Snap rolls - too big...
 

Please apologize for the newbie question, but I need some help trimming an used Eclipse I bought a couple of months ago as my first real world F3A plane. The model is equipped with an OS 140RX, push-pull controls with the rud and elev driven by Hitec digitals and Futaba 9102s with the ailerons. My biggest problem with the plane is the snap roll. They look really wide and kind of flown through instead of a quick snap. I added a flight condition activated by 95% up and 95% down increasing the rudder and elevator travel and slightly decreasing the aileron travel. Should I add more aileron? More elev? More rudd? All?

Thanks in advance

RE: Snap rolls - too big...
 

Go through the trimming chart first, make sure that your CG is in the right position. Too far forward may provide a challenge when snapping.

RE: Snap rolls - too big...
 

Have you checked the C.G.? You may find moving it forward slightly will speed up snaps. Also, you may want to check your battery pack voltage under load. If it's dropping voltage too much, you may not be getting full control surface deflection in flight.

RE: Snap rolls - too big...
 

I use the ele stick to activate the snap condition. Increase ail and ele throws, but decrease rud. As for percantage, depends on your plane.

Adrian

RE: Snap rolls - too big...
 

Do what Adrian said. I increase my ailerons by about 35%, elevator by 30% and reduce rudder by 25%.

RE: Snap rolls - too big...
 

Always more aileron.
The others are much more model-dependent---on wing size and shape especially,and on weight, and flight sp
eed on snap entry.

A good test for how much elevator is a power-off vertical down single snap(pos. or neg) on the centre line---watch for how much the nose is offline at the end of one rotation--in a positive snap this will be with the nose pitched up if there's too much elevator. And vice-versa in a negative snap.
Entry speed comes into this as well---check the effect at different points on the downline(and thus different entry speeds).

Play with different rudder throws to minimise how much yaw shows up at the completion of one rotation---this is very model-dependant---some will need more, some less----and in multiple snaps with part-complete numbers(like the 1 1/2 snap in PO7) there will always be some bodily sideways jump---so practice these so that you snap in the direction that makes it harder for the judges to detect!