P-51D "Mustang" vs. Fw-190 "Dora"
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Kurfürst
Staff Sergeant
Well we do know they had non-stop troubles doing so. Engine failures and problems at high boost were reported non-stop at 81" and it seems the cause was never really fixed.
As for the many Squadrons, I believe it was actually 2 Merlin Spitfire Squadrons and 2 Mustang III Squadrons, which consitutes operational trials at best.
Which is probably why the USAAF settled down at a modest boost increase with 71", after all they were doing long escort duty over enemy territory. Clearly they've choosen because anything higher was just not safe. The 75" readins are probably just mis-set engines, small, normal variations in actual boost pressures within tolerances, from which the usual amount of wishful thinking on that site wishes to make more out.
Not that 3" Hg boost would make any difference at all.
DonL
Banned
Sorry Gents
but which boost system do you talk about? I
Is it a boost system like MW50 or GM1 or is it the supercharger system?
but which boost system do you talk about? I
Is it a boost system like MW50 or GM1 or is it the supercharger system?
Well, it was actually the whole of the 2nd TAF, about 30 Spitfire squadrons iirc.
On the Merlin it was just allowing higher manifold pressure. 18 lbs/ 67" was the limit with 100/130 octane fuel, above that detonation would occur. 100/150 fuel allowed up to 25 lbs / 81" before detonation.
DonL
Banned
ok,
Is it the boost (compression) from the supercharger?
Or is it the compression from the Valves? (that's a very simple description because of my bad english)
This is the same at my car! When I get 92 octan fuel my engine has less more power cause of the compression from the Valve. If I get 95 or 98 octan I have full power.
Is it the boost (compression) from the supercharger?
Or is it the compression from the Valves? (that's a very simple description because of my bad english)
This is the same at my car! When I get 92 octan fuel my engine has less more power cause of the compression from the Valve. If I get 95 or 98 octan I have full power.
Kurfürst
Staff Sergeant
I'd like to see the evidence of 30 Squadrons actuallyconverting.
A proposal was given out in november 1944 for doing so, but it was never actually fully implemented due to re-occuring engine troubles that lead to fatal accidents over and over again after the fuel started being introduced in scale to the RAF in February 1945 (the USAAF was using 150 grade fuel from mid-1944 otoh, and they had far more operational experience with it).
The problems were such they've soon reverted to 130 grade fuel :
"The incidents followed a number of engine problems that were attributed to the introduction of 150-grade fuel in early feb. pilots mistrusted it, and were no doubt relieved when the AF brass decided to revert to 130-grade. "the vast majority of pilots, im sure, were beginning to wonder if the additional seven pounds of boost they got from 150-grade fuel were worth the price being paid." the matter was being dicussed at Wunstorf when, incredibly, a spark at the petrol dump ignited and two petrol bowsers containing almost two thousand gallons of the much-despised fuel burst into flames."
I would not rule it out pilots sorting out the fuel problem by themselves...
Not to mention to mention those 30 originally proposed Spitfire Squadron were but a part of the 'whole of the' 2nd TAF which had lots of Typhoons etc. as well that continued to run on 100 octane fuel, and very few Merlin Mustant Squadrons in it.
Few people realize the vast majority of RAF fighters were flying on the same performance as they did in early 1943, whereas the USAAF and Luftwaffe fighters gained several hundred horsepowers due to the introduction of higher grade fuels and water injective boosting systems.
Glider
Captain
I always thought that one of the problems the Germans had was the lower grade fuels that they had to use and this would have forced them to use boost systems to catch/keep up.
I openly admit I could be wrong on this and am happy to take better information than I have at my disposal.
Re the USAAF I was under the impression that most of the water based boost systems were for the radial engines not Merlin powered aircraft. As the RAF didn't use Radials in their fighters it wouldn't have been much of a problem.
As for the RAF they did increase the power of the engines via increased boosts but the biggest increase surely was the introduction of the Griffon for the Merlin iro Spitfires.
Lucky13
Forum Mascot
The only subsitute for cubic inches is more cubic inches, or how the saying goes....
drgondog
Major
You are correct in that only the -9 and -11 Packard Merlins had water boost and neither saw combat. The P-51H used the -9 and the P-51L was slated for the 2000 HP -11.
I don't recall water boost on any of the Allisons.
Regards,
Bill
The Allison V-1710-75 had Water / Alcohol ADI fluid. It made 1425 hp in the P-38K.
The Allison V-1710-89 WER rating of 2300 hp in the P-38H/J with trubosupercharger, 115/145 fuel, and ADI (water / Alcohol).
the -143 Allison made 2250 hp with Bendix fuel injection and ADI in the P-82E/F on 115/145 fuel.
The Bell XP-63H had a turbocompound Allison V-170 of 2980 hp, but never reached production due to the end of the war and the advent of jet engines.
Over 70,000 Allison V-1710s were built and DELIVERED.
The Allison was also one engine used in the Curtiss XP-60. Flight tests showed it to have performance among the best of the piston fighters. Since teh war was winding down, it wasn't produced, but would have given anything in the air using a piston engine a run for its money.
More than 10,000 Allisons used ADI or water/alcohol injection.
The Allison V-1710-89 WER rating of 2300 hp in the P-38H/J with trubosupercharger, 115/145 fuel, and ADI (water / Alcohol).
the -143 Allison made 2250 hp with Bendix fuel injection and ADI in the P-82E/F on 115/145 fuel.
The Bell XP-63H had a turbocompound Allison V-170 of 2980 hp, but never reached production due to the end of the war and the advent of jet engines.
Over 70,000 Allison V-1710s were built and DELIVERED.
The Allison was also one engine used in the Curtiss XP-60. Flight tests showed it to have performance among the best of the piston fighters. Since teh war was winding down, it wasn't produced, but would have given anything in the air using a piston engine a run for its money.
More than 10,000 Allisons used ADI or water/alcohol injection.
drgondog
Major
You are absolutely right - I should have researched before answering rather than rely on 'memory'
renrich
Chief Master Sergeant
Speaking of the difference in individual a/c of the same model. I had a long conversation a number of years ago with a Tomcat driver at an air show in Gunnison. It was an F-14D, the hottest version with the GE engines. The pilot said that the a/c that had been in the Top Gun school invariably came back to the fleet "bent" In other words they had been in so many violent maneuvers that they were racked out of true and did not perform as well as some of the Tomcats that had not been treated as roughly. I am sure that was true of ww2 fighters also. In fact I remember reading about in the BOB the lowtime pilots that joined a squadron always got the old a/c that were out of rig so they had to battle their lack of experience, the Hun and a under performing a/c.
Erich
the old Sage
again as you compare "testing and evaluations", please keep in mind the Dora 9, 11 and 13 will be covered soon by Eagle Editions in two volumes. Both volumes will cover the COMBAT OPERATIONS; volume 1 due out in August hopefully
Wow to get banned by Erich, you really had to do something bad!
