Rolling Out Quickly

"The Piper Cub was one of the easiest of all aircraft for the beginner to fly, but in the hands of an old pilot it is such a willing performer that it has one deadly flaw: when you roll out quickly from a steep turn it will - not often, but too often at that - stall out one wing at high speed, and the other wing that hasn't stalled acts like a powerful lever, spinning you so quickly you don't even know what happened, especially if you are at low altitude. The result is usually fatal." Bud Helmericks, Last of the Bush Pilots, pg. 139.

Any of you "old pilots" have a comment on this? Has anyone else found this to be true?

stall

Hi Anne,
Way to many years ago when I was first learning to fly my father a long time pilot
in Alaska taught me a lot of things about the cub with out geting in the plane with me.
I started out with a striped out 135 supercub that I had put together. One of the
things dad hammered into my head nonstop was a stall like you speak of. It was hard
to make this cub do it. some cubs are worse than others for what ever reason.
This is what i was told to do. Put on one notch of flap at about 2000 rpm and start
a turn like you were looking at something on the ground. As you come around titen
the turn and start to climb. get titer and steeper until you bring on a stall. This is a
standard high wing stall where the high wing falls into a spin entery. Every one
with a cub has done this. Now do the same thing only as the stall is just starting
cram the throttle and try to hold it in the same attitude. With my cub it took about 50
trys before what my father wanted happened. Most the stalls were normal only a
little more violent. The one that counted went like this, as the stall was just coming
on I was nose high tite turn. I crammed the throttle and the cub piveted on axcess
so fast that i went completely on my back while the nose was still pionting up. When
this happens it will take a good 200 more feet to recover. I personaly beleave this
is what is done in all to many of the so called moose stalls.
Over the years I have played with this stall and when it happens I went with it and
made the roll and was able to recover with less altitude lose. This is not a to try just
what I learned. Wayne. Good flying

Ann,

The most obvious scenario that comes to mind is a steep turn at fairly slow speed... the wing loaded and near critical angle of attack when the use of rapid (full?) aileron (deflected down) to roll out causes the inside wing to exceed its critical angle of attack and stall... tucking under rapidly as the outside wing is not stalled. This stall condition is further accelerated if by chance the pilot was using 'inside' rudder during the turn, causing the aircraft to skid... thus increasing the angle of attack on the inside wing also.

I often use a PA-18 to teach spins and this is one of my favorite 'gotchas' that I use... setting the student up subtly... and leaving a lasting impression of how critical coordination is when operating the aircraft to its extreme envelope. The stall from a moderately banked (base to final) turn with inside rudder (skidding) is often very violent... resulting in a spin with an extreme nose down attitude that requires a lot of altitude to recover from.... usually as much or more than 500 feet.

Because of this, I am a very strong advocate of teaching dutch rolls and full oscillation stalls (aka falling leaf stall) to make the students rudder control become instinctive... connecting the eyeballs to the feet, leaving the brain out of the system. If the nose doesn't yaw, the aircraft can't spin. Knowing how to do a spin recovery does little good below 500 feet agl if you don't recover before impact. Spin PREVENTION is the key to surviving in Cub flying.... and that means yaw control must become instinctive. You can hit the ground stalled (if straight) and survive if the aircraft has forward momentum. Hitting the ground during spin rotation is usually fatal.

I personally (within 50 yds) witnessed a fatal Pitts crash when an engine failure caused the pilot to try to return to the airport. The aircraft was 'bucking' as he tried to stretch his glide... only to spin from about 50 feet (only 1/4 turn) and impact nose first and burst into flames. Ironically... the aircraft landed in high corn. Had the pilot just pitched down and decided to ditch the aircraft, it most likely would have just flipped over and wrecked... with little, if any, personal injury.... Very sad. btw, the cause of engine failure was a small piece of rubber blocking the fuel line.

Hope this is what you were looking for...

John

Anne, a quick rollout from a steep turn can have exactly the effect you describe. The actual stall process is as both Wayne and mention, but your initiation sequence is somewhat different than they discribe. The rapid rollout stall initiates because both wings are relatively highly loaded with the inboard wing going somewhat slower than the outboard wing. When you initiate the rapid rollout, you significantly increase the aoa of the slower inboard wing while reducing the aoa of the outboard wing. So the inboard wing stalls and you wrap around very quickly. All three of these stalls proceed in pretty much the same manner after initiation.
All the best,
JimC

Thanks for the clarification on this stall, everyone. It sounds like a slower, coordinated roll-out is the key to not stalling in this situation.

