dave
    

    Dave,
    	I have seen two other cases of receiver failure (Both Futaba).  One
    was caused by a clipped component lead floating around in the receiver.
    The guy lost total control and regained it in time to save his pland
    and land.  We popped off the case and found a piece of wire that was
    sometimes shorting things out.  Sloppy workmanship!  The other case was
    a broken antenna lead right at the circuit board.  His receiver would
    work sometimes but when the engine was running, he was getting hit even
    on the runway at close range.  This failure might have been due to
    abuse since it did not happen when it was brand new.
    	I also saw a guy have a brand new plane with a futaba 1024 system
    (might have been 7 channel) go in on it's maiden flight.  He was the
    only one flying at the time and noone else had interference.  It just
    rolled over and went in without warning.  He could not get the radio to
    act up after the crash.
    
    Charlie