Originally posted by Crumpp
It's not being obtuse to take more than one source.
Crumpp,
It is in fact grossly obtuse to take data that directly addresses the issue of squadron service performance and discard it in favor of general comments from another source that only very indirectly address the subject at hand. Obviously, since it doesn't fit your agenda, you have no use for it. Perhaps you should take a more objective approach to selecting and weighting your sources.
Since you can't seem to accept the idea that AVIA 6/10618's expressed purpose was to test the expected performance of
average squadron aircraft:
The change in performance is known. It is the effect on the forces that is not. Is that hard to understand?
Please don't lecture me on understanding. You are showing a willful lack of understanding of the information provided to you. There is no mysterious alchemy involved here- no secret science that I am not a party to. Quite simply, a Mustang III (FB377) pulled directly from operational service (316 Sqn) achieved 383 mph at sea level with wing racks in place and a very poor surface condition. That same airplane, at exactly the same power setting, and under the same controlled and corrected test conditions achieved 403.5 mph after the wing racks and the small bracket at the base of the VHF aerial were removed, and the very poor surface condition restored. The Royal Aircraft Establishment at Farnborough, an exceptionally qualified testing institution, attributed 8 mph of the increase to the removal of the wing racks, 1/2 mph to the removal of the aerial bracket and 12 mph to the resoration of the badly degrade paint surfaces. In all other ways the airplane was identical.
Your attempts to obfuscate the results with repeated referrals to the exhaust stubs and resulting exhaust thrust ring hollow, I'm afraid. Further, I'm sure the realization that a well-used squadron service Mustang III with a six coats of badly chipped paintwork was faster than the fastes production Focke Wulf doesn't sit well with you, either.
Your patronizing attempts to convince me that I'm just too thick to understand the forces at work here are just a way for you to avoid directly addressing the findings of the report. The report doesn't support your premise so you want simply to ignore it.
Mute point anyway as this modification did not see production. However my questions clearly showed your lack of understanding of the science.
You still do not understand the relationship of drag forces and want to hold one example up as typical of the entire series.
I'm glad that you have finally accepted that the larger Spitfire-type exhausts fitted are
moot to this argument. After all,
the increase in speed attributed to the cleaned-up surfaces was determined before the exhaust stacks were replaced. It is you who exhibits a shocking lack of understanding of logic and reason here, Crumpp. And once again Crumpp, it was the Royal Aircraft Establishment, not me, that held this example as representative of the average operational aircraft. For the last time,
either tell me why they were wrong and you are right, or finally accept the uncomfortable truth.
Explain how the RAE is more credible than the NACA or the manufacturer of the aircraft?
I never said the RAE was more credible than NACA. Unfortunately for your argument, NACA never performed tests of operational P-51's expressly designed to determine how much speed could be gained in squadron service through a number of quantified actions. The Royal Aircraft Establishment, however, did.
Sure they were, otherwise the NACA's would not have had to quantify their findings on Mustang performance.
You can post that link until you're blue in the face, but that still won't cause the document to say something that it doesn't. You want to believe that it says P-51's taken on charge by the USAAF and RAF were of a much lower quality than the ones experimented on by NACA. It doesn't. It simply states that the manufacturing technologies of the day were not capable of producing the type of surface smoothness that was required to achieve laminar air flow in the wind tunnel. Even if the production tolerances were capable in that manner, it wouold have been impossible to maintain that surface quality in operational surface. Is it suprising that a production line, even a very capable one, was not capable of assembly hundreds of parts made from different materials with the same level of precision as the 1/3 and 1/4 scale hand-made mahogany and metal wind tunnel models. Even these custom creations with five layers of hand-rubbed lacquer only achieved laminar flow in brief fits and starts. What's so hard to understand about that?
Finally, I'm sure you will take no comfort from the fact that none of the USAAF's or RAF's official P-51 speed performance results were ever quoted from NACA data.
Regards,
Brent Erickson
