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There is little doubt that the "BIG" twin heavy bomber was a bad idea for the very reason you state. However the Merlin was a 27 liter engine, the Griffon a 36 liter engine and the Vulture was a 42.5 liter engine. With it's smaller cylinders, in theory the Vulture should have been able to turn more rpm. With any given fuel the Vulture should have been able to develop much more power than the other two. All things being equal, which they obviously were not.
As for the Pennine, Rolls built the Eagle why?
That is sort of my point.
How long did it take to "fix" the Vulture AFTER it passed a type test?
The P&W R-2800 had 3,500 hours before it passed a type test (on the "A" series engine) and the R-4360 had 15,000 ground hours on 23 engines. And it used R-2800 cylinders. 4 rows of seven instead of two rows of nine.
The Merlin had more development time in it, and had its own problems - but many of these were pre-war. They were trying to fix the Vulture in a time where they needed the resources for the Merlin and Griffon. The Griffon seems to have had a relatively trouble free development period - only 2 or 3 years before it was in production.
The Vulture should have easily been 2000hp+, and by the time the Merlin was pumping out 2000hp (1943) the Vulture probably would have been capable of much more. At the same BMEP as a Merlin with 2000hp at 3000rpm a Vulture would be giving well over 3000hp. Of course that needed, like the Merlin had before it, the reliability problems sorted before extra power could be sought.
Once again, that is sort of the point. The Vulture wasn't supposed to be a "NEW" engine. It was supposed to be a low risk, high power engine. Use Kestrel (or Peregrine) cylinders, space them out a bit and put four on each crank throw instead of two. The pistons/piston rings should be sorted out. The valves, valve springs, valve timing, cams, cam drives, combustion chamber shape, spark plug location should already be sorted out. And apparently they were because none of the accounts I have read mention any troubles in those areas.
The Vulture is sort of an answer to those who say "why didn't they JUST use the XXX cylinder blocks in an 'X' shape to make a high powered engine? It would have been fast and easy."
I really would like to see the office memos on that oneThe Eagle 22 was a parallel development to the Pennine, but was for a different market. The Pennine was designed for use in the post war transport industry. The Eagle was the next high performance military engine. Both were overtaken by the turbine.
Rolls-Royce, and the other British engine makers, had another situation again. They were rushing through because of an impending war.
Shortround6; how many engines R-R went through to get to the first "good" Merlin.[/QUOTE said:Honest answer?
A lot.
Cheers
John
I really would like to see the office memos on that one
Whoever 'OK'd' that plan should have been either fired on the spot or if that decision came as a result of months of wartime stress been sent home for a few months of bed rest.
"Lets build an air-cooled 24 cylinder "X" sleeve valve engine at the same time we are building a liquid cooled 24 cylinder "H" sleeve valve engine about 00.6% apart in displacement. It is only going to cost a few million pounds Stirling for R&D for EACH engine (if we are very lucky)* but we can limit return on investment by pitching each engine to a different market."
Rolls-Royce continued to fund development of the Merlin for commercial applications after the war. As did Bristol with the Hercules and Centaurus. Piston engine development did not stop in 1945-46. It may have slowed considerably but there was still a market for piston engines.
Not exactly. That is a V24, but it has two separate crankshafts that are not connected in any way. The rear crank drives the front prop, and the front crank drives the rear prop. The rear half carries the induction equipment (supercharger, carb) so has to be started first, and can run by itself. The front engine can't be started until the rear one is running.
There were a lot of development problems with the AS6, many related to fuel distribution.
Two quotes from wikipedia:
"In 1939, Chrysler was contracted by the US government to create a new engine for use in fighter aircraft. Chrysler responded by designing an inverted V16, the IV-2220. They tried many designs before choosing a hemispherical combustion chambered OHV head. The big V16 was rated at 2,500 hp (1,900 kW). It was finally tested in June 1945. It was installed in the P-47 Thunderbolt in place of a radial engine. This airplane was designated the XP47H. The change in engine and aerodynamics increased the top speed from 439 mph (707 km/h) to 504 mph (811 km/h). The war ended shortly after the tests, and the hemi V16 was never mass-produced, although the basic design and valvetrain setup live on in today's Hemi V8s."
"Two XP-47Hs were built. They were major reworkings of existing razorback P-47Ds to accommodate a Chrysler IV-2220-11 water-cooled 16-cylinder inverted vee engine. However, such large inline engines did not prove to be especially effective."
Anyone have some more data about this, or may verify this info?
XP-47H