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View Full Version : Wing Flex | 73H versus 320


PPRuNeUser0198
22nd Apr 2011, 02:01
Seeking some expertise around wing flex and "ride quality".

I note that the 738, in particular with winglets, has a considerable amount of wing flex closer to the outer-part of the wing against the A320.

Does this have any material affect of ride quality i.e. a smother ride?

As the wing flexes somewhat more in-flight, is there greater absorption during turbulence and as such, a smother ride on the 73 versus the 320?

Thanks.

Going Boeing
22nd Apr 2011, 03:39
I can't totally answer your question but I do know that the A320's Fly-by-wire Flight Control system has an Active Aileron function designed into it (originally pioneered on the Lockheed L1011-500). This is designed to move the ailerons to alleviate wing bending induced by turbulence, gusts etc and thus allowed the use of lighter wing spars in comparison to non load alleviation wings.

Although the A320 wings may not move as much as the B73H wings, the ride may be similar.

startingout
22nd Apr 2011, 05:11
Boeing, do you know if this active aileron function is connected in series with the two control surfaces or does it operate independently?

LAME2
22nd Apr 2011, 06:41
If your thinking of Load Alleviation Function (LAF), it is only on the early models. No longer a part of the algorithms of the FAC.

Both Ailerons would go up or down to alleviate turbulence etc sensed by the accelerometers of the IRU's.

ampclamp
22nd Apr 2011, 07:22
I believe it was the ELACs that did the LAF for the ailerons.
FAC did rudder travel limiting and yaw damping.Cant remeber any LAF function in the FACs.

woftam
22nd Apr 2011, 08:36
Sounds like PFM to me.