automatic cannon system concepts for attack helicopter

[tround]

Very interesting document.
There are five gun/ammunition concepts.Of course the xm230 gun with its HEDP ammunition is the best.

http://www.dtic.mil/dtic/tr/fulltext/u2/a018749.pdf

 

[Tony Williams]

A good find. Thanks for posting.

 

[tround]

Thank you also tony , for your website.

The 30mm concept B and the 40mm concept are too powerfull for a turret (for a long burst) and the m53 api is useless againt the material tergets.
Against the personnel tagets , the 30mm xm552 (father of the m788) round is better than the m56 round.
The UTS can accommodate the m230 chain gun with 500 rounds of ammunition.
Therefore, why the marines concerve the m197 on the AH1Z?

 

[Tony Williams]

Therefore, why the marines concerve the m197 on the AH1Z?

Perhaps because the 20x102 ammunition is already in USMC service, as it's used in the F-18 gun? The AH1Z is also the only aircraft cleared to fire the APDS round used by the Phalanx CIWS.

 

[tround]

You are right
A common ammunition is necessary for devices which operates far from their terrestrial bases.
I did not know that the ah1z was qualified with the APDS round.
A 20x102 APDS has a better probability to kill a armored target than a 30mm HEDP(bigger hole).

 

[Tony Williams]

Saboted ammo can't generally be used by fixed-wing planes because of the danger of the sabots being sucked into the engines, but presumably the location of the gun in the AH1, plus the powerful rotor downdraft, mean that the sabots drop down well away from the intakes.

 

[F-14D]

Therefore, why the marines concerve the m197 on the AH1Z?

Perhaps because the 20x102 ammunition is already in USMC service, as it's used in the F-18 gun? The AH1Z is also the only aircraft cleared to fire the APDS round used by the Phalanx CIWS.

The M197 has been on all USMC Cobras back to the AH-J. In fact, I think it's on all Cobras except the original -1G. It does all that they want of it, so USMC probably didn't think it was worth expense of going to a new weapon on the -1Z.

 

[Abraham Gubler]

From memory and the Bell bid for the Australian AIR 87 project the AH-1Z (or AH-1W(4BW) as it was once known) was to be (re)built with the 30x113mm M230 chaingun. But the 20x102mm M197 Gatling gun was retained as a cost saving measure. 30mm was more capable but 20mm was already paid for.

 

[F-14D]

From memory and the Bell bid for the Australian AIR 87 project the AH-1Z (or AH-1W(4BW) as it was once known) was to be (re)built with the 30x113mm M230 chaingun. But the 20x102mm M197 Gatling gun was retained as a cost saving measure. 30mm was more capable but 20mm was already paid for.

Minor nits to pick:

The 4BW was essentially the AH-1W fitted with an enlarged 680 rotor (hence the desiignator "4 Bladed Whiskey). It formed the basis for the Cobra Venom proposal to the UK for their new attack helicopter version, won by the AH-64. The -1Z was a more extensive change including electronics, defensive systems, new tail rotor, bigger wing, common power package with the UH-1Y, etc.


Australia was offered the Cobra twice. First, 40 AH-1Ws in the early '90s. Then, the -Z was offered for the Air 87 competition. it was eliminated in 1999 because it was deemed "too developmental", and the three contractors selected to proceed were Agusta (Mangusta), Boeing (Apache) and Eurocopter (Tiger). the latter won, but ironically has had so many delays that it didn't achieve full operational capability any sooner than the "developmental" Zulu Cobra.

I never knew that the Air 87 Zulu was intended to have the M230. Interesting detail I'll have to keep in mind...

 

[Abraham Gubler]

Australia was offered the Cobra twice. First, 40 AH-1Ws in the early '90s.

Actually this was the second time. The first time Australia actually ordered 11 AH-1Gs from Bell for delivery in ’72 but a change in government and rapid withdrawal from VietNam saw a last minute cancellation. The Cobras were to replace armed UH-1D “Bushrangers” and equip two gunship flights in two tactical helicopter squadrons (No. 9 and the planned to form No. 8 Squadron). The USMC AH-1Ws offered in the early 90s were the rebuilt AH-1Ts and alter sold to Taiwan (a somewhat common habit for ex US gear: offer to Australia, get rejected and sell to Taiwan). It was an obvious great loss to the Australian Army that these Cobras were not acquired at this date.

Then, the -Z was offered for the Air 87 competition. it was eliminated in 1999 because it was deemed "too developmental", and the three contractors selected to proceed were Agusta (Mangusta), Boeing (Apache) and Eurocopter (Tiger). the latter won, but ironically has had so many delays that it didn't achieve full operational capability any sooner than the "developmental" Zulu Cobra.

Bell appealed their exclusion from the shortlist for AIR 87 and were allowed back in. They couldn’t meet the initial operating capability date by 2-4 years so offered a lease of 8 AH-1Ws to cover this shortfall. Eurocopter did meet the IOC date but have hugely failed to meet the FULL operating capability. IOC was just before Christmas in 2004 and they still haven’t reached FOC release. Yet AH-1Zs have. Another win for ADF procurement. BTW Eurocopter won the contract by under bidding their TLS cost by 1/3. They later had to ask for an 1/3 increase in the budget to meet the TLS. Which they got and a follow on order for MRH90 which is late on FOC as well. Wins follow wins downunder!

I never knew that the Air 87 Zulu was intended to have the M230. Interesting detail I'll have to keep in mind...

I don’t think it was a specific offer for Australia but I think was a then (90s) paper plane spec for the AH-1W rebuild. From back before it was called the AH-1Z. I knew it had another name and went with 4BW as that was the first to mind. But I quick check of the net shows it was the CobraVenom and offered to the Dutch, British and Australians before the USMC expanded their systems upgrade (IWS) of the AH-1W into the AH-1Z.

 

[Pioneer]

Quote: Abraham Gubler
Actually this was the second time. The first time Australia actually ordered 11 AH-1Gs from Bell for delivery in ’72 but a change in government and rapid withdrawal from VietNam saw a last minute cancellation. The Cobras were to replace armed UH-1D “Bushrangers” and equip two gunship flights in two tactical helicopter squadrons (No. 9 and the planned to form No. 8 Squadron). The USMC AH-1Ws offered in the early 90s were the rebuilt AH-1Ts and alter sold to Taiwan (a somewhat common habit for ex US gear: offer to Australia, get rejected and sell to Taiwan). It was an obvious great loss to the Australian Army that these Cobras were not acquired at this date.

Wow I never knew this
What an operationally lost opertunity
Can you please give me the source of this Abraham Gubler

Regards
Pioneer

 

[Abraham Gubler]

Wow I never knew this
What an operationally lost opertunity
Can you please give me the source of this Abraham Gubler

Uhh, a guy who went to Texas as part of the contract told me... But thankfully there is the internet and a quick check of "AH-1 Cobra RAAF" comes up with:

http://adf-serials.com.au/3a16.htm

Which nicely lists all the aircraft ordered as part of this package: 84 OH-58A, 42 UH-1H, 11 AH-1G and 12 CH-47C.

 

[Rickshaw]

Saboted ammo can't generally be used by fixed-wing planes because of the danger of the sabots being sucked into the engines, but presumably the location of the gun in the AH1, plus the powerful rotor downdraft, mean that the sabots drop down well away from the intakes.

Aircraft velocity might also be a consideration. Fixed winged, particularly jet powered tend to fly into the sabot petals whereas the AH-1Z wouldn't.

 

[tround]

The DARPA has tested a remotely piloted helicopter in 1971 which fired DU flechette from a modified M3 machine gun.