From: Klusmanp@aol.com
Message-ID: <12.1af1cad1.29ab1d11@aol.com>
Date: Sun, 24 Feb 2002 23:52:33 EST
Subject: Re: Lancair 4P Vne & Mach Limit (Mmo)...True or False?
To: lancair.list@olsusa.com
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>>
Just curious, but did either of these tests include conditioning the 
composite samples to simulate hot/humid conditions? Moisture has a huge 
impact on the strength of composites. It can impact the stiffness as well. 
I'd be VERY careful about going past a published flutter limit - Lancair may 
be adding an extra margin of safety to account for the behavior of the 
structure in a test lab vs. real life.

Paul Klusman


In a message dated 2/24/02 1:03:48 PM EST, Brent@regandesigns.com writes:

<< 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. >>
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