Improved aileron control at low speed. Discussion/solutions?

[skywagon8a]

This thread on wing cover has migrated to wing twist and aileron control. http://www.supercub.org/forum/showthread.php?52436-Wing-recover&p=696288#post696288 So, let's start a new discussion here. I'm not suggesting that I have the solutions, only ideas.

Facts:
A Cub has equal aileron travel, 20 degrees +/- 2 up and down.
When a portion of a wing stalls that portion is no longer under control of the pilot. If that portion is the outboard section of the wing, even though the wing is still supporting the airplane, the pilot is only going along for the ride.
Down aileron produces more drag than up aileron. (Seaplane pilots use this feature while sailing backwards)
When a Cub is banked into a turn the down aileron holds back (more drag) the high wing requiring the use of opposite rudder to maintain a coordinated turn.
Down aileron increases the angle of attack of that portion of the wing. Thus increasing the stall speed of that section.
Most airplane manufacturers use differential aileron control. (more up travel than down)

Modifications:
During the late 1960s Jim Robertson designed his STOL kit for Cessnas which consisted of drooping ailerons and a drooped cuff on the wing leading edge.
Cessna during the early 1970s added a drooped cuff to their wings which improved the low speed performance and handling.
During the 1980s and early 90s Cal Center produced a leading edge drooped cuff mod for many different airplanes. This mod was very popular for low speed improved performance.
More recently there have been several STCs issued for the use of VGs (vortex generators) to improve performance. These are currently very popular. Caveat: An approved set of VGs were installed on a local PA-18 on EDO amphibs of which I was familiar. I flew this plane before and after and could not detect any difference in the performance or handling. Label me: "Unimpressed".

Solutions?:
Change the aileron system in a Cub to increase the up travel and reduce the down travel. This would necessitate a major alteration of which I have not been able to figure out a simple solution.
Move the ailerons further outboard to the wing tips. This would require squaring off the tips.
Install VGs on the leading edge in front of the ailerons only.
Install a Cal Center type of cuff on the leading edge ahead of the ailerons only. Caution: Do not fly with only one side installed. Years ago there was a -18 which had a cuff on one wing and not the other which stalled on take off with fatal results. Someone was anxious to go out in the bush for some reason.
The VGs or cuff ahead of the aileron would help the airflow over the aileron thus reducing it's airflow separation and stall speed.

sj, If this should be posted elsewhere in another forum, please do so. Forum: Super Cub Sick Bay
ps sj, This post has disappeared and changed type size all on it's own. Has been most frustrating.

 

[mvivion]

Pete, have you flown the BLR (now owned by Cub Crafters) VG kit? It has a staggered installation of tthe VGs.

Second, take a look at a Husky. All the Huskys have more effective ailerons than Cubs. The "New Wing" Huskys have amazing roll control, with their redesigned and deeper chord ailerons.

MTV

 

[stewartb]

Use PA-12 wings.

 

[hotrod180]

....Install VGs on the leading edge in front of the ailerons only.
Install a Cal Center type of cuff on the leading edge ahead of the ailerons only.....
The VGs or cuff ahead of the aileron would help the airflow over the aileron thus reducing it's airflow separation and stall speed....

Along this line, both the Swift and the Stinson 108 have slotted leading edges but only on the outboard (aileron) section of the wing.
Seen a lot of Swift slots covered over, I assume for speed increase.
Not so the Stinson.

 

[hotrod180]

......More recently there have been several STCs issued for the use of VGs (vortex generators) to improve performance. These are currently very popular. Caveat: An approved set of VGs were installed on a local PA-18 on EDO amphibs of which I was familiar. I flew this plane before and after and could not detect any difference in the performance or handling. Label me: "Unimpressed".....

I installed a set of Micro VG's on a C150/150TD several years ago and had a similar experience. Also unimpressed with them, at least on a stock Cessna wing.

 

[RaisedByWolves]

I notice a huge improvement with vg's. I think almost all my supercub time is with micro vg's and some with BLR. I had a stock 90hp supercub here and I was shocked when slow on final the aileron response was almost nothing. It is a bone stock cub.

I have flown the extended aileron with the drooping ailerons and I do not like it. I guess you could get used to it but you have no aileron control with the flaps extended at all.


