He 100 in service, but with caveats

[Engineman]

Engine cannon is interesting. The Germans seem to have pursued this aim with a single mind! The Jumo 210 seems to have been the first success in this in an early Bf 109, possibly with a machine-gun calibre. However, it seems that progress with cannon was slow, possibly reflecting the limitations of the weapons at the time, rather than the mounting on the engine.
That said, the Bf 109 E had a large oil tank where the motor cannon would have to fit and there was no easy place to reposition that! But there must have been considerable progress and impetus to fit the motor cannon because the Bf 109 F appeared with the oil tank repositioned behind the spinner and the coolant header tanks fitted at the sides of the crankcase, allowing a fully functional MG 151 15/20 to slot straight into position.

Eng

 

[Shortround6]

Yak-3 (159.8 sq ft) was with even smaller wing than the He 100 (157.2 sq ft.)

Wiki may be wrong
Point is that the Yak didn't use wing guns, In part due the construction of the wings and/or legacy engineering.

MG/FFMs don't synchronize.
There was a He 100 prototype or mockup with two guns in each wing root, they may have extended the wing a few inches?
Maybe you can get the MG/FFM in the wings of the HE 100. Smaller wing requires bigger lumps and bumps than 109E?

 

[tomo pauk]

MG/FFMs don't synchronize.

Maybe you can get the MG/FFM in the wings of the HE 100. Smaller wing requires bigger lumps and bumps than 109E?

Will indeed need to go outboard of the prop disc, plus whatever can fit as a motor cannon.

There was a He 100 prototype or mockup with two guns in each wing root, they may have extended the wing a few inches?

I've sifted through a lot of He 100 diagrams last couple of months, unfortunately anything bigger than 7.92mm seems elusive for the wing root place. Possibily the MG 131 can fit easy enough, the MG 151 will need a good deal of rework?

Heinkel have had second thoughts about the cannon of German origin, by 1937 they were mooting the 15mm cannon installation (obviously the MG 151/15; one per A/C?) for the He 100 V1.

 

[Shortround6]

Well, four 7.9s even if synchronized plus a 15mm gun isn't bad for some jobs.
The 20mm MG 151 can swap in for the 15mm when it becomes available.
Or swap in two mg 131s for four MG 17s. and the 20mm.

Trouble this thing will never be a bomber interceptor, Granted this is after the fact (1943) but that is want Germany needed in 1943, a better B-17 interceptor.
Not a better Potez 630 interceptor in 1940 or even a better Spitfire V interceptor in 1941. It might have done a bit better than a 109F not really enough to swing either France in 1941 or Russia in 1941.

 

[tomo pauk]

Trouble this thing will never be a bomber interceptor, Granted this is after the fact (1943) but that is want Germany needed in 1943, a better B-17 interceptor.

Will need better firepower to do it, certainly.
LW should have much better A/C for that job, though, including the jets.

Not a better Potez 630 interceptor in 1940 or even a better Spitfire V interceptor in 1941. It might have done a bit better than a 109F not really enough to swing either France in 1941 or Russia in 1941.

It should be no worse than Bf 109F if they share the engine type. Even the 601N in the nose should more than do it, so the 109F can have the 601E from mid-1941.
Both France and Russia in 1941 were pretty much swung in favor of Germany, though.

 

[Engineman]

Will need better firepower to do it, certainly.
LW should have much better A/C for that job, though, including the jets.



It should be no worse than Bf 109F if they share the engine type. Even the 601N in the nose should more than do it, so the 109F can have the 601E from mid-1941.
Both France and Russia in 1941 were pretty much swung in favor of Germany, though.

Yep, it needed to be about Fw 190 size, with the DB 603 A. The DB 603 was held up by the RLM, but possibly could have been introduced in the same timescale as the DB 601 E, so a 1750hp class fighter in 1941.

Eng

 

[tomo pauk]

Yep, it needed to be about Fw 190 size, with the DB 603 A. The DB 603 was held up by the RLM, but possibly could have been introduced in the same timescale as the DB 601 E, so a 1750hp class fighter in 1941.

Unless DB figures out that their lubrication system is wrong, and until RLM lifts the restrictions on nicklel, combalt and/or chromium, DB 603 will still be plagued with reliability problems as it was the case before 1944.
Especially if pushed to 1750 HP.

 

[Shortround6]

Both France and Russia in 1941 were pretty much swung in favor of Germany, though.

That is sort of the point. The He 100 doesn't change things enough when things are going in German's favor and it is too small to change things when things are going against Germany.
Best window of opportunity is in the BoB as an longer range escort against the British.
4-5 MG 17s may do the trick against the British fighters. Don't need them for bomber interception.

