Good question.
Specifically, did the intrinsic design of the V-1710 preclude development of it's supercharger in the ways that the Merlin supercharger developed?
Multi-speed, multi-stage, water cooling, etc.
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Okay, here's one for the technophiles (definitely not including me). The Allison engine in it's various guises has always seemed to play second fiddle to it's famous contemporary in the land of hope and glory, the Merlin. Was there any intrinsic design feature that precluded Allison engines from powering single engine fighters over Germany at 25000 feet, of was it all just a case of the American engine being hobbled by the thinking of the time - that high altitude fighters weren't required?
To get full marks, please include an objective comparison of the beers of both countries.
Somebody once said that with two stage superchargers the 2nd stage multiples any mistakes in the first stage design. An inefficient 1st stage with a large heat rise feeding a 2nd stage means some really high intake mixture temperatures (one reason just about all US turbo equipped planes used intercoolers).
The basic V-1710 mechanical supercharger seems to have been constructed so that the crankcase made up part of the supercharger housing. As far as I can tell, a mjor redesign would have been needed to install a two speed drive.Good question.
Specifically, did the intrinsic design of the V-1710 preclude development of it's supercharger in the ways that the Merlin supercharger developed?
Multi-speed, multi-stage, water cooling, etc.
Why was the engine have severe oil consumption? major flaw in the engine or something weird going on with the crankcase breathers?
I seem to remember something about cutting the ends of the breather tubes at a different angle solving the problem?
A certain altitude and speed combination almost acting like syphon and sucking oil laden air out of the crankcase?
There were only two allied V-12s operating at high altitudes that might require such a "fix" as the Madame Queen intake manifold. The radials used much shorter intake pipes and were either individual or paired? so such a device was not needed, Russian engines used a carburetor for every pair of cylinders so again, no long intake manifold to cause problems. Yes the Allison had a problem but you are rather over stating the case.
Problem also showed up when the Allies introduced a new fuel specification. It did two things. It allowed the use of 4.3 cc of lead per gallon instead of the previous 4.0 cc of lead (which had been changed from 3.0ccs of lead) all for 100/130 fuel. It also allowed the increased use of heavier aromatic compounds to blend the fuel than the previous specifications. This allowed for greatly increased output of 100/130 fuel from the same tonnage of crude. It also reduced the volatility of the fuel ( how well it evaporated and stayed evaporated in cool air).
Again, engines with long intake passages are going to be the most affected. Since only two stage engines used intercoolers all single stage engines had pretty hot intake mixtures and rarely ran into problems. Which leaves the Merlin and the Allison, it turns out the Merlin was not immune from this problem. In post war use on transports they ran into a cold mixture problem which was solved by reversing the coolant flow (valves were added to control this) so they actually heated the air in the "intercooler" when cruising at low power settings.
Again this problem was somewhat (but not entirely) supercharger set up dependent. The Turbo Allison being about the only V-12 where the pilot could "select" how much boost was being provided by the turbo and how much was being provided by the engine supercharger. He didn't do this directly (or even knowingly) but by selecting different RPM and throttle settings for the needed power at cruise quite different use was made of the turbo and intercooler system resulting it in a wide variation of possible intake mixture temperatures. A lot of bad "advice" was given to pilots on how to the fly the P-38 which added to the problem, advice that was was in direct contradiction to how Lockheed and Allison were saying the plane should be flown yet Allison gets the blame?
Unfortunately this system also required skilled/knowledge set up and maintenance. It seems the turbo controls were often miss rigged, causing higher than normal speeds and higher pressure/velocity at the carb leading to lean conditions. There was a hydraulic turbo control on the earlier planes with an electric control on the later ones. The early one was rather easy to adjust. the later one took a refit kit.
Again, all of this was "stuff" on the outside of the basic engine. It did greatly affect the reliability of the engine but was not an inherent defect in the basic engine or it's design.
Properly sorted out Allisons were quite capable of running at high power levels for considerable periods of time.
Okay, here's one for the technophiles (definitely not including me). The Allison engine in it's various guises has always seemed to play second fiddle to it's famous contemporary in the land of hope and glory, the Merlin. Was there any intrinsic design feature that precluded Allison engines from powering single engine fighters over Germany at 25000 feet, of was it all just a case of the American engine being hobbled by the thinking of the time - that high altitude fighters weren't required?
To get full marks, please include an objective comparison of the beers of both countries.
Okay, here's one for the technophiles (definitely not including me). The Allison engine in it's various guises has always seemed to play second fiddle to it's famous contemporary in the land of hope and glory, the Merlin. Was there any intrinsic design feature that precluded Allison engines from powering single engine fighters over Germany at 25000 feet, of was it all just a case of the American engine being hobbled by the thinking of the time - that high altitude fighters weren't required?
