Engine quastion about He-177

[Propellorhead]

If true then why didn't RLM just continue funding Ju-89 / Ju-90 / Ju-290 development? The Ju-90 was powered by 4 x 820 hp BMW132 radial engines. Replace them with 4 x 1,200 hp Jumo211 V12 engines and you've got a decent heavy bomber ready for mass production by 1940.

The Ju-290 was never suited to being a bomber because the spar ran beneath the fuselage, right at the centre of gravity where a bomb bay would need to be located.

The Ju-290 did evolve through various engine types. The Ju290 predecessor was the Ju-89 Ural Bomber contender. This underpowered aircraft had four DB 600A engines. As the early Ju-90 V-1 to V-5 it had the BMW 132 engine which was a German copy of the P&W R-1690 Hornet.

Later versions of the Ju-90 acquired the BMW 801MA engine and at Ju-90 V11 stage the aircraft design was frozen and redesignated as Ju-290. Round fuselage portholes on the Ju-90 became rectangular following this on the Ju-290. Later versions of the Ju-290 adopted BMW801D. The Ju-290 A-5 went to BMW 801G engines.

The Ju-390 adopted the BMW 801E and BMW 801F engines.

 

[Propellorhead]

and then there was the junkers jumo 222 which i believe{i'm currently sitting in my truck at a truck stop in waco tx}were two jumo 213's coupled together and used in a few Bomber B programe aircraft designs.I don't believe it suffered from the same problems as the db 610.Also from what i've read the low oil pressure problem of the db 605 was never completely solved which perplexed the engineers at the time.

Nope the Jumo 222 was not a couple of Jumo 213s bolted together. The Jumo 222 was a very promising but failed design, with six Vee blocks bolted together around a common crankcase resmbling a radial engine.

The Jumo 213 was a shrunken block version of the Jumo 211 with a pressurised water coolant system.

The Jumo 222 did find itself onto at least one He-177 B. The Jumo 211 was originally specified by RLM for the He-177 B.

I speculate here, but I believe the He-177A may have been fitted with the DB 606 due to failure of the Jumo 222 engine to materialise. The Jumo 222 offered the compact 2000hp required for an He-177A dive bomber with a huge power to weight ratio.

I am pretty convinced too that RLM intended the He-177A for dive bombing and the He-177B with Jumo 211 for level bombing based entirely around the Jumo 222 and that would explain Goering's surprise at the paired engine solution of the DB 606.

Goeiring did expect a conventional four engined layout from the He-177. It seems the Jumo 222's failure to deliver crashed the He-177 program in 1942.

 

[robwkamm]

wow lots of info in this thread. does anyone have a good piture of a coupled engine? also im not sure if you guys are aware but there is a book called "ernst heinkle stormy life.". it talks about this stuff in length. ive forgotten the details so i cannot comment yet. i have to re read it. its a pretty good book.

 

[davebender]

Hmm. Perhaps that's why the Ju-89 / Ju-290 program went nowhere even after RLM resumed funding for development.

Do you think a He-177 powered by 4 engines (either DB601 or Jumo211) would perform better then a Ju-290 powered by similiar engines?

 

[Siegfried]

One reason, perhaps the key reason, the He 177 ended up with coupled engines was that the structural costs to providing sufficient aeroeleastic rigidity with the the weight of the outer engines near the outer tips of the wings is much higher. This would be especially so in an aircraft intitially designed to dive.

The He 177 was definetly a 4 engined aircraft, an engine could be declutched and shutdown in flight to conserve fuel.

If it had of been a more competant and thorough installation it might have been one of the great bombers of WW2/

 

[davebender]

How much higher is "much higher"? Heinkel must have thought the He-177B practical or else he wouldn't have proposed the design during 1938.

 

[wuzak]

One reason, perhaps the key reason, the He 177 ended up with coupled engines was that the structural costs to providing sufficient aeroeleastic rigidity with the the weight of the outer engines near the outer tips of the wings is much higher. This would be especially so in an aircraft intitially designed to dive.

Surely the issue was drag? There being less drag in one nacelle than two.