By the way, by coincidence I came across a Twin Commander retraction.
I tried to set a start time of 46 seconds, but that doesn’t seem to work embedded, so just scroll forward to that.
Jacko wrote:
Yes, they stop remarkably quickly, but “he” was me, and I’ve never thought of dabbing brakes on take-off – until now.
Looks like your brakes need adjusting….probably not too relevant for a super cub on tundra tyres but that dragging brake pad will probably cost takeoff length to some extent…more relevant for smaller wheels I guess (less lever arm)…
This is a good video. You can totally understand why you’d want to stop the wheels spinning in this case, there’s a lot of exposure wiring / hydraulics in there that a shredded tire or debris from the wheel could do serious damage to:
I was told to dab the brakes at 300’ as I raised the flaps on a C152, when revalidating my expired PPL in 1987. From this thread, I take it the wheels had long stopped rotating by then.
My original PPL in 1964 was done on a type without brakes.
I like to touch the brakes after take-off on every airplane I fly, but it draws curious looks from the student pilots that I haven’t started myself, as other instructors do not do that. I was never taught to do it but started doing it after my initial retractable check-out, as it was in the POH (I think), and for the reasons mentioned above, including the slightly increased diameter from centrifugal forces.
Then I came across some fixed-gear planes whose tires vibrated after take-off for a considerable time if not braked, so I figured that dabbing the toe brakes could just become SOP for all types with toe brakes.
One small +1 for tail-wheel aircraft with toe brakes as they do not have a third wheel capable of making vibration after take-off while not being capable of braking…
As for the very nice video: I agree that tundra tires stopping so quickly after take-off without brake application cannot be turning anything like freely.
In “my” 747-400 have one brake unit out of the 16 :) is (was) deactivated. For that reason, I have to wait 3 minutes after liftoff to stop gear retraction by itself. This causes huge penalty on the second part of the climb, since the gear is down . (I had a takeoff mass 360 tons instead of 410. I admit, this a completly different ball game :)
Merry XMAS to all of You
Zsolt
Zsoszu wrote:
one brake unit out of the 16 … I admit, this a completly different ball game :)
Hub
Most Boeing’s have nose wheel mechanical snubbers that stop the wheels rotating as they arrive in the wheel bay.
A_and_C wrote:
Most Boeing’s have nose wheel mechanical snubbers that stop the wheels rotating as they arrive in the wheel bay
I don’t bother to brake the wheels before retraction. After take off my heels are on the floor with a lot of right rudder applied. Lifting my feet up to actuate toe brakes without causing a lurch in yaw is awkward. This is a time when I’m pretty busy anyway and can do without the distraction.
In any event by the time I’m well clear of the remaining runway the mains will have stopped rotating (there is always some drag from disc brakes) and the nosewheel has a mudguard. I usually retract at about 200ft.
