Merlin Carbs, did supply restrictions impact early performance?

[bbear]

Hi gang, I've been away for sometime.

Can anyone cast light on what seems to be a not very nice answer to an age old thorny question: Were the Rolls-Royce Merlin engines for early Spitfires and Hurricanes behind the curve in design as regards fuel systems? Negative G and fuel icing? For a long time I believed not, but
I find among the normal online sources, this:

According to Schlaifer, pages 100-102, improvements in aircraft engine carburetors foundered on the
monopoly held by Stromberg Motor Devices Company. The company's float carburetor hindered aircraft
maneuvers and was subject to throttle icing. Technical progress was limited even though a floatless
automobile carburetor had been developed by the end ofthe 1920s and the basic patent on the control used
in the floatless, nonicing carburetor produced by Stromberg in 1938 existed in the 1920s. Stromberg
made no effort to develop a suitable aircraft carburetor until after Chandler
Groves' floatless carburetor began. The competition caused Stromberg to invest capital in development
and stimulated engineers to rethink their views. The result was that floatless, nonicing Stromberg
pressure carburetors dominated U.S. high-power aircraft engines after 1945.

At that point I stumbled on this
The three-way arrangement among the aircraft-equipment firms of Bendix (US),
Zenith (England) and Siemens was an outstanding example of the prevailing
business-as-usual mentality the big companies during the war. Bendix, in which
General Motors had a controlling stock interest, had an agreement with Siemens
prohibiting Zenith from granting patent licences to the British War Office which
wanted to expand its production of aircraft carburettors. Bendix and Siemens also
freely exchanged data on automatic pilots and present and future aircraft instruments
and divided the world into sale areas. But the idea of granting licences to
the War Ministry had not even crossed the mind of the Zenith management. This
aircraft-equipment firm was:
"...anxious that post-war business should not be complicated by departing from the
conditions of the contract in the meantime and under the excuse of war conditions..."
in this source http://hourofthetime.com/1-LF/TheArtOfCloaking.pdf page20

Am I in conspiracy theory land or was there significant impact of national and commercial interests in this matter of sharing carburetor technology as in so many other ways?

thanks.

 

[tomo pauk]

Better carb, it this case the Rolls-Royce SU fuel pump, was found to give 8-10 mph and 1500 ft to the ceiling of the Spitfire V vs. float-type carb that was usually fitted: link

 

[Glider]

I agree that Rolls Royce were behind the curve at the start of the war re injection of fuel but the concept of British sticking to pre war thinking and 'playing the game' re copywrite and patent rules in the lead up to war was almost unbelieveable.
The best example I can come up with were MTB engines. The RN decided that th best engines were italian and the first MTB's were built using Isotta-Fraschini engines.
When war broke out we decided not to continue with these as to build our own (despite the fact that we had the tools and equipment designs etc) would involve breaking the law as the italians suprise, suprise, wouldn't give permission for use to build them.

 

[bbear]

Better carb, it this case the Rolls-Royce SU fuel pump, was found to give 8-10 mph and 1500 ft to the ceiling of the Spitfire V vs. float-type carb that was usually fitted: link

I'm more thinking of Mk 1 to Mk X Merlins and why R-R chose the original carbs when the Stromberg design was available. It seems that all the design principles were understood. Not invented Here disease? Or commerce as in the second source? Why when a hundred problems were pressing go to the bother of redesigning the carb. when you can make an appeal to the ministry and get pressure put on the UK company to get Strombergs built under licence?

Thanks for the link tho'

 

[tomo pauk]

Having the license for the 'pressure injection' carbs would've been a good decision.

I agree that Rolls Royce were behind the curve at the start of the war re injection of fuel but the concept of British sticking to pre war thinking and 'playing the game' re copywrite and patent rules in the lead up to war was almost unbelieveable.
...

The fuel injection systems, at least as I've read several times, have had number of parts comparable to the engine they were supposed to be installed on. So perhaps staying out of fuel injection game meant that UK engine companies were capable to outproduce Germany - as it was historically? IIIRC the production of Merlins (1939-42) was greater than production of DB-601 and Jumo 211 engines combined.

 

[Glider]

Production figure comparisons of any type between the UK and Germany I believe are skewed for other reasons. The main one was because the UK were on a full war footing from the start (or at least doing their damnest to get to that stage) , and Germany didn't until probably 1942.

I think it would be wrong to think because the UK produced X and the Germans Y then it was easier to build X. One well know example being the Me109 and Spit. The 109 was much easier to produce than a Spit because it was designed for mass production, but more Spits were produced.

 

[Shortround6]

I agree that Rolls Royce were behind the curve at the start of the war re injection of fuel but the concept of British sticking to pre war thinking and 'playing the game' re copywrite and patent rules in the lead up to war was almost unbelieveable.
The best example I can come up with were MTB engines. The RN decided that th best engines were italian and the first MTB's were built using Isotta-Fraschini engines.
When war broke out we decided not to continue with these as to build our own (despite the fact that we had the tools and equipment designs etc) would involve breaking the law as the italians suprise, suprise, wouldn't give permission for use to build them.

