Badlands STOL cuff a bad idea?

[thaefeli]

Has anybody installed this cuff with good results?
I met a guy on the RCV ramp last evening that is flying a well used Carbon Cub.
I had told him that I had put the cuff on my yet to be covered Javron 4S wings. He told me to be very careful. He had installed it and it ruined the airfoil. He said that the stall speed went up, and when it broke, it broke hard to one side.
Said he knows of four other Cub drivers that had the same experience.
Has anyone installed the Badlands cuff with positive results?
Tom

 

[skywagon8a]

Piper's airfoil is very good with a benign stall characteristics. What are you expecting from this modification which will improve the aerodynamic characteristics of your current airfoil? If this mod is not placed exactly identical on each wing, there is no telling what the characteristics will be. I have seen adverse stall characteristics of a wing with just a different color paint stripe placed in a certain position on the airfoil. Meaning the abrupt edge of the paint stripe caused a stall. Also on the same type of airplane where the radius of the leading edge was slightly different between each wing, there has been in some cases dangerous stall characteristics. I suggest, unless you are very knowledgeable on airfoil characteristics, leave it alone. Don't just throw mods on your plane because someone says they are good.

 

[BC12D-4-85]

Are you sure it was the named product the "guy" had installed, and not another that's available?

Gary

 

[akwing]

there's not a cuff on the market that will produce positive results

 

[KevinJ]

Guess I’d talk to Larry Vetterman and get his take before and after installing the badlands cuff on his javron(?). Looked pretty promising. Centers cuff seems to add more weight than function but I’m just a dumb Texican!

 

[thaefeli]

The YT video that Larry put out was what sold me. He speaks very highly of his cuff.
I spent an hour yesterday looking at comments here about the Center X-wind cuff. As usual, there were positive comments and quite a few "put it on, then took it off" comments.
Yet Jerry Burr speaks very highly of the X wind cuff. coupled with VG's.
That is why I am looking for real world experience with the Badlands cuff.
I have the one negative personal review, and he relates 4 others that have had bad experiences.

 

[Steve Pierce]

It is not Larry's cuff, it is Cliff's. I would be suspect if it fell off on one wing and increased stall speed that it was installed correctly. Knowing Larry I don't see him blowing smoke, Clint either.

 

[courierguy]

A highly respected 5000 hour+ pilot and multiple builder in the RANS S-7 arena, who, like myself, has been flying the 7 for decades and knows it well, who won the STOL event in his class at Pinedale WY last year, swears by it. What I still want to do, and it never occured to me on our 3 hr flight back from Three Forks MT. the other day, is to slow fly with him/see who can fly the slowest. Another 7 multiple thousand hour in type pilot, Hal Stockman, also says " it flies faster, and lands slower." So, at least for the 7 I'd say it's a proven idea, and I'd have one on my 7 already if I wasn't so busy flying and working. Plus, I don't care for the idea of moving my VG's, and having another leading edge wrap over the one already there, I have given serious thought (but too busy...) to building a new wing, hanging the old ones on the walls as spares, with the cuff built in, along with some other mods.

 

[BC12D-4-85]

One thing I'd be testing for with full span LE cuff is behavior when it stalls. Seems simple enough to suggest, but might take some flights at various CG's to fully explore. And that's assuming there's adequate elevator authority to achieve a stall at forward CG.

If and maybe when the wing's LE quits flying, there's not much left to defy gravity. That's why some aircraft builders prefer to install a partial LE cuff outboard with a sharp step between the cuff and standard LE. The wing tip with cuff keeps on flying, while the inboard without stalls. The step between creates a vortex that delays the outboard spread of the inboard's disturbed air flow. The break is moderated and spin resistance improved. Cirrus and Icon aircraft for example. Not news.

Varying the LE droop via physical or aerodynamic washout or shape form to increase it further outboard might help prevent the whole wing from suddenly loosing lift. Something to discover after modifying.

Gary

 

[DENNY]

Lots of factors to consider. First is the base aircraft condition. Was it a good flying aircraft to begin with? Trying to fix a problem aircraft with a cuff is not the answer. Was the washout the same on both wings or changed to correct for a bent/not correct fuselage? Was it installed correctly or was a more better trick tried? Did they even try to adjust washout after the edge was added (why/ because it is flying slower and now issues are more pronounced)? So lets say perfect airplane perfect installation and perfect washout after testing with cuff. If you have enough tail authority which is not hard if properly trimmed as Gary noted the wing will stall!! So did the pilot/pilots have the skill level to understand what was happening and why? Did they have an indicator airspeed sensitive enough to note a 2 mph change at 38mph? Unless you spend you day flying within 1-4 mph of your stall speed you only get 5 seconds maybe on every landing to really notice the change. Did they adjust trim or power to adapt to the increased lift the wing provided? Some things like a Borer prop/Bushwheels/better shocks are night and day difference other mods take a bit of time for the pilot to adjust his/her flying to get the best results out of the mods. It took me 3 years to figure out the conditions that the gap seal in the tail helped and it was not when I was landing.
DENNY

 

[BC12D-4-85]

Many of us have failed to test flight before (especially) and after mods. I'm very guilty of that....put it on and go gas'er to have fun. Sorta' like a test pilot, figure out how our plane behaves from WFO to stall. Control response, attitude, airspeeds, time for events, behavior, things like that. And keep a log book entry. Write down or record what's felt, seen, or even heard both then and after. A cam onboard can help with that later to review what the word outside the plane looked like when.....

