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Good news and bad news for Jeff.

The bad news is that he forgot that Mmo is TAS and Vne is IAS.

The good news is that 0.52 Mmo is likely very conservative. The reason makes an interesting story.

Without getting into a detailed explanation, suffice it to say that the calculated Mmo limit is partially dependent on the stiffness of the airframe. The design stiffness of the was determined by Martin Hollmann who, being the good engineer he is, performed tests on sample layups to determine their stiffness. (see "Composite Aircraft Design" M. Hollmann). Sounds great ..... except that the procedure Martin  used did not adequately allow for nonlinearities in the test fixture. According to a former PAC engineer, these tests were repeated for the certified aircraft program and it was determined that the original values were too low by about 25%. Based on the newer values, Mmo should be 0.58 or 342 KTAS at FL300.

This is the limit I tested my airplane to and used during the cross country race.

Having said that, I must restate that the published limit is 0.52 and under NO circumstances should you ever exceed the published limit.

Especially if you are racing against me.

Opps....did I say that out loud ?? :0

Regards.
Brent Regan

PS. Check the archives for Fred Moreno's explanation on accurately converting between TAS and IAS given the significant effects of compressibility at these speeds.
BR

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