P-39-style fighter by other people? (2 Viewers)

tomo pauk · 2024-10-30T09:24:46-0400

peceed said:
Both ADEN and DEFA entered service in 1954.

You are right.
For some reason, the DEFA 540 series also existed, that used a weaker shell, so I've assumed... Well, assumption is a mother of f-ups.

peceed said:
What about licensing the supercharger from Daimler Benz? Looks like a double win for me!

There is no doubt that DB series were with better S/Cs, and that the variable-speed drive was superior to the 1-speed drive.
With that said, not even the large DB 601, or even the huge 603 were suitable for motor-cannon installation of weapons that have large add-ons to the barrel - weapons like the M4, MK 101 and MK 103.

bf109xxl · 2024-10-30T09:45:48-0400

peceed said:
Because it uses an advanced primer ignition blowback mechanism.
The momentum of the bolt should be exactly half of the momentum of the projectile (and propellant). Too small recoil and weapon can not cycle properly, too big and recoil spring can not to absorb all kinetic energy of the bolt.

That's some new physics. According to the physics I learned, the momentum of the bolt must be exactly equal to the combined momentum of the projectile and the propellant.
How does the ignition mechanism miraculously change the recoil momentum?

peceed · 2024-10-30T11:05:50-0400

tomo pauk said:
With that said, not even the large DB 601, or even the huge 603 were suitable for motor-cannon installation of weapons that have large add-ons to the barrel - weapons like the M4, MK 101 and MK 103.

The T9/M4 had a narrow barrel and the gas tube could be oriented on the side opposite the engine.

bf109xxl said:
That's some new physics. According to the physics I learned, the momentum of the bolt must be exactly equal to the combined momentum of the projectile and the propellant.

Assuming the open bolt weapon is not API
Then half of the momentum is "reflected" by the recoil spring in the opposite direction, and then subtracted from the cartridge reaction on the next shot. After subtraction, "original" half is left to operate the next cycle of the weapon's operation.

tomo pauk · 2024-10-30T11:16:49-0400

peceed said:
The T9/M4 had a narrow barrel and the gas tube could be oriented on the side opposite the engine.

The gas tube is still there. Meaning that all the bits and pieces that lay within the Vee, most notably the compressed air intake piping, will also need a reshuffle.
Can it be done - probably yes.
Can it be done fast, with Allison still making all other improvements and different engine versions in 1939-41 so the engines are reliable and perform as promised - probably not; we can recall the reliability issues of the V-1710 that were still present ion 1941.

wuzak · 2024-10-30T12:15:59-0400

https://www.modelbouwleuven.com/uploads/1/2/3/1/123151528/p-40-v-1710-engine-006_orig.jpg

Allison V-1710 engine

Walkaround Allison V-1710 engine

www.modelbouwleuven.com

peceed · 2024-10-30T13:07:52-0400

tomo pauk said:
The gas tube is still there. Meaning that all the bits and pieces that lay within the Vee, most notably the compressed air intake piping, will also need a reshuffle.

The main manifold pipe can be moved upwards over the individual ones, as long as there are no carburetors directly connected to it.

tomo pauk said:
Can it be done fast, with Allison still making all other improvements and different engine versions in 1939-41 so the engines are reliable and perform as promised - probably not;

It should be done earlier, just to make P-39 in the standard layout possible.

tomo pauk · 2024-10-30T13:23:12-0400

peceed said:
The main manifold pipe can be moved upwards over the individual ones, as long as there are no carburetors directly connected to it.

It should be done earlier, just to make P-39 in the standard layout possible.

It can be done, however making it done might mean that an useful V-1710 is available from late 1941 instead of late 1940. Thus the USAAC is still buying 300 mph P-36s in 1940/41 instead of 350-360 mph P-40s and P-39s.
The V-1710 still has a bad S/C, BTW.

bf109xxl · 2024-10-30T16:49:54-0400

peceed said:
Assuming the open bolt weapon is not API

Good old fashioned physics should work for any bolt.

peceed said:
Then half of the momentum is "reflected" by the recoil spring in the opposite direction, and then subtracted from the cartridge reaction on the next shot. After subtraction, "original" half is left to operate the next cycle of the weapon's operation.

Ok, thanks for the explanation. I can hardly imagine how it was possible to bring this design to the required reliability, but the result is impressive.
I somewhat wonder why the Germans didn't consider the 23-25 mm caliber at all, demonstrating wonders of ingenuity to achieve perfection on a less suitable caliber instead. The 23mm caliber allowed to build a compact, rapid-firing gun with high ballistics, suitable for mounting both as a motor gun, synchronized gun and on high-speed jet fighters, providing effective fire from a longer range. The projectile power was quite sufficient.

peceed · 2024-10-30T18:04:17-0400

bf109xxl said:
I can hardly imagine how it was possible to bring this design to the required reliability, but the result is impressive.

Weapons using an API principle are simpler than any using a closed bolt and more gentle for parts than typical open bolt. That's why MK 108 was so cheap.

bf109xxl said:
The 23mm caliber allowed to build a compact, rapid-firing gun with high ballistics, suitable for mounting both as a motor gun, synchronized gun and on high-speed jet fighters, providing effective fire from a longer range. The projectile power was quite sufficient.

My hypothetical "ideal" ammo is the 20x110 upnecked to 23 mm.
135-gram mineshell with 30 gram PETN 850 mps, with more conventional shell as backup: 175 gram with 20 gram PETN, 750 mps.
Germans could use 24x138 mm, but mentioned earlier 30x111 analog (let's call it 30x110RB) would be the best option.
Preferred solution was to swap guns adequate for the mission, MK 108 or MG 151/20.
Against fast maneuvering fighters, hit probability was considered more important than shell power (even 20 mm hit was sufficient to cripple the enemy guaranteeing kill), and hit probability rises as the square of the projectile's speed.

tomo pauk · 2024-10-30T18:11:45-0400

peceed said:
Germans could reuse 24 mm from FLAK,

Care to elaborate about the 24mm from Flak?

peceed said:
and hit probability rises as the square of the projectile's speed.

Does it?

peceed said:
Preferred solution was to swap guns adequate for the mission, MK 108 or MG 151/20.

How was the guns' swapping done actually?

GrauGeist · 2024-10-30T20:35:51-0400

Perhaps by way of the rüstsatz kits?

Otherwise, I can't see swapping cowl or wing MGs/Cannon being very easy.

P-39-style fighter by other people? (2 Viewers)

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