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Monday, January 14th 2008, 5:45pm

You're comparing a WW 1934/1935 engine to a 1943 engine (service dates). Of course the earlier engine is not going to be as good.

Dropping the Planebuilder efficiency is not the idea, that pushes down your fuel economy (which is OK as it is). To adjust the horsepower, adjust either the propeller size or the bypass ratio.

The DB-603A is a 1750 hp engine, so it's efficiency is 0.862 HP/lb (my error, shows what I get for reading something rather than confirming it myself). Keep in mind, though, that it wasn't historically available in production quantity until 1943. The similar weight RR Griffon was available a little earlier but not much. In 1940, there simply weren't any 12 cylinder in-lines of 1600 hp available in production quantities (there were various racing engines, but they're not what you want for a bomber).

Kaiser Kirk

Lightbringer and former European Imperialist

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Monday, January 14th 2008, 7:24pm

Looking at my notes for 1940 engines, (presuming I have the dates and numbers right) 1940 saw the French come out with the Hispano-Suiza 12Z-17, 1300hp/1520lbs (1), 0.855 hp/lb while the Russian derivitaive of the 12Y, and I have the early M-105 was giving 1100hp (1941 version gave more) on a 1365 engine for 0.806hp/weight.

0.83 splits that difference and would be "bleeding edge" for 1935 but viable... a touch early for 1934.

(1) HS 12z-17 info


Saturday, March 8th 2008, 3:54am

Since people are already designing the Peshka...

here she is in Russian service!

First flight in 1936

Pe-2 twin engine bomber
Wingspan - 17m; Length - 12.65m; Height - 3.5m; Wing Area - 41m2
Crew - 4; Engines - 2x 1100HP Klimov in-line engines; Empty weight - 5,025kg; Maximum weight - 8,160kg
Defensive armament - 3x 14mm machineguns (Dorsal turret, nose and belly mounts)
Top speed - 349kts; Maximum altitude - 11,750m; Maximum range with no bombload - 3,000nm at 290 kts
Combat radius with 1,500kg bombload - 500nm at 290 kts

Recce and interceptor versions under consideration

This post has been edited 2 times, last edit by "AdmKuznetsov" (Mar 8th 2008, 2:50pm)


Saturday, March 8th 2008, 4:00am

Finally a Russian version!


Saturday, March 8th 2008, 4:03am

Correction, the "orriginal" version.


Saturday, March 8th 2008, 10:04am

Seems to be a fair bit faster than historically, but with less power. Is Russia going with the all tactical force like historically, or incorporating a strategic element with 4-engined bombers?


Saturday, March 8th 2008, 12:18pm

Depends on the timeframe of the war. Russia has a few hundred TB-3 equivalents that are transitioning to the transport role, but as of yet there is only a handful of the Pe-8 equivalents still being developed and evaluated. A production decision is expected in the next year or so.


Monday, June 30th 2008, 12:32pm


is a modification of the ANT-31, taking advantage of technical developments since the ANT-31 was introduced. Engine power, speed, and armaments are increased.

ANT-31b - A development of ANT-31
Wingspan - 39.6m; Length - 24.4; Height - 4.5m; Wing Area - 223m2
Crew - 7; Engines - 4x 1,000HP Klimov in-line engines; Empty weight - 12.000kg; Maximum weight - 21,000kg
Defensive armament - 6x 14mm machineguns in 3 turrets (Dorsal, Tail, Belly), 2x 14mm machineguns in nose
Top speed - 200kts; Maximum altitude - 10,500; Maximum range with no bombload - 3,000nm at 170 kts
Combat radius with 2,000kg bombload - 1,250nm
Combat radius with 4,000kg bombload - 900nm

This post has been edited 1 times, last edit by "AdmKuznetsov" (Jun 30th 2008, 12:32pm)


Monday, June 30th 2008, 6:07pm

I'm not sure on the need for all those heavy machine guns.


Monday, June 30th 2008, 6:29pm

Maybe they fear the offensive firepower of "The Flying Platoon" and need some defense for that. :)

This post has been edited 1 times, last edit by "Rooijen10" (Jun 30th 2008, 6:29pm)


Monday, June 30th 2008, 8:16pm

With fighters now packing 12-13mm mg

there's no sense in making new bombers with 7.62s.


Monday, June 30th 2008, 9:15pm

Actually, there is: the higher ROF of the lighter weapons, and the "fact" that the fighters are more vulnerable to damage than the bombers (especially when the fighter has to point it's nose, with vulnerable engines, radiators, etc) at the bomber. Not to mention the lighter weight, of course, for the weapons, the ammunition, the mountings, etc. Germany's planning on using a mix of 7.92mm and 15mm weapons for it's bombers for a while yet.


Monday, June 30th 2008, 9:21pm

Bombers don't need to shoot fighters down. You just spray a large amount of bullets in their general direction and hope they miss. With current fighters hardly packing any armour or self sealing tanks, the smaller calibre is a better choice. The heavy machine gun just makes a bigger hole but weighs considerably more.


Monday, June 30th 2008, 9:44pm

It also reaches out further

Don't want to give the fighters any stand-off advantage.


Monday, June 30th 2008, 9:50pm

That may be an argument when larger cannons start seeing widespread use with big HE loads, but a 12.7mm bullet won't penetrate much at range, especially after going through the skin and tumbling.

This subject came up on another board when looking at the 11.35mm Madsen. Twice the power of a 7.7mm round but only slighter heavier gun. Its helped by the short case and relatively low mv, similar to the MG 131.