Mary Shafer wrote:

The F-111 MLG doors open, the gear extends, and the doors shut.
Mostly because otherwise these huge doors would be hanging out being
speedbrakes.

F-4 doors stay open. So do F-15 and F-16 and B-52 doors. Ditto
YF-12, SR-71, T-33, F-104, X-15, F-18, CV-990, A-7, F-8, KingAir,
B-747, B-1, B-2, F-117, B-57, and U-2. Also Lear 24 and 25. And the
Orbiter. These are just the ones I've seen and can remember.

Not all the B-1 and B-2 doors remain open.

B-1 main gear doors open to allow the gear to drop, then close after
the gear is extended.

The B-2 nose gear door closes after the gear is down. This is possible
because the door is two pieces. The piece that covers the forward
portion of the nose gear well is rigidly mounted on the nose strut.
The strut's pivot point is at the far forward end of the nose well,
thus the "clamshell" covering the rear can be shut when the strut
assumes a vertical position.

It would be impossible to do this with the B-2 main gear, since each
of those doors is one piece.

At the end of a mission the B-2 nose door is opened before engine
shutdown so maintenance can easily access this area. That's why you
always see it open in ground photos. The door is closed after engine
start on the next mission. The switch that operates the door is on a
control panel attached to the nose gear strut.

--

Paul Hirose