What if:DB604 favored and works, enters service in 1942

[wiking85]

Daimler-Benz DB 604 - Wikipedia, the free encyclopedia

General characteristics
Type: Water-cooled 24-cylinder X (4 rows of 6-cylinders) piston engine
Bore: 135 mm
Stroke: 135 mm
Displacement: 46.38 L (2,830 cu in)
Dry weight: 1,080 kg (2,379 lb)

Performance
Power output: 1,835 kW (2,500 hp) at 3,200 rpm at 5,100 m (16,732 ft)
Specific power: 25.3 kW/L (0.9 hp/cu in)
Compression ratio: 7.0:1
Power-to-weight ratio: 0.59 kW/kg (0.95 hp/lb)
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Historically the DB604 was a back up to the Jumo 222 engine which never was able to fully function, which meant that the Daimler engine did not get favorable funding or backing from the Luftwaffe. Apparently it had more promise than the Jumo, but was not advanced past the experimental stage in 1939 and let to linger until being officially cancelled in late 1942.

So what if it had been favored and unlike the Jumo 222 actually worked by 1942?
What would it have been able to power and what could it have meant for the Ju288 or 388? How about the Do 217? Or the He177???
The enormous power would have even given German nightfighters the ability to catch up to the Mosquito, as apparently the Ju288A with the equivalent Jumo 222 could reach 417mph with 3 tons of bombs.

It seems the dimensions, if similar to the Jumo 222, would have made it a viable engine for the Fw190/Ta152 too.

 

[davebender]

That isn't true. Milch didn't like 24 cylinder engine programs so he killed them using bureaucratic methods.

April 1937.
RLM initiates 24 cylinder engine programs.
Specification requires 2,000 hp.

Jumo 222A engine passed a 100 hour endurance test during April 1941 @ 2,000 hp. DB604 engine first ran during 1939 and I wouldn't be surprised if it also passed a 100 hour test @ 2,000 hp during 1941.

It's not a matter of Jumo 222 and DB604 engine working. They worked just fine at original specification hp. Someone with authority to over rule Milch needs to order one of these engines into production and monitor the program so it doesn't get derailed as happened historically.

 

[wiking85]

That isn't true. Milch didn't like 24 cylinder engine programs so he killed them using bureaucratic methods.

April 1937.
RLM initiates 24 cylinder engine programs.
Specification requires 2,000 hp.

Jumo 222A engine passed a 100 hour endurance test during April 1941 @ 2,000 hp. DB604 engine first ran during 1939 and I wouldn't be surprised if it also passed a 100 hour test @ 2,000 hp during 1941.

It's not a matter of Jumo 222 and DB604 engine working. They worked just fine at original specification hp. Someone with authority to over rule Milch needs to order one of these engines into production and monitor the program so it doesn't get derailed as happened historically.

Why did he kill them if they worked and reached the 2500hp mark??? It seems insane that they would waste a perfectly good engine even if it was to maintain production numbers. The British had their Sabre 24 cylinder engine in the Tempest, so why couldn't the Germans use it with their FW190 or Ta152, as its dimensions were not really different from the DB603.

 

[davebender]

Why did RLM cancel DB603 engine program funding during 1937 to 1940? Why was DB601 factory construction funding cut from RM 50 million to RM 20 million during 1936 resulting in a shortage of DB601 engines prior to 1942? Why did Milch opt for the He-177A during 1938 when Heinkel recommended the four engine He-177B?

Germany didn't begin serious rearmament until 1935. I've got to assume the Luftwaffe made many mistakes due to inexperience. Give people like Milch 10 years to grow into their new jobs and they would get better. But time ran out.

 

[Shortround6]

Germany didn't begin serious rearmament until 1935. I've got to assume the Luftwaffe made many mistakes due to inexperience. Give people like Milch 10 years to grow into their new jobs and they would get better. But time ran out.

Will you please stop repeating this disinformation.

Germany was rearming several years before 1935 and you have been shown that several times.

 

[davebender]

Apparently you have a source for the German military budget other then Richard Gaettens. Please post your budget information and source.

