X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 19 Aug 2009 13:01:26 -0400 Message-ID: X-Original-Return-Path: Received: from [70.62.14.124] (HELO ustek.com) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3817932 for lml@lancaironline.net; Wed, 19 Aug 2009 06:29:27 -0400 Received-SPF: pass receiver=logan.com; client-ip=70.62.14.124; envelope-from=r.simon@ustek.com MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CA20B8.06DA72B2" Subject: RE: Strength vs. stiffness Content-class: urn:content-classes:message X-MimeOLE: Produced By Microsoft Exchange V6.5 X-Original-Date: Wed, 19 Aug 2009 06:30:04 -0400 X-Original-Message-ID: In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Strength vs. stiffness Thread-Index: AcoguAOVS/OCKiUyQvmOE1Y4NtEyYg== From: "Lancair" X-Original-Sender: "Robert Simon" X-Original-To: "Gary Casey" , This is a multi-part message in MIME format. ------_=_NextPart_001_01CA20B8.06DA72B2 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable When I contacted Lancair and told them that I wanted to remove the ES-P pressure bulkhead from behind the rear seats and fabricate a new one at a station aft of the baggage area they pondered the situation, ran some calculations, and suggested (demanded might be more exact) that additional graphite plys be carried all the way into the tail cone. This had the dual effect of making the fuselage tube stiffer and more capable of taking the pressurization and also making the empennage stronger. I went one step further and added an "obi" of graphite unidirectional in a band all the way around the fuselage at the location where the pressure bulkhead was removed. =20 =20 I have not tested this new design to failure ;-) but it seems to work just fine. Cabin distortion during pressurization is similar to the IV-P, I see no ill effects of the extra stiffness in the tail cone, and I kinda like the extra insurance. If the tail is stronger does that mean the weak link is somewhere else? Probably - and I hope never to find out. =20 Robert M. Simon ES-P N301ES=20 ________________________________ . . . I lost the original question on this, but someone asked about the wisdom of adding stiffness to the fuselage and whether that would make it more likely to break. . . . =20 ------_=_NextPart_001_01CA20B8.06DA72B2 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
When I contacted Lancair and told them that I = wanted to=20 remove the ES-P pressure bulkhead from behind the rear seats and = fabricate a new=20 one at a station aft of the baggage area they pondered the situation, = ran some=20 calculations, and suggested (demanded might be more exact) that = additional=20 graphite plys be carried all the way into the tail cone.  This had = the dual=20 effect of making the fuselage tube stiffer and more capable of taking = the=20 pressurization and also making the empennage stronger.  I went one = step=20 further and added an "obi" of graphite unidirectional in a band all the = way=20 around the fuselage at the location where the pressure bulkhead was=20 removed. 
 
I have not tested this new design to failure=20  ;-)  but it seems to work just fine.  Cabin distortion = during=20 pressurization is similar to the IV-P, I see no ill effects of the = extra=20 stiffness in the tail cone, and I kinda like the extra insurance.  = If the=20 tail is stronger does that mean the weak link is somewhere else? =20  Probably - and I hope never to find out.
 
Robert M. Simon
ES-P N301ES 

 .  . .  I lost the original = question on=20 this, but someone asked about the wisdom of adding stiffness to the = fuselage and=20 whether that would make it more likely to break.   . . .=20  
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