Leading Edge Cuff

Naah, it was directly on topic. Shedding 50 pounds would be one of the cheapest mods I could do, albeit one of the most difficult to 'install'. Thanks for reminding me.

" Putting Vg's on would re-energize the boundary layer and might keep it attached longer which would probably have worked. Note what Jerry Burr was saying about the Vg's attached close to his LE cuff and reattaching the airflow there"

They wll also trip the flow to turbulent if it is not already so. The advantage being that the trip is often to turbulent attached flow, rather than turbulent seperated flow. Generally, I'd rather have an early trip from laminar to turbulent attached flow than a later trip from laminar to turbulent seperated flow.
JimC

JimC

Weight

Hi Kid Cub. I couldn't agree with you more!! One year I lost 17 lbs to compete at Gulkana. I couldn't take any more off the airplane so I was next in line. At my last physical the Dr. told me to gain 3 or 4 lbs. Don't hear that too often. I run 30 to 45 miles per week. Keep up the running. Jerry.

Just wanted to add my .02 worth. I let Charly Center talk me in to putting leading edge cuffs on my 18 after I put it on its back following one of my "wish I would have looked over that landing area better" landings on a Montague Island beach.
This was 17 years and 2000 hours ago. I never could notice a difference other than it made it more difficult to put the wing covers on, due to the stall fences which are part of the mod. Maybe if you really fly your cub on the edge all the time you would notice a difference, but the way I fly I couldn't discern any.
As far as frost, I try to use covers and not fly with frost on the wings. The few times I have I couldn't tell much difference from the wing I had before the mod
Bottom line-- I wouldn't Put this mod on unless someone was holding a gun to my head!!

cuff

I'm with you on that point Rock. Most of the cub drivers in the North are using their cubs to get themselves and friends out to hunting and fishing spots. Many are trapping or spending weekends out at the cabin or camping/ skiing. In other words we aren't parking in the hangar every night like our more civilized brethren to the south. The got to have every lift or power mod. crowd don't have to deal with some of the practicality issues that we do in the North. Lightweight cubs are the way to go. I could care less about Gulkana and how many mods that you can put on your cub to get off the ground faster/shorter, some people seem to be obsessed with that whole scene. I don't like the way a cub flies with extended wings. In the forward CG range(180hp) the tail becomes less than effective at slow airspeeds. I'd rather land at minimum airspeed without having to carry a bunch of power.
> ksecub says we would all have 180hp. cubs if we could only afford them. Man are you clueless or what. I've yet to fly or see a lightweight 180hp.cub. It's an oxymoron. ksecub when you get that 1300lb(after you empty it) pig stuck in the snow by yourself out in the middle of nowhere, you might begin to understand what I'm talking about.

Jerry Reply

Jerry: This is a reply to your previous post, or should I say attack called "Pig Theory". Lets get one thing straight. I fly a late 70's Piper PA-18 Super Cub. You fly a modified 1930's J-3. They are apples and oranges as far as comparison. The "Gold Standard" I use to base my comments on is the factory 150 hp Piper PA-18 not your "one off", super modified J-3. This site is called "SuperCub.org" not "Modified J-3.org". Back to your comments:

1) The Atlee Dodge folding front seat adds ZERO weight.

2) I use Northland Mfg. 1/4" birch plywood floor boards, the same thickness and weight as Piper, only better quality and better looking.

3) I use .016 2024 T3 for my interior panels, Piper used .020 S.O. with a heavy tar based product sprayed on the back side for sound proofness. They are twice as heavy as mine.

4) I remove the vacuum system and all the heavy instruments, filter, regulator, hoses etc. that go with it.

5) I replace the starter, alternator, and oil cooler with all the light stuff.

6) I gut all the wiring and use basic electrical and breaker swithes in the panel.

7) All of the above removes about 45 lbs from the original PA-18.

8) Then I believe in adding some extra horse power to get the crate quickly moving so the wing will produce the required lift in the shortest distance possible.

9) I don't use my plane to impress the ladies with how short I can get off. I haul moose, gear and people in mine. When was the last time you hauled a moose plus 300 lbs of gear, 450 miles home in one trip?

I respect your knowledge on short take off, special use wings and if I needed a set I'd come to you. We use our planes for different purposes and live in different environments so we will never see eye to eye. I will leave it at that. Best wishes to you always. Crash

P.S. My post was just agreeing with Nooky from Nome, why didn't you get on his case, after all he was the one stirring up the big VG debate.

Wow Nanook I feel the love! This is a great country, everyone can express their opinions freely and everyone can disagree.

Nanook, I know you are a Husky lover so you might appreciate my new wing project. I am putting Husky flaps on my PA-18 wings. However I am extending the wing and adding droopy ailerons. I know, I am ruining another perfectly good set of Cub wings. I am a disgrace to Super Cubs.

Nanook, I think a stock cub is great, its just fun to experiment. I get tried of watching sitcoms at night. I need to do something to entertain myself.

Pig Theory.

