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Performance STOL flap testing

I've been thinking the same thing....It's probably a dangerous habit, but fun.

Seems like it would be effective with an airfoil shaped stabilizer and the proper curve leading into the elevator.

But I get hung up on making it effective in two directions.

I believe Doug Keller produced an airfoil stabilizer in an attempt to solve a tail buffet some early flap customers were experiencing. I don’t know whatever became of the stabilizers or the buffet. I haven’t heard anything about that for a few years.

And with a quick search? Here you go. Read post #16 in particular.
http://www.supercub.org/forum/showthread.php?51746-Modified-horizontal-stabilizer
 
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I have gotten a little stick shake when slow on one of the 3 sets I have installed so far. Not as much as I have felt on the Dakota wing with the long flap. Not a big deal but you just feel it a little. The installation instructions say 50.5 degrees +/- 4 degrees. The bottom of the wing is somewhat concave so it is a bit subjective. I use a long straight edge between the leading edge and false spar and zero my digital level on that. I have been getting between 55 and 60 degrees but then when you put a simulated wind load on the flap you get within the spec. The last one I did I was flying the approach at 38 IAS and 35 on the GPS without much wind At all and it was solid. I would really like to try on my Super Cub because I am pretty intimate with it but it is just not in my budget. One thing I did notice was when doing stalls and when it breaks you are way nose down staring at the ground. It breaks straight but it is a lot different than a stock flap in the stall. I just finished my third install with a fourth set waiting. I have tweaked the installation procedure and will post about the way I have been doing it with a lot of pictures when I get some time.








 
Greetings,

We have a CC/PA18-180. Half it's hours are spent on amphibs, the other half on skis or 35". The latter is driving the desire for these flaps, but the former drives this question....

Has anyone had trouble with an already nose heavy Cub, on amphibious floats, with these flaps? Neither Wip, nor Airframes, will attest to anything along these lines.

Thanks, and Merry Christmas!

First of all, is this a CC-18-180, or a PA-18, according to the airworthiness certificate? The difference being that these flaps aren’t approved on the CC-18-180, which was certificated by Cub Crafters, not by Piper.

Second, all amphibious float equipped airplanes tend to be forward CG, unless ballast has been added aft. Personally, I wouldn’t add permanent ballast aft.....”install” some survival gear back aft. Now your “ballast” at least may serve additional function.

The CC-18-180s I have flown were both heavy and forward CG, even on wheels.

MTV
 
Has anyone had trouble with an already nose heavy Cub, on amphibious floats, with these flaps? Neither Wip, nor Airframes, will attest to anything along these lines.

Thanks, and Merry Christmas!

What trouble would you anticipate? My Cub is nose heavy/forward CG. Even before I figured out that I needed to add aft weight to calm the plane in cruise? Slow flight with these flaps was a joy. Unless you get critically slow you'll have enough elevator authority to round out and you can always limit your flaps to less than full when on floats. I doubt you will, though. On a standard Supercub with standard wings I always figured the best place for PStol flaps would be on floats.
 
I've got a few hours on my flaps, and I like them. Mine went on during a major rebuild so I can't do a direct comparison, but the claimed 4-5 mph reduction feels about right. I've been getting some buffet while slow, probably from the flaps going all the way to the fuselage. Nothing major, just noticeable.

Now I'm playing around with different takeoff techniques. So far, I like accelerating three-point then popping the flaps without getting the tail up first. It just jumps off the ground. Thrustline seems to compliment these flaps well.
 
Did Airframes get the airfoil tail design with the flap purchase or did Doug hold on to that? I’m surprised there isn’t more chatter about it.
 
I think these flaps are great! I have the 8 1/2 ft Doug Keller flaps on my Experimental Cub with his airfoil tail. Zero buffet with full power-on stalls with 31 in. ABW, Micro VG's and extended wings. Touch down speeds on the GPS with no wind and light on the fuel at 5000 to 6000 ft. elevation has been around 27 MPH full stall landings around 40 degrees F. Bringing it in with a little bit of power on the approach to touch down. At full flaps they are about 80 degrees down and they blow back about 5 degrees in flight. Be cautious, when making these improvements to slow down our airplanes to make them fly slower, you also lose aileron and rudder effectiveness at slow speeds. It's a lot of fun to go out and fly these airplanes in a no wind conditions, but as the wind picks up I carry a little more speed for controllability. When a gust of wind hits you and drops a wing, you still have control.
 
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Be cautious, when making these improvement to slow down our airplanes to make them fly slower, you also lose aileron and rudder effectiveness at slow speeds. It's a lot of fun to go out and fly these airplanes in a no wind conditions, but as the wind picks up I carry a little more speed for controllability. When a gust of wind hits you and drops a wing, you still have control.

