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Cub wings

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Cub wings

I often hear people say how great it would be to bolt Cub wings onto (whatever aircraft) for backcountry flying. Maybe I am just getting old and grizzled now I am 30, but I wanted a separate thread to discuss it:

Are Cub wings really still revolutionary these days?
Would you want to bolt them onto a modern-day aircraft?
Sure they are good, but so are a lot of other wing designs...

Looking at a Cub, it seems to me the Cub has enormously long wings for its size, and it pays an unduly heavy airspeed penalty for it.
Cub:
Area 178.5 sq ft (16.58 m²)
Span 35 ft 2½ in (10.73 m)
Cruise 80-85kts Yes some will say 100... but you need 180hp and to flog it pretty hard (2500rpm)

By comparison, look at a couple of modern alternatives. The wings the SuperSTOL for instance - they are midget wings side by side with a Cub. It still performs like a Cub at similar weights in terms of STOL.
Super STOL:
Area 132 sq ft (12.3 m²)
Span 30 ft 1 in (9.17 m)
Cruise 87kts (again, optimistic from Wikipedia!) But remember that is with a fraction of the horsepower.

For a fairer comparison comparison to a longer winged Cub variation, with a modern aerofoil:
Patrol:
Area 180 sq ft (17 m²)
Span 33 ft (10 m)
Cruise 122kts

The Patrol wing area is larger than the Cub, except the Patrol will fly about 30% faster than a Cub at equal power settings - which is a LOT given drag increases with the square of velocity. And that for only a knot or two difference in stall speed (demonstrated with a stock wing).

I am not trying to start a contest here, just to demonstrate my point - there are clear competitors - what is it about the Cub's wings which makes them special in the eyes of many?

What say you?
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Re: Cub wings

I'm definitely not a high time Cub driver (a hundred or two hours in a J-3), but I believe that the reason for the religious loyalty that so many people have for that wing is that it is not only predictable at all times... but it is trusted to be very gentle when pushed to its limits. It's definitely not the most efficient or highest lift, but I believe that when put into the really harsh environment (aerodynamic) that some bush aircraft fly in, it allows the airplane to be flown right at its limits without any surprises.

The "real" bush guys here can correct me, but I remember hearing a story that a large government agency switched from the Super Cub to the Christen (Aviat) Husky because it was "better" in some way. But after a while they had people getting hurt because the Husky could not hang in there safely at the lowest speeds and tightest turns. And the Husky wing was VERY similar to the Cub, both flat bottom bigh lift wings. So apparently they went back to the Cubs. I'm sure s omeone here knows the details of that story.

Another important thing is that all the graphs and wind tunnel tests and NACA aerodynamic data and all the theory in the Abbott & Costello book do not factor in the real-world conditions of dirt, leading edge lumps and bugs,pinked edge tape, duct tape, mud splatter etc. that wind up on these wings. I suspect that this is one of the big things where Cub wing owners know that their wing is not sensitive or greatly affected by all this mud and moose poop. It is completely possible (likely actually) that you can hve a "book" airfoil that is twice as "good", twice the L/D, twice the lift, etc. and if you built identical Cubs with each of these wings the old crappy USA-35 would fly better and do more in real-world operations. There's a guy named Bill Montagne who found that out the hard way.
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Re: Cub wings

Years ago I happened to be in Del Rio TX
a lot when the Border Patrol was switching from Cubs to Huskys.
The "problems" were that the Huskys had been outfitted with full panels, stacks of radio's and were out of forward CG for
Non-government aircraft. The trim system on a Husky is only a bungee to help pull the stick back and the tail/elevator was stalling.
Wasn't a wing problem, if anything a elevator trim/ CG problem.
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Re: Cub wings

I never pushed Cubs, with students, as hard as Pawnees. But my spray mechanic said they had the same wing. MTV has explained that here somewhere. Anyway, the advantage of the heavily loaded Pawnee wing over the Callair (also flat on bottom, curved on top) or Cessna wing is that it shakes the airplane violently before stalling. Most airplanes mush some before stalling, but the big, thin Cessna wing can quit rather suddenly. I know nothing about the Husky.