Hi Crash. You want to get it straight. I want to get it right. My Cub is a 1947 J-3, and at one time it had a stock 150hp S.C. wing on it.
The (Pig) theory was from your post. And it was not intended to be an attack but a question. Which I still don't believe was answered. A couple of questions. How heavy is your Moose that you are hauling with 300lbs of gear? And what is your empty weight? Thanks Jerry.

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Moose

Moose weight: I wieghed one with about a 60" rack and it came in at 580 lbs. The rack is around 50lbs. Crash

History

Hi Nanook. Thanks for all of the interesting information about you Alaska Bush Pilots. Maybe you have forgotten that I was flying for Fish and Game on the chain in a Super Cub when I first heard about Gulkana. And yes the Super Cub had a Cuff and long wings. Jerry.

cuff

ksecub: Husky lover? I'm more partial to German hunting dogs, huskies are kinda dumb, they won't bring the bird back they just eat it. I hear you on the sitcoms, TV has gone down the tube.

> Jerry: and your point is? (besides being old like me.)
On the Chain? I'm sure you mean the AK. Pen. No one with a brain would fly a cub out the Chain.

Re: Moose

Crash said:

Moose weight: I wieghed one with about a 60" rack and it came in at 580 lbs. The rack is around 50lbs. Crash

Click to expand...

How do you lift a 580 pound anything into a supercub. Or is a "moose" a another local colloquialism term for a big woman and she actually climbs up into the plane herself?

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Moose

Diggler, you forgot the half rack of beer I took along to drink on my flight home.

It was no GW kit, just a mile long F-15 (abandon airbase) runway. I know a guy that flys gas out to is lodge. Get this... 2 Dodge tanks = 61 gallons, an old Sorsen 80 gallon belly tank and 30 gallons in fivers on the back seat. That is about 1,100 lbs plus plane and pilot. Takes him the entire Birchwood runway to get off.

Last fall I hauled two Caribou (300#), my 160lb son, our entire camp and gear plus about 40 gallons of gas out of Iliamna in the PA-14. It got off in about 400' with a 10mph wind coming down the runway. These Cubs will haul a load if you let them. Crash

Has anyone done any testing before and after install of the cuff to see what if any increase in AOA is achieved or if the power on stall speed is reduced. Perhaps Jerry can comment on this.

I am guilty as most of us in making multiple mods at once during rebuild and not being able to distinguish which mod generates the most effect. In a perfect world we would all make one mod at a time and evaluate the results before adding another, but this is not always practical.

I am getting ready to redo my experimental wings and I can't make up my mind on which leading edge device to put on if any. So far my choices are Wayne's slats, cuff, or nothing. I will put VGs on what ever I do. I have Waynes droopy ailerons and will be putting extended (110") Husky slotted flaps on the wing. The ailerons will be full length out to the squared tip. I also have Sullivan's tips. I welcome your comments and suggestions.

I was in Sioux Falls last weekend and flew a 160 hp PA18 with Dakota Cub Slots on a Square wing.. Flaps are 90 1/4 in and standard length aileron moved out to the tip. Took off and landed in 150 ft grass area with 375 lbs of people and 36 gal gas, 10 kts wind. I would pull full flaps before I thought it would fly and every time it popped off the ground and with the slot you can climb as steep as you want. Its the 3rd aircraft I have flown with the slot and every time they really impress me. I think Waynes slat would be the way to go for you ksecub.

Kase,

Thanks for the reply. With the slotted wing, did you feel like you had to fly at a higher angle of attack in order to fly slower? Everything I read about slots and slats indicate that the coefficient of lift does not increase until the angle of attack increases beyond that of the stall of the plain or flapped wing. This to me means that the takeoff distance will not be shortened unless you have some means of increasing you AOA by longer gear or other means. I have 3" extended gear and 31" BW with the zero thrust line mod and don't really want to reduce my over the nose visibility any more. As far as landing goes, I guess you can tip the nose way up and fly slower, but I question how short I will really be able to land over an obstacle like a river for example when touching down on a gravel bar. I had a Husky once and I think I could get it to land shorter than a cub if I really tipped the nose up and did not care were I touched down. I could always land a cub shorter when coming over an obstacle because I had visibility and I could hit my spot better with confidence.

I really want to put the slat on but this visibility issue really concerns me. I have thought about adding incidence to the airplane by changing the wing attach points on the spar. I can increase the incidence by a degree or so this way which should help a little. According to the books I have been reading, the sharp increase in lift is a result of delaying the stall by increasing the AOA by approximately 10-15 degrees. Do you think a person could get used to flying at these large deck angles and still be able to hit your spot accurately.

As I said before I really want to put the slat on, if nothing else to experiment. It looks like a blast to fly. I would be interested to hear what people thing about it in a real bush environment, not just as a show plane.

i think the fact that you get to fly slower means you land shorter and can get stopped much sooner. so its safer and even if you misjudge the spot some you still are stopped shorter. maybe. i think getting used to flying nose high is what it takes as you still can look to the side. taking off is another issue as you say as its harder to get the high angle for best efficiency. with the helio you arent totally flying nose high with the slats.
i like the idea of slots on a wing for slow flight, and am considering building up a set for something super cub like.

ksecub,
I dont know if I can really answer your question. You do need a higher AOA for the slot to work. This cub was on standard gear with 26 in tires. I was just coming in and doing a normal short field landing like I would in my cub. I felt like the longer flaps were making it take off and land short more so than the slot, because of the standard gear . I would like to fly that cub some more and then put on 3 in gear with 31 tires and try it.

