[bugmenot]

Originally Posted by IvanK

The chart is one of the earliest plan Fan plots (or "Dog house plot" in US terms) that I have seen. As such its straight Energy Manoeuvrability theory that is Excess Power (ps) applied to the turning problem. As such it takes into account the total Airframe engine combination so Wing loading,planform,wing section etc is part and parcel of plot. The actual RAE derivation of these charts is discussed in great detail in AVIA 6/2366 RAE report "Notes on the dogfight" A more detailed version of the Spit fan plot chart from this report is shown below. In this case the study also takes into account various extrapolated wing areas and therefore wing loading etc.



I dont agree that their assumptions were made on false grounds. Everything I have read in these reports indicates to me that the boffins doing this work were really on top of their game. Here is some of the data they were using in this report obtained from a physical specimen BF109E3:





The USN also produced a comprehensive study on turn performance on the F2B (Buffalo) that is equally involved and again is based on straight out EM theory applied to the turn problem and again chock full of fan plots.

Here is another chart from the same source source document as the original Fan plot came from (AVIA 5/2394 "Messerschmitt Me.109 Handling and Manoeuvrability Tests" which is a pretty exhaustive 63 page document. This chart provides similar data to the fan plot but perhaps in a more easily digestible format as both Spitfire and 109 plots are overlayed on the same chart.

The problem with Me performance numbers

Case: Bf.109E

"Another problem is with the test itself, when compared to a Spitfire. Overall the accuracy of the test suffers from the fact that it was flown with a crash landed plane wirh a worn, several years old engine producing less power than usual. It was then flown against a brand new Spitfire with a 1940 engine. As shown by the test data, the turns were made in the 120mph range which is too slow for the 109 slats to be deployed, which doesn't compare the maximum turning abilities of each aircraft."

http://www.virtualpilots.fi/feature/...s/#testflights