Takeoff with light quartering tailwind
Joined: Mar 2011
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From: U.S.
Different machinary, different techniques required. Boeing did publish that,it is a direct cut and paste from the latest update
My goodness you're authoritive for someone who has never flown the aircraft you are giving advice on.
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From: PARIS FRANCE
Thank you for all those insights.
In fact, I would avoid taking off with a tailwind, but if it cannot be avoided, then, as Captain Claret wisely said, ailerons are for roll control!
You use the tiller (is that right? I mean using the nose wheels orientation) , at the start of the take off roll, then remember that what is important is acceleration, to V1 and Vr...putting weight on one main landing gear by using ailerons is not, I beleive, a good idea, especially as the wind is "light", by the topic"s description. Use slight rudder inputs afterwards to keep the airplane centered, and rotate with the ailerons still neutral. I am always surprised to find that now, everything needs to be written and explained, when in fact, there are so many different conditions which cannot be all adressed. It is, in fact, state of the art piloting...I learnt by looking at (and admiring...) how the old hands did it, then later shared it with the younger ones...No need to cut entire forests to write that in the SOPs...
In fact, I would avoid taking off with a tailwind, but if it cannot be avoided, then, as Captain Claret wisely said, ailerons are for roll control!
You use the tiller (is that right? I mean using the nose wheels orientation) , at the start of the take off roll, then remember that what is important is acceleration, to V1 and Vr...putting weight on one main landing gear by using ailerons is not, I beleive, a good idea, especially as the wind is "light", by the topic"s description. Use slight rudder inputs afterwards to keep the airplane centered, and rotate with the ailerons still neutral. I am always surprised to find that now, everything needs to be written and explained, when in fact, there are so many different conditions which cannot be all adressed. It is, in fact, state of the art piloting...I learnt by looking at (and admiring...) how the old hands did it, then later shared it with the younger ones...No need to cut entire forests to write that in the SOPs...
Joined: Apr 2007
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From: UK
framer, your are correct mate.
Same general wording as my 747-400 manual.
They don't want you barreling down the drag strip with the spoilers up on one wing, eating up tarmac, reducing lift, reducing tailstrike margin...etc etc.... when ultimately, only a smidgen of into-wind yoke may be needed.
Maybe full aileron in a small/light aircraft without spoilers would be appropriate. As has been said...different methods for different machines.
Same general wording as my 747-400 manual.
They don't want you barreling down the drag strip with the spoilers up on one wing, eating up tarmac, reducing lift, reducing tailstrike margin...etc etc.... when ultimately, only a smidgen of into-wind yoke may be needed.
Maybe full aileron in a small/light aircraft without spoilers would be appropriate. As has been said...different methods for different machines.
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From: nowhere
Bottom line....When it comes right down to it, not all airplanes fly the same.
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From: 41S174E
Crashdriver
Someone tell you that in the hangar Crashdriver? Or the result of years of research flying many types in the exact same fashion? It sounds quite good,gives you an air of experience and wisdom, but it's not true.
If you started your roll on a 737 with full aileron and reduced it so that you rotated with ailerons neutral in a stiff crosswind, it would be an almighty cock-up. Simple as that really. If you did it in your B200 it might work pretty well......it's starting to look like
is just a convenient saying.
If anyone reads this thread for advice I'd suggest they be rather judicious about who they take it from, better yet, follow the manufacturers guidelines.
STBYRUD
I'd be really interested in nailing that figure down. Have you still got access to the AMM?
When it comes right down to it, no. All airplanes fly the same, from a J3 to an A380.
If you started your roll on a 737 with full aileron and reduced it so that you rotated with ailerons neutral in a stiff crosswind, it would be an almighty cock-up. Simple as that really. If you did it in your B200 it might work pretty well......it's starting to look like
All airplanes fly the same
If anyone reads this thread for advice I'd suggest they be rather judicious about who they take it from, better yet, follow the manufacturers guidelines.
STBYRUD
As I said, thats approximately 1.6 units as indicated on the yoke on the 737 if memory serves me right.
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From: U.S.
Someone tell you that in the hangar Crashdriver?
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From: 41S174E
Ahhh come on Crashdriver, we were on the verge of learning something then. Lets get to the bottome of it 
He should get in touch with Boeing and tell them their FCTM is incorrect and that the same crosswind departure technique as the J3 Cub will suffice.
My favourite part of the acedemic conversation thus far has been
No actually it was a university professor in aeronautical physics.
I will leave it at that and leave you to your own devices, since an academic conversation cannot be completed here.
Pull back the houses get smaller, push forward they get bigger.
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From: GPS L INVALID
framer: Tell you what, I will do some empirical testing during the next flight control check, aided by either the ACMS or the sys page if the bird has the flight control display - don't have access to the AMM at the moment unfortunately 
Fleet Manager
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From: various places .....
All airplanes fly the same, from a J3 to an A380
I think one might choose a Type a little more modern than the Cub. However, with that caveat, it is not unreasonable to suggest that Types certificated to modern Standards - FAR23/25, for instance, generally will fly in reasonably predictable and similar manner.