Germany Military Budget. Billions of RM. (Richard Gaettens).
1933. 1.9. 3.3% of GDP.
1934. 1.9. 2.9% of GDP.
1935. 4.0. 5.5% of GDP.
1936. 5.8. 7.1% of GDP.
1937. 8.2. 9.0% of GDP.
1938. 18.4. 18.4% of GDP

 

[Shortround6]

I don't need a Military budget.

Germany was ordering planes and other military equipment several years before 1935. Most of the planes were totally obsolete by 1938/9 just like other countries 1933-36 aircraft but that doesn't mean they were not ordered, built, flown, and used to train with and intimidate other countries.

You also have to start someplace. The planes and equipment ordered in 1933/34/35 allowed for the construction of factories and the training of work forces to handle the bigger orders of 1936 and up.

Germany did not decide to re-arm in 1935 and start from there. The decision to re-arm was made earlier. Because of the treaties a lot of the re-armament had to be hidden, which meant that truly large expenditures (large production) had to be hidden, but much planning, prototype construction, testing and such was going on well before 1935.

 

[wiking85]

The basis of rearmament was laid in 1933-5, though by 1935 the Luftwaffe was announced with hundreds of 'combat' aircraft, which meant that they had to be built in 1933-4. So there was rearmament to a less degree, but that was only because the means of rearmament needed to be built.

But getting back on topic, supposing that the DB604 were functional and combat ready by 1942, what would it mean to have a 2500hp engine for the Luftwaffe?

 

[wuzak]

But getting back on topic, supposing that the DB604 were functional and combat ready by 1942, what would it mean to have a 2500hp engine for the Luftwaffe?

For one, they'd have a more suitable engine for the Me 264....

 

[stona]

That isn't true. Milch didn't like 24 cylinder engine programs so he killed them using bureaucratic methods.

Milch? At what dates? Certainly not anywhere near the dates you quoted for the tests. That wasn't his job at that time.
Steve

 

[davebender]

DB604 were functional and combat ready by 1942, what would it mean to have a 2500hp engine for the Luftwaffe?

During 1942 it would be a 2,000 hp engine per original specifications. Like most engines there would be more powerful versions later in the war.

Ju-288 bomber and He-219 night fighter were designed for the new 24 cylinder engine so those aircraft are almost a sure bet.

Ju-288 would replace He-111 and Do-217 level bombers.

He-219 night fighter would probably be produced ILO Ju-88G night fighter.

If enough 24 cylinder engines are available then other aircraft manufacturers will find ways to use them. For example Focke Wulf had a design proposal for a fighter aircraft using this engine.

 

[wiking85]

During 1942 it would be a 2,000 hp engine per original specifications. Like most engines there would be more powerful versions later in the war.

Ju-288 bomber and He-219 night fighter were designed for the new 24 cylinder engine so those aircraft are almost a sure bet.

Ju-288 would replace He-111 and Do-217 level bombers.

He-219 night fighter would probably be produced ILO Ju-88G night fighter.

If enough 24 cylinder engines are available then other aircraft manufacturers will find ways to use them. For example Focke Wulf had a design proposal for a fighter aircraft using this engine.

I have to disagree about the power output; it was started in 1937 and by 1942 would have reached 2500hp just like the Jumo 222 had by then.
Let's look at the DB603 as an example: initially it was given a 1400-1500hp range in 1936, but had reached 1750hp by 1940. So in four years the DB604 could have easily reached gotten that 250-350hp bump, but even taking the equivalent Jumo 222 as an example it would have been up to 2500hp thanks to it v24 instead of only v12 in the DB603.

 

[tomo pauk]

Let's look at the DB603 as an example: initially it was given a 1400-1500hp range in 1936, but had reached 1750hp by 1940.

That's a new one, DB603 reaching 1750 HP in 1940. Wasn't it late 1942, with serial produced examples having issues in Do-217 in 1943, as documented in the book about the Do?

