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- #81
davebender
1st Lieutenant
Not exactly a ringing endorsement of the Hs.820 cannon from the USAF Armament Laboratory.
Why does the German Army like 20mm auto cannons so much?
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Not exactly a ringing endorsement of the Hs.820 cannon from the USAF Armament Laboratory.
My point exactly..... '6 of one 1/2 dozen of the other'
I didn't even look up the Hispano gun, the way it was first mentioned I just assumed it would have a significant drop in performance over a revolver-cannon.
Still, I suspect a revolver cannon would have a higher sustained fire performance. DEFA/Aden are common designs, and DEFA have pretty good barrel life. It's Soviet guns that have shocking barrel life, do you reckon it's the metallurgy or the guns? I'm thinking of the Gsh-301, it can fire what, 500rds before a barrel change? Must be one tight chambering and strong rifle, probably super accurate I guess.
Still, I suspect a revolver cannon would have a higher sustained fire performance. DEFA/Aden are common designs, and DEFA have pretty good barrel life. It's Soviet guns that have shocking barrel life, do you reckon it's the metallurgy or the guns? I'm thinking of the Gsh-301, it can fire what, 500rds before a barrel change? Must be one tight chambering and strong rifle, probably super accurate I guess.
French 20 mm/90 GIAT M693 and 20 mm/73 GIAT M621
Hs 820 Barrel life is 16,000 rounds compared to 9,000 for the Oerlikon competitor.
Britain, Switzerland and USA 20 mm/70 (0.79") Oerlikon Marks 1, 2, 3 and 4
Mk 16 20mm gun was a derivative of the earlier Hs 404 gun got only 6500 barrel life.
The Naval Institute guide to world ... - Norman Friedman - Google Books
According to this site the ADEN/DEFA 30mm gun was only rated 5000 rounds, while it confirms that Russia guns were only about 2000 rounds.
Hs 820 Barrel life is 16,000 rounds compared to 9,000 for the Oerlikon competitor.
Britain, Switzerland and USA 20 mm/70 (0.79") Oerlikon Marks 1, 2, 3 and 4
Mk 16 20mm gun was a derivative of the earlier Hs 404 gun got only 6500 barrel life.
The Naval Institute guide to world ... - Norman Friedman - Google Books
According to this site the ADEN/DEFA 30mm gun was only rated 5000 rounds, while it confirms that Russia guns were only about 2000 rounds.
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- #85
davebender
1st Lieutenant
Sounds durable enough. That doesn't mean it was reliable under typical combat conditions. Unfortunately the USAF Armament Laboratory report did not provide a lot of specifics other then noting the Hs.820 cannon performed poorly in dusty conditions.
I've spent 14 years in the U.S. Army. Dust is the norm for vehicles of any type operating off road.
I've spent 14 years in the U.S. Army. Dust is the norm for vehicles of any type operating off road.
The Aden gun was twice the mass of the Hs 820 gun and burned through barrels at three times the rate, which makes it a deal breaker. From the POV of purchasing a fire support weapon for the SPz 12-3, Aden was just too big and probably too expensive. It certainly would have been if it chews through barrels at 3-4 times the rate. Hs 820 and follow on Rh 202 were ideal for German Panzer grenadier doctrine and certainly more cost effective from a coldwar POV.
parsifal
Colonel
All these weapons seem remarkably similar except for barrle wear and, i guess, reliability. Except if cost is no object, this has to be a major point....those that wear parts out the quickest are the least desirable, surely
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- #88
davebender
1st Lieutenant
I think the Hs.820 was just an interim weapon until Germany regained the ability to manufacture munitions. The Rh.202 is exactly what the Heer wanted, which is why it has remained in service so long.
On paper the WWII era MG301 prototype had performance similiar to the Rh.202. Did the MG301 serve as a starting point for development of the Rh.202 cannon?
On paper the WWII era MG301 prototype had performance similiar to the Rh.202. Did the MG301 serve as a starting point for development of the Rh.202 cannon?
Shortround6
Major General
Barrel wear is largely dependent on cooling. The Hotter the barrel the faster it "wears". Actually each cartridge/round is a cutting torch that lasts for micro seconds. A gun with air flowing over it at 400-700mph ( aircraft gun) can fire longer bursts than a ground gun and fire closer spaced bursts than a ground gun.
You could probably wreck any of the mentioned barrels in just a few hundred rounds if they were fired in one long burst with little or no airflow over the barrel. Even US aircraft .50s had some rather sever restrictions on firing and cooling limits in order to reach "book" barrel life figures.
You could probably wreck any of the mentioned barrels in just a few hundred rounds if they were fired in one long burst with little or no airflow over the barrel. Even US aircraft .50s had some rather sever restrictions on firing and cooling limits in order to reach "book" barrel life figures.
Making some good sense there Shortround, didn't even think about cooling. Of course the Aden and similar are aero guns, they probably weigh half as much again adapted for ground use.
