Message-Id: <9809089052.AA905294967@inet001.cardell.com>
Date: Tue, 08 Sep 98 18:42:55 -0500
From: <dechaze@cardell.com>
To: <lancair.list@olsusa.com>
Subject: Re:360 tail flutter 
Mime-Version: 1.0

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Angier Ames wondered why no one responded to his post on MKII tail flutter and
the flap preload.  

I guess everybody is still exhausted from the discussion 3 months ago on the
tail question.  I telephoned Martin at that time to understand his view of the
situation and came away unconvinced that there is a problem.  Apparently his
ground vibration experiment validated his FEA model but there's been no attempt
to validate the aerodynamic excitation conditions (forcing functions for those
of you with dim memory of introductory dynamics).  Martin explained that this
part of the model is used by Boeing and taken on faith.

My skepticism arose because he predicted flutter at very low speeds and if he
was correct I would have expected a rash of related accidents.  To my knowledge
there have been none so the most likely explanation is that the analysis is
incorrect - probably related to how aerodynamics are handled in our category of
aircraft. 

I have not heard anything about flap preload either.  BTW Angier, if your plane
goes together anything like mine, I bet those rear windows are really gettting
in the way right about now.  The worst part of the whole construction process so
far has been lying across the seat back and rear bulkhead reaching into the tail
section for antenna placement (Com2, ELT, HSI flux module).  Damn am I glad the
hydraulic pump is behind the seat!

Best Regards,
Ed de Chazal