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I think RR could have made the Vulture work if it wasnt for all that other "Merlin" nonsense and that silly carry on called a "war". Maybe not in time for the outbreak of the war but certainly in time to see off the Fw190 threat more reliably than the Sabre.People tried with X, H and W layouts, some worked better than the others, even if the layout was the same. So how should the least troublesome, not too heavy or bulky, and very powerful 24 cyl engine looked like? We need it for the 1st version(s) to be in service when ww2 erupts, ie. in September of 1939.
Forget the Sabre, have Napier make Griffons freeing up RR so they can make Merlin XX's then 60 series so we have Spitfire MkIII's and XII's late 1940, MkVIII's in '41 and MkXIV's in '42. If you really want Typhoon's and Tempests fit them with multi speed multi stage Griffon's.I think RR could have made the Vulture work if it wasnt for all that other "Merlin" nonsense and that silly carry on called a "war". Maybe not in time for the outbreak of the war but certainly in time to see off the Fw190 threat more reliably than the Sabre.
Sounds like you've arrived in the wrong thread. We're discussing the best possible 24 cylinder engine, not if the resources to make it are better invested elsewhere.Forget the Sabre, have Napier make Griffons freeing up RR so they can make Merlin…
You're really asking the wrong question. If you're asking what is the best layout for 1,500hp on 1/Sept/'39, the answer is 14 cylinder radial - It will give you 1,500 hp on 87 octane fuel reliably when war erupts. It will have room to improve 1,900 hp with 100/130 fuel and improvements to supercharging (mechanical and/or turbine) and inter-cooling.People tried with X, H and W layouts, some worked better than the others, even if the layout was the same. So how should the least troublesome, not too heavy or bulky, and very powerful 24 cyl engine looked like? We need it for the 1st version(s) to be in service when ww2 erupts, ie. in September of 1939.
If there was a better 24 cylinder engine it would have been made, from where I sit engines like the sabre didn't do anything other than waste resources, maybe that's why 12 cylinder engines won out?.Sounds like you've arrived in the wrong thread. We're discussing the best possible 24 cylinder engine, not if the resources to make it are better invested elsewhere.
If that's your view, that the entire premise of the question is unfounded, why are you here?If there was a better 24 cylinder engine it would have been made,
??You're really asking the wrong question. If you're asking what is the best layout for 1,500hp on 1/Sept/'39, the answer is 14 cylinder radial - It will give you 1,500 hp on 87 octane fuel reliably when war erupts. It will have room to improve 1,900 hp with 100/130 fuel and improvements to supercharging (mechanical and/or turbine) and inter-cooling.
Vulture is done in more by 100 octane fuel than by the Merlin. In '35, RR is working on engines in 4 classes: Kestrel XXX - 750hp (engine is changed so much it is renamed Peregrine),
Messerschmidt and Daimler-Benz fought over what caused the issue (oil tank or oil pump design), in the end, Messerschmidt installed oil/air separators and resolved their issues. I am not aware that Heinkel ever did (Not enough planes made it back to properly diagnose the issue and resolve it?)
Which leaves us with the sleeve valve engines for H engines - and sleeve valves were definitely the "fad" in '35 and pretty good solution if you are stuck with 87 octane. You can't replace a 2,000 hp Napier Sabre (87 octane rating) with a hypothetical 1,250hp RR Griffon in '39 (the engine that is being completely redesigned to be a 2k hp engine on 100 octane, while Napier is forecasting well over 2,400hp for Sabre on same fuel). OK, Napier could have used a little assistance from the gov't to pass on how Bristol resolved the sleeve valve issue. (As gov't is paying for the engines, assigning the patent for center-less grinding and bringing in efficiency experts from automotive e.g. Ford would have solved most of Napiers issues). >5k Sabres isn't the 100k for Merlin, Cyclones or Wasps, but given the limited number of planes using (chicken/egg thing?), still more than all the other combined during war.
Based on historical - flat H sleeve valve.
I'm not aware of any "flat H" engines with poppet valves in the power range we are talking. I suspect that having poppet valves with their associated springs and cams made the engine too wide for the air frame guys. I've seen the drawings for the Merlin "vertical H" engine, and it is seriously tall.
You're really asking the wrong question. If you're asking what is the best layout for 1,500hp on 1/Sept/'39, the answer is 14 cylinder radial - It will give you 1,500 hp on 87 octane fuel reliably when war erupts. It will have room to improve 1,900 hp with 100/130 fuel and improvements to supercharging (mechanical and/or turbine) and inter-cooling.
How about Packard's X-2775?
Packard X-2775 24-Cylinder Aircraft Engine
The Packard X-2775 (1A-2775) X-24 was a light, compact, and powerful aircraft engine. Trouble with the Kirkham-Williams and Williams Mercury Racers prevented the engine from proving itself.oldmachinepress.com
The hex 24 has all the connecting rod bearing issues of the X engine with 2 more slaves per rod. You also have to deal with primary and secondary vibrations of 6 - 4 cylinder engines which a hex more/less is. Junkers couldn't get them past the prototype stage even by end of war and built fewer than 300. We don't have until '50 when Dobrynin got a couple dozen running.
Vulture is done in more by 100 octane fuel than by the Merlin.
The nail in the coffin from 100 octane fuel - it allows 60%+ increase in power. RR can't figure out a way around the French multi speed patent, so until France falls, you are stuck with single speed engines.
So, the Peregrine needs to be redesigned for 1,200hp, the Merlin for 1,600, the Griffon for 2,000 and the Vulture for 2,400. And there is a war on so pick 2 - RAF needs Merlin for its front line fighter, FAA has funded the Griffon, Avro says they can redesign their bomber around 4 Merlins and it will be better able to take war to Germany.
My first thought would be that one would want to limit the engine to banks of six cylinders, so this means only the X (and and possibly hex), double-V (like the Allison V-3420), and H layouts are likely (the W layout would have 3 banks of 8). Of the three, my preference would be an X-configuration, as it would have only one crankshaft, which eliminates all the issues with phasing plus, since the crankshaft is the heaviest moving component in any engine, probably saves some weight.
However, if we never start the Vulture but rather commence with a double V Kestrel, we are sacrificing 2/3 of mid-war Merlin production. Vulture heads and cylinder blocks have same bore spacing as Merlin (even though the Vulture has same bore and stroke of Kestrel), so the manufacturing floor equipment could be converted to making Merlins with relative ease.
I think RR could have made the Vulture work if it wasnt for all that other "Merlin" nonsense and that silly carry on called a "war". Maybe not in time for the outbreak of the war but certainly in time to see off the Fw190 threat more reliably than the Sabre.