Inaccurate performance data for BOB fighters in COD comparing to RL data

[NZtyphoon]

Fair enough I missed #205; here's #205

Originally Posted by TomcatViP

Wrong. See my post above and data pasted bellow. You need to take into account the s/c !

MerlinXX !

ALT(ft) SHP BHP (diff correspond to the power used to drive the supercharger)
15K 1267 1048
20K 1298 1073
20K+ 1362 1126
25K 1162 960
30K 945 778
35K 700 568


More over the subsequent Merlin (the XX) developed to give more power to the Hurri (what the RaF felt was more a need) was limited to 9lb at 20Kft but 12lb in T.O/Emergency


I think that you are confounding higher grade and NOS and don't forget all the cooling prob with the Merlin in the RAFFC's fighters

Quitely again as I hve said it does not fit any logics.

~S!

This is a post about the Merlin XX, which is a completely different engine from the III, using a two-speed supercharger which drew more power than the single-stage single speed unit of the III:
otherwise there is No evidence provided that R-R routinely tested its engines without superchargers, No documentation, No mention of a History of Rolls-Royce.

[TomcatViP]

Originally Posted by NZtyphoon

Fair enough I missed #205 because it was so tedious reading all of your nonsense over again; here's #205


This is a post about the Merlin XX, which is a completely different engine from the III, using a two-speed supercharger which drew more power than the single-stage single speed unit of the III:
otherwise there is No evidence provided that R-R routinely tested its engines without superchargers, No documentation, No mention of a History of Rolls-Royce.

I quoted the exact title of the book elsewhere (sry not with me as for now). It's one of the RR heritage trust. It's a study extracted from RR sources and internal documentation.

As I said, this small book written in 1941 explain why RR had to create new methods to predict the perf of a S/C Engine at alt due to the divergences of predicted perf and the real ones achieved during flight test. The authors were the very same guys conducting the work at the time.

It is also explained how the US was slightly in advance in that way. But also why RR conducted that work as improvement were still on demands.

The base engine to conduct this work was the NEW MerlinXX flight tested in a Hurricane II.

There is a lot of interesting curves that I hve re-used in my post (but no scan). Most notably no perf test was seen using the 12lb boost when top performance was the very base of that work

The book itself is cheap (10 to 20$ ?) and can be ordered simply via amazon if I do remind well. I had to wait 1 or 2 month to get a new print out of the roll. You may read (or ask ?) Viper2000 posts with whom I heard first abt that book.

~S