Also, Shortround, is this a reason aero gun barrels tend to be lighter than their ground based equivalent? I always thought it was just a weight thing...but then some pretty weighty guns are still installed.
Also, Shortround, is this a reason aero gun barrels tend to be lighter than their ground based equivalent? I always thought it was just a weight thing...but then some pretty weighty guns are still installed.
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- #91
davebender
1st Lieutenant
The Rh.202 cannon is a ground based weapon that fires 1,000 rounds per minute. How do they cope with barrel heat?
Shortround6
Major General
A heavy barrel (28KG) and short bursts. Most guns will stand 2-3 second bursts or even several in a row. What they won't stand is 5-10 second bursts in rapid succession. Some modern cannon may use chrome lined bores or even stelite linings.
If the "practical" rate of fire is under 200rpm due to cooling issues then trying to use high cycle rate guns (aircraft type) for ground support really doesn't buy much. High cycle rate is useful for fleeting targets like aircraft to increase hit probability for the few seconds the target is within firing range of the ground gun but for use against ground targets high cycle rates don't have much advantage.
If the "practical" rate of fire is under 200rpm due to cooling issues then trying to use high cycle rate guns (aircraft type) for ground support really doesn't buy much. High cycle rate is useful for fleeting targets like aircraft to increase hit probability for the few seconds the target is within firing range of the ground gun but for use against ground targets high cycle rates don't have much advantage.
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- #94
davebender
1st Lieutenant
How many rounds in a burst? With a rate of fire that high it must be at least 10.
I naturally assumed IFV were initially largely AAA armed anyway, I mean anybody else using IFV in the 50s had HMG on board, a markedly dual purpose armament.
I should think at this point the IFV was less an assault AFV like a StuG or a tank-killer (at least until AT-missiles were widespread), it was more like a scout with some light-AAA or infantry support capability.
Later on IFV continued with dual purpose armaments, NATO tended to go with things like DP Bofors whilst the Soviets went AT-missiles and lightened field guns on theirs with coaxial HMG or light, rapid cannon, obviously the motorised rifle brigade utilised different combat doctrine and deployment to the west. Later Soviet IFV are more like lightened MBT amphibs than IFV, the whole fleet is fully NBC sealed too.
The later Marder II SPG is an AAA complex. Marder was originally an AT-field gun. I was just naturally thinking this general shift in thinking represented NATO influence of IFV becoming dual purpose AFV with strong AAA leanings, rather than infantry assault guns with an anti-tank emphasis.
I should think at this point the IFV was less an assault AFV like a StuG or a tank-killer (at least until AT-missiles were widespread), it was more like a scout with some light-AAA or infantry support capability.
Later on IFV continued with dual purpose armaments, NATO tended to go with things like DP Bofors whilst the Soviets went AT-missiles and lightened field guns on theirs with coaxial HMG or light, rapid cannon, obviously the motorised rifle brigade utilised different combat doctrine and deployment to the west. Later Soviet IFV are more like lightened MBT amphibs than IFV, the whole fleet is fully NBC sealed too.
The later Marder II SPG is an AAA complex. Marder was originally an AT-field gun. I was just naturally thinking this general shift in thinking represented NATO influence of IFV becoming dual purpose AFV with strong AAA leanings, rather than infantry assault guns with an anti-tank emphasis.
Shortround6
Major General
During the 1950s a 20mm gun on a IFV was hot stuff. It wasn't meant to be anti-tank but anti-APC. With a number of armies still using large numbers of essentially armored trucks, or tracked armored boxes with 1/2in (12mm) armor a 20mm gun could take out quite a number of battle field ground targets when you add the vehicles to the fire support targets like MG positions and such.
AA capability was limited. May work against helicopters but most mounts didn't have the traverse or elevating speeds needed to track jet attack aircraft, while the Marder IFV does it's predecessors used manual turrets. Anything is better than nothing but the US .50 cal MG AA capability was pretty dismal in WW II. It may have scared off a number of attackers but the number of rounds fired vs the number of aircraft brought down would have any accountant looking for another solution. There is a huge difference in the effectiveness of a power operated quad .50 and four separate .50s on pintle or ring mounts.
AA capability was limited. May work against helicopters but most mounts didn't have the traverse or elevating speeds needed to track jet attack aircraft, while the Marder IFV does it's predecessors used manual turrets. Anything is better than nothing but the US .50 cal MG AA capability was pretty dismal in WW II. It may have scared off a number of attackers but the number of rounds fired vs the number of aircraft brought down would have any accountant looking for another solution. There is a huge difference in the effectiveness of a power operated quad .50 and four separate .50s on pintle or ring mounts.
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- #98
davebender
1st Lieutenant
Or anti-infantry as the flakvierling was employed during WWII. 20mm mine shells have a small casualty radius but the high rate of fire allows you to quickly smother an entire enemy infantry squad. The 20mm M197 gatling gun employed on some Cobra gunships would have a similiar effect vs infantry.
futuredogfight
Senior Airman
They are highly effective, thats why. BTW 50th post w00t!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