I believe the Isotta's were imported. No tooling existed in the UK for manufacture. The problem with being on a war footing sooner than the Germans was that much of the existing machine tools and shops are already spoken for (assigned to an existing or higher priority program). All of the Fairmile launches up to the D were powered by imported Hall -Scott engines and I believe a few of the smaller MTB/MGB were powered by them too between the stopping of the Isotta imports and Packard supplying teh v-2500 marine engines.
In 1940 and 1941 production managers were also extremely cautious about pulling any item out of production and replacing it with a "better" one and taking the hit in production that would entail in the short run. A few weeks or months lost production doesn't look so serious in total production over 6 years but in 1940-41 after Dunkirk and with the Battle of the Atlantic not yet won a few weeks lost production looked a lot more serious.

 

[tomo pauk]

Production figure comparisons of any type between the UK and Germany I believe are skewed for other reasons. The main one was because the UK were on a full war footing from the start (or at least doing their damnest to get to that stage) , and Germany didn't until probably 1942.

I think it would be wrong to think because the UK produced X and the Germans Y then it was easier to build X. One well know example being the Me109 and Spit. The 109 was much easier to produce than a Spit because it was designed for mass production, but more Spits were produced.

There was more Bf 109s produced, ~34000 pcs (plus Czech & Spanish copies) vs. 20351 Spitfire.
But, granted, there is much more to the mass production numbers than just the simplicity of the produced item.

I'd venture to say that Germany (industry included) was on war footing from 1935 as much as there was the money for it, the economical strain of that being so big that state was on verge of bankrupcy. Hence the drive for Czech & French gold reserves. UK was far better off when it was about money, so much that they were able to purchase stuff around the world, even the expensive American aircraft.

 

[Shortround6]

A lot of arguments can be made about the economies of both countries. Much is often made of German production of "luxury goods" like women's make up during at least the early part of the war. However there are an awful lot of details ( and I won't pretend to know them all) like the fact that about 20% of Germany's National income in 1933 came from the chemical industry. The Germans may actually have had surplus chemical production that was not needed for war production in 1939/40 (or later). Many nations were moving away for mining saltpeter for the nitrogen for explosives and chemical processes. The Germans were leading in the production of nitrogen from ammonia for example. The German Steel industry was larger than the British steel industry, however the British ship building industry was larger.
Not sure were Steam locomotive production ranked, Germany having a much higher amount of losses during the war (but could loot occupied countries of locomotives and rolling stock). Germany may have out produced the British by 4 to 1 or more in steam locomotive production during the war. Can't find pre-war in a quick search.

Germany was certainly on a much narrower path than the British when it came to finances before the war. Imports did have to be paid for with exports and some of the German industry was set up accordingly. That is to say making goods for export despite needs at home. You can only do so much with "funny money" and controlled economies or controlled exchange rates run into snags after a while.

 

[greybeard]

The fuel injection systems, at least as I've read several times, have had number of parts comparable to the engine they were supposed to be installed on.

Having worked for decades in electronic fuel injection systems, initially flanking in same plant production of carburetors and diesel injection, I can confirm this; a mechanical fuel pump is like an engine in miniature, with pistons and cylinders requiring tolerances in the thousandth of millimeter. Same for injectors internal parts. Not negligible is also their material technology, requiring tempered steel alloy. A carburator is made by a number of parts in the order of 1 to 10, in comparison with injection, made of an alloy of aluminium and zinc, with tolerances in the order of the tenth of a millimetre.

 

[Jenisch]

Guys, I'm with a doubt about this carburetor subject and will use this thread to ask something about it.

I have watched this video:



Which explains how the engine cuts out in planes like the early Spits and Hurricanes, which had a float type carburetor.

At 2:27, it's clear for me why the fuel cannot reach the engine. But when the float chamber is totally upside down and the needle valve is pumping fuel uncontrollably into the float chamber, what exactly happens with the engine? Does it comes back momentarily and works for some time in a rough manner before it quits due to fuel flooding?

 

[fastmongrel]

There was more Bf 109s produced, ~34000 pcs (plus Czech & Spanish copies) vs. 20351 Spitfire.
But, granted, there is much more to the mass production numbers than just the simplicity of the produced item.

.

Possibly Glider was talking about early production when the Merlin had the negative G problem. 109 production was inflated by late war production when mostly fighters were produced. Up to 1943 109 and Spitfire production isnt that far apart yet iirc 14,152 109s were built in 1944 compared to approx 3,500 Spitfires. I cant find an exact Spitfire production number for 1944 I just roughly added the order numbers for Spits.