Conference vmszoo::rc

    I highly recommend the installation of spoilers on all gliders in
    which it is practical to do so.  Two meter floaters(ie Gentle Lady,
    Oly 650, drifter, etc.) probably do not need spoilers because they
    fly very slowly and don't have that great a l/d ratio.  However
    they can be very helpful if you ever find yourself in a booming
    thermal, and need help descending.  For gliders with high wing loadings
    (10+ oz./sq.ft.) the spoilers really help with landings in limited
    area.  The need for spoilers for contest work is self evident. 
    Although the Oly II flys slowly, I would recommend spoiler installation
    for the above reasons.  The only thing you need be aware of is the
    tendency of the nose to drop when they are fully deployed.  This
    can be counter acted by applying up-elevator.
    
    Regards,
    
    Jim

Having just read all the Flaps notes and having just test flown my Sagitta
last weekend and really playing with the spoilers for the first time I
have the following observations:

If I am on the wrong track - experts please correct me.

Spoilers seem to provide almost the opposite effect of flaps in
many ways.  Makes since cause they are on the top of the wing
and not the bottom.

When deploying spoilers the nose will drop instead of rise like most
flaps.  Instead of slowing up you accelerate.  This is because you
have just destroyed lift and are now trading energy from height to
speed.  Although like flaps they also increase drag - because they
decrease lift (the opposite of flaps) the net result is increased
speed.  You can compensate and hold the nose up with elevator but
with the spoilers deployed you will drop and you will accelerate.

As an aside I have seen several sailplanes come off a winch and
have their spoilers deploy and the pilot panic.  After a few gyrations
around the sky with the pilot yelling "I'm getting hit!" they pop back
down and he has a normal (tho shortened) flight.  The moral here is don't
just use weights to hold the spoilers closed.  Create a torque rod, or
install rubber bands, or put positive up and down linkage and make
darn sure you have complete freedom of movement.  A spoiler stuck up
can spoil your whole day.

Remember the observation of increased speed is based on my Sagitta.
I am anxious to here other observations.

P.S.  Proportional is the type of control you want.  That way you can
      milk it into the right glide path for spot landings and also
      when you get caught in a boomer you can just ease a little spoiler
      in to maintain altitude and keep the thermal.

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

    Kay,
    
    The spoilers on my Sagitta 600 are the most powerful and have the
    most dramatic effect of any ship I have ever flown or seen.  If
    you can use the spoilers on the Sagitta 600, I think you can use
    the spoilers on any other design!  It took a while to get used to
    them, but I really got to like them.  The most controllable and
    easiest to use are the Schempp-Hirth scissor type spoilers manufactured
    by Graupner and Multiplex of West Germany.  They are available through
    Hobby Lobby(mail order) and are rather expensive($33-$40).  The
    only other drawback is they might not fit in thin airfoils.  They
    really work beautifully, providing what seems to be linear control
    of descent depending on how fully they are deployed.
    
    Regards,
    
    Jim
    

    Steve-
    
    Did you get one of Elliott's ships?  If so, I think you'll be in for a
    treat.  How about a review when you get it tested...
    
                             |                      
   \	       	         ____|____                      /   Regards,
    \________________________O_________________________/    Frank.
    

    RE. .4 Frank
    
    	Yup, called Elliot yesterday and was sold after about 5 minutes.
    I can't wait to get my hands on it and will certainly give a review
    when I do.
    
    Steve

    I know this may start the religious wars... :-)
    
    What is the "standard" configuration of spoilers when they are on the
    throttle stick??  Should stick forward ==> deploy spoilers or retract
    spoilers??
    
    I think it should be set up so that the stick forward = deployed.  I
    say this because on a 7FGK, the "throttle" trim is only effective at
    stick back.   This would give me fine control over small amounts of
    deployment and "more coarse" control on full deployment...
    
    Comments??
    
    
    Also, the spoilers on the Drifter-II and Spirit use rubber bands to
    retract them...  But the spirit plans call for lead weight to close
    them.  Has anyone tried the weights??  How did the work?  I would think
    with an outside maneuver you run the risk of having them open on you...
    
    thanks!
    jeff
    

Hi Jeff, dont worry about spoilers comming open in flight.  Unless they are real
heavy, the presure from the air going over the surface will keep the spoilers
closed.  Again, I have stated other places.  For a spoiler the absolute best 
closing mechanism is go down to Radio Shack and buy 4 of their 16 cent round 
magnets.  Glue one of these to the bottom of your spoiler and the other one in
the spoiler bay, make it so when the spoiler is closed, the magnets either touch
or come close to each other.  It gives what none of the other ones will.  The
pull is strongest when the spoiler is closed and weakest when it is open.  All
others the more you open the spoiler the more resistence the more pull there
is trying to close it back.  So I found that sometimes you could not get the
spoiler open enough because their was excess tension on the spoiler from the
closing mechanism.  It works GREAT!!!!!

