"Paul J. Adam" wrote in message ...

What I find curious is why, when the ADEN 25 fell over, the Harriers
couldn't just shrug, reprogram the gunsight and put the old pods back
on. Failing to maintain a common interface seems _really_ silly, and I'm
really curious as to why an iteration of a revolver cannon is allowed to
be so incompatible with its predecessor. (After all, if ADEN 25 is so
good, why not go for a common interface and hang it off Sea Harrier and
Hawk too?)

The Aden 25 was designed to be compatible with the earlier Adens, so
it could just slot in as a replacement, which was the Grand Plan.
Unfortunately it was unable to meet the RAF's requirements, which
translated means that it was too unreliable and wore out too quickly.
And this was after ten years of massive effort to make it work - the
first guns were being tested at the end of the 1980s and production
contracts were being awarded from around 1990 to as late as 1997, but
it wasn't finally canned until 1999 when about 100 guns had been made.

Revolver cannon are very tricky to get working properly, with precise
ignition timing being essential. The 25x137 ammo is of course
percussion-primed, whereas the ammo for all other revolvers has used
the more precise electric priming, which does make me wonder if they
were tackling an impossible job.

There is a body of opinion which dislikes aircraft guns. The vibration
upsets the instrumentation, the muzzle gasses can be corrosive, and if
all goes well missiles will do the job....sadly, this viewpoint
ignores the fact that no military action has ever followed the script,
because the enemy has his own scriptwriters.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/