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Spoilerons ?

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Protech Racing

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Jul 10, 2020
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I did the search . Has anyone used up only spoilerons for the only roll control? Maybe added to some dihedral?
Also... I want to mount mine at 25% , front spar firm. I cant see why it wont work. Ugly maybe but should work fine IMHO.
I want this plane to be light enough for 22 HP and adding enough structure along the TE seems like a waste if the main spar will work.
One reason for the spoilers is that I flew a Banty and it had so much counter yaw that we gave it away.
 

Victor Bravo

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Spoilerons are perfectly usable, but have limitations. They will be less powerful in zero-G flight. This may not seem important for a non-aerobatic airplane, but in reality it means you might have less control during a gusty landing, or be unable to turn away from a hill or mountain when you really need to.

Spoilerons coupled with regular ailerons was used very successfully in the Helio and other aircraft.
 

Dana

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I believe the MU-2 has spoilerons... and is one of the few specific airplanes with special training requirements mandated by a special federal air regulation.

Early Quicksilvers had spoilerons, too, but they weren't terribly effective, with all the dihedral they had the rudder was a much more powerful roll control.
 

BoKu

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Unless you have long swept wings they are hateful things that lead to poor control feel and counterintuitive control response at the times you most need positivity and effectiveness.

Your choices are pretty much:
* Make spoilerons, be disappointed, and then re-jigger most of the wing for ailerons.
* Make ailerons, be happy.

Choose wisely.
 

Chilton

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Unless you have long swept wings they are hateful things that lead to poor control feel and counterintuitive control response at the times you most need positivity and effectiveness.

Your choices are pretty much:
* Make spoilerons, be disappointed, and then re-jigger most of the wing for ailerons.
* Make ailerons, be happy.

Choose wisely.
The Cessna 208 Caravan uses spoilers to increase roll control, not instead of ailerons, the handling is ok there, at least no worse than any other Cessna single engine.

The reason for fitting the spoilers on the Caravan was to improve low speed roll response as the ailerons became ineffective even at landing speeds, so the spoilers give that control back.

The issue onthe MU2 basically comes down to pilots trying to fly it like a Senecca and with an engine failed they want to apply roll towards the failed engine. With aileron control this improves single engine performance, but with spoilers emerging it will clearly worsen the situation.
 

BrianW

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Jul 2, 2018
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Altus SW Oklahoma
First design that came to mind was the Wright Flier 1 (1903).
Lest we forget: the wing trailing edge that warped down, rolled & yawed down.
Gossamer Condor rediscovered the same effect. (1976).

Brian W
 

Bille Floyd

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Sep 26, 2019
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Unless you have long swept wings they are hateful things that lead to poor control feel and counterintuitive control response
...
They work Great on my Exxtacy, and Atos gliders ; but both
are Long, and swept flying wings, so that's probably why they
work ?

Bille
 

TFF

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Spoilers with ailerons help the top surface equal the drag of the opposite down aileron. If sized perfect no adverse yaw. Differential aileron throw can do the same thing. Move the up aileron more than the down. Spoilers only is a take on no down aileron, no drag. The issues are adverse yaw and control linkage. Each design needs something different.
 

Protech Racing

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I have a few reasons to consider these. As an Ultralight, It needs to stay light. I dont want to stiffen the TE enough for big ailerons.
I will have folding wings, these wont be in the way.
The adverse yaw factor is gone.
Mounted on the spar at 25%, allows no more structure while possibly keeping the spoilers in clean air.
I could simply increase the dihedral and leave them off.
This maybe a 2.5 axis control plane :)
Thanks for your help,MM
 

pictsidhe

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Providing hinge points for the ailerons should not be a difficult job. Ultralights have slow roll control anyway. Subtracting from that with spoilerons does not seem a good idea.

No offence, but if you are going to stray from established design, your aero and structural theory and ability needs to be excellent. From the questions you are asking, you really, really, should be building to plans.
 

Tiger Tim

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There are cases where roll spoilers work quite well but there are a couple areas I’d watch out for:

-a dead spot in roll when the stick is near centre. My gut feeling is that the dead spot is measuring the depth of the boundary layer over the wing.
-less control when the wing is unloaded and the possibility of having some bank angle that it’s just not rolling back from (see Fairchild AFB B-52)
-a history of UL designs that had roll spoilers initially but evolved to having ailerons. It would be worth researching why they made the changes they did to see if the drawbacks they experienced will apply to your design.

There’s some good stuff that comes with roll spoilers too, like the ability to run full-span flaps. Also, the MU-2 maintains full roll authority right down to and even beyond the stall. It’s kinda neat to have idle power on, nose high, coming down like an elevator but still being able to steer around normally.
 

Protech Racing

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FWIW I always consult known good values. I have designed many model planes( and sold kits) and utilized lots of innovations in many areas of engineering.
Airplanes; gurney flaps, Tip plates , VGs , forward sweep , etc.
I will always stress test anything that holds my ass off of the ground .
Cars, FWD racing, I steer them from the back . works . go faster .. etc. Ihave some of the fastest OVAL track, SCCA, Chumpcar etc. FWD cars using my setups. FWDracingguide .

My prior full scale UL was tweaked as I did not like the pitch moment value. of the normal Flea. The wings are too close . The Center of lift of the front wing is very close to the CG . Seems to work OK but bothered me.

I increased it spreading the wings and moving the pitch away from the CG. Much safer , easy to fly . Lovely airplane . The tandem wing small airplane is my favorite . Have e to be careful with the front wing changing lift values tho .
Thus the Simple flyer/Demoiselle .
I cant remember building from plans. I have bought complete combat models from Uryvenko. Beautiful craft.

The spoilerons I want to use will be 4 ft by 10in on a 12 ft wing .
I was was going to mount them flush. But thinking about the wash behind , I will mount them about 3 in above the wing, allowing a slot and air flow behind the tipped up spoiler . I can't find any other aircraft doing this. Maybe because its gunna be ugly
I know that they will be ugly, sitting on the front spar but should fly much better than the TE mounted/partially hid Spoilers.

Spoiler alert!! Also !! I have to keep them inboard enough not to induce an early tip stall. Dont need that.
AS I type this I realize that they have transformed into front mounted ailerons . Passing air on both sides.
 
Last edited:

flywheel1935

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Nov 1, 2018
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Downham Market, Norfolk, UK.
Just short of 40 years ago I was selling 'Hummer' Ultralights here in the UK, The early 2 axis butterfly tail things, anyway they flew dreadfully. I was a pen pal of Francis Rogallo, the Hang Glider inventor, and he recommended Spoiler/Spoilerons that he had fitted to a J3 Cub, and they were fantastic at low speed roll control, and transformed the Hummer to a proper 3-Axis aircraft.
 

Sockmonkey

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Flint, Mi, USA
They work Great on my Exxtacy, and Atos gliders ; but both
are Long, and swept flying wings, so that's probably why they
work ?

Bille
AFAIK flying wings are one place where spoiler only roll control can work because when mounted sufficiently outboard their drag gives you proverse yaw. You still need a separate pitch control surface of course. I'm more an idea guy than engineer, so take this with salt.
 
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