Good point, As with all mods that bring about better low speed performance, another set of issues are created. Spoiler boards have helped tremendously with the 35 mph and slower approaches on my mount. Also, not only are the performance dominoes activated when adding different mods, You also have a new set of piloting skills that are required!
The great thing about this mod, is even if you do not plan to lower your approach speeds, it’s still lowers the nose and it appears to be well worth it.
 
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1. It’s a CC/PA 18/150, built while they could under PMA.

2. We keep it legal with weight in tail. I have no doubt it would be legal CG wise. My concern is for the reduced angle of attack, and the toes digging in when landing on water.

35 years ago I flew a 235 Pacer. The empty legs were sporting on floats. Smallest sweet spot in my experience.
 

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You can pull the nose up, you still have full control it just flies slow flatter than stock flaps where you can 3 pt slower
than you can wheel land. Probably help your CG since the flaps weigh 12 lbs more than stock.
 
Most Cubs achieve their slowest flight by trimming nose up and maintaining a high AOA. Float guys give up most of that in lieu of a more useful attitude. Pstol flaps will give you slower speeds in a more useful attitude for float ops. The nose heaviness limitation is about ability to trim. I'd think these flaps will reduce that problem, not add to it.

Piper flaps on floats were not my fav after years in Cessnas. Pstol flaps would change that. I've dreamed a little about my exp Cub on floats. It would be big fun.
 
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Won't the angle of attack, that the wing stalls at, still be the same with the Keller's deployed? BUT, I'll bet, you are slower at and before that critical angle of attack, with the Keller's installed, so effectively you can come in at a much flatter angle and hopefully be slower than you were coming in, with stock flaps, at a high angle of attack? I bought those bad boys at the May "show" and they are now installing them as they are rebuilding my wings. Can't wait to try them out!
 
Won't the angle of attack, that the wing stalls at, still be the same with the Keller's deployed? BUT, I'll bet, you are slower at and before that critical angle of attack, with the Keller's installed, so effectively you can come in at a much flatter angle and hopefully be slower than you were coming in, with stock flaps, at a high angle of attack? I bought those bad boys at the May "show" and they are now installing them as they are rebuilding my wings. Can't wait to try them out!

No.

Changing the chamber of the wing (deploying flaps) changes its Cl/Cd curve, changes the wing’s performance. Different flaps affect wing performance differently.

Don’t confuse wing angle and fuselage angles here, that’s an easy mistake to make!
 
I have gotten a little stick shake when slow on one of the 3 sets I have installed so far. Not as much as I have felt on the Dakota wing with the long flap. Not a big deal but you just feel it a little. The installation instructions say 50.5 degrees +/- 4 degrees. The bottom of the wing is somewhat concave so it is a bit subjective. I use a long straight edge between the leading edge and false spar and zero my digital level on that. I have been getting between 55 and 60 degrees but then when you put a simulated wind load on the flap you get within the spec. The last one I did I was flying the approach at 38 IAS and 35 on the GPS without much wind At all and it was solid. I would really like to try on my Super Cub because I am pretty intimate with it but it is just not in my budget. One thing I did notice was when doing stalls and when it breaks you are way nose down staring at the ground. It breaks straight but it is a lot different than a stock flap in the stall. I just finished my third install with a fourth set waiting. I have tweaked the installation procedure and will post about the way I have been doing it with a lot of pictures when I get some time.









Do you, or anyone you know, have experience with these flaps on a 180HP Cub on amphibs?

I’ve pulled the trigger and bought the flaps, but still a bit leery


Sent from my iPhone using SuperCub.Org mobile app
 
No, the shake I experienced in one but not in the other 5 I have been involved with. It is not really a shake but a vibration. I am a dealer for these flaps and can offer some solutions to a few of the installation snafus that I have experienced in the installs I have done. Installed a set over the weekend for a guy from Califoria who bought his Super Cub new in 1977 and has flown it all over Mexico, Utah, Idaho and Canada. He had a grin from ear to ear after his first flight with them and then called me on his trip home to tell me how much he liked them. He said it was like flying helicopters on landing. Still trying to work them into my budget.
 
Not the flaps your talking bout , Or even a Cub, But does demonstrate the same tendency to shake the tail when the 3rd notch of flap is pulled which causes the stick shake. Can be minimized by applying a little power.


https://vimeo.com/338443318
 
Friend just installed them. I flew his cub. He asked me what I thought of them. Had no comparison. Hadn't flown a supercub since 1975.
 