Sent from my iPhone using Tapatalk

 

[mike mcs repair]

Change the aileron system in a Cub to increase the up travel and reduce the down travel. This would necessitate a major alteration of which I have not been able to figure out a simple solution...

simple, make a bell crank in wing by aileron(existing location of aileron cables/bell crank on aileron), and then have a single rod continue to aileron

 

[bob turner]

I am with Pete. I have 5000 hours in Cubs, mostly in the pattern or teaching/demonstrating flight at stall. I can detect no significant difference from stock to Micro to BLR. The early "Center" wing will lose aileron control in the stall, but a stock Cub will retain control.

I loved the Stinson ailerons. The day I sold our Dash 3, I aileron-rolled it. Faster than my Decathlon with spades!

A Super Cub can be improved for shorter landings. Just re-adjust the flaps back to 50 degrees, and add the tolerance. Or get the new slotted flaps! Or slotted wings and slotted flaps!

 

[cubdriver2]

I notice a huge improvement with vg's. I think almost all my supercub time is with micro vg's and some with BLR. I had a stock 90hp supercub here and I was shocked when slow on final the aileron response was almost nothing. It is a bone stock cub.

I have flown the extended aileron with the drooping ailerons and I do not like it. I guess you could get used to it but you have no aileron control with the flaps extended at all.


Sent from my iPhone using Tapatalk

I can dance down the runway from one tire to the other at about 25 mph with aileron only, or carry a slip to touchdown. No Vgs.

Glenn

 

[SteveE]

I can dance down the runway from one tire to the other at about 25 mph with aileron only, or carry a slip to touchdown. No Vgs.

Glenn

Ya, and sometimes on purpose.


Sent from my iPhone using Tapatalk Pro

 

[RaisedByWolves]

I can dance down the runway from one tire to the other at about 25 mph with aileron only, or carry a slip to touchdown. No Vgs.

Glenn

Someday I hope I'm half the pilot you are.


Sent from my iPhone using Tapatalk

 

[Speedo]

Pete, you pose an interesting question, and it makes me think about adverse yaw. When you're slow aren't you typically nose high, and doesn't one typically need to use lots of rudder to counteract adverse yaw? I wonder, if someone wants more aileron for more roll, don't they also want more rudder? Maybe they don't even need more aileron - maybe they need to use their rudder more. It's been my observation that when pilots get slow and want to turn that they use the aileron but very often forget the rudder (and I'm quite guilty of this myself), so my thought would be to confirm that the person wanting more aileron first ensures that he's using the rudder.

 

[mike mcs repair]

Pete, you pose an interesting question, and it makes me think about adverse yaw. When you're slow aren't you typically nose high, and doesn't one typically need to use lots of rudder to counteract adverse yaw? I wonder, if someone wants more aileron for more roll, don't they also want more rudder? Maybe they don't even need more aileron - maybe they need to use their rudder more. It's been my observation that when pilots get slow and want to turn that they use the aileron but very often forget the rudder (and I'm quite guilty of this myself), so my thought would be to confirm that the person wanting more aileron first ensures that he's using the rudder.

sounds like the pacer/tripacer setup... interconnected

 

[skywagon8a]

Pete, have you flown the BLR (now owned by Cub Crafters) VG kit? It has a staggered installation of tthe VGs.

Second, take a look at a Husky. All the Huskys have more effective ailerons than Cubs. The "New Wing" Huskys have amazing roll control, with their redesigned and deeper chord ailerons.
MTV

Mike, The Micro Vortex VGs were installed on that Cub, wings and under the tail. That was the only VG modified airplane which I've flown. I have not flown the new Husky. It is interesting that they too do not have differential ailerons, 15.5 +/-2* up and down. Does the new Husky use spades? If so this could be a reason for the increased effectiveness.

Along this line, both the Swift and the Stinson 108 have slotted leading edges but only on the outboard (aileron) section of the wing.
Seen a lot of Swift slots covered over, I assume for speed increase.
Not so the Stinson.

The Swift slot closure was indeed for a speed increase. I'm not certain exactly what the original purpose of the slot was. I do know that the Swift originally had spin issues and the slots may have been installed for recovery purposes. Also at the time when the slot closure was approved, the CAA (or maybe the FAA) was more lax than they are today. Also a tapered wing stalls from the tip inboard so the slots could be for enhanced aileron control. Perhaps the ailerons were also used to assist in spin recovery?

simple, make a bell crank in wing by aileron(existing location of aileron cables/bell crank on aileron), and then have a single rod continue to aileron

Yes mike, that would be one method.

