X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-d07.mx.aol.com ([205.188.109.204] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6729690 for lml@lancaironline.net; Wed, 12 Feb 2014 14:27:46 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.109.204; envelope-from=Sky2high@aol.com Received: from mtaomg-mae01.mx.aol.com (mtaomg-mae01.mx.aol.com [172.26.254.143]) by omr-d07.mx.aol.com (Outbound Mail Relay) with ESMTP id E4C5A701E51E0 for ; Wed, 12 Feb 2014 14:27:11 -0500 (EST) Received: from core-mlc004c.r1000.mail.aol.com (core-mlc004.r1000.mail.aol.com [172.29.188.210]) by mtaomg-mae01.mx.aol.com (OMAG/Core Interface) with ESMTP id 945A53800008D for ; Wed, 12 Feb 2014 14:27:11 -0500 (EST) From: Sky2high@aol.com Full-name: Sky2high Message-ID: Date: Wed, 12 Feb 2014 14:27:10 -0500 (EST) Subject: Re: [LML] 320 / 360 Flutter Page To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_e2bca.eebfdd.402d250e_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1392233231; bh=zLUgNPw2FGZfcjwnwKr++28f9LJ1Wr/45jbVifKZ7qY=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=u72Qbe3IQGMM4/wqqKhQVuhnKOG7qDUzM0u3l2wW8EHVJ6p36tPLiENKmOw6h+th6 uv4WiQ0I/b9FnIi1pz4kwpyh/fFTprvh+6WXNs10POV0oDT6c8Z8Rry555TnC1bRgh ZlD01bNxAY6ERU30GalDFvdAwWkVoPFanXv95mzA= x-aol-sid: 3039ac1afe8f52fbcb0f64f6 --part1_e2bca.eebfdd.402d250e_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Tom, Consider this. The relationship between the horizontal and vertical stab on the 300 series is very rigid. That is, if you move the tip of the horiz up and down, the vertical willdutifully follow suit left and right. The issue you reference is really related to deflections of the tail cone ahead of the bulk head that goes up the leading edge of the vertical. Such deflections more likely occur in twist rather than vertically. The reason for this is that the strong oval shape of the tail cone is incomplete once the vertical stab starts to rise up out of the cone. Note that the two halves of the vertical stab are only held by 2 bid on the outside of the seam in this area (one cannot get to the inside if one is over 4 years old). For racing Legacy's, Lancair wraps carbon glass around that part of the tail cone and up the vertical stab. Another solution to add some rigidity to the 300 series tail is to flox stiff foam into the fuselage from where is starts the vertical stab rise back to the bulk head, shape the foam to follow the interior oval form and apply bids of glass or carbon over the foam and well onto the fuselage to keep the strength of the oval shape. Scott Krueger PS Mark Ravinsky came up with this in light of longitudinal cracks in the area that rises up from the fuselage. I added this to my airplane even though I did not perform aerobatics like Mark. Several others may have done this also. In a message dated 2/12/2014 12:16:08 P.M. Central Standard Time, marv@lancair.net writes: Posted for dudewanarace@yahoo.com: So, I get a fair amount of emails through my 360 website from people researching the 320/360 airplane. Almost always, the questions come up about flutter, how to 'fix' it, big tail vs small tail, etc.. One of the biggest issues I have to deal with is what is found on this page: http://www.lancair.net/flutter.html First let me offer my opinion on the content of that page. I know a bit about the late Mr Hollmann and it isn't confidence inspiring. Even if his vibration analysis was done properly, his solution really doesn't make any sense to me. Combine that with the thousands of hours of operation without major flutter problems that I know of, it seems all this page does is cloud the water. Also, a back and forth banter where neither side produces a definitive answer isn't productive, much like politics! lol If you google "Lancair 360" it is one of the top results, probably within the top 5. I guess my question is this: Is this page really doing any of us any good? As a community can we make a decision on this and either chnage/update it, remove it, or I suppose I'm crazy and do nothing at all. I'm all for making the tail stronger, don't get me wrong. When I finally get the motivation to cut out my horizontal to change the incidence, I plan on wrapping the tail just like the Super Legacy modification, given the above average speeds I fly. Although I'm open to opinions on other ways to do this. Tom McNerney http://www.N54SG.com [First time it's come up in a number of years, however, if it's outlived its supposed usefulness I'll be happy to remove it. ] -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_e2bca.eebfdd.402d250e_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Tom,
 
