ETLB Squawk Forums — Archive

Has anyone on here seen or used half span aileron similar to legal eagle?

Why?

Minimize adverse yaw and save weight

Im no aeronotical engineer and the max is a proven design but to me with full span ailerons moving the same amount creates more drag in some spots on the wing than it would lift adding to adverse yaw. Say like pulling flaps on the rising wing every time you bank essentially. One could argue that the opposite aileron deflects the same amount and offsets the adverse yaw however that wing recieves reflex which decreases drag. Not increases it. Further adding to the same issue. Ive never flown one but im guessing the minimax suffers adverse yaw more than normal and probably requires a lot of rudder input to counteract.

That and i could finish my wings faster! and have a lighter aeroplane! Or could split the aileron and actually have a functional flap. Tho that is a bit way over kill im sure and heavier and adds to my build time... no thanks!

You don't mention rudder input? Cessna drivers don't tend to use rudder but we taildragger sky-gods know better  

Im no aeronotical engineer and the max is a proven design but to me with full span ailerons moving the same amount creates more drag in some spots on the wing than it would lift adding to adverse yaw. Say like pulling flaps on the rising wing every time you bank essentially. One could argue that the opposite aileron deflects the same amount and offsets the adverse yaw however that wing recieves reflex which decreases drag. Not increases it. Further adding to the same issue. Ive never flown one but im guessing the minimax suffers adverse yaw more than normal and probably requires a lot of rudder input to counteract.

That and i could finish my wings faster! and have a lighter aeroplane! Or could split the aileron and actually have a functional flap. Tho that is a bit way over kill im sure and heavier and adds to my build time... no thanks!

Dont know why i re posted. But fair enough internet. You win per usual.

I did just briefly there at the end. Haha. (Not much in my log book and 0 tail wheel for the record... cant find someone close) Still... more efficient banking and less rudder required could only be a good thing? And also less weight? Tho the push pull cable would need to run out a strut and be longer which wouldnt be so good... just curious if anyone has or what any input may be!

I know a man that works on challenger aircraft and he cut his ailerons down and made the rest into flaps. He said it much improved roll rate and gained flaps for shorter and slower landings.

Per plans, the MiniMAX has differential ailerons so the UP and DOWN ailerons don't move equal amounts. DOWN aileron moves less than the UP aileron. That lessens adverse yaw.

Re-designing a MiniMAX to use partial span ailerons would take a significant amount of re-design of the control mechanism. As it is, the MiniMAX controls are very simple and don't have many moving parts.

Want to fly something with a LOT of adverse yaw? Find a Kitfox II. The aileron differential is opposite of what it SHOULD be. At least it was on the one a friend and I bought. Move the stick to one side and all it did without rudder is lean over and slip.

Lynn

I built my second minimax with half span ailerons and loved it. Harmony in the controls was much better.  I used a 1 1/4 inch aluminum tube that went from the  inboard aileron rib to the root rib with a horn on it so that all controls were exactly the same,  minus half the aileron.

Quoted from lowflyer ... he cut his ailerons down and made the rest into flaps. He said it much improved roll rate and gained flaps for shorter and slower landings.

Disregarding control stick forces, why does going from full span to ~half span increase the roll rate?

The full span ailerons are driven from their inboard ends. They do twist a bit under flight loads when the wings are at a high angle of attack and loaded. For example in a steep turn and going a bit slower than would be wise. Then the twist produces washout - hope that's the right term. Whatever, that twist will reduce the tendency for the wing tips to stall because they are at an 'overall' lower angle of attack. So a stall, if it happens, will begin more inboard of the wings. That makes a nasty wing drop less likely than if one of the tips stalled first.

Does that theory hold water? If so, making them shorter and stiffer removes that advantage.

Adverse yaw just ceases to be any problem when wearing a Minimax if you always automatically apply a proportion of rudder input at the same time as roll input. Not perfect, but guaranteed wipe out any problem with adverse yaw.

Adverse yaw completely dissappears when you add some finesse to your automatical rudder input, and that finesse comes very quickly with practise.

FFS! they are just SO easy to fly, incredibly responsive and FRIENDLY - as designed!

The rectangular wing stalls root-first without washout.  The Maxes only used full-span flaperons in order to claim a 2.0 CL for calculating the stall speed to satisfy Part 103.