Sport ailerons

[fastj22]

I have only had a very brief turn on the controls of a Sonex with the larger ailerons but my main impression was that they felt very heavy. With the standard ailerons the control balance feels pretty good at low speed, but at higher speeds the ailerons become fairly heavy whereas the elevator seems to become more sensitive, a difference which I think would be exacerbated by the larger ailerons.

Peter

At normal/pattern speeds, the aileron stick loads are very similar. At full throw aerobatic movements, the sport ailerons are much heavier, but give you a great roll rate. Often, when I do aerobatics, I find myself grabbing the stick with both hands if doing an aggressive roll. Its logarithmic, the farther you throw the control, the more force it will take. But for normal flying, its not even noticable.

[daleandee]

Ok, I've got to ask you barn door flappers. If you only had 20 degrees of flaps available, could you land your aircraft safely?

As Curly Howard would say: https://www.youtube.com/watch?v=g5j8Jioan1w

I took my nine year old grandson for his first flight today. I was quite hazy & bumpy but he really seemed to enjoy it ... more than I did. I landed with 20º flaps. I have practiced landings with all flap settings and even no flap landings. Not an issue as the difference is a bit higher approach speed and a flatter approach angle without flaps. Good stuff to practice.

I also made a clean take-off (zero flaps) and like them much better. I'll sometimes use 10º if I'm trying to get up and gone in a hurry but with my grandson and 14 gallons of fuel we were off and climbing in 500' or less. I don't fly aerobatics so I don't have a need for the big ailerons ... so I'm glad I have the barn doors to hang out when I need them.

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
170.5 hours / Status - Flying
Member # 109 - Florida Sonex Association
Latest video: https://www.youtube.com/watch?v=1VP7UYEqQ-g

[avee8r]

I built my Sonex with the Aerobatic Ailerons. The technical data supplied by Sonex says the stall speed is 42 vs. 40 for the standard aileron / flap combination. During flight test, my plane stalled right at 42, very predictably. I use full flaps for landings and they do a great job.

I also happen to like the balanced look of the shorter flaps with longer ailerons.

Happy Landings
John
N50NX

[daleandee]

I built my Sonex with the Aerobatic Ailerons. The technical data supplied by Sonex says the stall speed is 42 vs. 40 for the standard aileron / flap combination. During flight test, my plane stalled right at 42, very predictably. I use full flaps for landings and they do a great job.

I also happen to like the balanced look of the shorter flaps with longer ailerons.

No one has mentioned it but it crossed my mind that the longer ailerons, by design, would cause more adverse yaw as there is more drag being made by the larger surfaces moving. This would no doubt be more noticeable at lower speeds. I've never flown the longer ailerons so I have no experience to frame this with. The air frame doesn't have much if any adverse yaw with the shorter ailerons so if there is an increase it may not be very noticeable.

As far as the look of the aircraft ... I noted in another post that I prefer the look of the Legacy model A over the model B. I also prefer the look of the barn door flaps ... especially when they are deployed fully on final as they work well! My stall speeds are a bit higher with the increased gross weight of 1250 lbs. I recorded Vs @ 48 & Vs0 @ 45. Full flap three point touch down (wheel chirp) happens at 37 IAS as seen in this video:

https://www.youtube.com/watch?v=WjA7JDJVKeQ

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
170.5 hours / Status - Flying
Member # 109 - Florida Sonex Association
Latest video: https://www.youtube.com/watch?v=1VP7UYEqQ-g

[lutorm]

it crossed my mind that the longer ailerons, by design, would cause more adverse yaw as there is more drag being made by the larger surfaces moving.

I'm not so sure. For a given roll rate, the longer ailerons also need to deflect less, so it's a matter of the lift/drag at the two different deflections. My guess would be that the airfoil with lower angle of attack, ie the one with less deflection, would operate at a better lift/drag point.

[daleandee]

I'm not so sure. For a given roll rate, the longer ailerons also need to deflect less, so it's a matter of the lift/drag at the two different deflections. My guess would be that the airfoil with lower angle of attack, ie the one with less deflection, would operate at a better lift/drag point.

I'm not an engineer & couldn't afford a night at Holiday Inn but what you're saying makes sense to me. I was just thinking that the further inboard the ailerons come the larger the surface to increase drag. But as I mentioned earlier the adverse yaw in the design is not a concern ... in fact there's a lot to like about it.

Dale
N319WF

[peter anson]

OK, this is only a guess, but I think the reason that the Sonex doesn't exhibit much adverse yaw is because when an aileron goes up, the gap on the underside of the wing widens causing extra drag, matching the drag of the down-going aileron. If that is correct, longer ailerons shouldn't produce any extra adverse yaw. It has also occurred to me that fitting a trim strip to fill that gap on the lower wing, as was discussed in several other threads, might drastically change the handling characteristics of the aircraft by increasing adverse yaw.

So, it looks like the owners with the short ailerons are happy with them and the owners with the longer ailerons are happy with them, so do what you like.

Peter
352 hours of happy flying with short ailerons!

[Rynoth]

Adverse yaw... that's what the rudder pedals are for!

[Bryan Cotton]

If you have never flown a Grob G103, you don't really know what adverse yaw is! I used to turn it with the rudders and use a little aileron to coordinate it.

[sonex1374]

OK, this is only a guess, but I think the reason that the Sonex doesn't exhibit much adverse yaw is because when an aileron goes up, the gap on the underside of the wing widens causing extra drag, matching the drag of the down-going aileron. If that is correct, longer ailerons shouldn't produce any extra adverse yaw. It has also occurred to me that fitting a trim strip to fill that gap on the lower wing, as was discussed in several other threads, might drastically change the handling characteristics of the aircraft by increasing adverse yaw.

Peter,

You are correct that the shape of the hinge line is largely responsible for the canceling of adverse yaw. The NACA did a study on different hinge designs, and the shape used by Sonex (hinge on one side with a triangular opening on the other) was tested along with many other styles. It turns out that the effect is very similar to a frise aileron, and has the added benefit of being easy to manufacture and very strong (sound like standard Sonex qualities?). I've had the same discussion with others about covering the hinge gaps. I'd expect the feel of the surface to change somewhat if gap seals were installed, but the changes would only really be noticeable at larger control deflections.

Jeff