The Pawnee also has a spring assist trim system to help hold up the weight of a full hopper. Even with this most forward CG loading, there is no danger of running out of up elevator. When fully loaded, however, it flies like a pig. For a small spray plane, it is the hardest on ones back of any I have flown.
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Re: Cub wings

I was taking care of a Border Patrol aircraft when they went from Cubs to Husky's... the big problem they were having was nose heaviness, and they were winding up on their back/nose from pilots wheeling them on, and getting on the very good brakes.... Our guy wound up with a 182, and really wasn't happy about it.
I'd say that the main reason that the "cub wings" is mentioned so often is partly what Bill says above, the Cub is very honest at the edges of the envelope, and a very capable aircraft. I agree there are better out there in many parameters.... but the Cub has that "legend status".... be that due to accomplishments or advertising.
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Re: Cub wings

You may know better than I but I don't think that their is an apples to apples comparison with the Patrol and Super cub meaning that the angle of incidence may be higher on the cub, etc. I think that the maule uses a cub airfoil and with the added power of a 180 to 200+ engine it flies as fast as a Bearhawk. The Patrol makes up for slow flight lift with those massive flaps, no? Also, Pacers, with some cleaned up of cooling drag, 180hp engine, etc. will cruise at 140+ mph with the shorter wing.

I like the comparison of a cub vs a taylorcraft with its 230 series airfoil. It is a good 15% faster airfoil. That series is also used on RVs. I've of late been considering a bearhawk or stretching a pacer to go experimental and have not decided yet. It does not seem though that the Bearhawk airfoil alone is a great advantage. Its more in the overall design and how the design features work together.

Maybe I'll stretch a pacer, put taylorcraft wings on, add huge flaps...oh to dream!
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Re: Cub wings

dplunkt wrote:
Maybe I'll stretch a pacer, put taylorcraft wings on, add huge flaps...oh to dream!



That'd be a winner IMHO. The T-craft wing with flaps would give you tremendous overall capability. As everyone knows there would be a small number of strips you could not get into because the Cub style wing has a tablespoon more lift in the very bottom of the bucket. But you could go to places where they could not go because of the lower drag, which provided more range (or a slightly lighter airplane because less fuel was required for the same distance), etc.
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Re: Cub wings

dplunkt wrote:You may know better than I but I don't think that their is an apples to apples comparison with the Patrol and Super cub meaning that the angle of incidence may be higher on the cub, etc. I think that the maule uses a cub airfoil and with the added power of a 180 to 200+ engine it flies as fast as a Bearhawk. The Patrol makes up for slow flight lift with those massive flaps, no? Also, Pacers, with some cleaned up of cooling drag, 180hp engine, etc. will cruise at 140+ mph with the shorter wing.


I think that's underlying an interesting question, whether people like the underlying aerofoil or actually the whole wing as-built.

For instance, the achieved aerofoil on a Maule, with a flush metal wing, will certainly be better than the fabric surface on a Cub. I didn't know they used the same aerofoil.

I would also say I find there's little difference between slow flying and stalling in the BH and the Cub, certainly a line call, both are very forgiving. Seeing as you've noted it uses a similar aerofoil, does a Maule have a similarly forgiving stall? It's been a long time since I've done stall practice in the M5...
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Re: Cub wings

Hi Battson,

Yea the cub uses a 35B while the Maule uses a 35B Mod. I'm not sure what the real difference is. I've heard but not experienced that a Maule has a mild stall like a cub. The Maule does extend and has bigger flaps plus the aileron design is modified so you can't guarantee similar stall performance.

I will say this too. I fly a tripacer, I've not done this but...If you reduce the dihedral and washout on a pacer you get a more severe staff with increased speed from the plane. Which is why its kind of tough to compare different airfoils on different planes as you are seeing. The Maule has different rigging I assume.
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Re: Cub wings

You can drastically adjust the stall characteristics on any of them by adjusting the ailerons 3/4 of and inch up or down, or even.
:shock:
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Re: Cub wings

X2

Don't you just love old model airplane builders =D>
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Re: Cub wings

dplunkt wrote:I will say this too. I fly a tripacer, I've not done this but...If you reduce the dihedral and washout on a pacer you get a more severe staff with increased speed from the plane. Which is why its kind of tough to compare different airfoils on different planes as you are seeing. The Maule has different rigging I assume.


Yeah that is an interesting one too.

I am flying the Bearhawk 4 place 99% of the time now, and I can't understand how with zero washout in the wings, constant aerofoil section, and only 1.5 degrees dihedral - how it can be so stable in a stall? You can literally fly it through 15 degree bank turns provided you stay in balance with rudder and aileron.

Adding VGs made the stall noticeable more pronounced, though still quite well balanced, but not as good as the stock wing.
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Re: Cub wings

EZFlap wrote:I'm definitely not a high time Cub driver (a hundred or two hours in a J-3), but I believe that the reason for the religious loyalty that so many people have for that wing is that it is not only predictable at all times... but it is trusted to be very gentle when pushed to its limits. It's definitely not the most efficient or highest lift, but I believe that when put into the really harsh environment (aerodynamic) that some bush aircraft fly in, it allows the airplane to be flown right at its limits without any surprises.