 

[wiking85]

That's a new one, DB603 reaching 1750 HP in 1940. Wasn't it late 1942, with serial produced examples having issues in Do-217 in 1943, as documented in the book about the Do?

Which book on the Do217?
focke wulf 190 daimler benz engine db603
The racing DB603 reached 3500hp in 1939. I haven't found a quote about the HP range when the first serial version was ordered in 1940, but I thought that it was close to the 1750hp of the A series.

 

[wuzak]

I wonder if both the DB 603 and DB 604 could have been developed concurrently by Daimler Benz?

If not, I think I would go with the DB 604. It has more power, more potential though it is slightly heavier (c. 2400lb vs c.2000lb). I think it would be shorter, though, and would comfortably fit in most places a DB 603 would.

Also, I wonder if the financial support for the DB 603 was withdrawn early on because of the priority with the DB 601 and DB 605, and that Daimler Benz coudl no hope to develop all three at the time.

 

[davebender]

wonder if the financial support for the DB 603 was withdrawn early on because of the priority with the DB 601

DB601 engine had a relatively low priority prior to 1940.

Jumo 211 was highest priority engine during late 1930s by a wide margin with three times the production capacity of DB601 engine.

 

[tomo pauk]

Which book on the Do217?
focke wulf 190 daimler benz engine db603
The racing DB603 reached 3500hp in 1939. I haven't found a quote about the HP range when the first serial version was ordered in 1940, but I thought that it was close to the 1750hp of the A series.

Book by Manfred Griehl. You can check out the excerpts here:
http://www.ww2aircraft.net/forum/aviation/db-603-vs-ju-213-a-34815.html
The racing Merlin, the engine for planes, not cars (like pre-war 603) was making 2000 Hp in Speed Spitfire, before the ww2. It took RR 5-6 years to have 2000 Hp Merlins in a 'regular' aircraft.
The DB-603A indeed was producing 1750 HP, the second half of 1943 might be the time when that power was achieved reliably, ie. in a military useful fashion.

 

[Shortround6]

One can also look at the DB 601-605 for an estimate what the DB 603 might have given at a certain point in time.

The DB 603 was about 30-31% bigger than a 601 and about 24-25% bigger than a 605.

IF the bigger engine could put out the same power per unit of displacement ( it won't, more later) it would have been good for about 1838Hp at the time the 1475hp DB 605 was introduced. And we know the DB 605 had a bit of trouble with the 1475hp rating for a while.

To put out the same power per unit of displacement, everything else being equal, the two engines need to run at the same RPM and the same manifold pressure. We know that the 603 was running at 2700 RPM and the 605 at 2800 RPM. Just that drop in RPM brings us down to 1772 HP. Was the 603 operating at 1.42 or 1.4 AtA??

A DB 601 that was putting out the same power per unit of displacement as a 1750hp DB 603 would put out 1337hp, or just about what the DB 601E engine did.

It would appear the a DB 603 in 1940 had no chance of making 1750hp in service form. It might be possible in late 1941 or early 1942.

A lot depends on how many rpm you can make the engine spin at. At the same piston speed the 603 was running at you could have a 601/605 turning 3038 rpm. Piston speed equal friction and it equals stress on the crankshaft/crankcase, the engine has to be built to take the higher rpm as do the bearings. Perhaps teh 603 was designed in 1937 to run (in aircraft) at those speeds, perhaps not? And perhaps the DB engineers used what they learned form working on the DB 601 series to redesign/modify the 603 so it did give the 1750hp when introduced?

 

[davebender]

It doesn't need to. Early model DB603 only needs to perform better then BMW 801 engine to make mass production worthwhile.

BMW 801C. 1941 engine. First production model.
BMW 801 - Wikipedia, the free encyclopedia
1,539 hp for take off.
Reliability was poor. I have seen numbers as low as 25 service hours.

 

[Shortround6]

This may be low ball, but 30% more than 1100hp (DB 601A-1) is 1430hp and 30% more than 1175 hp (DB601N) is 1528hp. A 1940 DB 603 may be a bit lighter than a 1943 603.