Luftwaffe Cannons and Machineguns topic. (1 Viewer)

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Didn't felt that this table warrants a whole new thread of its own :)
What the Fw company was mooting as suitable weapons for their 190 some time in early 1942. The MK 108s were not suited for synchronised installation, hence my ?? remark.

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It's kind of interesting to see that in the post-WWII era aircraft guns have largely converged to 25-30mm caliber ones, the USA being somewhat of an outlier with the 20mm Vulcan but that has been replaced by a 25mm gatling gun in the F-35. Of course jets are powerful enough that they can afford to carry a high-velocity gun (typically muzzle velocity is around 1000 m/s) with a high rate of fire (gatling or revolver cannon type), but they haven't gone up from 30mm either.

In the WWII era it seems a 30mm high velocity gun entailed too much compromise (see how massive the Mk103 is, and relatively low RoF). But maybe a high velocity 25mm gun could have been feasible for mounting in a typical WWII fighter?

As for the mechanism, yeah it seems the API blowback used by the MG/FF and Mk108 was somewhat of a dead end, and not really suitable for higher velocity guns. One sort of hybrid mechanism that supposedly achieves fairly high RoF and is usable for higher velocity guns as well is "gas-unlocked blowback", where instead of the mass of the bolt preventing the backwards movement in the initial stages after firing, the bolt is locked and there is a gas mechanism that unlocks the bolt and then the rest of the action happens by blowback.
 
The German's MG213 and MK213 was highly innovative, and were 20mm and 30mm respectively.

There is a certain point where the caliber of the weapon along with it's weight, has to be worth the effort to be used in an aircraft's armament.

With the exception of the GAU-8, which had an airframe built around it, most cannon have to be able to work within the aircraft's performance profile.
 
In the WWII era it seems a 30mm high velocity gun entailed too much compromise (see how massive the Mk103 is, and relatively low RoF). But maybe a high velocity 25mm gun could have been feasible for mounting in a typical WWII fighter?
25mm guns were probably missed opportunities for Germany, japan and Soviet Union.
Soviets have gotten close with the VJa-23 (although it's usage on fighters was meager).

As for the mechanism, yeah it seems the API blowback used by the MG/FF and Mk108 was somewhat of a dead end, and not really suitable for higher velocity guns. One sort of hybrid mechanism that supposedly achieves fairly high RoF and is usable for higher velocity guns as well is "gas-unlocked blowback", where instead of the mass of the bolt preventing the backwards movement in the initial stages after firing, the bolt is locked and there is a gas mechanism that unlocks the bolt and then the rest of the action happens by blowback

API blowback was also used on the high-velocity Oerlikon S gun.
API allowed for the cartridge to be fired before it is chambered, that in combination with mass of the bolt and it's supporting members, as well as the strength of the return spring was sufficient to keep everything safe. A way to improve the RoF on the API blowback guns was to lighten the recoiling members + stiffer main spring + installation of recoil buffers; Swiss (for the Oerlikon S that became the SS2 now) and Japanese (Type 99 Mod 5) did that by the end of the war.
See here.
Germans were increasing the RoF on the MK 108 from 600 to 850 rd/min when the war was ending.
 
The German's MG213 and MK213 was highly innovative, and were 20mm and 30mm respectively.

There is a certain point where the caliber of the weapon along with it's weight, has to be worth the effort to be used in an aircraft's armament.

With the exception of the GAU-8, which had an airframe built around it, most cannon have to be able to work within the aircraft's performance profile.
The MG213 must rank as the premier air to air gun, for longevity, performance and widespread application.

Eng
 

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