To get full marks, please include an objective comparison of the beers of both countries.
Okay, here's one for the technophiles (definitely not including me). The Allison engine in it's various guises has always seemed to play second fiddle to it's famous contemporary in the land of hope and glory, the Merlin. Was there any intrinsic design feature that precluded Allison engines from powering single engine fighters over Germany at 25000 feet, of was it all just a case of the American engine being hobbled by the thinking of the time - that high altitude fighters weren't required?
To get full marks, please include an objective comparison of the beers of both countries.
American tanks were rationed in their use of HVAP ammunition (tungsten cored) for the same reason.This source suggests that the failure to develop a better turbo-supercharger was based or prioritization of tungsten for other purposes. This is in keeping with other things I have read about very high priority being given to use of tungsten in machine tools in order to maintain high industrial production.
Allison V-1710 Engine
This source suggests that the failure to develop a better turbo-supercharger was based or prioritization of tungsten for other purposes. This is in keeping with other things I have read about very high priority being given to use of tungsten in machine tools in order to maintain high industrial production.
Allison V-1710 Engine
American tanks were rationed in their use of HVAP ammunition (tungsten cored) for the same reason.
Nowhere in the article is said that there was a 'failure to develop' better turbos due to the lack of tungsten.
It is pretty well known, most US tanks had 2-5 rounds of HVAP as official load if they had 76mm guns. Ammunition supply sometimes did not allow this.The Shermans with 75mm guns didn't get any HVAP. At the velocities the 75mm gun operated at they thought the increase in penetration would be marginal, still won't got through the front of a Panther or Tiger.Do we have a good source for that?
Resp:If Britain faced a shortage of Merlins it could theoretically have powered the Lancaster, Wellington, Halifax & Beaufighter with the Allison. It was a while before the two speed superchargers were used on the Merlins I believe.
The turbo-charged Allision probably could have been fitted to these British bombers. A Turbo charged Allison on a Lancaster might give it quite a good altitude performance, perhaps as good as the Liberator.
USAAF policy seems to have been to use simple single speed single stage non intercooled superchargers, some were two speed superchargers without intercooling, for low flying aircraft and turbo-superchargers for high altitude. This infamously left the P39, P40 and P51A with poor altitude performance while the P-38 went through years of extended debugging and the P-47 was still in development.
The US Navy had quite a different policy, it used multispeed multi stage superchargers with independent stage drives and intercooling. Eventually these navy R2800 engines did find themselves on some USAAF aircraft.
Unfortunately the USN never used the Allison and aircraft (only air ships), had it have chosen too it might have provided the funds and impetus to develop a mechanical superchargers for the Allison.
Resp:I don't have a problem with you.
They may be good engines, but in WW2 they were largely an also ran. Relegated to aircraft that would, for the most part, be considered second tier.
I was wrong about the ammunition . It seems that by mid 1943 there were ample supplies of tungsten.Unfortunately, some of claims require a truckload of salt so we can digest them. Like:
The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature.
There was not a 'few of turbo-suercharged Allisons' made, but around 20000 thousand (there was more than 10000 P-38 produced). To put the number of 20000 in perspective, this is about as much of Spitfires produced, or Fw 190s produced. Or, almost 50% more than what P-40 production needed when it is about the engines. Trick might be that turbo installation on the P-38 actually worked, while on the Curtiss and Bell prototypes did not?
Then:
Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era.
There is no picture, diagram or flight test of a P-40 that was experimentally equipped with turbo-superchargers, 75-80 years after the supposed aircraft was supposedly outperformed those two fighters (of what version - that we also don't know). Perhaps due to the simplest reason: there was no such P-40s?
Further:
It wasn't until the XP-40Q was modified with a "bubble" canopy, cut-down rear fuselage, wing radiators, clipped wing tips, a four-blade propeller, water injection and weight reduced to 9,000 lb that the XP-40Q attained a maximum speed of 422 mph.
Nowhere in the article is mentioned that XP-40Q that did 422 mph was outfitted with a 2-stage supercharger. Bubble canopy and better prop can't earn 30-40 mph. 9000 lb heavy P-40 is not a sign of weight reduction, but of gaining the weight.
Nowhere in the article is said that there was a 'failure to develop' better turboes due to the lack of tungsten.
Do we have a good source for that?
The outstanding performance was by the Packard engined version. The famous long distance flight was Merlin powered. The Allison powered version was slower and had a lower rate of climb, when it was actually working.Resp:
The post WWII production F-82 used the Allison engine, as the Packard Merlin production license was about to expire. The F-82 had outstanding performance.
Resp:
The USN used an inline aircraft engine in their PT Boats.
I admit that I am not intimately familiar with the materials used for the various parts of the WWII GE turbos. Does any one have info on what parts used tungsten alloys? I would appreciate the info.