Quote:
Originally Posted by TomcatViP
Most of the time the variation will be minimal, just like in British summertime for a British engineered plane.
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For once Tomcat is talking sense here!
I'm not a pilot (but I am a practicing physicist) perhaps others can confirm or refute the following suggestion: I strongly suspect that the RAF/Farnborough & Boscome Down used an Atmosphere that was representative of British conditions (particularly latitude), also probably spring/summer/autumn temperatures because aircraft would do most of their flying time at these times. I also suspect that the International Standard Atmosphere was not available until post-war.
However I do not know whether the testing authorities normalised their measurements to some British standard atmosphere.
SO - as long as the CloD atmosphere is reasonably representative of British conditions the speed or climb variations due to minor (day-to-day, or during the day) can be easily corrected by correcting for the density for a particular atmosphere in CloD without having to do anything more sophisticated.
(As an aside - temperature DOES affect the compressibility in the supercharger, as well as input density, but it'll be fairly second-order because the two are coupled in a gravitationally stratified atmosphere)
This is what I believe Klem has done (at least in some of his other posted data, I haven't checked this post).
The differences between CloD data measured by Klem and measured performance (albeit slightly affected by local conditions on the day) are now so large (and even worse - inconsistent between 'plane variants - and even more worse, between red and blue) that issues of British atmospheric variations pale into insignificance.
56RAF_phoenix
07-14-2012, 03:12 PM
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