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You would have to say that with no specialist role for the type, a problematic engine, a design difficult to stretch, and what appears to be high production costs (2 engines to one in the 'main" types) that cancellation was entirely justified.
As a two engine type, the whirlwind was not comparable to either the beau or the Mossie. Both these types were built for different purposes, and incorporated range and size to allow them to complete quite a range of different mission types. Daytime Escort LR fighter was not one of them, so the RAF continued to battle on wthout an adequate indigenous fighter to fit this spec. A great pity really
While I don't doubt that that is all in the archives some of it rings a little hollow. The development needed to go from 87 octane to 100 octane should be minimal. The Merlin required a number of hours of testing before it was approved but actually needed no new parts (maybe a new spring in the pressure regulator?) Both Bristol Mercury and Pegasus engines could operate on on 100 octane fuel. Granted you don't get the full benefit without some redesign but the Merlin went from 1030hp to 1310hp with just an adjustment of the pressure regulator. perhaps there was something about the Peregrine that would break trying to put out 30% more power but some increase should have been possible without much work. Granted the switch to 100 octane does nothing for altitude performance. I can't fault the men in charge for making decisions based on the evidence they had but history shows that some of their choices turned out not so well. The Tornado/Typhoon turned out to have very little capability that a MK II Whirlwind ( with Peregrines) wouldn't have had and 110mph landing speeds while not normal were certainly in use (P-47s). later Whirlwind pilots claimed no problem flying at night but with only 3 planes to go on the experience wasn't there.
The Spitfire was close to cancellation at times in 1938-39 for many of the same reasons ( slow production, bad workmanship, millions invested with no airplanes to show), fortunately the right decision was made in that case.
From a financial stand point I can understand RR wanting to get rid of the Peregrine, it was too small to ever be more than a niche engine. Bristol may have never made any money on the Taurus compared to the investment they put in.
You would have to say that with no specialist role for the type, a problematic engine, a design difficult to stretch, and what appears to be high production costs (2 engines to one in the 'main" types) that cancellation was entirely justified.
You are correct. The Merlin only needed adjustment to the boost regulator to use 100 octane fuel, but it did need some testing to be sure.
The effect of the higher octane fuels tended to reduce the full throttle heights of an engine.
It appears that way but the engines made just as much power as they ever did at the altitudes at and above the old full throttle height. Full throttle height being just what it says, the height at which the throttle can be fully opened with damaging the engine. The higher octane fuel allowed the throttle to be fully opened at a lower altitude without risk of detonation and so made more power at lower altitudes. The Merlin III's supercharger could supply 16lb of boost at 5500ft, 12lbs at 9000ft and 6lbs at 16,250ft. Changing fuel did nothing to affect the air supply. It just allowed the engine to use the extra air available at the lower altitudes.
Merlin 24 is a two speed engine. Peregrines had teh single speed supercharger.
Merlin 32 was rated, according to Rolls-Royce Merlin - Wikipedia, the free encyclopedia, at 1645hp at 2500ft. An equivalent Pergrine could have been used for a Whirlwind LF.II. If we use the 70% theory that would be 1152hp at 2500ft.
If we use BMEP for comparison, your Merlin 46 comparison goes from 990hp @ 14,000ft to 1112hp @ 14,000ft @ 3000rpm. If we have to restricte the rpm, as was done for the Vulture, to say 2850rpm then we are back to 1056hp.
I feel that, if Rolls-Royce said that the work couldn't be done, without some disruption (including delays to the Griffon,) and a great deal of time, you should do them the courtesy of believing them, after all, no company is going to turn away work, unless it has to.
Remember that the Germans were sending the 109F over the U.K., before the end of 1940, and reports anticipated that it could reach 38,000', which even the Spitfire struggled to reach, and neither the Hurricane, nor the Whirlwind, had a hope of getting there. The Merlin 45 was on its way (first flew in a Spitfire V in April,) which the RAF would need desperately.
Just to help make up the minds of the hierarchy, Supermarine had managed to fit the longer Merlin 45 into the same engine space as the Merlin III (something they hadn't been able to do with the XX, which, as with the Hurricane, made the Spitfire III fuselage 4" longer.)
Edgar