...I have flown the extended aileron with the drooping ailerons and I do not like it. I guess you could get used to it but you have no aileron control with the flaps extended at all.

Tom, The above -18 also has the drooping ailerons. The droop is tied in with the flaps. When the ailerons are drooped the neutral location is moved down, thus limiting the up travel while increasing the down travel. Since it is the up travel which has more authority over the down travel for roll control, it is expected that when ailerons are drooped their roll authority is also reduced. This is not good in a plane which has barely enough authority to begin with.

 

[skywagon8a]

sounds like the pacer/tripacer setup... interconnected

That was a nuisance at times when there was a little turbulence. A wing would drop so you'd pick it up with a little aileron. The interconnect spring would pull the rudder yawing the airplane. The two coupled together will set up an oscillation making for an uncomfortable ride. It is interesting that the interconnect system was not installed in the Colt making it a more comfortable ride for a short coupled airplane.

 

[BC12D-4-85]

Didn't/doesn't the Husky and new CC (X-Cub?) employ ailerons with increased radius leading edges that rise above and below the upper and lower wing plane? Supposed to make them more effective?

I mentioned before extending the flap gap seals out over the ailerons as an experiment. Sorta' like Maule's wing design. Was a good mod at the time. Did it before adding VG's. VG's...work good on my Taylorcraft but not so much for me on the Cubs I had.

Gary

 

[C130jake]

The new Cubcrafters ailerons on the EX2/FX/EX3 are very light and responsive compared to my first gen EX. The trailing edge well and aileron shape/pivot changed to make a big difference.


Sent from my iPad using SuperCub.Org

 

[Steve Pierce]

I installed VGs on a 90 hp Super Cub that I was very intimate with before the installation. First flight I noticed the increase in aileron responce at slow speeds. Did the same thing with an A1A Husky. Every Super Cub I have flown flies different. Flew a Carbon Cub today after the owner tightened up the aileron cables. Totally different on the ailerons and roll control was very heavy after he tightened them. My point being there are lots of variables between Super Cubs.

The X Cub and new Carbon Cub has really nice, responsive ailerons. Lighter and more responsive than I am use to. I have been thinking they might be a nice STC'd modification for the Super Cub.





I think most of us have gotten use to the Super Cub as a rudder airplane. Making a river run last weekend and coming around a tight corner with a want to be pilot on the controls with me he noticed how much rudder it took to make those turns. I guess it has just become the norm for me.

 

[mike mcs repair]

..
I mentioned before extending the flap gap seals out over the ailerons as an experiment. Sorta' like Maule's wing design.
Gary

done that, kinda fun at top aileron cable, if you do do that make sure wing is on plane or sitting on saw horses with proper twist, and horses located at root, and at strut attach, or they will bow if saw horse is at tip

 

[mvivion]

Pete,

the new wing Husky has differential ailerons, and they are aerodynamically boosted. No spades. The old Huskys had spades and simple ailerons. The new wing has a much deeper chord aileron than the old, and a bit less span. Dramatic improvement in roll. And the old wing Husky had really quick ailerons, far better than a cub, but with spades.

MTV

 

[skywagon8a]

View attachment 32818

This picture says a lot aerodynamically. The portion ahead of the hinge being below the bottom of the wing rib deflects the air, accelerating it over the lower aileron surface producing down lift. This being equivalent to increasing up travel. Perhaps a fairing could be placed on the Cub aileron mimicking this shape? That would be an easy modification.

 

[skywagon8a]

Pete,

the new wing Husky has differential ailerons, and they are aerodynamically boosted. No spades. The old Huskys had spades and simple ailerons. The new wing has a much deeper chord aileron than the old, and a bit less span. Dramatic improvement in roll. And the old wing Husky had really quick ailerons, far better than a cub, but with spades.

MTV

Mike,
This is the latest TC for the Husky. Is this the model to which you are referring? Notice that the ailerons have equal travel up and down.
TYPE CERTIFICATE DATA SHEET NO. A22NM
V - Model A-1C-200, 2PCLM (Normal Category), Approved September 24, 2007
Control Surface Movements:
Elevator UP 29° ± 1° DOWN 15° ± 1°
Ailerons UP 15.5° ± 2° DOWN 15.5° ± 2°
Rudder LEFT 25° ± 2° RIGHT 25° ± 2°
Flaps UP 0° DOWN 30° + 0°, -2°

 

[BC12D-4-85]

I looked at an A-1C Husky today. Rounded extended LE to the aileron that extends into airflow when deflected. Normal opening between LE and rear of wing not sealed tight. Similar to the CC pics above I guess but front of aileron more pointed.