It's common to note the after effects of mods, but were they really any different before the change?

Gary

 

[thaefeli]

I am not disparaging Larry or Clint. They both hold high regard from me.
I went to the Hot Springs fly in last year specifically to talk with Larry about it. I asked about Levi's (he is actually to one you talk to to order) cuff and Larry told me "It's my cuff, I developed it. Gave it to Levi to sell it."
The only issue is hearing from one guy that it did not work. He is a STOL demo/race guy. Maybe he is playing the "if a little droop is good, more is better" game? He told me of four others that had the same experience and removed the cuff.
I was hoping that some of those guys would chime in with their experiences.
Also hoping to hear from guys that had good experiences.
As Courier Guy alluded, the S7's that I know of have had good experiences. Yes, I know: different airfoil, wing, platform.
I will call Levi tomorrow and discuss.
Tom

 

[bob turner]

I am with Gary. Too many modifiers fail to do before and after testing. I am reminded of my buddy who hung a Sportsman on a good 180 (it had a factory cuff) and then immediately put Micros on it using the stock wing pattern.

I flew it before and after, and was never really comfortable when approaching at low air speeds after. It was never thoroughly tested once the mods started to appear.

I bet the Center wing was better with VGs. I personally did not care for the loss of aileron control at very low speeds.

 

[BC12D-4-85]

Do the cuff developers offer test data before and after change on a Cub? Site: https://www.titanaviationinc.com I did find videos and prior threads here. Maybe there's more somewhere? Just curious.

Gary

 

[courierguy]

To further confuse the issue, I just got my butt kicked in my stock S-7 (except for Micro VG's) by this much modified teed off looking S-7, both in take off and landing. It was my idea to set up a mini STOL event today, and he took off (4450' ASL, 80 degrees, gravel/grass) in 80'. One landing about the same, winds were light and partially buffered by hangars, not much help if any. He has hot wired cut styofoam cuffs, glued on, and covered wth Monocoat. The wing thingies are a new innovation, they are not baggage pods, he is still playing around with their AOA, but they are specifically for STOL comps, making it a sesquaplane I guess. From what I saw today, he is going to win again at Pinedale. A stock Rotax, other than the exhaust system, the French E prop is adjusted for....6000 static RPM, way over what they recommend and his cruise r's are also quite high as a result, even for a Rotax!. We did three runs and his results were all similar, and all better than mine by a large margin. Though he made his own cuffs, I believe he modeled them after Clint's, both in shape and placement. He also has full ribs, clear out to the fences, which I don't.

 

[skywagon8a]

What airfoil is on that S-7?

 

[courierguy]

Who knows. not me! It looks kinda T-Craft like, to this former T flier. If there is a formal designation for it, I've never heard it. Typical experimental, all we care about is how it works. RANS has been using it for decades now, with good results.

 

[KevinJ]

Ole skinny prop is a mile long!

 

[BC12D-4-85]

If correct from here: https://m-selig.ae.illinois.edu/ads/aircraft.htm

RANS S-7 Courier NACA 2412. Same as Cessna, similar to Taylorcraft 23012, but "the NACA 2412 airfoil uses a 2% camber (first digit) 40% (second digit) along the chord of a 0012 symmetrical airfoil having a thickness 12% (digits 3 and 4) of the chord."

Gary

 

[Super11XP]

Lots of interesting comments here, myself or Larry would be happy to field questions about installation and performance changes that we noticed.


My understanding of the carbon cub is that the foam blocks were installed too high. Although the blocks pretty much “key in” to the rib, there is some subjectivity in where they can be placed. This is also the case with the sportsman stol kit on the Cessnas. I suspect that more than a few Cessnas have needed the eccentrics tweaked after a stol kit being installed, but I could be wrong.

Ive heard of, and flown cubs that were out of rig that had a real wing drop, no matter how coordinated you were in a stall. Adding a cuff changes the airfoil. If there’s any asymmetry in how they go on, rerigging will be a must.

 

[tempdoug]

i guess a question would be, when you were trying things did you find a spot for the foam blocks? rotating them up or down that worked the best? or noticed the best results? each plane might vary some?

 

[BC12D-4-85]

Just speculating but I'd consider setting the tip blocks at at slightly lower AOA on the LE than inboard. Try to delay the stall from the aileron section. An upper wing fence or lower vortilon (search for them, they are different) might also help contain the upper disturbed air.

Gary

 

[DENNY]

Just speculating but I'd consider setting the tip blocks at at slightly lower AOA on the LE than inboard. Try to delay the stall from the aileron section. An upper wing fence or lower vortilon (search for them, they are different) might also help contain the upper disturbed air.

Gary

The problem of trying to lower AOA on the LE inboard is now are inducing wing washout from both the cuff and the rear strut. Trying to get the balance correct between the two wings could be an issue. But on that same line of thought would it be best to pull the wings and install on saw horses to insure both the wings had the same twist (washout) set into them from the start. You should be able to do it on the plane with a smart level but something to think about.
DENNY

 

[BC12D-4-85]

Lower AOA LE outboard over aileron section was my thought only if wing is flat. But yes if washout is desired (it need not be for some aircraft) there's no need for the blocks to be asymmetric. But, if tuft and performance evaluation indicates undesirable behavior at the stall, then a "vortex block" or fence can help retain it inboard some. "Some" being determined via testing and ideally documented with tuft images. Put a cam on the upper tail or over the wing at the root looking outboard like from seaplane lift tabs (?).

Gary