F-15A: Prior to Not a Pound for Air to Ground

[rickshaw]

Why does a retractable foot step slow down the wheel retraction time? 

And how does a retractable foot step cause, "additional avionics requirements"?

[tahsin]

Though not aware of the specific case how about the wheels and this step sharing the same hydraulics or something that slows the gears with the tech/reliability of the 50s, leaks and malfunctions and the similar. Meanwhile the plane will be wanting to accelarate all the time with pilots wary of throttling down at a critical speed -with the spool-up times of the day in mind, they can't simply wreck the gear with going faster than their airspeed limits. So the company will add up an auto-throttle function to keep all the variables in check, though of course there would be more pressing requirements for such a system. Those people were good talkers but any good talk requires at least a percentage of truth. Boyd wouldn't have mentioned such a ridiculous thing if it hadn't happened.

[PR19_Kit]

Somewhat unlikely I think............

The amount of hydraulic power used to retract a step would be about 5% of that required to retract the gear, just think of the relative masses involved. Not to mention that the step would be retracted BEFORE the aircraft even started to taxi, let alone before it got airborne. In which case there would be no demand on the main hydraulic system at that time except retracting the step.

[tahsin]

Bowing to actual knowledge and experience. Mine was just a hunch, though I could maybe claim that an extra system meant extra connections to leak.

[ajmadison]

Sorry. Guess I should made it clear that a foot step actually shortened the wheels up time. If the pilot can get into the plane that much quicker, and get it off the ground quicker, then the plane can become a quick response interceptor in addition to being an air superiority fighter. Except, to perform all weather intercept the plane would need a more advanced radar, etc. etc. Not the best example, was just trying to illustrate why a motto might be a really good idea.

[sandiego89]

Actually a quick acting ground crew can pull a simple, well designed boarding ladder off quite quickly before taxi. Neglible impact on scramble time.  A large boarding ladder or platform can be more to handle.  I read Boyd's book and he did fight the inclusion of a internal boarding ladder on the F-16, and it was all about weight.  He wanted the lightest, simplist, pure fighter.  Others kept on pushing for more gizmos and gold plated parts, and as others have stated, every pound came at a cost, causing a bigger airplane. Others pushed hard for an internal ladder.  Having no internal ladder made operations away from home base slightly more complicated (ie do they have the right ladder at that base?)  Makes things tougher when you stop on a cross country for a cheesburger.

IIRC the best ladder story is the one on the F-117.  No internal ladder, so the Lockheed technicians grabbed one of those cheap foldable ladders that can be positioned at many angles, cut off a small section and wrapped the legs with some foam and duct tape to protect the aircraft skin.  Worked great, but the brass thought it looked too hill-billy and released a contract for a real boarding ladder, which unsurprisingly was many times more expensive than the perfectly functional field mod ladder.