Jay Leno's Garage - the Merlin engine

Even more amazing in a way were the Rolls Griffon and DB-605 engines, which were both substantially larger than their predecessors and yet both fit in their respective fighters (Spitfire and Bf 109) without looking out of scale.

 

There is a famous anecdote about the R-2800 that sums it up nicely, but for the sake of me I can’t remember who did actually pronounce it; too good a lunch today and too much wine do not help, either; so I would have to go back to the archives, books, etc… to be really assertive.

BUT anyway: the story goes that when the first P-47 to crash-land in Germany was thoroughly examined by German experts in 1943, one engineer from either BMW or the Luftwaffe technical department was closely looking at its R-2800 engine and marveled in the fact that it didn’t leak oil anywhere, and said: “Gentlemen, if the Americans are able to produce such an engine in great numbers, then we have lost the war already”

Rgds

 

Thanks.. that makes sense and refreshes my memory of what I saw/read on the subject

I believe that on both "Fifi" and "Doc" the superchargers and or turbo's have been removed from the the engines to improve reliablilty, and that they could do this because they will never need full "war time" power ?

 

The turbo superchargers were not needed because the airplanes would no longer be flown at 30,000 feet at high boost. The engine mounts on the case of R4360 powered B-50's were magnesium so that if there were a fire they would burn first and allow the engine to fall off instead of allowing the fire to migrate to the wing.

 

Thanks... did not know that. Great idea.

Talked to a crew member of FIFI last summer here at Rocky Mountain and he said they never exceed 10k feet above sea level. And it's no longer loaded with tons of bombs.

 

Beautiful marriage of American engineering and British horsepower....P-51 Mustang.

 

The P-47 would get extra horsepower with water injection and extra cooling on the R-2800-59.

 

It was also turbocharged.

 

The P-47 had the unique configuration of mounting the supercharger aft of the wing in the belly of the airplane, hence the deep fuselage and big airscoop in the cowl under the engine. Engine exhaust and air was ducted aft to the turbo and compressed and cooled air ducted forward to the engine. I think that Taz posted a picture of his dad in the duct intake. Everything about that airplane was huge and powerful. With 8 cal 50's it was a superb strafer.

 

There's a pic in wiki of a P-47 with cowlings off showing the ducting to/from the turbo which was behind the pilot, as Bob said.

Wikipedia 'P-47'.

 

I was thinking about the fire power of the combatants and I saw the destructive power of 6 cal 50's at the point of convergence and it was total. I never saw what 8 cal 50's would do but I can imagine it. I knew a P-38 fighter ace who said that if he hit his target with everything firing, the target was obliterated. In one fight his airplane was heavily damaged when it flew through the debris of a dispatched target. It then flew through the debris of several more during the fight and damaged it further. His crew chief was shaking his head when he pulled into the hard stand. My friend said that he enjoyed shooting up the tanks, trucks, and trains in his strafing operations. He was shot down on one of them and somehow escaped capture and made it back to friendly lines. Different times and different people.

 

I remember reading that the allison was a better stronger engine than the merlin, but that it lacked the two stage supercharger and things like the oil lines etc were not optimsed for altitude. The p38 didnt work in europe because it was not great in the real cold and high altitude.

Since the p51 had a wing that could take advantge of altitude the merlin was a natural fit.

I know the unlimited merlin race engines use allison rods.

 

The Lancaster flys low over my house almost every weekend. I hear her well be fore I see her. Such a wonder sound she makes. She did a fly over yesterday in fact.

 

Here is crappy pic of her and a b17 that was up for a visit last month. Both flew over one after another..rrally cool too see and hear.
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It only loaded the one..oh well..

 

I just watched an interview with Richard Candeleria (P51 ace) he said that he witnessed two P47's strafe a German locomotive at the same time with armour piercing incendiary shell..that's 16, 50 caliber machine guns. He said the combined firepower literally tipped the locomotive over...he said he had a lot of respect for the Jug after that.

 

Sparky mentioned that Allison rods were used in Merlins. Was modification of the big end and small end necessary and if so, how was it done? I can't imagine that both engines had the same size wrist pins and journals.

 

I do know that when the British ordered P-38s, they specified removing the turbochargers, which of course resulted in poor performance at altitude. I have never seen an explanation as to why they did that.

 

That is odd, I didn't know that. My late friend, Larry Blumer, flew them in France, 9th AF, and shot down a bunch of FW-190's in 10 minutes so I guess that the lack of turbo chargers didn't bother him. I recall that he did a lot of strafing on trains and armored columns so that must have been the forte of the P-38 over there.

 

Jim- Affirmative on the turbo-chargers. Two versions of the story, one, they did not want them, and two, the turbochargers were classified and we would not give them to the RAF. One is more believable. I seem to remember they wanted both engines turning in the same direction, too, ala Mosquito. They were quite useless in that configuration and delivery was refused. My father flew P-322s out of Williams, but they had been retrofitted by then and were used only for training.

