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Old 01-10-2018, 11:25 AM   #181
Yo-Yo
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Yo-Yo I feel a lot is being missed in translation here because it honestly feels like you've not read my posts at all....

1) I agree that there are actual P-51 flight test data in TN 1044, and I am saying you need to compare that side by side with the flight test data of the F6F (because it features the same airfoil selection as the Fw190) in the same report

2) If you want to use WT numbers then the 1.58 figure applies for a clean aircraft with the NACA 23015-23009 selection.

To be more specific I am not saying a Clmax of 1.35 is wrong, what I am saying is that anything higher or similar for the P-51 is wrong, and that based on all the data available.

However if you want to use solely WT figures to simulate a perfectly smooth and ideal airfoil, as seems to be the case for the laminar flow airfoil, then you need to do the same for the conventional types, and then 1.58 applies for NACA 23xxx.
You really never read my posts... and every time you distort the point. There was no discussion about new or worn wing... it was a long story why 2D section data can not be applied to the real aircraft. So, I quit...
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Old 01-10-2018, 11:41 AM   #182
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Let it be… He probably realised he was mistaken and tried to get a honourable exit. Can't blame him.


Nevertheless, great FM talking .


S!
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Old 01-10-2018, 12:09 PM   #183
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You really never read my posts... and every time you distort the point. There was no discussion about new or worn wing... it was a long story why 2D section data can not be applied to the real aircraft. So, I quit...
New or worn wing? No, the 1.58 figure was a WT figure for a clean aircraft, no flaps, which was the first argument (You argued it was with flaps), I provide NACA report 824 to show it clearly wasn't. Then you move on to explain why you didn't use such WT figures due to them leaving out trim loss and the difference between perfectly smooth WT models & the real aircraft etc. - which is a fair point and one I completely accept (!). But the very same precaution needs be applied to all aircraft/airfoil selections then. The point is to be consistent, and not cherry pick and mix WT & flight test figures.

Next you bring up NACA report TN 1044 as the source for your laminar flow & conventional type airfoil characteristics at varying Mach numbers, yet at the same time you choose to ignore the relevant tables and use completely irrelevant aircraft with symmetrical airfoil selections as substitutes for the F6F/FW190 and compare them with the P-51. As a result you end up with figures that simply don't correlate with the actual differences recorded during flight testing under similar conditions, see Fig 4, 14 & 12.

Thus how you can feel that I distort anything is beyond me, but so be it, I've tried my best to explain the discrepancies that are present and where you might have made a small error. I don't want to argue just for arguments sake, I am only pointing out all of this in the hopes of correcting any possible mistakes and crucially achieve transparency about the sources for the FM.

Last edited by Hummingbird; 01-10-2018 at 12:11 PM.
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Old 01-10-2018, 01:53 PM   #184
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I am only pointing out all of this in the hopes of correcting any possible mistakes and crucially achieve transparency about the sources for the FM.
And you pointed it out many times, and you have been answered many times (even if its an answer you don't like or understand), so now it's done. Yo-Yo/ED doesn't think there is an issue. End of story.
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