Of course since the German bombers have crap for defensive guns flying another 100 miles in Britian in day light may not be the best plan even with He 100 s as escorts.

 

[tomo pauk]

Best window of opportunity is in the BoB as an longer range escort against the British.
4-5 MG 17s may do the trick against the British fighters. Don't need them for bomber interception.

Of course since the German bombers have crap for defensive guns flying another 100 miles in Britian in day light may not be the best plan even with He 100 s as escorts.

Yes, crucial thing will be how good it is in 1940.
Germany will need to make a lot of them - good hundreds - by Spring of 1940 in order for these to matter, best part of them with Jumo 211s at least. Armament of at 6 MGs (2 synchronised, 4 outboard of the prop disc) should do against the RAF's opposition.

 

[BarnOwlLover]

Well, the He-100 was (sort of) resurrected as the P.1076. Of course, it was a lot larger (similar dimensionaly to the Griffon Spitfires and Merlin Mustangs, and heavier than either), Jumo 213 or DB603 powered, and armed with 3x30mm cannons. Of course, it was claimed to be capable of 550mph. Especially in 1944, a piston engine fighter capable of being as fast or faster than the Me-262 seems a dubious claim. Not even the fastest Reno racers are really able to get to less than 10mph of the 262.

Probably the closest that the He-100 or a derivative came to Luftwaffe service, though, outside of propaganda purposes.

 

[Engineman]

Unless DB figures out that their lubrication system is wrong, and until RLM lifts the restrictions on nicklel, combalt and/or chromium, DB 603 will still be plagued with reliability problems as it was the case before 1944.
Especially if pushed to 1750 HP.

Well, the DB 603 A did reasonably well. If anything, it might possibly have got in a bit ahead of some of the metal problems if pushed in 1939. I do not know a German fighter engine in 1938 to 1945 that did not have reliability problems, some worse than others, but all seem to have had problems.
A big help for the DB 603 A was its sheer size. With 44 Iitre capacity it only needed to run at 1.42ata (6lb Boost) MAP to make 1750 PS on B 4 fuel.
There was no engineering in the DB 603 A that was not in the DB 601 E, so the engines could in theory have existed at similar timescales. In fact, I think the DB 603 A was sketched-out before the DB 601 E, they look like scale copies.

Eng

 

[tomo pauk]

There was no engineering in the DB 603 A that was not in the DB 601 E, so the engines could in theory have existed at similar timescales.

Both DB 601E and 603A (and DB 605A) were without the 'mechanical'oil de-aerator, whose purpose was removal of air bubbles from the oil system (see pg. 355 of the 'Secret horsepower race' for example). DB relied on simple, gravity-based solution, that ended up being insufficient when higher powers were required. Both were lacking the resilient valve coating. Good thing might be also to go with pistons with thicker crown, too.
See here for DB 603 troubles in 1943.

tl;dr: until DB 603A receives the treatment the 605A received by late 1943, it will be as much as a damning as it is a blessing.

 

[Engineman]

Both DB 601E and 603A (and DB 605A) were without the 'mechanical'oil de-aerator, whose purpose was removal of air bubbles from the oil system (see pg. 355 of the 'Secret horsepower race' for example). DB relied on simple, gravity-based solution, that ended up being insufficient when higher powers were required. Both were lacking the resilient valve coating. Good thing might be also to go with pistons with thicker crown, too.
See here for DB 603 troubles in 1943.

tl;dr: until DB 603A receives the treatment the 605A received by late 1943, it will be as much as a damning as it is a blessing.

Good link with the 603 thread.
Yes, those quoted faults with engines are pretty much normal in development. If I told you that 65% (2/3rds) of Merlin engines failed before reaching their overhaul life you might be surprised? But that is a very good figure for WW2 Combat engines.
The lack of an Olschleuder (or oil de-aerator) was an issue for many engines. It is a complicated subject that is being studied in detail by myself at this time. As for burned pistons, this was common and 91 hours is not unusual. These problems effected all the engines you are talking about so there is no real point in just running through the quotes, there are thousands of technical reports about engine failures. What is worth noting is though, that the DB 603 was the only 1750 hp class engine that might possibly have been available in 1941 and it suffered similar failure problems to the other much lower power engines of the time.
Interesting quote in the link that the RLM were holding back the DB 603 as early as 1937.

Eng

 

[tomo pauk]

What is worth noting is though, that the DB 603 was the only 1750 hp class engine that might possibly have been available in 1941 and it suffered similar failure problems to the other much lower power engines of the time.