    Jeff,
    
    	I currently have the spoilers on the OLY II connected to the
    flap switch. This gives me two positions and auto elevator mix.
    I'm trying this as an experiment. Previously, I had the spoilers
    plugged into the throttle channel. Stick back was closed, and stick
    forward was open.
    
    	Some people have told me that's backwards. Forward throttle stick
    means "fast" which means spoilers down, and backward throttle stick
    means "slow" which means spoilers up.  My own feeling is WHO CARES!!!.
    What feels right to YOU. Either way don't amount to a hill of beans
    as long as YOU know which is which.
    
    	For what it's worth, I also use the rubber band closure mechanism.
    You can check everything out Saturday.
    
    Steve

    I would hesitate to use weights for closing the spoilers. Weight
    to a glider is a dirty word. Also, it's possible, during landing
    for the weight to have enough play to move around and break something.
    The magnets should work fine if that's the way you want to go and they
    weigh hardly anything.
    
    Steve

    Mark is absolutely right about using magnets on spoilers. No other
    system is as good overall on the flap type spoiler. 
    On the sissors type spoiler, Graupner, Multiplex,etc., the servo
    positively controls movement through the entire range, but investing
    $20-40 for spoilers on a $30-40 plane is debateable.
    
    Common practice is to have forward (up) stick deploy the spoilers.
    Just as forward stick is down on the elevator, then forward spoiler
    stick is open spoiler=plane goes down.
    
    Also, when using magnets on spoilers it helps to use kevlar pull
    cord, to avoid that slight amount of stretch in nylon cord, at the
    max tension point just before the spoilers pop open; and the kevlar
    cord, once tensioned properly, never changes with temperature.
    
    Terry

    My wife got some flat magnet ribbon that was light and sticky on one
    side for some Girl Scout projects. This stuff seems like it was made to
    stick onto spoilers 8^)

    I have push/pull on my SPIRIT spoilers and it works great.
    I used the smallest (I think) golden rods (something like 3/32)
    tube with steel flexible cable. The trick was how to mount a
    a 2 piece wing (which made it even harder) spoiler cable(s) at the
    field. So what I did was installed a brace (1/4 x 3/8 balsa) accross
    the cockpit just in front (torwards rear of plane) of the servo's
    then I put two notches in the brace. Then I found some plastic
    servo nuts (came with airtronics servo tray). I drilled 4 of these
    out to the outside diameter of tubes. I slide the nuts onto the cables.
    Hook everything up to the servo (with a standard quick connect gadget
    on the horn). Then I push the cable into the nothes in the brace and
    snug the nuts up to the brace. Then I C/A's the nuts onto (the sanded)
    tubing. Be careful not to C/A the whole thing in (pull the cable out
    of the notch before it really gets cured. The brace is flush with the
    bottom of the canopy and hold the cable in place. But they actually
    hold them selves it's such a snug fit. I would use hard wood for the
    brace if I where to do it again. No weigths, No magnets, No rubber
    bands and they close as tight as a drum.
    
                    Notch
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        Brace  -->|||  Plastic nut
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      o<Servo arm | |
    --o------     | |   |Fuse cockpit
    | O     |     | |   V
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    I saw a very experienced pilot get himself into a hell of a mess(his
    own fault- should've checked his repair properly) anyway he ended up
    with up elevator but no down and it was stalling all over the show,
    because of the continual stalling he lost full rudder authority, it
    looked like it was going to be a plastic bag job,but a bit of lateral
    thinking saved him and the answer SPOILERS opened them up nose droped
    end of stall rudder authority back, he was then able to make a nice
    decsent and land safely!!!
    This should be a lesson to us all, after any repair check all functions
    (he had replaced a rudder hinge and it was fouling the elavator crank
    inside the tail) but secondly if you get into trouble don't panic
    lateral thinking may help.... can another function help you? at the
    worst can you dump it somewhere soft??
    
    I was quite impressed to see what looked like a disaster (I'd have
    panic'd) turned around into a successful landing!!!
    
    Richard