M111 Self-Propelled Anti-Aircraft Gun

[rickshaw]

The T249 Vigilante was a prototype 37 mm self-propelled anti-aircraft gun (SPAAG) designed as a replacement for the Bofors 40 mm gun and M42 Duster in US Army service. The system consisted of a 37 mm T250 six-barrel Gatling gun mounted on a lengthened M113 armored personnel carrier platform with a radar system.




The US Army was quite impressed with the performance of the T249 but however realised that the system had severe limitations in the form it was designed.  Treating the T249 as a "proof of concept" the Ordnance Board ordered that a better vehicle be designed to fix the problems encountered.  Perhaps the worst was the limited amount of ammunition which was carried onboard the vehicle, barely allowing more than three or four engagements before it had to be replenished.  Then there was the problem that the gun had to be reloaded from outside the vehicle, which was clearly unacceptable if it was operating in a Nuclear, Biological or Chemical environment.   While the radar was an excellent improvement over the vehicle it was intended to replace, the M42 Duster, which had none, it's range and discrimination was limited and it was felt a more powerful unit would be required.

In order to accommodate all those things, a larger, roomier vehicle than the M113 was required.  While it was possible to lengthen the M113 chassis, the M113 production was running at full speed, just keeping up with the existing orders for standard vehicles to re-equip the Army.   Casting around, the decision was taken to utilise the M109 Self-Propelled Howitzer chassis.  This was large and was readily and cheaply available.  So, the M109 was adopted.  A new belt feed ammunition supply was designed, using "cassettes" which could be easily loaded in and out of the large rear hatch on the vehicle.  With a crew of three (Commander, gunner and driver), carrying sufficient ammunition for 10 or more engagements and a substantially more powerful and larger radar, the M111 SPAAG was adopted into US Army service as the M111 SPAAG.

The vehicle depicted, is that of the first M111 SPAAG which was presented to the Press on 7 June 1966.  It was later deployed to Europe where it made a valuable contribution to deterring Communist aggression from the USSR on the German border.   The value of such vehicles were proved when several, supplied to Israel, successfully defended the Dimona nuclear reactor against an unsuccessful Iraqi air attack in 1991.  Several MiG-23 aircraft were downed, described as having been "shredded" by the firepower of the 37mm Gattling guns.











The Model

The model is a venerable Italeri M109 SPG, with suitable modifications.   The gun was what held up the build for some time as I attempted to work out some way in which to produce consistent circles and hexagons (and drill them well enough, without splitting) to hold the gun tubes, made from brass tube.   The radar aerial is from Shapeways and intended for for a 1/16 scale U-boat.  It is a little large but I think looks quite good.  The 3d printed material though, proved to be difficult to paint, basically sucking in the paint applied (which was acylic) so I sealed it first with a weak solution of PVA glue which seemed to stop it.   The vents are Gundam vents, from HLJ, suggested to me by Gingie.  The acquisition radome came from the top of a large, multicolour pen.  

[Weaver]

That's excellent: what a cool project! 

[kerick]

Awesome! There should be signs on the sides of the vehicle telling people to beware of flying 37mm shell casings!

[Captain Canada]

That's got to be one of the coolest looking tanks on the site ! love the look of this one. The colours look spot on as well.....like it just drove off an early 80s army base !

Nice work indeed.

[NARSES2]

That's really good mate.

There is no way the US Army would have purchased it however.....looks far to Soviet 

[PR19_Kit]

I thought it was an RW build actually, but I know naff all about tanks. It looks terrific Brian. 

What happened to the T249 project in the real world? Did they just give up on the idea?

[jsport]

reat idea and great build. 

[Army of One]

Oh sweet moly.......this is awesome......large calibre multi barrelled.......what's not to like.........what a fantastic build..........

[GeorgeC]

A 37mm gatling gun - gosh     Great model.

[rickshaw]

I thought it was an RW build actually, but I know naff all about tanks. It looks terrific Brian. 

What happened to the T249 project in the real world? Did they just give up on the idea?

Basically yes.  They decided they preferred the idea of a one shot-one kill missile system in the Martin Mauler SAM.  That too was abandoned as being too technically difficult and in the end they got the Chapperall SAM system - Sidewinders on the back of a tracked load carrier.

[sandiego89]

 Awesome! Great idea and execution.

I nominate for a whiffie, armor category.  I'm away from my home computer and can not do the proper links for a nomination.

[zenrat]

Cool. 

[PR19_Kit]

I thought it was an RW build actually, but I know naff all about tanks. It looks terrific Brian. 

What happened to the T249 project in the real world? Did they just give up on the idea?

Basically yes.  They decided they preferred the idea of a one shot-one kill missile system in the Martin Mauler SAM.  That too was abandoned as being too technically difficult and in the end they got the Chapperall SAM system - Sidewinders on the back of a tracked load carrier.

OK, thanks for that. I can see their logic but the Eastern Bloc and their buddies had that four gun system on a tank chassis that seemed to be well feared, didn't they? Wasn't that called a ZSU somethingorother? I'd have thought the US would have tried for an equivalent at least.

[rickshaw]

I thought it was an RW build actually, but I know naff all about tanks. It looks terrific Brian. 

What happened to the T249 project in the real world? Did they just give up on the idea?

Basically yes.  They decided they preferred the idea of a one shot-one kill missile system in the Martin Mauler SAM.  That too was abandoned as being too technically difficult and in the end they got the Chapperall SAM system - Sidewinders on the back of a tracked load carrier.

OK, thanks for that. I can see their logic but the Eastern Bloc and their buddies had that four gun system on a tank chassis that seemed to be well feared, didn't they? Wasn't that called a ZSU somethingorother? I'd have thought the US would have tried for an equivalent at least.

The ZSU-23-4 Shilka quad 23mm cannon on a modified PT-76 light tank chassis, which was the Soviet system but it post-dates the T249 by about five years.  The US Army's equivalent to that was the M247 Sgt.York DIVADS which mounted twin 40mm Bofors guns on an M48 MBT chassis which was developed after the Shilka was seen to be so effective in the 1973 Yom Kippur War.  The M247 failed 'cause the radar system didn't work.  It once tried to track the ventilator fan in a toilet block behind the audience at a demonstration.   

They could have fixed it but the Soviets had already countered the system in exactly the same way the Americans had countered the Shilka - by extending the range of their helicopters  AT missiles, so they could fire them outside the engagement range of the guns, so the Pentagon came up with various excuses and abandoned it.

[PR19_Kit]

It once tried to track the ventilator fan in a toilet block behind the audience at a demonstration.   

I hope it wasn't in 'Auto Fire Mode', if only for the sake of the toilet's occupants!

Thanks for all that, very educational.