Consider this.  The relationship between the horizontal and verti= cal=20 stab on the 300 series is very rigid.  That is, if you move the tip of= the=20 horiz up and down, the vertical willdutifully follow suit left and right.&n= bsp;=20 The issue you reference is really related to deflections of the tail cone a= head=20 of the bulk head that goes up the leading edge of the vertical.  Such= =20 deflections more likely occur in twist rather than vertically.  The re= ason=20 for this is that the strong oval shape of the tail cone is incomplete = once=20 the vertical stab starts to rise up out of the cone.  Note that the tw= o=20 halves of the vertical stab are only held by 2 bid on the outside of=20 the seam in this area (one cannot get to the inside if one is over 4 y= ears=20 old). 
 
For racing Legacy's, Lancair wraps carbon glass around that part of th= e=20 tail cone and up the vertical stab. 
 
Another solution to add some rigidity to the 300 series tail is t= o=20 flox stiff foam into the fuselage from where is starts the vertical=20 stab rise back to the bulk head, shape the foam to follow the interior= oval=20 form and apply bids of glass or carbon over the foam and=20 well onto the fuselage to keep the strength of the oval shape. 
 
Scott Krueger
 
PS Mark Ravinsky came up with this in light of longitudinal cracks in = the=20 area that rises up from the fuselage.  I added this to my airplane eve= n=20 though I did not perform aerobatics like Mark.  Several others may hav= e=20 done this also.
 
 
In a message dated 2/12/2014 12:16:08 P.M. Central Standard Time,=20 marv@lancair.net writes:
=

Posted for=20 dudewanarace@yahoo.com:

 So, I get a fair amount of emails th= rough=20 my 360 website from people
researching the 320/360 airplane.  Al= most=20 always, the questions come up about
flutter, how to 'fix' it, big tai= l vs=20 small tail, etc..   One of the biggest
issues I have to deal wit= h is=20 what is found on this=20 page:

 http://www.lancair.net/flutter.html


First l= et me=20 offer my opinion on the content of that page.  I know a bit
abou= t the=20 late Mr Hollmann and it isn't confidence inspiring.  Even if his=20
vibration analysis was done properly, his solution really doesn't mak= e any=20
sense to me.  Combine that with the thousands of hours of operat= ion=20 without
major flutter problems that I know of, it seems all this page= does=20 is cloud
the water.  Also, a back and forth banter where neither= side=20 produces a
definitive answer isn't productive, much like politics!=20 lol


 If you google "Lancair 360" it is one of the top res= ults,=20 probably within
the top 5.  I guess my question is this: Is this= page=20 really doing any of us
any good?


 As a community can = we=20 make a decision on this and either chnage/update it,
remove it, or I= =20 suppose I'm crazy and do nothing at all.

 I'm all for making = the=20 tail stronger, don't get me wrong.  When I finally
get the motiv= ation=20 to cut out my horizontal to change the incidence, I plan
on wrapping = the=20 tail just like the Super Legacy modification, given the above
average= =20 speeds I fly.  Although I'm open to opinions on other ways to do=20
this.

 Tom McNerney
 http://www.N54SG.com=20


[First time it's come up in a number of years, however,= if=20 it's outlived its supposed usefulness I'll be happy to remove it.=20  <Marv>    ]


--

For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html=
--part1_e2bca.eebfdd.402d250e_boundary--