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Always intruiged me that the marks I to IV had so much trouble but the mark V in the Hawker Tornado didnt seem to have any trouble or none that I have come across. Is it possible the V was a hand built prototype and that the engine was fine when hand built but it was when put into production that problems appeared.
BTW: Is the Vulture manual generally available?
The take-off power is suspiciously low - 1800 HP @ 3200 rpm? Lumsden gives the same values, though.
The take-off power is suspiciously low - 1800 HP @ 3200 rpm? Lumsden gives the same values, though.
Otherwise, the power at low altitudes is comparable with single stage R-2800, while above 14000 ft it does give more power. The exhaust thrust is also greater, for mid-war installations. The weight penalty is somewhat greater than for the R-2800, with cooling system of the Vulture adding another ~500 lbs? The single stage R-2800 was at 2300-2400 lbs, dry.
The max continuous power for the 1-stage R-2800 'B' was 1600 and 1450 HP, in 1st and second gear respectively; A series was at 1500 and 1450 HP. The B series will also give 200 HP more for take off vs. Vulture.
The contemporary Sabre, on +7 lbs boost, was giving a bit more power down low, but it was certainly not a more reliable powerplant than Vulture.
Germans have endured the rough time with BMW 801 on their fighters, but it seems the 801A (on the Do-217) have had less problems, because it was not cleared for Notleistung (being a 'bomber' engine)? The max T.O. ('Start') power of 1560 PS is not that great, either. The Jumo 222 was plagued with problems, the DB 603 is both late and have had own reliability problems initially.
The Soviets have had the AM-38, 1600 CV for take off, but only 1 supercharger speed, set for low level (~4800 ft rated altitude). A bit less weight and problems, but also less power, especially above 10000 ft.
The data card of Mancherster, with powers you state is dated at 7th August 1941. Do we know when the power restriction took place, and on what power ratings?
The take-off power of 1800hp doesn't seem out of line for 87 octane fuel. Throttle is part shut to limit boost to 6lbs at take-off. Something was going on if there was no increase in power with 100 octane fuel? Just the ability to run on it?
Even the Mercury and Pegasus picked up a bit of power with 100 octane.
A 1944 edition of Wilkinson's "Aircraft Engines of the World" gives take-off power of 2010hp at 3000rpm at 48.2in (9lbs) on 100 octane for the Vulture II but is not a primary source and is several years too late. Dry weight is the same though.
A 1942 edition of "Jane's" gives few details as the engine was still 'restricted' at the time.
Something was going on if there was no increase in power with 100 octane fuel? Just the ability to run on it?
Even the Mercury and Pegasus picked up a bit of power with 100 octane.
I suspect that because of the mechanical issues extra boost couldn't be used. It is slightly less than maximum power, with the additional 200rpm slightly compensating for the throttling of the carburettor.
Bear in mind that these ratings were for both 87 octane and 100 octane fuel - suggesting that no real benefit (power wise) was gained using the latter. I don't think the R-2800 was ever rated with 87 octane fuel.
The weight of the Vulture would have been reduced in later versions by replacing the reduction gear with a planetary reduction gear system. A svaing of aroun 100-200lbs was expected.
Interestingly there was a tolerance of ±2.5% on the dry weight. Seems rather a lot.
The B series was later in timing than the Vulture. I suspect if Rolls-Royce put the time, money and effort into the Vulture that Pratt Whitney did to update the R-2800 A series into the B series it would be susbtantially more power than the figures here. I have had it confirmed by RRHT that Rolls-Royce had tested the Vulture at 2,500hp before its cancellation. Not sure what conditions that was done under, though. Lumsden states that it was tested at 3,000hp, but RRHT could not confirm that.
The contemporary Sabre was, dare I say it, a hand built and fitted prototype engine. This report is dated December 1940.
I think the biggest success for teh DB 603 and BMW 801 came after the Vulture was cancelled and out of production.
Interesting that you mention the Do 217. It had similarly powerful engines as the Manchester, but was quite a bit smaller and lighter.
Big capacity with low rpms.
Credit is due to the engineers who persevered with it and particularly the men of No. 207 Squadron and later No. 97 Squadron who flew the thing early on, but it was all for naught. The surprising thing is that Rolls Royce didn't officially terminate the Vulture programme until April 1942.
I read an interesting excerpt from The Magic of a Name that it was Hives who suggested to Chadwick that replacing the Vulture with the Merlin would have been a better option before the Manchester was put into production.