Aaron747 From Japan, joined Aug 2003, 8584 posts, RR: 27 Posted (8 years 11 months 1 week 1 day 20 hours ago) and read 18884 times:
Don't usually ask too many questions around here but this is one of those obscure things that has been nagging at me for some time.
Over the years I've noticed that with regard to ground spoiler deployment on landing, certain Boeing aircraft have curious properties. On the 777, for example, (pardon my no doubt incorrect nomenclature) the #2 outboard spoiler panels have a more shallow angle than the other four.
And on the 737 classics, the first two panels have the same setting whereas the last two panels have full deflection. The 73G models have an even more unusual arrangement where the last outboard panel is standing all tall with other panels recessed.
Surely there is a rhyme and reason to this but for the life of me I can't guess what it might be. Can some of you more in the know folks please shed some light on this technical oddity?
If you need someone to blame / throw a rock in the air / you'll hit someone guilty
HAWK21M From India, joined Jan 2001, 31792 posts, RR: 55
Reply 3, posted (8 years 11 months 1 week 1 day 14 hours ago) and read 18835 times:
Firstly the Numbering should be from Left to Right so the Spoiler in question for the B777 should be #4.I suspect its the Ground spoiler.
On the B757 also certain Spoilers have a different angle of Deployment than others in Air & on Grd depending on the Aircraft.The Inboard Spoilers will deflect less in Air when used as Air brakes to avoid Turbulence affecting the Horizontal Stablizer behind.
ChrisMUC From Germany, joined Jul 2006, 66 posts, RR: 0
Reply 5, posted (8 years 11 months 1 week 1 day 13 hours ago) and read 18825 times:
The two shallower ones on your pic from the 737 classics are Flight Spoilers, so most probably their movement is limited to that level to make it impossible to deploy them to far in flight (valve failure or any other problem).
I could imagine that's it the same with the 777.
Tristarsteve From Sweden, joined Nov 2005, 4204 posts, RR: 32
Reply 12, posted (8 years 11 months 6 days 3 hours ago) and read 18514 times:
Quoting Tom12 (Reply 9): Interesting post, do you have a link where i could read into this further
No sorry it is out of The B777 MM Pt 1. Cant reproduce it here.
And I forgot to add this is all in normal mode, There is also a secondary mode when some computors are downgraded, and a direct mode. The laws are different in each, there is less computor interference.
The reason that 5 and 10 do not deploy in flight is to do with turbulence over the stabilsor.