Reflex, Camber and Crow

[jetsmell]

After over twenty years, I've decided to get back into RC airplanes. The first two planes will be the Radion Pro and the Airfield Cessna 182. Both planes have flaps. Can someone explain what Reflex, Camber and Crow mean? I have seen very brief desciptions, but what are they used for? Thanks

[Leadchucker]

Mostly sailplane oriented but much applies to other aircraft as well:
Relfex: Upward trim of the flaps or ailerons used in small amounts can increase speed of a sailplane for covering distance looking for lift or for getting out of brick lifter thermals. In larger amounts it can act much the same a spoilers although the effect is more from creating drag rather that dumping lift off the wing. The winch launch pilots sometimes use it to increase speed on the winch line for zoom at top of pull. Some pylon racers use aileron reflex to act as speed brakes slowing down the plane for landing.

Camber: Downward trim of flaps or ailerons to increase lift of the airfoil. Mostly this is the function of flaps, in small amounts such as 5* it can be used while thermaling to increase lift and slow down aircraft to take advantage of the thermal lift. Small amounts can be used on launching either winch planes or e-powered if the pilot feels the need. In large amounts such as 35* it can be used to slow down aircraft for landing control by adding drag somewhat in the effect of air brakes. Camber in the form of flaps are used on other aircraft as well to provide additional lift for take offs and for landing.

Crow or butterfly: Mixing of two control surfaces on the wing in opposite directions. Commonly it's setup with upward aileron trim and downward flaps which increases drag greatly. It could be used again to jump out of strong thermals and also for landing control.

All three require retrimming of the elevator surfaces by thumb/stick or by TX mixed trim to maintain attitude of aircraft on the pitch axis as desired. Reflex trim on ailerons should be added in small steps as too much could possibly result in loss of roll control due to restriction of aileron movement.

[jetsmell]

Very good explanation,thanks

[AEAJR]

I suggest you join one of the BIG Radiant Pro threads.

[jetsmell]

Good idea, thanks

[AEAJR]

BTW in reference to Reflex, camber and crow, the use of these mixes and the convenience of using them is dependent on your radio to a large degree.

I have reflex and thermal camber on switches so they go to preset positions at the flip of a switch. I have removed crow from most of my planes as I don't find I need it for thermal duration landings. So I use a simple flap to elevator mix for landing and I control that from a variable control, usually the left stick, but that is on pure gliders rather than electric gliders.