Going through threads as I’m considering slats on my bow tip cub wing. Don’t know how I missed this thread. I have to ask, Cory, am I reading your original post correct?? Touch down speeds at 25mph across the ground with stock length Keller’s!!?? If so, I hate to be that guy, but I have a hard time with that 100% true. I have an 1115 lb 360 cub with increased incidence, as far up as I could go without chasing my tail elsewhere, inboard Keller’s, TL, VGs, little tweaks here and there and a pretty long/flat prop (creating a decent brake with power) that I have 500 ish hours in. A lot to learn, but feel I’m fairly intimate with it. And I can not come no where near 25mph (groundspeed)! What am I missing???? Speeds in the high 20’s are what guys with 100+” flaps, slats etc are seeing. That is with the nose to the sky. Fairly safe to say most stock flapped cubs (no Keller’s) doesn’t like flying much slower than 40 with no wind and still being able to land on the mains with much visibility. Your saying a 12+mph reduction?? With my mods above, which in all reality isn’t much or anything crazy, I have a hard time dragging the tailwheel on the ground while keeping the mains up much under 33-35, can go a tad slower but there’s ore power in. I guess I need to up to 300 hrs a year instead of 200
 
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Would just like to clarify that the flaps are most definitely an awesome investment and no downsides other than 12lb ish gain which is nothing compared to the pros. Don’t mean to be confusing for others when referring to them as Keller’s.
 
... If so, I hate to be that guy, but I have a hard time with that 100% true. I have an 1115 lb 360 cub with increased incidence, as far up as I could go without chasing my tail elsewhere, inboard Keller’s, TL, VGs, little tweaks here and there and a pretty long/flat prop (creating a decent brake with power) ........ I can not come no where near 25mph (groundspeed)! What am I missing???? Speeds in the high 20’s are what guys with 100+” flaps, slats etc are seeing. That is with the nose to the sky. Fairly safe to say most stock flapped cubs (no Keller’s) doesn’t like flying much slower than 40 with no wind and still being able to land on the mains with much visibility. Your saying a 12+mph reduction?? With my mods above, which in all reality isn’t much or anything crazy, I have a hard time dragging the tailwheel on the ground while keeping the mains up much under 33-35, can go a tad slower but there’s ore power in. I guess I need to up to 300 hrs a year instead of 200
What is your CG when you are checking these speeds? The description of your plane indicates that it is nose heavy unless you have ballast of some sort. Try loading it to a CG of 20", check your landing ground speed in no wind and report back here.
 
Composite prop, no flywheel etc. most definitely is not nose heavy. I was under the impression the whole thing about the flaps is too keep visibility and nose down while losing some speed.?? I am not buying a pretty much stock cub other than the flaps coming in with good visibility and plopping it on the mains at 25-28mph in no wind. I would like to see even a highly modified cub do that. At those speeds I would guess the landing distance is almost never over 100’??
 
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I installed Performance STOL Flaps on my Super Cub in July. My Cub is 1132 lbs, on 31s, Baby Bushwheel with 8241 prop, 3" Atlee gear, micro VGs and Thrustline mod. They slowed me down but I am not in the 20 on ground speed, in the 30s. When I bought my Cub 5 years ago it was pretty much stock with VGs. I have incrimentally made all the changes and the flaps were the biggest enhancement in my opinion. The airplane is noticably slower and conciderably shorter landings. The flat pitch is great as well as I am not a fan of dragging it in. 3of us with 160 hp Cubs and P STOL flaps got to play some last weekend and pushed the limits pretty good. To me all this stuff is like crack, I get use to the added performance and now I want more. Less weight and a better prop is net I guess.
 
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Any experience, anyone, with getting so caught up in the enhanced low speed/short landing improvements, that you have landed an off airport site, then realized you couldn't get back out?! I was thinking of that a couple days ago, circling a ridge side and eyeballing a site, , then seeing another nearby one that was even shorter and thinking "if I had slats.....", but I guess if it comes in slower and shorter, it'll get off shorter also, is that the "plan?" I guess the mature pilot takes all that into consideration, and that's exactly why I would worry about doing just that. Right now, I know if I can get in, I can get back out. Greatly shortening the landing length required without a commensurate decrease in the takeoff length required would get me into trouble. I still want some, slats and PSTOL flaps, like crack indeed. I'm at 31 mph right now touchdown speed.
 
I can get out of anywhere I can land. Took more getting use to the take-off technique with the P-STOL flaps than the landing.
 
That was a concern when I was flying the 135hp SC. At lower weights and density altitudes, a 150/160 should be able to get out of anywhere it can get in with clear approach and departure paths . Higher elevations change that.
 
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