Perhaps it just might, but with as much as unreliability that it historically had in 1943, prompting RLM/LW to restrict it's RPM and boost just like it did with DB 601E, 605A and 801D. Talk Fw 190 saga, just with a V12 in the nose instead of BMW 801.

OTOH, LW with a fighter powered by 1750 HP in 1941 does not change much when compared with a 550-600 km/h fighter that has range substantially better than the Bf 109, does that on dime, and it is there in 1940.

 

[Shortround6]

If I told you that 65% (2/3rds) of Merlin engines failed before reaching their overhaul life you might be surprised? But that is a very good figure for WW2 Combat engines.

Not really.
The overhaul life was by no means a guarantee.
It was the time that the engines should be pulled if nothing had gone wrong with it first. It is max life of the engine.
You know, little things like bullet holes/flak holes in the water jacket or hitting prop on landing and bending the prop shaft up a few degrees.
Yes others were pulled because no external damage they showed metal particles in the oil or broke a valve some other mechanical failure.

 

[Engineman]

Not really.
The overhaul life was by no means a guarantee.
It was the time that the engines should be pulled if nothing had gone wrong with it first. It is max life of the engine.
You know, little things like bullet holes/flak holes in the water jacket or hitting prop on landing and bending the prop shaft up a few degrees.
Yes others were pulled because no external damage they showed metal particles in the oil or broke a valve some other mechanical failure.

Not quite. The engine overhaul life statistics for the Rolls Royce Merlin are the engineering related failures, not crashes or damage caused by other factors. The total mortality including crashes, accidents, enemy action and engine failures combined is far worse. No, the 35% survival figure for overhaul life is based on engineering problems, and they do include things like
loss of compression, burned pistons, broken rings, low oil pressure etc.

Eng

 

[Shortround6]

" Percentage of total engines to reach time expiry passing through repair organization from 1942 onwards.....................................................35%"

The Merlin In Perspective- the combat years, Aleck Harvey-Bailey. Page 90.

No qualifiers as to type of damage given.
But this certainly seems like it was taken from another source.

However

"Average life of engine passing though repair organization from 1942 onward......................Approximately 60% of normal life for type"

Page 32 and 33 briefly describe (with illustration) a repair for cracked crankcase due to forced landing with welds to the reduction gear housing and steel tie rod from the reduction gear housing to crankcase (between the 1st and 2nd cylinders).

 

[Engineman]

" Percentage of total engines to reach time expiry passing through repair organization from 1942 onwards.....................................................35%"

The Merlin In Perspective- the combat years, Aleck Harvey-Bailey. Page 90.

No qualifiers as to type of damage given.
But this certainly seems like it was taken from another source.

However

"Average life of engine passing though repair organization from 1942 onward......................Approximately 60% of normal life for type"

Page 32 and 33 briefly describe (with illustration) a repair for cracked crankcase due to forced landing with welds to the reduction gear housing and steel tie rod from the reduction gear housing to crankcase (between the 1st and 2nd cylinders).

Yes. I did not intend to raise this as a distraction about the German engines but, you seem to want to, so hopefully, nobody minds.
Those quotes exist but you are taking them out of context and not giving the full information.
The crankcase repair is an example of a repair from damage in forced landings, nothing to do with engine overhaul life statistics.
So, on engine lives, Rolls Royce used an empirical guide that they used to update different engine type projected life. They found that "if 1/3rd of engines were reaching time-expiry and the mortality figure (average life to failure) was 60% of the nominal life, it was time to consider a life increase" etc. So, 35% of engines reached nominal life and the average life was 60% of nominal. The figures are based on engine problems. Other causes like crashes and enemy action were recorded separately.
These details are listed on p.36 of my copy of The Merlin In Perspective.

Eng

 

[tomo pauk]

Possible looks of the He 100 with the I-F Delta engine. 1st 700-750 HP at 4000m, later 800 HP at 5000m.
Produced instead the SAI light fighters. Two HMGs for starters.

 

[Zipper730]

Are you referring to what Heinkel was saying, or to the premise of this thread?

Both

Looking at the surface-evaporative cooling system: It's cooling system takes up nearly the whole aircraft.

Ernst Heinkel didn't received the news of defeat of the He 112 vs. Bf 109 with joy, to say at least
We can see at least two things here: he had the 109 in his sights (figuratively speaking, ofc) and he distributed tasks to his 'deputies' to find the way of making the 'Super fighter' lighter and much more aerodynamic than the 109. He was also keen to have the DB 601 powering his fighter, even if the 601 still had some time ahead itself before the series production.

When he said "high temperature cooling", I assume this didn't mean just temperature, but pressure as well?