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Stephen Lindberg

Well Known Member
I recently flew my PA-12 in a strong wind and noticed something I thought unusual. I was taxiing for takeoff on runway 26 and was therefore headed 080 on the way to the runway. The wind was reported as 180 to 220 at 18 kts. gusting to 26, and the windsock was consistent with that. Pretty strong for the Pacific NW and that's why I'm asking for help from prairie state pilots because I know this is routine for you. Because of the right quartering tailwind I positioned the stick full forward and to the left, "climb into the wind and dive out of the wind". To my consternation, the airplane took a strong list to the left, enough so that I momentarily wondered if I had biten off more than I could chew. I just had to experiment so I moved the stick, still full forward, fully to the right. And lo! The airplane righted itself and the alarming list went away. My explanation is that raising the upwind aileron (moving the stick to the right) spoiled lift that was somehow being generated by wind flowing retrograde over the right wing. Pure speculation on my part. Does anyone have a better explanation? This calls into question the old rule of thumb mentioned above. BTW, the four TO&Ls were big fun. The wind blew the plastic deck chairs at the FBO across the patio.
 
I don't have a better explaination for the taxi dilema, but for take-off and landing, there have been times that I have called upon "Instant Runway Construction Co." to build a better runway for me to use. One time in particular, I was trying to take-off from an airport whose only runway in use was the long, wide jet runway which had a 70 degree, very strong, gusty crosswind from the left. I just pulled the C-172 all the way over to the right side of the runway and pointed the nose at about a 40 degree angle toward the other side of the runway. About 1/3 flaps and the plane was airborne before the centerline! Already had the perfect crab to continue along on runway heading. Tower thought it was really cool, too!
 
Chase the Hat

In quartering tailwinds I always chase the hat. Point the stick in the direction that a hat would be blowing. Works for me.
 
Gary, that "hat trick" is a great way to think about it.

But I gotta play devil's advocate...where would the hat blow if it was sitting on your HS? With any amount of prop RPM, I believe the hat blows BACK...even in gusty quartering tailwind.
 
dan said:
Gary, that "hat trick" is a great way to think about it.

But I gotta play devil's advocate...where would the hat blow if it was sitting on your HS? With any amount of prop RPM, I believe the hat blows BACK...even in gusty quartering tailwind.
Click to expand...
I previously did not mention that fore and aft movement of the stick, which I tried, did not raise or lower the tail on the tailwheel spring, which it most certainly did when I was facing into the wind. So I think the tailwind was balanced out to a great extent by the propwash. I suspect that in all but the strongest tailwinds it makes more sense to hold the stick back rather than forward, which I believe you are implying, Dan. Back to my original question... Has anyone seen the phenomenon I described, ie: upwind UP aileron rather than DOWN aileron being better in a quartering tailwind? I rarely fly in such strong winds so I haven't previously noticed. I'm just reporting what I saw, hoping that someone that does this routinely knows the answer.
 
It's typically pretty windy where I live. My experience has been that all bets are off when you're taxiing near structures, trees etc. The winds at the windsock don't nescessarily bear any resemblance to the wind at your particular location on the taxiway, especially if it's gusting. Sometimes, you just have to feel it out and give the plane what it's asking for....just like you did. :D

my $.02
 
Learned to fly in Windy Wichita

I can count on my left hand the number of calm days to fly while I was taking flying lessons in Wichita, Kansas. When the winds settled into the 10-15 mph range, there was a mad rush to the airport to fly "while it was calm".

The previous example of "chasing the blowing hat" is ideal.
That is what I was taught in Wichita. Prop wash at or near idle on a rear or rear quartering wind is minimal (at least with the strong winds in Wichita). Gusting winds were worse than a steady wind as it creates momentary "uplifts", which is what I suspect occured when the pilot of the original post experienced and needed to alter from the norm. My instructor's voice still sits with me today "fly the plane...even when it is on the ground." I know I contributed to his aging process while I was beginning the ongoing learning process we call flying.
Have I got some wind stories I can share........
Safe flying.

Pat Garboden
Ozark, MO Building in Wichita...will test fly in windy Wichita
RV-9A 942WG (reserved) slider
RV9-A 942PT (reserved) tip-up
 
Steven,

I have no idea why the right wing was up with that control configeration and quartering tail wind, but you sure did the wise thing moving the stick from left to right, much better than "but the hat is over there" and chasing it.

A friend showed me his Cub this past week end and explained how he finally figured out why it taxied with one wing low. The gear strut bungies were of a different size diameter.

Maybe the wind had nothing to do with it. :)

dd
High wind survivor
 
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David: New gear legs (late PA-12 and PA-14 style) a few years ago with new bungees, the heavy duty type... I still favor the theory of retrograde lift production. I am thinking that there may be some Alaska Super Cub guys who have seen this. Steve.
 
I know exactly what happened, Steve. Seen it before.

Someone put the left aileron on the right side and the right aileron on the left side the last time it was in maintenance. :D

Sorry I couldn't provide a more constructive comment! I'm baffled by what you experienced.
 
Why does it roll?

I suspect that DOWN elevator in a tailwind keeps the tail on the ground because the Elevator is virtually equal in area to the Horiz Stab. The flow over the Elev might be stalled but the down force would still be significant compared to any lift on the Horiz Stab.
However, with the 'Down' Aileron it may produce down forcee but it is very small compared with the size of the wing which will still hve Lift.
As some one suggested early, having the aileron UP probably stalls or blankets the flow over the wing.
Pete.
PS Caution. I once watch a young chap trying to turn a Citabria 'out' of a very strong wind, being continually defeated by the weather cocking effect. In desparation he gave it a BIG handful of 'Go Juice' and around it went, the tail being lifted by the centrifugal force and/or the prop wash, let the tailwind under the tail and he buried the propellor into the ground before he could blink.
P
 
Is it possible that you suddenly experienced a short gust of wind exceeding the 220 degree's reported...possibly over 260 degrees for a short gust...that would have wanted to "weathervane" you the other direction???
 
Terry: Directional control was not the issue; I had no trouble taxiing straight. The thing I noticed was this: With a right quartering tailwind the airplane leaned to the left with left stick, and straighted up with right stick, which is not what I had been taught. I noticed this all the way down to the end of the runway (2000 feet taxiing) so I don't think this was a transient gust. The wind direction remained the same during the four TO&Ls I shot so I think it was a stable weather situation. It is a mystery to me. It is not likely I am the first to notice this phenomenon and maybe it is peculiar to Cubs. I don't often fly in such winds but I am going to make a point of doing so to see if I can learn more. These were unusually strong winds for the Pacific NW.
 
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