The "real" bush guys here can correct me, but I remember hearing a story that a large government agency switched from the Super Cub to the Christen (Aviat) Husky because it was "better" in some way. But after a while they had people getting hurt because the Husky could not hang in there safely at the lowest speeds and tightest turns. And the Husky wing was VERY similar to the Cub, both flat bottom bigh lift wings. So apparently they went back to the Cubs. I'm sure s omeone here knows the details of that story.

Another important thing is that all the graphs and wind tunnel tests and NACA aerodynamic data and all the theory in the Abbott & Costello book do not factor in the real-world conditions of dirt, leading edge lumps and bugs,pinked edge tape, duct tape, mud splatter etc. that wind up on these wings. I suspect that this is one of the big things where Cub wing owners know that their wing is not sensitive or greatly affected by all this mud and moose poop. It is completely possible (likely actually) that you can hve a "book" airfoil that is twice as "good", twice the L/D, twice the lift, etc. and if you built identical Cubs with each of these wings the old crappy USA-35 would fly better and do more in real-world operations. There's a guy named Bill Montagne who found that out the hard way.


Here we go again with the old "I've never flown one, but I heard a story....." BS, pure and simple. You heard wrong.

The Husky wing is pretty close to the Cub wing, both in airfoil and planform. That airplane has no ugly stall characteristics that I've ever been able to discern....and that's based on over 3500 hours of working the airplanes, not "I heard....".

The problem the Border Patrol had was the flight profile they were flying with the airplane, not the airplane.

Forward CG? Not the ones I've flown, and I've flown them in most of the worst case configurations (amphib floats and retractable wheel skis). Yes, they tend to be somewhat heavy forward, particularly if the 80 inch Hartzell propeller and harmonic damper are installed (it wasn't on the BP airplanes). But, I've flown several hundred hours in Huskys with that setup as well, and it is easy to remain well within the CG envelope.

A couple of agencies have now switched back to Top Cubs, for several reasons. Not the least of which is that Aviat has not always treated their customers well. And, there's always that old "you can't beat a Cub" legend.....true or not.

Both are good airplanes, and flown well, they'll do a great job for you. But, dangerous stall characteristics? Nope. And, I've stalled them both many, many times, and poked them in all sorts of ways to see just how ugly they can get. Neither has any really ugly corners.

One is better in circling flight, down low? Again, horse pucky. How many Super Cub pilots have screwed their airplanes into the ground in the infamous "moose stall"? ANY airplane can react badly in that environment. I don't circle stuff close to the ground any more. I knew too many pilots who were killed circling animals close to the ground. Several of those were in Super Cubs, one in a Husky, one in a Taylorcraft, and one in a Cessna 185. One or two of those had witnesses on the ground.

I firmly believe that these are all cases of the pilot allowing airspeed to decay a bit (remember that stall speed increases as bank angle increases) in the turning, maybe kicks just a bit of rudder in to move the "target" out from under a wing tip, and gets just unlucky enough to encounter his/her own wake vortex in just precisely the wrong angle and place to trip the wing. And, do that at low level, and you're very likely to meet your maker. I know one gentleman, a superb pilot, who did just this and survived. His airplane (a Super Cub) rolled over the top and spun, but as it entered the spin, it struck a canyon wall inverted, and slid down the canyon wall. Both occupants were severely injured, but lived. The pilot, a very experienced Cub driver, is convinced that what caused the departure from controlled flight was a wake vortex encounter of his own wake.

Note that this is an entirely different scenario than the Border Patrol accidents, where the airplanes did not spin, they went straight in, nose down.

FWIW. Don't circle stuff on the ground at low level....there are much better ways to look at stuff on the ground. And, don't spread BS rumors.

MTV
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Re: Cub wings

FWIW. Don't circle stuff on the ground at low level....there are much better ways to look at stuff on the ground. And, don't spread BS rumors when you know nothing about the subject.

MTV

I very much agree with MTV on this. Circling is the absolute worst way to look at stuff on the ground. Use the crop duster P turn return to target. From cruise over the target, fall off the target downwind a little in a strong crosswind or quite a bit in a no crosswind. Now use this cruise speed kinetic energy to pitch up wings level to slow down and gain altitude. When comfortably slow and high, bank steeply upwind and use enough rudder (it will take a lot) to bring the nose on around to the target (energy management turn.) DO NOT PULL BACK ON THE STICK IN THIS TURN. PULLING BACK IN TURNS NEAR THE GROUND IS WHAT KILLS PILOTS. As the nose comes around onto the target, LEVEL THE WING FIRST and then pull out of the dive to level the aircraft.

