I mentioned this in another thread but I wanted to explore this particular idea further. I like simplifying control systems as much as possible and have been thinking about elevons in a three-axis tandem design. Here's a quick sketch.
The idea would be to use a control mixer to apply pitch and roll inputs with the front wing elevons only (shown in yellow). They are tapered to increase the incidence of the root more than the tip as they go down and so induce a safe, root-first stall progression in which the tips would remain unstalled to provide roll control and the stalled root would then allow the nose to drop and recover unstalled flight. The elevon taper could be increased and/or stall strips and/or vortex generators used to tweak the behavior as needed.
The optional trim flap on the rear wing (show in green) would probably not be needed in the simplest application, but if the elevons were to be used as flaperons, the trim flap could also be lowered to compensate thereby increasing lift and eliminating any significant fuselage nose-up change with lowered flaperons.
Feedback welcome!
The idea would be to use a control mixer to apply pitch and roll inputs with the front wing elevons only (shown in yellow). They are tapered to increase the incidence of the root more than the tip as they go down and so induce a safe, root-first stall progression in which the tips would remain unstalled to provide roll control and the stalled root would then allow the nose to drop and recover unstalled flight. The elevon taper could be increased and/or stall strips and/or vortex generators used to tweak the behavior as needed.
The optional trim flap on the rear wing (show in green) would probably not be needed in the simplest application, but if the elevons were to be used as flaperons, the trim flap could also be lowered to compensate thereby increasing lift and eliminating any significant fuselage nose-up change with lowered flaperons.
Feedback welcome!
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