Guided 40mm shells...?

deathjester · April 15, 2010, 02:43:18 PM

Hello chaps! In your opinions, would it be possible to create guided 40mm cannon shells, and what would be the best sort of gun to fire them?
Got an idea in mind, but since I prefer all my Whiffs to have some basis in (some sort of) reality, I thought I'd run it past you guys first.

beowulf · April 15, 2010, 04:24:37 PM

http://en.wikipedia.org/wiki/M982_Excalibur

similar idea to that?

rickshaw · April 15, 2010, 07:50:21 PM

OTO-Melara from Italy have been working on a 40mm guided round now for about 3 decades. I remember reading about their experiments back in the 1980s. Dunno if its ever amounted to anything.

Mossie · April 16, 2010, 02:36:24 AM

I'd say it's not outside the realms of possibility. BAe proposed the 81mm Merlin Smart Mortar. It would probably have worked, but it would have been costly. The Starstreak SAM consists of three 22mm darts all of which are independently guided after seperation.

Applying the technology to a cannon or gun round might be possible, one problem is that the cost of the round would be significantly increased. You'd want to pretty much guarantee a hit.

Weaver · April 16, 2010, 04:03:01 AM

BAe worked with OTO-Melara on a "course corrected" shell for the 76mm, and 40mm was the next target. The main problem is not so much the guidance, but fitting a control system powerful enough to change the shell's course significantly without reducing the explosive content so much that the exercise becomes pointless. IIRC, the 76mm shell was command guided for minimal electronics in the shell itself. The steering system was a ring of charges arounds the shell which, fired at the right moment, could give a one-off course change of about 10 deg. The shell wasn't tracked, rather the fire control system predicted where it was going to go and then triggered the steering system if that no longer coincided with the target position.

I know I've got some info about this at home, so I'll check tonight.

GTX · April 16, 2010, 02:27:31 PM

See here for a proposed 50mm guided AA shell application.

Regards,

Greg

Weaver · April 16, 2010, 02:44:38 PM

Quote from: Weaver on April 16, 2010, 04:03:01 AM
BAe worked with OTO-Melara on a "course corrected" shell for the 76mm, and 40mm was the next target. The main problem is not so much the guidance, but fitting a control system powerful enough to change the shell's course significantly without reducing the explosive content so much that the exercise becomes pointless. IIRC, the 76mm shell was command guided for minimal electronics in the shell itself. The steering system was a ring of charges arounds the shell which, fired at the right moment, could give a one-off course change of about 10 deg. The shell wasn't tracked, rather the fire control system predicted where it was going to go and then triggered the steering system if that no longer coincided with the target position.

I know I've got some info about this at home, so I'll check tonight.

Okay, had a look now. My description of the 76mm guided shell was pretty much correct: it also has flick-out fins to slow the spin down to a reasonable rate. Announcement was in 1985 and test firings in 1987. The cost target was 1/20th that of a navalised MANPADS such as Mistral. A guided round called DART is now being marketed. The most comprehensive info I can find is in this LINK

Raytheon did some work (got as far as practical demos) on a 40mm guided round using similar principles in the mid 1980s, although this was more in the context of air-to-air work, the objective being to shrink it even further to smaller calibres.

In the late 1990s, Bofors was working on a course-corrected 40mm round which could make several corrections: LINK

deathjester · April 16, 2010, 03:03:06 PM

Well, guess the question should be why don't we use this now?!!
So now I just need to work out what kinda plane to strap this system to?

rickshaw · April 16, 2010, 09:24:02 PM

Quote from: deathjester on April 16, 2010, 03:03:06 PM
Well, guess the question should be why don't we use this now?!!
So now I just need to work out what kinda plane to strap this system to?

It was primarily intended for AA work. I can't see much point in putting a 40mm gun on an aircraft nowadays when a rocket can do the same job, cheaper and less stress on the airframe.