Mr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 21
Reply 2, posted (11 years 2 months 3 weeks 5 days 10 hours ago) and read 2490 times:
Noticed that Airbuses' flight controls droop pretty easily... I mean almost all kinds of their planes have the ailerons droop or 'drop' when the hydraulics are turned off but I don't seem to notice the same trend on many Boeings. Especially for the B744s, which the control surfaces are supposedly heavier but they don't seem to droop, not even the high speed ailerons... same goes for the B767.. or so. But the B777s do have the control surfaces droop pretty easily. Is this due to the different systems that power the controls? Seem to notice that FBW can droop easier...
Starlionblue From Greenland, joined Feb 2004, 17432 posts, RR: 66
Reply 4, posted (11 years 2 months 3 weeks 5 days 9 hours ago) and read 2480 times:
The construction of the actual hinge and mechanism probably differs slightly from plane to plane, which would explain the differences in behavior. I don't know exactly how they are built, but a simple counterweight in the mechanism would eliminate drooping, for example.
"There are no stupid questions, but there are a lot of inquisitive idiots."
320tech From Turks and Caicos Islands, joined May 2004, 491 posts, RR: 5
Reply 7, posted (11 years 2 months 3 weeks 5 days 7 hours ago) and read 2446 times:
What's with all the drooping aileron questions lately?
A320 series ailerons and elevators droop because pressure is not retained in the servos when hydraulics are off. There is nothing special about fly by wire that would cause it, other than the lack of cables.
Rudders on all large aircraft will displace in a strong wind. Large aircraft don't have gust locks on the rudder (not even the Dash-8), they have dampers, that protect the rudder from being slammed over.
Incidently, the newest A320 series ailerons don't droop. Not sure what's different about them, I'll see what I can find out.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.