In the pull up to gain altitude and slow the aircraft we are trading speed for altitude. In the dive to the target, we are using gravity thrust of altitude to get back to cruise speed when low. Crop duster turns, fighter yo yos, ground attack helicopters and airplanes, fire fighter aircraft, pipeline and powerline patrol aircraft, etc., all use this kind of energy and wind management to safely maneuver near the ground.

Yes. Powerful airplanes can circle and observe somewhat in the turn. As MTV says, it can get complicated. Like in turns about a point, the bank will have to increase in the downwind part of the turn. The target cannot be seen with the down wing in the way. Increasing the bank, increases the load by a factor (gets worse fast.) Attention must be shared between obstacles in the aircraft track and the target, unless there is an observer. With the gun run or crop duster turn, the target is always up front when we are observing it closely. We don't try to fly/observe out the side window.

The energy management turn does not need to be a wingover to work well. It can be as gentle or as aggressive as the pilot wishes. One common error, however, is not getting the turn completed quickly. This leads to the down wing being near obstacles and terrain late in the turn to target.

I see a lot of advantages with the energy management turn for maneuvering flight work. But then I have never tried circling. Do you guys think I would still be here if I had been circling for 17,000 hours?
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Re: Cub wings

contactflying wrote:Use the crop duster P turn return to target. From cruise over the target, fall off the target downwind a little in a strong crosswind or quite a bit in a no crosswind. Now use this cruise speed kinetic energy to pitch up wings level to slow down and gain altitude. When comfortably slow and high, bank steeply upwind and use enough rudder (it will take a lot) to bring the nose on around to the target (energy management turn.) DO NOT PULL BACK ON THE STICK IN THIS TURN. PULLING BACK IN TURNS NEAR THE GROUND IS WHAT KILLS PILOTS. As the nose comes around onto the target, LEVEL THE WING FIRST and then pull out of the dive to level the aircraft.

I was using this turn the other weekend, spotting deer and mountain goats (chamois). I liked it, I think I will use it more often.

Pax don't like it so much! :mrgreen:
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Re: Cub wings

mtv wrote:
Here we go again with the old "I've never flown one, but
(snip)
And, don't spread BS rumors.

MTV


delete
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Re: Cub wings

Circling close to the ground is like any other flight maneuver, safe enough if done properly. NEVER circle close to the ground? I've done it too many times to stop now, I just pay close attention, just like flying up canyon or other flight maneuvers other then straight and level. I can bank the S-7 up and hold a spot and observe it as long as necessary, and sure sometimes I hit my wake but it's a burble and that's it. Maybe if I slowed it down too much, it'd be a different story. In fact for sure it would be! Maybe the Cubs and Husky's are different in their stall spin characteristics, but in 21 years of flying low level in the mountains in the VG equipped S-7, I (blah blah blah)..... what a minute, I just noticed the thread title "Cub wings", disregard the above #-o

I don't want to diss the Cub wing, just saying when the pilot screws up, he screws up, not the maneuver that's at fault. I do agree that there is more then one way to eyeball things then circling, and probably safer, but circling is still my first choice, I make downwind turns low level also, same deal, maintain thy airspeed and pay attention.
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Re: Cub wings

Courierguy,

It is very hard for experienced pilots to change. Success with a particular technique over time will entrench same.

I have had a large number of very good, old pilots consider going into crop dusting as a second career. Not all, but in most cases, it just didn't work. After considering the pressure to get through acres and the necessity of different techniques, most chose not to complete an Ag course.

You are getting along fine with the level circling turn with wind, terrain, angle of bank, etc., parameters that make it safe for you. And the game is not shooting back.

When I teach these maneuvering flight techniques, especially now that my legs don't work as well, I encourage students to stay within their comfort zone. In the past, when I was quite quick, there were times when I had to stand on a rudder to get the nose around before the down wing struck. That sort of thing should not be necessary if you stay way ahead of your little, powerful airplane.

Best regards,

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Re: Cub wings

I would say the main reason to use a cub wing on a experimental plane is the availability of parts or spare wing when you bend one. If you want trick flaps, slats, tips, or tanks it is all ready figured out. You can make them longer/shorter all ready been done. If you put a tree branch through the fabric it is a simple repair. Depending on the mission I think you could find a better wing. BUT, if I needed a right wing for my plane today there are several sitting at my airfield waiting rebuild I could slap one on and go.
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Re: Cub wings

DENNY wrote:....BUT, if I needed a right wing for my plane today there are several sitting at my airfield waiting rebuild I could slap one on and go.
DENNY


That might be true in AK, but anywhere else.... :mrgreen:

Agree on your other points though!
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