oviedoed

A general question looking for a general answer.
Any ideas as to cause and cure for a plane to "snap-out" when pulling a inside loop?

GrnBrt

My Feedback: (5)

To much elevator. tone the throws down a bit and see what happens.

dalolyn

My Feedback: (7)

hate when that happens. bigger loops the plane pitches to fast so the wing loses lift and stalls

michpittsman

My Feedback: (11)

That is one wing tip stalling before the other. Check for equal washout:both tips should be slightly twisted up at the trailing edge. How much is not as important as both being equal. 1/4" should do it.

DBCherry

My Feedback: (4)

While unequal washout is a possibility, it is MUCH more likely that too much elevator is the culprit. You're essentially causing a high speed stall with too much "up".

As has been said, reduce elevator throw and the problem will go away.
Dennis-

Flypaper 2

Another reason is one wing being heavier than the other. Try balancing it laterally.

dalolyn

My Feedback: (7)

might not be the case, he did say "snap out" when one wing is heavier the plane would roll slightly

Tall Paul

c.g. aft and/or too much elevator.

cap10b

Had an RC test pilot, who flew allot of OTHER PEOPLES expensive planes, tell us this.

We were triming a friends new 84" Laser 200 18lbs with a 3.2 (50 cc ) gas engine.

1. Fly straight and level 1/2 - 1/3 throttle pull full elevator to do a loop if the plane snaps out keep dialing down the elevator until
a loop can be done.

2. Once that is accomplished turn on your VTR rate or expo rate and work the elevator until you have a ratio that will let you pull a loop
and not loose the plane to a snap and still have enough elevator to three point the landing.

This method takes a while to get done and you need a computer radio to accomplish it. Aft CG helps on the three point and keeping the whole airplane light also helps. Using a large flat blade prop helps too on down wind breaking. Its a combination of radio, CG, motor and flying skill (what level you fly at) that determines how complicated you want to get.

Hope that helps

JDS

cappio777

My Feedback: (2)

Start doing outside loops instead!

Azcat59

Tail heavy, too much elevator, high wing loading, sharp leading edges, all can cause this. Cut the elevator throw down (or try using less than full stick on your loops and see if it gets better), and if that doesn't solve the problem, add a little nose weight.

Hope you get it solved, it can be very annoying and can cost an airplane if it happens at a bad time and altitude.

Clair

oviedoed

Thanks to all for the info. All good advice. Side to side bal. is OK, throws are not to much I don't think. I am going to move the c/g forward a little more and try. Thanks again!!![8D]

Wine Country Flyer

My Feedback: (5)

You may not think the throws (elevator) are too much, but I'll bet that LESS of it will stop the snaps. I've seen it fixed at my field more than once. As the throw is lessened, the snap is less violent. The manufactures recomended amount is just that, recomended. Every plane is a little different. Try the first suggestion--it'll work--you'll like it. Happy flying.

greenboot

My Feedback: (1)

Less elevator is definitely the solution. There is no need to reconfigure the plane however, just don't pull back as far. If you are trying to make a big loop, you will need lots of speed and don't rush it. If you are trying to make a small loop, you must slow down to a crawl and gently ease it around.

If you yank it, it will snap. An aerobatic plane is supposed to be that way.

Tom