Daimler-Benz proposed the DB603 to the RLM in the autumn of 1936 and received permission to develop the engine. On March 11, 1937, the RLM had development stopped, paying D-B's accrued development costs. The reason was that "in the BMW801, we already have an engine in development that will meet all our requirements in this power class". D-B people were sure that with properly funded and supported development, the 603 would have been ready for series production before the start of the war. Low-key development obviously continued in the form of the marine and tank derivatives (DB 503/507); the Daimler-Benz land speed record car of 1939 was intended to be powered by an early DB603 prototype (likely one of the ten engines that the RLM had financed) that had produced a test-bench output of 2800 HP with 3500 HP likely to be achieved. The RLM was still not interested, indeed it was considered to offer the engine for export (imagine Japan buying the engine program!). All that changed with the war; D-B received the first order for 120 engines on February 3, 1940. Series production started in 1941, but output was initially low (and was needed for any number of prototypes). Focke-Wulf made a preliminary design for a DB603 installation in the 190 in February, 1940, estimating that speed would rise by 50 km/h and the engine installation would even weigh less than the BMW801. The RLM was still not interested - the BMW is all we need for the Fw190. When the engine was available in production numbers, it was obviously needed for more important applications like the ME 410 - see above reasoning. From April, 1942, Focke-Wulf built three prototypes with the DB603 - V13, V15, V16. The V15 reached 696 km/h at 6950 m with combat (max continuous) power. Daimler-Benz brought the V16 to 724 km/h at 7000 m with Notleistung (take-off power), and with an improved supercharger to 722 km/h at 9000 m. Not needed, says the RLM, since the 190 will be used in the east, where high-altitude performance is irrelevant - the Me109 G is all that is needed in the West. Stymied by bureaucracy - a common theme in the Third Reich where know-it-alls with good contacts made the decisions.
The Jumo 222 did work eventually. The most persistent problem stemmed from the bearings - plain bearings made of an RLM-mandated bronze alloy containing antimony instead of tin. Only when tin was used could that problem be solved. Incidentally it was found that lubricants containing sulfur worked better with highly-loaded bearings. The Jumo 222 suffered from its connection with bomber programs - bombers not needed, then again needed, meaning production was ordered, then cancelled, then ordered again. The engine was ready for production in December of 1942, but production and development capacities were repurposed for the DB603 and Jumo 213. The engine would have been just right for the He219 night fighter, which was seriously underpowered with the DB603 - see "Winkle" Browns opinion.
It seems that by December 1941 the Luftwaffe was becoming aware of the limitations of the BMW801. The In line V12 offered at least the same power but with much lower drag (the main reason the Fw 190D was faster) and could do the job on lower octane fuel. Gollub in this report concludes that that the BMW801 will remain unreliable for so long that Fw 190 production vs 109 should be less than 50:50 for quite a while due to maintenance difficulties until the engine matures, that the radials were only interim and that the V12 will be needed longer term.
BMW did get the 801 to 2000hp, did develop a 2 stage 4 speed version the 801R (not produced) and did develop a turbocharged version the 801TJ. The DB603/Jumo were pushing beyond this already.
I think they should have cause to regret putting the DB603 on the back burner. The 'management' of the Luftwaffe can be acknowledged for having a large number of high performance aircraft in service and in production in 1939 so many of their decisions made sense, else they could have been as poorly prepared as say France was. Delaying the DB603 seems to have been an unnecessary own goal.
This is a tidied up machine translation of the Austrian Luftwaffe "ace" Gordon Gollub's report comparing the Me 109F4 to the Fw 190A2 testing at the Luftwaffe's test and development centre at Rechlin. The Report is dated
December 1941.
Kurfürst - Vergleichsfliegen Bf 109 E, Bf 110 C, Spitfire, Hurricane und Curtiss.
4: The following considerations are made regarding the already established production ratio of the FW 190 to the Bf 109: The engine is currently so unreliable that, in the opinion of Colonel Galland, the aircraft is only partially operational and an operation over the sea and England is currently out of the question.
According to engine experts, after many changes (already20 ) the BMW 801 C engine and D will only be so operationally secure in half a year at the earliest that it can withstand any load, i.e. is as ready for the front at the same standard as the DB 601E. (used on the Me 109F4)
For the longer term future, it it can not to be assumed that a reliable air-cooled engine will develop to the 2000 hp range.
The development of this fine aircraft will mean that we will have to resort to liquid-cooled engines, despite the great advantages of air-cooled engines. It is intended to install the DB 603 as the next liquid-cooled engine after the BMW 801D in the FW 190.
It should also be said that the
DB 603 is a completely new engine, which will also have its teething problems. It is not to be expected that this engine will appear at the front for at least a year, but at least then the 801 D will have just become fully ready for the frontline. The 801 C engine today only reaches 25 operating hours on average!! Technical difficulties will therefore last for a long time with the FW 190, while the only really front-ready fighter, the Bf 109 F4 or G (newly developed engine as well ! ) will remain so. T
he installation of the BMW 801 C and D can only to be regarded as an interim solution. Just as unsafe as the operation appears over the Channel, it remains over other seas or areas over Russia.
The composition of the pilots is no longer such that losses due to technical defects can be accepted. The use of the FW in the tropics will encounter major engine difficulties and the possibility of this will not be possible for a very long time.
As long as the BMW 801 can withstand only so few operating hours, i.e. with maintenance intervals reaches 50 hours, a lot of engines have to be pushed back.
This will create difficulties once several squadrons are converted to FW 190. The intended production ratio of about 50% FW 190 and 50% Bf 109 indicates the early conversion of other squadrons
Once this has been done, however, it is no longer possible to use these squadrons only over their own territory and either these technical defects on the engine must be stopped by then, or so many engines have to be pushed back that it is possible to change engines at an early stage, which is hardly to be expected. The development also clearly shows that the Bf 109 will always remain faster and have a higher climb rate than the FW 190.
However, the best climbing ability cannot be dispensed with If at the moment
it is sufficient in the peculiarity of the use on the English Chanel at the FW 190, or does not play such an exhaustive role, then its inferiority with BMW
801 C compared to the Bf 109 F 4 with 50% of the climbing time of the F 4 to 10000m must not be overlooked under any circumstances. With the BMW 801 D, the
inferiority is still estimated to be 25 to 30% of the climb performance of the Bf 109 F4.
From the considerations that have been made, the ratio of 50% for the FW 190 seems to be too high, even when taking into account the greater fire sensitivity of the Bf 109. gez. Gollob .
Distributor: GL Techn. Amt 2 x Genst.Leadership Staff Group T 1 x E'Stelle Rechlin 1 x For the correctness of the copy KdE 1 x Rechlin, the 6. 1. 1942. [gez.] Lieutenant and Adjutant