In article ,
Elliot Wilen wrote:

Or generally, is there some reason that some
jets are designed with gear doors that stay open, while others have
doors that close after the gear are extended?

Apart from what's already been mentioned I can add that
the gear bay can contain things which you want to access
during normal handling on the ground. On Draken for
example the ground crew data entry panel is in the nose
gear bay. That's why they open almost 180 deg.

And speaking of air brakes, Gripen's front nose gear door
doubles as one -- but only on the single seat version.
--
Urban Fredriksson http://www.canit.se/%7Egriffon/
1) What is happening will continue to happen
2) Consider the obvious seriously
3) Consider the consequences - Asimov's "Three Laws of Futurics", F&SF, Oct 74