aileron length

[andrewchapman]

Hi everyone,

Just thinking about whether to use full or partial length ailerons on my next model (aerobatic park flyer).

I was thinking that putting them just on the tips would have the most affect on roll performance, but I'd also like to have a server per aileron to allow for flap mixing. But in that case you're increasing the lift on the tips which would cause tip stalls wouldn't it?

Any suggestions?

AC.

[me11owman]

I'd go with full length....
but that's just my $.02 worht

Jim

[andrewchapman]

Yeah, I've always gone full length before, but that's because I've always used a single aileron servo.

This time I've got one in each wing so all the options are open.

Thanks Jim.

[Gary Warner]

There is no steadfast rule on this, but I've found the keeping the ailerons to 2/3 the span per side works well. It's the 1/3 of the inner span that produces excess drag for the amount of rolling forces seen.

That's my 2cents...

On second thought... the prop blast that is near the fuselage on a conventional plane would be able to increase the rolling forces much more than just clean air. Need to ponder more... if I can find a few million brain cells to spare.

[Ollie]

Like most design decisions the best arrangement depends on the purpose of the model. In level flight, the outer portions of the ailerons do most of the work rolling the model because they have the most leverage. In a slow vertical climb or hover the aileron segment in the propwash is virtually the only thing that controls roll. So, if you want to be able to do slow vertical maneuvers, extend ailerons to the wing root or couple ailerons to "staberons."

[Dereck]

Andrew
Being inclined to think simplicity is much easier to keep working and usually lighter, my recent designs have used a wing section and structure that 'ends' at the aileron LE for the full span.

The fuselage's wing aperture matches this shape. The ailerons are just the rest of the wing section, top hinged to the main wing TE, and go from tip to just short of the fuselage. I always use two servos nowadays, as that's much easier than messing with torque rods and other such inventions of the devil ;) While the ideal servo location is at at the aileron mid-span, it seems to work well enough putting them just outside of the fuselage and driving the ailerons near their roots.

Everyone loved torque rods for years - and they drove the inboard ends of the aileron by a twist-able piece of wire, so I don't lose sleep, or need extension cables, over root mounted servos.

Two small units of internet currency's worth - infinity invaluable at the price :)

Regards

Dereck