Crosswind 90 degrees. Which Way?

[Grogmonster]

I have a question for all you pilots out there. This question is one I have put to many people and I never get the same answer.

You are flying a high performance American single, ( A36, C210, SR22), or similar. The wind is blowing across runway 18/36 at exactly 90 degrees relative to the runway. Which way would you think it would be safer to take off ????? Assume the wind is just on the maximum demonstrated crosswind limit for your aircraft.

Think carefully before you answer. This old chestnut came up again as a result of the Avalon post that stated that a Mustang had to abort a take off and ended up in the grass off the side of the runway.

I will be watching the replies with interest.

Groggy.

[AerocatS2A]

Assuming the runway is physically the same in both directions (slope, obstacles, etc) then anyway will do. Why do you think one way should be better than the other?

[waren9]

For the singles you mention, I hardly think they face the same issues as the mustang when it comes to crosswind sensitivity from one side compared to the other.

Whats your point?

Give Tim Wallis a call. Im sure he'll have some sympathy for our Mustang pilot today.

[Arnold E]

American or English engine?

[Icarus53]

Takeoff with the wind from the right. I've got at least a 50% chance of getting it right (unless it's a CASA exam in which case there will be a more correct answer because of some grammatical intricacy)


I do actually have a logical basis for my answer but like Grogmonster I'm happy to fish for the moment!

[AerocatS2A]

Well sure, if it's a taildragger take-off with the wind working against the torque and slipstream effect, but for a supposedly "high performance" single like a C210 I'd just use the runway that was most convenient. The max crosswind figures don't say "valid for a right crosswind only."

Any talk of torque and slipstream is irrelevant if you're aborting the take-off anyway.

[Roger Copy Ta]

This is a trick question right?

The answer is use 09/27 you bloody idiot!

[Altimeters]

The only thing that I can think of that Grog may think is a 'trick' would be the fact that on take off in a single we have the slipstream effect. Add to that a xwind from the left and the problem is exacerbated by the aircraft weathercocking even more so to the left. So I think a xwind from the right should even out the slipstream effect.....right?

[AussieNick]

on a tailwheel with a anticlockwise rotating engine you want a right crosswind, and vica versa for a clockwise rotating one.

not as much of a problem in a tricycle UC

offtopice slightly, how did trappo's P51 fair after its excursion into the ditch?

[tmpffisch]

I'm with Altimeters. May as well use the xwind to counteract the slipstream effect. But when it comes down to it, it doesn't really matter.

Go in the direction you're intending to depart towards?

AV tower was giving the option of either direction today as for a while it was at 90 degrees or so.

[Arnold E]

I'm with Aussienick, hence the question about the engine

[Extra260]

This is a trick question right?

The answer is use 09/27 you bloody idiot!

Ahh... bit hard when someone built a damned shopping mall, 3 car parks and 5 office buildings where 09/27 used to be

[Joker 10]

So right hand tractor or left hand tractor, which way the engine goes detimines the best way to handle the way the wind blows.

[MakeItHappenCaptain]

If we're talking about a tailwheel, and especially one with such a large rotating mass and arm as a mustang, you'll need to consider both p-effect and gyroscopic precession, both for raising the tail and for rotating.
I would suggest that a clock-wise rotating prop, having a left tending p-effect and precession raising the tail would benefit more from a right x-wind and vice versa. The slipstream effect will exaggerate this before the aircraft accelerates. The take-off rotation would be the lesser consideration.

[ForkTailedDrKiller]

I read recently that "you can run out of rudder taking off in a left x-wind in a V-tail Bonanza"!

I thought that was kinda interesting cause I almost "lost" the FTDK taking off at Karumba in a howling left x-wind - not long after I got it. Closest I have come to bending one.

I got it straight again - so I don't think I had "run out of rudder" - just a once in 30 yr brain fade!

I have taken off and landed the Bo in strong gusty x-winds - can't say I have noticed any difference, but I did flat-spot a tyre last year landing at YTWB in 20kts gusting to 35 - all x-wind. One of those times when being on the ground had much more appeal than being in the air. Fortunately the tyre was due for replacement at the next 100 hrly.

Dr

[glekichi]

The direction with the shortest taxi/backtrack!

[the wizard of auz]

Watch for the occasional gusts and take off into them. they are sure to be one way or the other.

[Lodown]

Having experienced an attempted takeoff with a 'strong' crosswind from the left, as the speed builds on takeoff, you'll very quickly find that right rudder is not required and then shortly after you can't put in enough left rudder to stop the drift to the right. (With a nosewheel, it doesn't feel so much that you run out of left rudder; more that the left rudder just doesn't seem to work at all or still has the rudder lock in place, if that makes sense - in my case, I hadn't got to the point where the nosewheel was off the ground yet and it wasn't going to steer left no matter how hard I pushed). The aircraft will just go further to the right as the speed builds and there is absolutely nothing you can do about it without reducing the power/speed. You'll be in one hell of a bind if you continue with the takeoff: aircraft drifting further from the runway direction and getting a stronger tailwind component at the same time. Abort the takeoff (control comes back very quickly when power is cut), go to the other end of the runway, put the wind on your right and it's a straightforward takeoff. Makes you wonder whether you were imagining things with the wind from the left. Reverse the directions for a Tiger Moth.

Ask a cropduster pilot and they'll tell you the same thing.

Having said this, at max demonstrated crosswind, your aircraft should be able to take off safely in either direction.

[gassed budgie]

As I was skittering sideways in the wet down 18L departing Avalon, the tower decided to let everyone know the crosswind wind component was bang on 38kts. No wonder I couldn't keep it straight!
If he'd been 30 secs earlier with that bit of info, I could have launched right out of taxiway foxtrot, straight across 18L and got the 172 airborne before I got to the other side of the runway!
I might add that the two twins behind me declined the towers invitation to line up and depart.

I read recently that "you can run out of rudder taking off in a left x-wind in a V-tail Bonanza"!

Haven't experienced that before Forky, but I can tell you that with exceptionally strong crosswinds and a forward C of G you can run out of elevator authority in the V-tails. Used to fly KWK a quarter of a century ago and can remember that happening once or twice.

[tinpis]

If we're talking about a tailwheel, and especially one with such a large rotating mass and arm as a mustang, you'll need to consider both p-effect and gyroscopic precession, both for raising the tail and for rotating.

Oh good oh. I'm presented with this dilemma daily when taking the old P-51 out for a gallop