(Tony Williams) wrote in message m...
A few comments on recent posts:

The M61 is an extremely reliable and long-lasting gun. However, the
little 20mm shells only weigh 102g compared with 180g for the 25mm
GAU-12/U, 260g for the 27mm BK 27, 270g for the 30mm GIAT 30M791 and
390g for the Russian 30mm guns. This means that the M61 has to score
many more hits than 30mm guns to have the same effect on the target (I
have read an estimate of around 20 hits needed to bring down a modern
fighter).


I suspect it may be possible to fit proximity fuses to 27mm/30mm class
amunition to improve Pk and open up engagement envelope. Los Alamos
Labs developed single chip radars sever years ago and combined with
new explosives and fragmentation methods migh make such munitions
usefull.

Here is a swedish 'radar on a chip' program:
http://www.ek.isy.liu.se/2003/radaronchip/

Also laser beam riding guidence similar to the guided darts on the BAE
starstreak MANPADS missile could be integrated into 27mm/30mm class
munitions.

There have been a number of guided cannon shell projects. The Italian
OTO Malera companies efforts on is 76.2mm cannon (laser beam rider I
think) and then efforts by the USAF for the 105mm howitzers on the
AC130 gunships (laser spot homming to open up range) and USN work on
its 5 inch rocket boosted shells and US Army work on its 155mm
howizers. (GPS and/or laser homming)

Actuators relying on piezioelectric forces working on nose twisting
simplify such shells.

Such development smigh extend the effective range of cannon by a large
amount (out to 3-4 km I suspect) and favour big 30mm cannon such as
the Oerlikon KCA used on the Viggen.

On the other hand a turreted or tail sting 30mm cannon of ADEN sized
recoil firing guided munitions might make possible some interesting
defensive/offensive concepts.