New Axsis bomber

[ChopSaw]

Originally posted by Krusty
"... and dive-bombing was never the same afterwards..."

Yeah, yeah.  I think we can all agree, dive bombing using Lancs is not nice.

[HoHun]

Hi Karnak,

>Unsurprising seeing as the Manchester had the same sort of engine concept as the He177, i.e. two less powerful engines slapped together to make one powerful engine.

Hm, actually it was a completely different concept.

Each of the Manchester's Vultures was a single X-engine based on the Kestrel development line, while each of the He 177's DB606 engines consisted of two independendly operating DB601 V-engines (two DB605s in case of the DB610). They were started independendly and connected to the propeller by a clutch that automatically disengaged a failed engine, making 3-engined flight possible.

The problems with the Manchester were entirely caused by its engine, while the problems with the He 177 were caused by the airframe design issues which screwed up engine cooling and introduced the well-known fire hazard.

Regards,

Henning (HoHun)

[Angus]

Didn't later He 177's have 4 engines too.....I mean 4 props as well???

[Lusche]

Originally posted by Angus
Didn't later He 177's have 4 engines too.....I mean 4 props as well???

No, they did not. (well, in fact all 177´s had 4 engines)

The 4-engine, 2 prop layout was choosen because the Luftwaffe wanted to be the new heavy bomber to be capable of dive-bombing! (doctrine vs reality, hehe) Even before trials showed the problems of this configuration (see the posts above), Heinkel came up in 1938 with the proposal of producing a conventional 4-prop version, but his wish was denied by the Luftwaffe, for such a version could not dive bomb (well, they did not see our Lancaster in AH2...)

After the first few losses, Heinkel rebuilt a standard He 177 A-3 into 4prop configuration using 4 BMW 801 engines. This was done as a private venture without Luftwaffe support. As far as i know, there was only one prototype, but defenitely no serial production.  In 1944 this project evolved into a planned He 277, a true "heavy bomber" with 4x 2000HP and a loaded weight of 42000kg.

Another spin-off was the He 274 high-altitude Bomber with 4 DB603 engines and a planned ceiling of 14000m The prototype was build by Farman in Suresnes near Paris, but of course the French were not in a hurry, and the Machine had it´s first flight well after the war...

[HoHun]

Hi Lusche,

>Heinkel came up in 1938 with the proposal of producing a conventional 4-prop version, but his wish was denied by the Luftwaffe, for such a version could not dive bomb (well, they did not see our Lancaster in AH2...)

Well, since Heinkel actually seems to have been the driving force behind the development of the double-engine powerplants (for the He 119), it would be interesting to see if the sober Heinkel files maybe tell a different story than designers' post-war memoirs. I'd suspect this issue was actually more complex than the simple dive-bombing story.

(In fact, I don't see any causal link between number of propellers and dive bombing capabilities :-)

Regards,

Henning (HoHun)

[Lusche]

Originally posted by HoHun
Well, since Heinkel actually seems to have been the driving force behind the development of the double-engine powerplants (for the He 119), it would be interesting to see if the sober Heinkel files maybe tell a different story than designers' post-war memoirs. I'd suspect this issue was actually more complex than the simple dive-bombing story.

(In fact, I don't see any causal link between number of propellers and dive bombing capabilities :-)

Regards,

Henning (HoHun)

I am afraid you are fully right if you say that the whole story is much more complex than outlined by me. Like others (Messerschmidt for example), Heinkel tended to "simply" his memories after the war...

But underlying concept for the He177 WAS to make a plane that large capable of dive-bombing. Which was not
fully unreasonable, as level bombing gave at that time more than lousy results (But that´s another story)

The link between dive-bombing and number of propellers (or better: engines)  is stress. A divebomber has to endure much greater forces than a "simple" level bomber. Especially the wings are much more stressed. And if you link two engines together like in the 177, you can put those masses much closer to the fuselage. The resulting wingspan is also a bit shorter. I think vibrations could be an issue too, but this is just a rather uneducated guess of mine

[HoHun]

Hi Lusche,

>Especially the wings are much more stressed. And if you link two engines together like in the 177, you can put those masses much closer to the fuselage.

Actually, in flight the lift is exerted on the wings while much of the weight/inertial force is exerted on the fuselage, so mass near the fuselage actually increases the wing root bending moments. You'd want the mass on the wings to avoid this.

Regards,

Henning (HoHun)

[Wilbus]

I'd actually rather see a Ju188 or a 388 instead, now those would be awsome!

Not that I wouldn't want a He177

[Angus]

Ehhh, from HoHun, or a reply vs the first statement:
"Especially the wings are much more stressed. And if you link two engines together like in the 177, you can put those masses much closer to the fuselage.

Actually, in flight the lift is exerted on the wings while much of the weight/inertial force is exerted on the fuselage, so mass near the fuselage actually increases the wing root bending moments. You'd want the mass on the wings to avoid this."

This is boulderdash. The further out you move the mass, the more stress there is on the roots of the wings drastically increased with a little G load. Putting the mass nearer to the fuselage is very logical, and the law behind this is...Archimedes himself.

[Schwein]

Originally posted by Karnak
Mmmm, Mossie food.

Of course that is true of all German bombers other than the Ar234, so I guess that doesn't distinquish it.

Troll.