45mm CTA

[tround]

This gun was presented in 1992.
The ammunition could have the same performances as the 45mm comvat: 1.095kg HE shell with a muzzle velocity of 1100ms.
Rate of fire is 400spm.

 

[jsport]

Thank you Tround, can't beleive it has been so long since this was introduced...Is there a contractor for this particular --assuming US gadget?

 

[Abraham Gubler]

Thank you Tround, can't beleive it has been so long since this was introduced...Is there a contractor for this particular --assuming US gadget?

The CTA guns developed in the US from the 1970s were done by ARES which was the company Eugene Stoner, of AR15 fame, ended up in. There CTA weapons family ranged from small arms through to 75mm and the American technology pack sold to the Anglo-French has resulted in their 40mm CTA weapon.

 

[jsport]

Thank you sir, am familiar w Ares on the 75mm.

 

[tround]

Yes, there was a co-operation between ARES and GIAT.

GIAT industries began its work on the CTA in 1985 with a 12.7mm cartridge.
After ,they manufactured demonstrator XT2000 in 35mm (in 1987).
At the same time, Eugene M. Stoner worked on the TARG and the PCTA , both were patented .

For the drawbacks of the CTA, read the report of the Office of the inspector general.
abstract : "Cased telescoped ammunition is ballistically inefficient with inherent performance , weight , volume , and cost problems."

 

[tround]

I think the inspector general is harsh against CTA.
The erosion of barrels is high because the muzzle velocity is high. Look the 20mm AGT , it's a monster.
With the specifications of the 25mm GAU7/A (3000 gr with a muzzle velocity of 4000fps) , CTA can work.

 

[jsport]

from Wikiped.."The Army is pursuing cased telescoped ammunition. This development is far along, and they say a new LMG could be fielded within two years (2014) with unequivocal support. The Marine Corps is pursuing caseless ammunition, which is less developed and will take several more years to refine.[10]"

there is thread on LSAT as well..

Also didn't follow the issue close but thought the euros(maybe Rheinmetall, Ruag, Bofors/BAE etc..) never stopped pursuing for autocannon..

 

[Rickshaw]

I think the inspector general is harsh against CTA.
The erosion of barrels is high because the muzzle velocity is high. Look the 20mm AGT , it's a monster.
With the specifications of the 25mm GAU7/A (3000 gr with a muzzle velocity of 4000fps) , CTA can work.

Erosion might also be caused by leakage around the projectile before it engages the barrel. A normal non-telescoped round doesn't cause that as the projectile is rammed into battery it is already engaging the barrel or so close to it that when the round fires, there is minimal leakage before it does engage.

 

[ouroboros]

Would a sabot-like object on the front of the round extending to the end of the case help deal with the erosion, if it really is the leakage causing it?

 

[skylancer-3441]

article

 

[skylancer-3441]

Separately photographed pics

 

[isayyo2]

So neat!

 

[skylancer-3441]

Two more articles from JIDR, including one reconstructed from Google Books snippet view version

 

[Colonial-Marine]

Fascinating stuff. I'm still bewildered as to why it seems the US lost interest in CTA autocannons despite having spearheaded their development. As far as I know no CTA designs are being considered for the future IFV.

 

[scrubhead]

COMVAT 45mm Advert from AUSA 1990

https://emu.usahec.org/alma/multimedia/984668/20181815MN006669.pdf

^
source for above

Search Result - Arena4-UAT

arena.usahec.org

Comparison between this and the French xt2000 system with some specs:

https://emu.usahec.org/alma/multimedia/446230/20184655MN0011349.pdf

^
source for above

Search Result - Arena4-UAT

arena.usahec.org

 

[Tony Williams]

Fascinating stuff. I'm still bewildered as to why it seems the US lost interest in CTA autocannons despite having spearheaded their development. As far as I know no CTA designs are being considered for the future IFV.