I flew Dakota Cubs Pacer with the slotted wing and it has really tall gear. It comes off the ground way before you think it should, and thats with a 150 Lyc. It flys exactly like a super cub.

ksecub,
I looked pretty hard at Storch kits for awhile. Slats, high AOI, spectacular (reported) STOL performance, but really slow in cruise. Maybe the Storch specs can help you decide.
SB

FWIW, leading edge slots, as in Dakota Cub wings, do not, repeat not affect cruise speed. Slats may be a different story but the leading edge slots do not affect cruise.

Slot cub I was flying indicated 105 mph with a 8244 prop, unverified no gps.

Can you buy a slot kit to add to existing wings? Or do you have to buy a whole new wing from Dakota? How much does the kit cost if it exists?

Critical AOA

If your current stock wing goes away (stalls) at 18deg as most do. And you install a slot then the wing will fly at 18deg. You can push it to 19,20 or 21 deg, but you don't have to. My point is that the slot will still fly at the same AOA that the stock wing quits. And be a long ways from critical AOA not on the edge as you are now, at 17 deg. Jerry.

It would seem to me that the angle would only be a consideration in ascention not descention. While descending, wouldn't you be forcing air through the slot making it venturi over the wing; thereby increasing the effectiveness of the airfoil. In ascention it seems to me you would have to open the face of the slot by increasing the angle for the venturi effect. I am not sure the word venturi is being used appropriately here. This is me thinking rather than related fact. I would appreciate an explanation of why it is wrong if it is. I hope I didn't waste my money on the darn thing.

Jerry, I like you logic!

I have been leaning toward the slats for some time now, but I do have some reservations as I have stated before. Perhaps my concerns will not be a problem, but I don't have any experience with them and I don't want to do the wrong thing. I have done mods in the past that have not worked as well as hoped and I am just trying to minimize the possibility of doing something that I will regret later. With that said, the only real negative other than extra cost, work, and weight is DRAG. I have got slightly conflicting reports from people who have Wayne's slats. I have been told that it slows the cruise speed down from 3-7 MPH. If it is only 3 MPH then it's a no brainer, but if it is 7 MPH, it makes you think a little. Perhaps you can shed some light onto the cruise speed penalty Jerry. I have a 180 cub with a very flat 90"propeller so I am not going very fast to start with and to loose more on the cruise end would hurt. I have to be honest, even if it is a 7 MPH penalty in cruise I will still probably put them on. I have the bug to try them out good, bad, or ugly. Jerry, how much do you thing Wayne's slats weigh installed? By the way, Wayne is a hell of a guy and a wealth of information. I am just wondering what everyone thinks about them.

I want to play too! The Cub I had was a 180 hp X-Wind Stol equipped Cub with drooped Tips and 3" ext gear 26" tires and saftey cables and 61 gal Dodge Tanks. Of course a bunch of airframe mods and a panel with way too much crap! Weight was 1204 lbs. Actual weight, not calculated. How many of you actually roll your cub on the scales for a real "come to Jesus" meeting? As for the x-wind kit, I liked it. Never flew a Cub with out it though. 180 hp I liked it. Only had 5 hours in a 160 hp Cub.
As for the load, I wish I could shoot my moose on the runway in King Salmon or Galena(Bishop), but mine came off small lakes and little ridge tops. Here is the kicker, "keep 'em lite" people my weigh 50lb less in the hanger, but on that ridge top or lake we both weigh 1750lbs or 2000lbs (or in Crashs case 2300lb + ! ) Sooo.... I have 20 or 30 more ponies and a bigger wing to move the same load. Who do you really think wins? I know I know - the better pilot! But given "equal" pilots, my cub wins. Wish I hadn't sold it!

I do ackowledge I would have liked VGs and a stock wing does look better. Also it is easier to put wing covers on a stock wing, but I would rather have my performance in the air, not in the wing cover phase of the trip.

venturi effect on descent.

HI Groundloop. Next time you want to descend, pull the power back but keep the nose on the horizon. I don't know how to push more air through the slot that than that. Jerry.

Slat speed

Hi Ksecub. If you are cruising in third gear in your car and come to a hill you usually slow down a little pulling the hill. If you are cruising in second gear you don't notice the hill, because the engine already has the advantage. Same could be said with the flat prop and slat. Most of Waynes Slat Cubs have had different engines and wing combinations. Your speed will depend on that combo and how you choose to fly it. I have never heard of one that was 7 mph slower than stock. I don't know what the new mounting system weighs. But if you don't want them on for a particular flight, they can be removed in about 3 minutes. Jerry.