Do we want more down lift on an up-deflected aileron, or more drag like the PA-12's shaped ailerons create? Both?

Crosswinds' STOL kit used to seal the ailerons and flaps with untreated covering fabric. Cal, Gordon Mandell, or ? had a hand in that STC. I flew it one winter on a PA-18 that belonged to my trapping partner. Did good and was easy to control slow. Felt solid all the way through the stall series. Only issue was snow melting and refreezing above the fabric so that had to be dealt with.

Gary

 

[mvivion]

Mike,
This is the latest TC for the Husky. Is this the model to which you are referring? Notice that the ailerons have equal travel up and down.
TYPE CERTIFICATE DATA SHEET NO. A22NM
V - Model A-1C-200, 2PCLM (Normal Category), Approved September 24, 2007
Control Surface Movements:
Elevator UP 29° ± 1° DOWN 15° ± 1°
Ailerons UP 15.5° ± 2° DOWN 15.5° ± 2°
Rudder LEFT 25° ± 2° RIGHT 25° ± 2°
Flaps UP 0° DOWN 30° + 0°, -2°

Yes, Pete, my bad. As Gary noted, they are aerodynamically boosted, not differential.

in any case, they work effortlessly, and are incredibly powerful. And, differential or not, they don't require anywhere near the rudder to coordinate. Normal turns you can get away with feet on floor, or close. The difference between these and the earlier iteration, which were great themselves, is nothing short of remarkable.

It would be fun to roll one, simulated., of course.

MTV

 

[BC12D-4-85]

Stick VG's on the forward bottom of the ailerons (consistent with cove clearance at down deflection) for more down lift? If down lift is what's best when the aileron is deflected upwards.

Or stick them top and bottom (consistent with cove clearance when deflected both ways) and test to maybe simulate an increase in the leading edge radius.

Edit: Some tuft testing of the aileron's air flow behavior as observed by a video cam would be interesting. Especially how much flow gets diverted through the cove gap at various deflections, and how well surface flow remains attached to the aileron. At low airspeed/high AOA I think the main front to rear surface flow would be under the aileron and disturbed/detached/or even reversed above (?). If so then the drag of the down aileron would have to be offset by similar drag from the other...like a PA-12 and others with a projecting bottom lip into the wind or differential deflection as noted earlier.

Gary

 

[hotrod180]

FWIW my 53 C180 has differential ailerons, up 20 & down 15 per the TCDS.
So more drag on the wing you're turning into,
to reduce (not eliminate) adverse yaw.

 

[BC12D-4-85]

done that, kinda fun at top aileron cable, if you do do that make sure wing is on plane or sitting on saw horses with proper twist, and horses located at root, and at strut attach, or they will bow if saw horse is at tip

I was pleased with the results and had no issues with control. But then rudders are my friend and first responder.

Gary

 

[stewartb]

SQ-12 ailerons are dramatically different from standard Cub and they seem to work pretty well. Deep chord replaces width and allows for monster flaps. That's state of the art for slow flying Cub wings in my mind.

https://youtu.be/QFllgHbjnlU

 

[stewartb]

PS, re: aileron drag for sailing a floatplane. Look at surface area and relative wind in a resting AOA.

 

[fobjob]

Bear in mind that on high-lift airfoils , the top surface air flow mostly separates before it reaches the ailerons, so the air flow below the aileron is considerably higher energy than the airflow above it. That's why my aileron effectiveness improved dramatically when I added VGs to the wing....the airflow stuck to the top surface longer, and more energy reached the ailerons. Frise ailerons have pointy leading edges ahead of the hinge that stick down below the wing to add drag and to re-direct high energy air to the top surface of the aileron to be deflected. I think the best aileron system would be deep chord narrower span Frise surfaces combined with spoiler ailerons located at the top of the wing curvature.

You also need to decide whether to extend the slow speed of the wing to the absolute maximum, or to retain roll control deep into the stall.....compromises....