Originally Posted by
Time Traveller
I know this is as per the Boeing fctm, but I really find it poor theory and poor practice.(I agree with everything else you say though).
Spoilers work by spoiling lift, not creating drag (the form/profile drag of spoilers at takeoff speed is naff-all.) During the takeoff roll, you're not creating lift so the only extra drag is the tiny frontal area of one roll spoiler and deflected ailerons.
The cross wind limit of the 737 is pretty high, and in anything near those conditions, anyone who applies just 1 unit is going to have the wing lifting dramatically, and they'll be squirreling all over the runway. But they do it because the manual says so.
My TriStar instructor taught me to hold in full aileron in any significant crosswind, including during the rotation. It works, although I do limit its use during the rotation, because then you are spoiling lift, and that increases risk of tailstrike.... That said, the guidance of "enough aileron to keep the wings level" is kinda meaningless, because with a weedy input, they rotate, the wheels leave the ground and "bam" - the upwind wing lifts and you've got a sudden 20 degrees of bank. So that's a balance.
But extra drag during the roll ... No, not in any significant way.
Agree on almost all you said
Theres a lot of needless hysteria
regarding the use of into wind
aileron on a crosswind
take off
The spoilers extended on the
upwind wing are not creating
significant drag until airborne,
at low speed with full into wind
deflection there’s little effect
anyway, as you accelerate and
flight controls become more
effective your inputs will naturally
be reduced
If you’re easing off control
deflection too soon it’s quickly
apparent with increased
difficulty in maintaining the
centerline
But it’s important to maintain that
into wind deflection throughout
rotation, too much or
too little is easily determined
depending on upwind or downwind
bank and an immediate
correction can be made