Landing gear door operation

In another online forum, it has been claimed that on the F-18, F-14,
F-4, and possibly F-8, A-7, A-6, and A-4, all the landing gear doors
stay open when the gear are extended. While typically (or at least in
most other military jets), some of the landing gear doors open only
during extension/retraction, and are closed while the gear are
extended.

Can anyone comment on the extent to which this is true? If so, there's
an obvious pattern of this characteristic appearing in fighter/attack
jets which were originally designed for the Navy. Is this due to Navy
"culture" or somehow related to a safety/reliability issue for
carrier-based operation? 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? (The only reasons I've
seen that make sense are simplicity versus air drag and, in some
cases, ground clearance.)

Many thanks in advance.

--Elliot Wilen

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

"Urban Fredriksson" a écrit dans le message de
...
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.
--
snip

The same on F-18 ... Maintenance Codes Panel is in nose wheel well and air
pressure indicator for APU in right main wheel well and associated hand pump
in case of pressure lost (good work-out for tech if pressure drops
regularly). There are also assorted pressure gauges and humidity indicators
visible ... without having to open panels.

Although having open wheel wells on landing does occassionaly (very
occasionally) allow FOD to strike inside where there are a lot of small
hydralic lines. A good post-flight inspection can help prevent a problems in
this area.

From what I have seen, other fighters seems to be built in the same way. I
would assume cargo & civilian a/c are similiar.

Pat