Luftwaffe copy the Merlin

[PeterVerney]

Re the B29/Tu4. The story goes that Stalin ordered the copy, saying "It must be exact, down to the last nut and bolt". Stalin's orders were not disobeyed, to do so meant a bullet in the back of the head.
So, the Russians produced nuts and bolts and everything else, to the American imperial measures, not even daring to use their own perfectly adequate metric equivalents. Thus prolonging development even further.

[Håkan]

Hello,

As an interesting side note regarding copying of available equipment, the Swedes made a copy of the Pratt & Whitney Twin Wasp called the STWC-3. This was done due to the U.S. embargo on war material to Sweden. The copy was made without hardly any access to drawings etc. They also converted it from inches to mm. Totally 434 engines were made. A retroactive licence arrangement was later made after the war, something never expected by the US, the American firm claiming nothing but a symbolic payment (reputedly a licenses fee of 1 Swedish krona). The engine was used in types including the SAAB B 17, SAAB B 18 and FFV J 22.

Best wishes/Håkan

[Graham Boak]

The French did have plans for using the Merlin in their fighters and bombers. However, given the designs they had coming along, setting up a line for the Spitfire would not be worthwhile. Although they fought the Battle of France largely with inferior types, the D520 was pretty good and other prototypes were flying.

[Tapper]

I appreciate its where do you stop when you start copying enemy equipment, but with something as vital and war winning as an aero engine why not. By WW2 all sides appreciated that the war could not be won without winning the air war first. We all agree i am sure, that this is why D Day was a success and would not have even been contemplated without holding the air above the beaches.

By late 1941 the FW190 had made its appearance and had proven more than capable against Spitfire's however, I sure that the huge development potential for the Merlin had been recognised...that would have been the time to copy and improve for Germany.
Could the 109F have been fitted with the Merlin?
Would anyone care to guess on the 109F with a Merlin...better or worse?
And am I correct in saying that the potential for the Merlin was greater than any German liquid cooled engines of that time?

[Birgir Thorisson]

Graham Boak.

The question is; what where the prospects in 1936/37, when french re-armament plans were in deep trouble. The 1934 program had produced failed prototypes. (MS 405, Ni 161, Loire 250 and D.513). The 1936 program was some years into the future.
Hispano-Suiza and Lorraine-Dietrich were both having serious problems with the next generation of inline-engines. (Therefore the eventual use of Merlin in the D.521).

On the other hand, the Spitfire was flying, it´s performance was already in the range expected from the 1936 program-fighters, and Rolls Royce had spare capacity in mid 1938.
Vickers Armstrong had been connected to Wibault in France. RR did not licence it´s engines, but there was a long tradition of engine technology being passed back and forth over the channel.
So, why not order a stop gap quantity of 2-300 Spitfires, to be built in the new factories in France?
The main difference between the french and british aviation industries was not the nationalization in France, versus private enterprize in Britain. In both countries, the state built up the production capacity, which was run be favoured industrialists. Rather, the difference is that the french engineers failed to provide good-enough aircrafts, and aero-engines in time. No use having a large crop of super planes for use in 1941.
The importance of engines should not be underestimated. IF the MS 406 had been replaced by MS 411, it would have been far more competitive in may/june 1940. The 200 hp that the H-S 12Y was short in 1940 were sorely missed.

Birgir Thorisson

[Graham Boak]

Birgir: This overlooks the problems and delays in getting the Spitfire produced in the first place.

I think you over-rate the Morane, although I entirely agree about the value of extra power.

Tapper. No, you are not right about extra potential. Yes, the 109F could have been fitted with the Merlin, as the Buchon proved, but at that stage (late 1940/1941) the DB601 had as much (or more) power as the Merlin so no advantage could have been gained - even ignoring the key point that only the previous year's Merlin could have been made available in any numbers.

[Kutscha]

The Griffon would have been a better engine to have been used. A much better engine all round.

[Graham Boak]

But the Griffon was not something that the Germans could have copied, because of a lack of access to examples. Not were they without their equivalents: the DB603/Jumo 213 had the power and potential of the Griffon. The Jumo 222 and DB610 had even more potential - as indeed did the Eagle and Clyde, if rather further behind in development.

The Germans and the British had rather different development approaches (as indeed did the US) but it can't be justified that one was significantly superior to the other: certainly not to an extent to justify a direct copy.

The closest that actually occurred would be the way that the Centaurus was redesigned to an aft-exhaust system, in the light of Fw 190/BMW 801 experience, but this was a matter or airframe integration rather than internal engine design. It might be interestingly argued that this redesign, if producing a superior engine in the long run, meant that (arguably) Britain's finest aero engine missed the war. But that would be another thread altogether.

[Birgir Thorisson]

Graham:

If I overrate the MS 406, then you too overrate the D.520. Back in 1978, the belgian researcher Gaston Botquin sent to the Air International his figures for how many enemy planes were claimed, (confirmed and probable) for each french fighter pilot killed. I calculated the same statistic for the british Hurricane force from Brian Cull´s et.al. Twelwe Days in May. The figures are as follows.

MS 406 = 1:2.5
MB 151/2 = 1:2.9
H75A = 1:6.2
D.520 = 1:7.7
Hurricane = 1:11.1

The Hurricane is much superior to the D.520. Also, if you look at the Campaign in Syria in 1941, where the best French outfit faced fairly ordinary Hurricane outfits, the Hurricane still comes out on top. Ditto Operation Torch. Small samples to generalize, but...
One shortcoming of the MS 406 was that it rarely performed up to it´s advertized performance. (As is confirmed by Finnish performance tests). The HS 12Y-31 engine wore out quickly, and also lost power with altitude quickly. (Similar to the Allison V-1710.) It was only with the addition of the Szydlowski-Planion supercharger that this defect is alleviated. The MS 405 was of the same technical generation as the Hurricane. With comparable engine (MS 411) the aircraft should have performed similarly. The MS 406 had superior armament, (the motorcannon). The two/four wing-mounted machine guns were largely useless.

That brings up a different issue, which is more pertinent to the main theme of this thread. It is well known how the allies "lost" the opportunity to get their hands on the direct injection system before the war. But why didn´t they copy the strong points of the DB-601 series, as soon as war broke out. The Bosch injection system, and the supercharger gearing system. Both features kept the DB engines competitive for most of the war. Surely not Patent rights

[Flitzer]

It would have made more sense to keep the DB engine and copy the Spitfire!

http://www.unrealaircraft.com/hybrid/spitfire.php