That is not to suggest that different Types won't have specific differences, of course.
I suspect that the original statement would have been somewhat along such lines. Certainly, I have heard much the same comment from a variety of competent folk over the years.
I think one might choose a Type a little more modern than the Cub. However, with that caveat, it is not unreasonable to suggest that Types certificated to modern Standards - FAR23/25, for instance, generally will fly in reasonably predictable and similar manner.
That is not to suggest that different Types won't have specific differences, of course.
I suspect that the original statement would have been somewhat along such lines. Certainly, I have heard much the same comment from a variety of competent folk over the years.
Joined: Apr 2008
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From: nowhere
Back to the crosswind stuff. Seeing as most aircraft seem to use a technique of reducing aileron into wind as airpeed increases on the takeoff roll, can we get any confirmation on this idea that Boeing is suggesting the opposite.
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From: 41S174E
This is my take on it and I'm happy to be corrected by folk more knowledgable/ more experienced than me;
When you are rolling along the runway at speeds where the rudder is effective during a crosswind departure, you want to control your direction with your rudder while preventing the upwind wing from creating more lift than the downwind wing. If you end up in the situation where the aileron input is creating a drag towards the upwind side of the runway, then the opposite rudder you will need isn't to counter the wind, it's for the aileron/spoilers.
I have a feeling this happens quite a bit.
I think Boeings technique is designed to prevent excessive control inputs.
When you are rolling along the runway at speeds where the rudder is effective during a crosswind departure, you want to control your direction with your rudder while preventing the upwind wing from creating more lift than the downwind wing. If you end up in the situation where the aileron input is creating a drag towards the upwind side of the runway, then the opposite rudder you will need isn't to counter the wind, it's for the aileron/spoilers.
I have a feeling this happens quite a bit.
I think Boeings technique is designed to prevent excessive control inputs.
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From: 41S174E
PS Jammed Stab,
I don't think Boeing are suggesting that the inputs continue as the airspeed increases. I'l paste below so it's easy to reference;
So what happens is that aileron goes in as required until the point is reached where it is sufficient and then it is held. (this is normally only a very small input) My experience is that as the airspeed increases and slightly less rudder is needed then the aileron is reduced a fraction with the rudder..... almost like they are connected really. Until rotation of course when the into wind aileron is pretty much doubled or trippled in order to keep the wings level.
I don't think Boeing are suggesting that the inputs continue as the airspeed increases. I'l paste below so it's easy to reference;
Throughout
the takeoff roll, gradually increase control wheel displacement into the wind only
enough to maintain approximately wings level.
the takeoff roll, gradually increase control wheel displacement into the wind only
enough to maintain approximately wings level.
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From: US
All airplans fly the same? To some degree yes, to some degree no.
Anyone think a swept wing, hard wing fighter would react differently to a rudder input at high AOA, like landing, than a Piper Cub?
Ailerons are neutral and only enough input is needed to keep the wings level during takeoff roll.
In strong crosswinds the plane typically doesn't 'lean' until it's moving fairly quickly so a small, or perhaps moderate, amount of roll input might be needed but that will gradually be reduced as speed, and thereby roll effectiveness, increases.
Anyone think a swept wing, hard wing fighter would react differently to a rudder input at high AOA, like landing, than a Piper Cub?
Ailerons are neutral and only enough input is needed to keep the wings level during takeoff roll.
In strong crosswinds the plane typically doesn't 'lean' until it's moving fairly quickly so a small, or perhaps moderate, amount of roll input might be needed but that will gradually be reduced as speed, and thereby roll effectiveness, increases.
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Hello guys,
I was briefed during my type rating that the Boeing technique for crosswind take-off has to do with the swept wing.
Not 100% sure about this but I think it was this.
The wing which is on the crosswind side gets air over the wings at an higher angle (closer to perpendicular) than the wing on the other side (closer to parallel). So the wing on the crosswind side is creating more lift and this needs to be countered by applying aileron into the wind. As speed increases the effects gets bigger, so more aileron needed.
I was briefed during my type rating that the Boeing technique for crosswind take-off has to do with the swept wing.
Not 100% sure about this but I think it was this.
The wing which is on the crosswind side gets air over the wings at an higher angle (closer to perpendicular) than the wing on the other side (closer to parallel). So the wing on the crosswind side is creating more lift and this needs to be countered by applying aileron into the wind. As speed increases the effects gets bigger, so more aileron needed.
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From: US
Boeing has stated what they expect a pilot in their aircraft to do. They do not say "keep the wings level". They say "approximately level."
They are more concerned with drag by excess control wheel displacement vs. not being perfectly level.
Using control wheel inputs in a jetliner that are appropriate for light aircraft flying shows a failure to understand what you're doing with the control wheel(drag) vs. how jet performance is calculated.
They are more concerned with drag by excess control wheel displacement vs. not being perfectly level.
Using control wheel inputs in a jetliner that are appropriate for light aircraft flying shows a failure to understand what you're doing with the control wheel(drag) vs. how jet performance is calculated.