 

If it was 9th AF, they would have been standard USAAF P-38s, which meant that they still would have had the turbos, and hence, the performance.

 

Thanks, Jim. I was thinking about the big fight that Blumer's squadron got into in eastern France. He told me that they went into a long shallow dive to get to the fight and had his airplane on war emergency power and forgot about it during the fight. When they terminated the fight he immediately pulled power back and headed for home, destroying a train on the way. His engines were still running when he got to his base but they were done. Speaks well for the Allison, I think.

 

I had also read that oil lines froze at altitude in Europe.

There is also no question that a twin engined fighter is more expensive to buy and operate than signle engine. Once the p51 came along it was probably why bother with anything else.
Wonder how a p38 compares in a dogfight to a p51, its a heavier plane and was designed earlier.

In the pacific it was more low altitude, temps were warmer and two engines could get you home over oceans.

I also read that the unlimted hydroplanes used allsions because they were plentiful cheap and also stronger than merlins when really boosted.

 

Found this on the googly

"Allison had been leaning heavily towards exhaust-driven turbochargers instead of the more common mechanically-driven superchargers, feeling that their added performance more than made up for the added complexity. Thus little effort was invested in equipping the V-1710 with a reasonable supercharger, and when placed in aircraft designs like the P-39 or P-40 which lacked the room for a turbo the engine suffered tremendously at higher altitudes. It was for this reason in particular that the V-1710 was later removed from the P-51 Mustang and replaced with the Rolls-Royce Merlin.

The Merlin was a better developed aero engine and more appropriate for the needs of WW2 fighters. Mind you, the lack of power was not Allison's fault but,the US Army's thing about turbo chargers.

The Army had earlier decided to concentrate on turbosuperchargers for high altitude boost, believing that further development of turbochargers would allow their engines to outperform European rivals using superchargers. Turbosuperchargers are powered by the engine exhaust and so do not draw power from the engine crankshaft, whereas superchargers are connected directly by gears to the engine crankshaft. Turbosuperchargers do increase the exhaust back-pressure and thus do cause a decrease in engine power, but the power increase due to increased induction pressures more than make up for that decrease. Crankshaft-driven superchargers require an increasing percentage of engine power as altitude increases (the two-stage supercharger of the Merlin 60 series engines consumed some 230-280 horsepower at 30,000 ft). General Electric was the sole source for research and production of American turbosuperchargers during this period.
Turbosuperchargers were indeed highly successful in U.S. bombers, which were exclusively powered by radial engines. The P-47 fighter had the same combination of radial engine (R-2800) and turbosupercharger and was also successful, apart from its large bulk, which was caused by the need for the ductwork for the aft-mounted turbosupercharger.
However, mating the turbocharger with the Allison V-1710 proved to be problematic. As a result, designers of the fighter planes that utilized the V-1710 were invariably forced to choose between the poor high-altitude performance of the V-1710 versus the increased problems brought on by addition of the turbosupercharger. The fates of all of the V-1710 powered fighters of World War II would thus hinge on that choice.

Technically clever, the turbosupercharger.

The P-38 was the only fighter to make it into combat during World War II with turbosupercharged V-1710s. The operating conditions of the Western European air war – flying for long hours in intensely cold weather at 30,000 feet revealed several problems with the turbosupercharged V-1710. These had a poor manifold fuel-air distribution and poor temperature regulation of the turbosupercharger air, which resulted in frequent engine failures (detonation occurred in certain cylinders as the result of persistent uneven fuel-air mixture across the cylinders caused by the poor manifold design). The turbosupercharger had additional problems with getting stuck in the freezing air in either high or low boost mode; the high boost mode could cause detonation in the engine, while the low boost mode would be manifested as power loss in one engine, resulting in sudden fishtailing in flight. These problems were aggravated by suboptimal engine management techniques taught to many pilots during the first part of WWII, including a cruise setting that involves running the engine at a high RPM and low manifold pressure with a rich mixture. These settings can contribute to overcooling of the engine, fuel condensation problems, accelerated mechanical wear, and the likelihood of components binding or "freezing up."
Details of the failure patterns were described in a report by General Doolittle to General Spatz in January 1944. In March 1944, the first Allison engines appearing over Berlin belonged to a group of P-38H pilots of 55FG, engine troubles contributing to a reduction of the force to half strength over the target. It was too late to correct these problems in the production lines of Allison or GE, and so the P-38s were steadily withdrawn from Europe until they were no longer used for bomber escort duty with the Eighth Air Force by October 1944. A few P-38s would remain in the European theater as the F-5 for photo reconnaissance.

If my life depended upon it, I would choose the reliable Merlin"