Mid 1942. Battle of the Giants.

Historical Timeline.
25 July 1941.
Ostmark engine factory construction begins. Built to produce the Jumo 222 engine.

Oct 1941.
Jumo 222A engine completes 100 hour test on dynamometer.

24 Dec 1941.
Production of the Jumo 222A engine cancelled. Instead the new Ostmark engine plant is to produce DB603 engines.

March 1942.
Ostmark engine factory construction completed.

What if……
The Jumo222A engine had not been cancelled? How does it compare with the competition? Comparison date is summer 1942.

Jumo 222A Engine. Enters mass production during April 1942.
…..1,088kg.
…..2,464hp Takeoff.
…..2,200hp @ 5,000 meters.
…..1,873hp Cruise.

P&W R2800-8 Engine. F4Us produced during 1942 and 1943.
P&W R2800-10 Engine. F6Fs produced during 1942 and 1943.
…..1,073kg.
…..2,000hp.

How many hours was the R2800 engine rated for during mid 1942?

Another rathered flawed comparison?

A "what if" engine compared to one in production?

Why was the Jumo 222 canceled?

The R-2800 had passed a 150 hour type test on the dyno in Feb 1941.

Comparing the dry weight of an aircooled engine to the dry weight of a liquid cooled engine is a little bogus.

Other "Giants" include the R-3350 with 30 produced by the summer of 1942.

The R-4360 had done initial test runs in April of 1941 although it would be years before it was ready for use.

The Wright Tornado was still struggling along.

Dry weight for the Allison V-3420 is given as 1043kg in one old reference book.

The British can chime in with both the Napair Sabre , which passed an Air Ministry 100hr type test at 2200hp in June of 1940 making it the worlds first 2000hp production engine, and the Bristol Centaurus which was type tested in 1938 and flying in several aircraft in 1941 including a Hawker Tornado.

Perhaps the less said about the R-R Vulture the better?

One point of all of this is that there is quite difference between passing a type test and being really ready for service use.

dont forget the RR Griffon

The key here is reliability.

The 222A/B were simply not reliable enough for regular service at their intended output levels.

In 1942 Junkers made the decision the scrap the A/B, upping the displacement, changing the bore and stroke and making plumbing changes to the engine. The resulting engines were only a little better in terms of reliability, although they were able to put out close to 3,000 hp on bench tests.

The R2800 was complex but reliable - being based on the successful Wasp family - and able to produce 2,000 hp from the get go and 2,400 hp by 1941.

If the 222A goes into production in 1942, the outcome is going to be similar to the early British experience with the Napier Sabre; three out of ten Typhoon test flights were ended due to engine trouble, and another one in ten due to outright engine failure.

I considered the RR Griffon. Versons available during mid 1942 produced only about 1,750hp. That puts the Griffon in the same class as a DB603. Nice engines but not in the same league as the Jumo222 and P&W R2800 monster motors.

davebender said:

I considered the RR Griffon. Versons available during mid 1942 produced only about 1,750hp. That puts the Griffon in the same class as a DB603. Nice engines but not in the same league as the Jumo222 and P&W R2800 monster motors.

Click to expand...

The Jumo 222 may not be compared with any production engine - simply because it never competed so we know nothing about unit cost, reliabilty, mean time between overhauls, etc, etc.

Engines with great Power to weight ratios and engine envelopes, and reliability are in great demand. When they aren't 'bought' there is usually a critical objection?

davebender said:

Jumo 222A Engine. Enters mass production during April 1942.
…..1,088kg.
…..2,464hp Takeoff.
…..2,200hp @ 5,000 meters.
…..1,873hp Cruise.

Click to expand...

Isn't that the persistent issue with German piston engine tech?
5,000m is not really 'high altitude' is it?

If they could have made their turbocharging tech work properly and in time that would have been much more useful, surely?

Then you'd be talking about simply needing turbo'd reliable DB603/605 Jumo 211/213's which would be giving the necessary true high altitude performance reliably.

Having said that a reliable turbo'd Jumo 222 or DB604 would have been a monster motor if they had been able to perfect them they'd have been world-leading designs.
As it was, on paper at least the plain-Jane supercharged versions were very impressive but even if they had been perfected I still see the LW having real problems dealing with high altitude aircraft.

Perhaps if they had been available they'd have dragged things out some, maybe they'd have cleared the skies of B17s but skies full of B29's?

Like a lot of this stuff all I can ever imagine it doing is delaying the inevitable.
'The bomb' would have been the game changer but engine tech - even jet engine tech - was really move/counter-move.....with Germany increasingly being hemmed in by material shortages.
My 2 pennies.

Early model Jumo222 engines were intended to power the Ju-288 fast medium bomber. For such an aircraft 5,000 meters would be a good cruising altitude.