Rotate...Gear up.

Posted:
Mon Dec 02, 2024 5:40 pm
by Splitpin
My question is what happens between the subject line call outs....regarding big Jets in particular.
Do the pilots use the brakes at the positive climb phase to stop the wheel rotation, or is there an automated system...or doesn't it matter.
Just thinking.
Re: Rotate...Gear up.

Posted:
Mon Dec 02, 2024 6:28 pm
by cowpatz
SP it is an automated braking system on the main gear. Not only does this stop the wheels from spinning in the wheel wells, but it reduces the gyroscopic force produced by the wheels when rotating, therefore easier to retract. This is not an issue with the nose wheels as they rotate in the same plane as the retraction path. The nose wheels do not have brakes but are slowed by snubber pads on the ceiling of the wheel well bay. The tyres rub against these snubbers.
I believe that the 777 is also unique in that when taxiing at speeds less than 45kts, the antiskid system releases brake pressure to the brakes of one axle pair of each main landing gear. So each application sequences on to the next axle pair. This extends the service life and also reduces brake sensitivity when taxiing. The full “oh s**t” option of full braking still remains at any time/speed.
Re: Rotate...Gear up.

Posted:
Tue Dec 03, 2024 4:54 am
by Splitpin
CP, amazing reply! Knowledge gap suitably filled ...thank you Sir.
Re: Rotate...Gear up.

Posted:
Wed Dec 04, 2024 12:36 pm
by SA227
SP, here is a video showing the 737. Brakes are automatically applied when gear is selected up.
https://www.youtube.com/watch?v=7Y3lpgbTu6kEven the old classic has one or two smart features

Re: Rotate...Gear up.

Posted:
Wed Dec 04, 2024 1:07 pm
by deeknow
SA227 wrote:Even the old classic has one or two smart features

Don't say "Classic" on nzff.org !!!!

Re: Rotate...Gear up.

Posted:
Wed Dec 04, 2024 5:00 pm
by Splitpin
Great link SA, Thanks for posting...I love all this tech stuff
