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  #1  
Old 08-25-2017, 12:54 PM
David-aviator David-aviator is offline
 
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Default Hazard of quartering tail wind

Budd Davisson commented at OSH forum about hazard of landing in quartering tail wind.

It is indeed a squirrelly experience, had it happen again today, makes you feel like going back to drawing board.

The airplane wants to head for boonies half flying half skidding while trying to get slowed down. Finally got tail wheel down and control of direction. Really a challenge.

And it happens with as little as 6 knots reported wind, but as he commented, reported wind and what is experienced on runway are never same. Even wind sock 20' up does not reflect surface wind.

We have to deal with whatever wind is and be aware it will be tricky if comes from rear.
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Old 08-25-2017, 06:17 PM
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rzbill rzbill is offline
 
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Honestly, I am not trying to start a configuration debate.

I am curious if Budds comentary was for all craft or specifically taildraggers.
Is it the post touchdown regime you described where one has to be careful?

I ask because one airport I fly into weekly for cheap gas frequently has a tailwind (usually a northerly breeze on the right rear quarter) on the most convenient runway. The tower always asks if I mind that one. Nope. Really has not been an issue. Happened today.

I want to make sure I'm not being oblivious to a flying aspect that needs attention.
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  #3  
Old 08-26-2017, 12:17 AM
David-aviator David-aviator is offline
 
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It is a tail dragger issue. Has something to do with partial loss of control before tail is down.

Just something tail wheel pilots should be aware of.

He did say he has cancelled flying because of it. That got my attention.
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Old 08-26-2017, 05:42 AM
master pilot master pilot is offline
 
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Default Tailwind

Budd primarily flyers the Pitts which is a handful in any situation, especially in a quarterly tailwind. Also might apply to all others in a lesser way.
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Old 08-26-2017, 06:00 AM
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Everyone knows landing downwind in any airplane results in a faster than normal groundspeed, that's why we try to land upwind. Landing downwind your primary nose pointing device (rudder) will lose authority at a faster speed than normal. That leaves either brakes or a steerable wheel. If the steerable tailwheel is still in the air due to a wheel landing, better be right there with the brakes. Or 3 point it for more control.
Uh oh, wheel or 3 point.
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Old 08-26-2017, 06:42 AM
F1R F1R is offline
 
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Quote:
Originally Posted by master pilot View Post
Budd primarily flyers the Pitts which is a handful in any situation, especially in a quarterly tailwind. Also might apply to all others in a lesser way.
While refueling on a sumer vacation trip, I heard a propellor and engine winding up to take off power followed by a very loud but dull thud, followed by total silence. I stood up and looked in the direction of the thud. A new pitts owner had tried a take off with a light quartering tailwind and discovered the expensive way, that when the ground speed equalled the tail wind speed the rudder had absolutely zero ability to keep him lined up. Worse yet the cross wind component of the quartering tail wind has considerable effect when you don't have any rudder. The runway broke about 18" of one prop blade completely off. The runway had a wild set of skid marks from the mains , wingtip and propellor. The pitts looked like a lawn dart stuck in the runway with the tail several feet up almost vertical. A multi thousand hour ag pilot was helping to clear the runway so we could all get on our way again. The 6 hour pitts pilot was adamant that standing on the rudder had absolutely no effect. He just didn't understand the physics at play. The ag pilot calmly said that even with a few thousand hours, that he just would not do a quartering tailwind take off or landing, period.
I was thinking how much nicer that sounded than "Do you feel lucky, Punk ? "

Be very vigilant, the same physics are at play with any TW AC in a quartering tailwind.

Last edited by F1R : 08-26-2017 at 07:43 AM.
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Old 08-26-2017, 09:21 AM
David-aviator David-aviator is offline
 
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The trap is a light and variable wind.

ATIS was reporting a 6 knot wind almost down the runway but I heard tower report a light 90 degree cross wind to pilot ahead of me. When I turned final the report was "light and variable", a euphemism for "don't ask for change of runway".

The tower is good at swapping runways, they've done it for me, but some days it won't help, the wind is just too unpredictable.

That was the set up yesterday, it was a quartering tail wind when I landed. Ten minutes later it was not so.

Makes flying interesting.....BLAH!
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Old 08-26-2017, 09:52 AM
luddite42 luddite42 is offline
 
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Quote:
Originally Posted by F1R View Post
The 6 hour pitts pilot...
The wind may have been a slight factor, but I think the above is what actually sums it up. A Pitts at full power generates a lot of prop wash over a powerful rudder. Would take a helluva quartering tailwind to take this away. A "light quartering tailwind" won't do it. He had other issues going with that take off.
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Old 08-26-2017, 02:01 PM
Cannon Cannon is offline
 
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Quote:
Originally Posted by luddite42 View Post
The wind may have been a slight factor, but I think the above is what actually sums it up. A Pitts at full power generates a lot of prop wash over a powerful rudder. Would take a helluva quartering tailwind to take this away. A "light quartering tailwind" won't do it. He had other issues going with that take off.
Agreed 100%.

We had a Pitts for 19 years. It was the most powerful rudder *by far* of any airplane I've ever flown. Couple that with a significant amount of gyroscopic stability at full power and it was not the monster people claim it to be. Something else was going on. Had it happened on landing, I'd be more inclined to blame the wind.

Otoh, I generally agree with the original post. Quartering tailwinds can be a challenge for sure given the right (wrong?) airplane - especially during a wheel landing. Something to keep in mind when deciding whether or not to three point it.
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Last edited by Cannon : 08-26-2017 at 02:08 PM.
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Old 08-26-2017, 03:30 PM
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Default Good insight

Quote:
Originally Posted by dlloyd3 View Post
Landing downwind your primary nose pointing device (rudder) will lose authority at a faster speed than normal.
That's a good insight right there. On takeoff, my rudder doesn't gain authority until about 40 KIAS. I usually line up left of centerline aiming 5 degrees right so I make a nice arc to the centerline so I don't have to drag the brakes. My tiny little tires will flat-spot themselves if I apply brakes above 45 KIAS. I have to be very careful landing in any kind of crosswind.

So would this same theory apply on a very cold day?
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