Just took mine out for its maiden (after waiting impatiently for it to be delivered from the US). Damn was it squirrelly, bobbing about all over the place. Brought it down, added D/R and expo, didn't help at all, now it's in three pieces (counting the nose peice). Anyone had similar experience? Will some reflex sort it out?
The one thing hardly ever mentioned is how to properly set up a flying wing for optimum performance and stability. Just doing an Elevon mix and adding some reflex may help get it in the air but it could still be far from a pleasant experience.
After balancing the plane as per the instructions and implementing the mix there are a few further steps that will improve your flight experience. For a plank type flying wing the standard mix does not allow for the short coupled nature of the elevator function and so you either have a bird that maneuvers well in pitch and poorly in roll or good in roll and far too sensitive in pitch. If this is part of your problem then you will need to alter the standard elevon mix ration from 50:50 to something like 60:40 where the lower proportion is the elevator function.
Expo is recommended strongly with around 30% a good starting point though if a relative beginner then perhaps 40% may be a better starting point.
After setting up the mix ration you will need to fly the bird, (high enough for safety), and do a stall test by cutting the throttle and bringing the elevator input to maximum. If at stall the bird becomes directionally unstable and even drops a wing and dives then the CG is too tail heavy, whereas if the bird starts to drop its nose and then the nose suddenly rises only to fall and rise again in a rapid nodding fashion the bird is too nose heavy. Ideally the bird should settle into a flat and slow decent with full roll control maintained.
After fine tuning the balance point then you can adjust your reflex to obtain stable level flight. If it nose dives when you centre the controls you need more reflex and if it noses up or climbs you require to reduce the reflex . Do all adjustments finely. NO sudden and massive adjustments.
When you have finished fine tuning the set up you will find that you end up with a very nimble and stable bird which can really perform and yet is almost impossible to stall on landing.
IF you increase the weight of the bird, (fit larger batteries or add FPV gear) then you may need to adjust the reflex to compensate or it will tend to drop its nose or sink when you centre the controls in level flight. (More reflex means greater AoA and therefore greater lift).
I hope the brief outline of a decent setup helps in taming its performance for you!
Have fun!