This is an extract from my new book, Autocannon:

In 1996 the Inspector General of the US Department of Defense issued a report on DoD Cased Telescoped Ammunition and Gun Technology Programmes. This covered the following projects:

1. 20 mm AGT (1982–1992): USAF Advanced Gun Technology: 20 × 140, 42 mm diameter; total weight 453 g; propellant 112 g, projectile 90.7 g; MV 1,500 m/s, ME 102,000J.
2. 25 mm CTCA (1991–93): USAF Cased Telescoped Combat Ammunition: 25 × 152, 46.2 mm diameter, 179 g propellant pushing 149 g projectile at 1,500 m/s, ME 168,000J.
3. 30 mm COMVAT: 30 × 207 mm, 54 mm diam, 1,043 g cartridge, 304 g propellant, 245 g projectile at 1,460 m/s, ME 260,000J.
4. 45 mm COMVAT (1986–91): 45 × 305 mm, 70 mm diameter, 3,175 g cartridge, 615 g propellant firing 755 g projectile at 1,350 m/s, ME 688,000J.

The Inspector General’s report concluded that cased telescoped ammunition is ballistically inefficient with inherent performance, weight, volume, and cost disadvantages. The report argued that CTC cases are wider so contain far more propellant generating a very high MV – this is ballistically inefficient, more complex and costly, adds weight and bulk, and brings heating and rapid barrel wear problems. Barrel obturation is a major problem, leading to blowby of the propellant gases, balloting of the projectile, and muzzle debris. He stated that CTC is not necessary; conventional cannon are satisfactory and much cheaper to develop.

While some of the Inspector General’s conclusions have some validity (the technical issues over obturation and balloting, and the higher cost) most of them do not. There is nothing inherent about the considerable quantities of propellant used in the listed cartridges (the cause of the other complaints); that was the choice of the designers, and could be avoided simply by dialling back the high-velocity requirement, thereby reducing the quantity of propellant needed and resulting in slimmer cases, avoiding the bulk, inefficiency, over-heating and barrel wear (problems which would also occur with conventional systems of the same performance).

 

[Colonial-Marine]

Do you have any more information on the 25mm CTCA? What was its intended use. I know the 20mm AGT was originally planned to be the gun armament of the ATF/F-22) but I hadn't heard of a 25mm telescoping ammunition design since the less-than-successful GAU-7.

 

[Tony Williams]

Do you have any more information on the 25mm CTCA?

No, I was only aware of it as a result of the DoD report.

 

[trajan]

pdf about 40mm CTA

 

[scrubhead]

More info on the comvat 45mm, might repost to the asm thread in the bigger post that I have yet to start, I am very lazy. This is dated September 1991, no day is given.

[MESSAGE TRAFFIC FROM CDRAMC TO VARIOUS REGARDING COMBAT VEHICLE ARMAMENT TECHNOLOGY 45MM CANNON PROGRAM]

https://emu.usahec.org/alma/multimedia/1002039/20184655MN0008384.pdf

short 5 pages.

"TLDR":

Spoiler

45mm Comvat completes firing tests, both automatic and single fire, defeating targets of interest

Represents breakthrough in armament design ( More ammo/ stowed load for given volume because CTA, 50% lethality growth potential, reduced weapon station volume for more efficient turret and vehicle integration because of 'high survivability design', fewer moving parts (Probably because of linkless feed and chamber design), weighs 43% less than the rh503 cannon in 50mm configuration )

TRADOC didn't express any interest in any medium caliber cannons for FIFV ( read https://emu.usahec.org/alma/multimedia/563768/20184655MNBT989110488F024533I029.pdf ) despite COMVAT being the lead candidate for the FIFV design

COMVAT was the only gun design of these 5 that offered significantly increased stowed/ ammunition load and reduced weight

The 35mm RH503 will NOT defeat the FIFV threat at ranges of interest ( Whatever that is and those are ) and the Germans also stopped or slowed worked on the 50mm version.

Because of lack of TRADOC support and funding for future development, COMVAT was set to be put on the back burner in 1992 and possibly killed despite advantages.

Questions of future interoperability, NATO Panel III is stressing for the standardization of the next NATO medium cannon caliber. If COMVAT dies and the Germans keep moving forward with the 35mm, the ability to influence future decisions is diminished. Try to attempt to sway the British and French and find others willing to pay R&D Costs and if possible, try international cooperation with the french and their own 45mm CTA program.

 

[徐童昕]

COMVAT 45mm Advert from AUSA 1990

https://emu.usahec.org/alma/multimedia/984668/20181815MN006669.pdf

^
source for above

Search Result - Arena4-UAT

arena.usahec.org

Comparison between this and the French xt2000 system with some specs:

https://emu.usahec.org/alma/multimedia/446230/20184655MN0011349.pdf

^
source for above

Search Result - Arena4-UAT

arena.usahec.org

The pdf is unable to open