You donīt want to understand obviously. Those lines drawn in 20seconds are not 100% correct and i donīt want to say the spit performed exactly this way. I just want to give you an imagination about the effect. You better look at the climbrates, which depend much more directly on power instead of speed.
I agree they demonstrate the effect, but that effect is present in the documents I linked to.
Your calculations show speed and climb should both be reduced with an increase in critical altitude.
The documents show that they are, for example the aircraft with 12K FTH is approx 6mph slower at sea level.
I accept the theory, and the documents support the theory. You seemed to be arguing the effect should be greater than the documents suggest.
B) the date in the bottom right corner says July 46. Those charts were made over 1 year later then the end of the war, or 2 years later then the introduction of the Spit14 in the RAF. You have to decide yourself whether you consider those charts, maybe from spits produced under civil circumstances instead of wartime (what also could mean not in armed mode), are representative for a ī44 spit14.
Looking at the PRO catalogue, the charts are probably from the tests carried out on the Hornet.
A few things make me believe they are of a standard wartime Spitfire XIV in combat trim.
1, They match what you could expect from a Spitfire XIV with increased full throttle height.
2. At FS altitudes they match the test results of the prototype Spitfire XIV, which the test reports says was in combat trim.
3. There is little point comparing various combat aircraft if they are not in combat trim.
4. I doubt new performance tests were carried out on the Spit XIV in 1946. It had already been superceeded by the Spitfire XVIII and 21, 22 etc.
5. The report I mentioned on raising the speed of various fighters at 3000 for V-1 chasing was produced in mid 44, and gave the speed of the Spitfire XIV as 372mph at 3K, the same as the later report showed. The prototype Spit did 380 mph at 3000ft.
I have seen peak output quoted for the Merlin 66 as 1670hp or 1760hp. That looks like a misunderstanding to me, but could be a genuine power difference.
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I assume that one power output is for sealevel, the other for the critical altitude of the 1st gear. The power outputs for the RR engines are very often given for the critical altitude of the 1st gear, what is usually higher than sealevel output. The griffon is given with 2050hp, but at sealevel the output was only 1850hp-1900hp. This way the power output looks better, german engines are usually given with sealevl output AND sometimes, especially in case of the 801 with the reduced poweroutput due to rameffects. (static thrust 1800PS, dynamic 1730PS or 1700hp).
No, I am sure the 1760 hp figure is just a misunderstanding of the 1670hp figure.
The Merlin 66 was very similar in MS gear to the Packard -7 engine, and that was rated at 1500hp at sea level, 1670 in MS gear, iirc.
Your second sentence demonstrates your agenda, I think.
Engines can be rated in many different ways. Most people talking about an engine want to know maximum power, so that is what is most commonly talked about. British engines were rated at max, max continuous, 30 min rating etc.