Anne.

You can also drop the nose slightly (no, I don't mean rudder into the turn). The key is to remove some of the g loading from BOTH wings as you roll out, but remove more from the outside wing. Caution, you are likely to lose altitude when you do this, unless you were climbing when you initated.
JimC

Wayne

Would in a rollout not a good amount of outer side rudder accelerate the inside wing and therefore help prevent the stall?

Hans

Hans,

Using aggressive top rudder during the rollout will definately help prevent stalling.... especially if you slightly pitch forward (altitude permitting).

btw, are you near Zurich... Just found out I will be there in early June for a day or two.

John

Hans & John, using agressive top rudder during rollout can help prevent the low wing from stalling. But if you are near the limit on both wings, it can also stall the high wing. If that happens, the low wing will go over the top. A very entertaining stall sequence. I don't recommend practicing it at low altitude. It is safer to unload the plane if you are rolling it out of a tight turn rapidly.
JimC

Using aggressive top rudder during the rollout will definately help prevent stalling.... especially if you slightly pitch forward (altitude permitting).

JimC,

Pitching forward will unload the wing.

stall

Jimc,
I agree that to unload the wing is the most important thing to save the stall. As the stall
begins you are almost allways comeing on with full power and will have good pitch and
rudder control. I have found that when it begins that if you go allmost negitive nose
down and full rudder the nose down that you can recover before the stall becomes
a shore thing. Go up high and practice this a few times and you will see that only a small
loss of altitude. It is rather unorthodox but works. Wayne

Yes,

Full power and lower the nose slightly will get you out of it sometimes. You may lose no altitude if you have enough power to add in and are close to the roll out point. We're all commonly taught to dive the nose toward the dirt, gain speed, and recover from a normal stall. Hard to do if you're only a few feet off the deck to begin with. If you picture the wing stalled, all you have to do to get it unstalled is drop the AOA a tad and add in power. With practice, you can eventually stall with no discernable loss in altitude as long as some power is held in reserve. Practice at altitude, since you will fall out of a few of them.
flagold
Matt

Ah, the joy of supercub.org! I go and fly my cub, then come back to log on and find yet another way in which my seemingly benign aircraft is waiting to kill me.

I am safely cured of wishing to do steep turns with flap and full power anywhere near the ground, at least until I come to the US and fly with one of you fellows.

BCB

BritishCubBloke said:

I am safely cured of wishing to do steep turns with flap and full power anywhere near the ground, at least until I come to the US and fly with one of you fellows.

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Didn?t we do allmost that all the time during our glacier flight? I guess not steep enough?

I think, the Super Cub is the almost only airplane that does not kill it's pilots, that you have to do yourself. Keep trying! :lol:

Hans

Didn?t we do allmost that all the time during our glacier flight? I guess not steep enough?

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Hans,

I thought you flew very conservatively and not at all steeply! I wasn't scared at all, even when we hit that air pocket on the Petersgrat.

BTW, this evening I went into a farmer's field on the North Cornwall coast -- the nice side of flying in Britain.

All the best,

David

P.S. No, sorry, I was a bit scared when we landed on the Wildhorn.

Hi, David. When I learned to fly in a J-3 in 1965, the cub had the third highest fatality rate per hour flown of all aircraft. Not because of any flaw in the design, but because of the type of flying they were often used for. Like a good lapdog, they were quite benign but would bite if you stepped on their tail. I wonder how the cub rates these days?
All the best,
JimC

THE CUB IS ONE OF THE SAFEST AIRPLANES EVER BUILT. IT WILL JUST BARELY KILL YOU.

I wonder how the cub rates these days?

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I believe the NTSB stats show it to have the highest fatal stall-spin accident rate of any light aircraft. The 182 has the lowest.

I'm sure this bears out what you say.

David

Rolling out quickly

When I was pooting around in a 7AC twenty years ago, landing in everyones' backyard, I was told the 7AC was the worst. I figured it was because of same situations J3's are asked deal with, but with a tad more wingloading. Don

rolling out quickly

Regarding this subject: could someone advise what bank angle is steep? what speed is more critical? other factors to consider?

Thanks

John