X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 14 Oct 2010 19:55:40 -0400 Message-ID: X-Original-Return-Path: Received: from web36906.mail.mud.yahoo.com ([209.191.85.74] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with SMTP id 4506019 for lml@lancaironline.net; Thu, 14 Oct 2010 12:15:36 -0400 Received-SPF: none receiver=logan.com; client-ip=209.191.85.74; envelope-from=chris_zavatson@yahoo.com Received: (qmail 34258 invoked by uid 60001); 14 Oct 2010 16:14:58 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type; b=vyC3kVfqH3rzCXZmYrmnknenyL6riwdm0SuLJBQu0bG7EKt9Ht6/DdnXZJUkw1SzG1/HWkKC4XCnjlyXF0nsQeDOvwwe4208+zzpUXjjK5dFaa7hoccfAq2oh2wkrQw9dePmS7uDFSvrW0yz2DTSAPlto+IbA8q5IcXYnl/UILc=; X-Original-Message-ID: <633869.34234.qm@web36906.mail.mud.yahoo.com> X-YMail-OSG: wyQ1y9cVM1lI6KriQnLbRyXRmkxPiXX2O1f8C59GPcXEOrX uoWAkWkokrcMQsqKaPk1ce4mJwkYhAA4HPccdlVTbCApSNmStll7i5JSZ283 NIyTAK3cuqVSzQ5sNbzKPzqZfKKk6sn0.gaz2RG2AyhPz1p.IdGJCoy7H.LV yVGmCGMbYKYlPndCSliv3jEJXGpe3rvwFy7amRk.lIY8bYcIAQf6t9lJKlUM xiuUGquWDQGy_gZorNCrpY1olW94_s9d6BmMBSKYb05nGXTTLYssvDsbwuKl SJ3YBd_BJI9hzHStbRntOt36.9MUO5y5Qz2nGkAjaBsY3LYFskISXWjDT4OT a.NItAjSNXwTo18KNquhO3CK1lUZFF6CHhgxTCg-- Received: from [76.246.62.55] by web36906.mail.mud.yahoo.com via HTTP; Thu, 14 Oct 2010 09:14:58 PDT X-Mailer: YahooMailRC/504.5 YahooMailWebService/0.8.106.282862 X-Original-Date: Thu, 14 Oct 2010 09:14:58 -0700 (PDT) From: Chris Zavatson Subject: [LML] LNC 2 inner gear doors vibrate X-Original-To: Lancair Mailing List MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1826328728-1287072898=:34234" --0-1826328728-1287072898=:34234 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable =0AJack,=0ABased on some Barnstormer photos, it would appear you have the o= utback gear.=A0 I =0Aam not completely sure which issue you are describing.= =A0 I'll take a stab at a =0Afew possibilities.=A0Relative to rigidity, the= outback gear=A0has some inherent =0Adrawbacks simply due to geometry.=A0 T= he moment arm on the the actuator=A0when =0Acompared to=A0the increased len= gth of the door is problematic.=A0Tolerances in =0Ajoints and simple flexin= g=A0of components leads to the doors visibly shaking when =0Aextended on th= e ground with the engine running.=0ADoorShake.wmv=A0 (white door is the ori= ginal)=0A(http://www.n91cz.com/Outback-Gear/DoorShake.wmv)=A0=0AYou mention= changing the hinge.=A0 The original was prone to cracking near the =0Aactu= ation point.=A0 The with the actuation arm attached beyond the hinge, a =0A= disproportionate load is applied to the very first link.=A0 I first discove= red =0Acracking during instrument training several years ago.=A0 The doors = spend much =0Amore time hanging out in the breeze during instrument approac= hes that they do in =0Athe traffic pattern.=A0 Extending the hinge forward,= beyond the =0Aactuator,=A0distributes the load across the hinge sections m= ore evenly.=A0 This =0Asolved the cracking issue.=A0=A0=A0=0Ahttp://www.n91= cz.com/misc/gear_hinge_small.JPG=0AThe final rigidity solution stems=A0from= a redesign tackling a different issue.=A0 =0AIn resolving the=A0problem of= the outback doors deforming under aerodynamic =0Aloads=A0and the trailing = edges subsequently being pulled down in flight, the =0Ainboard gear door wa= s shortened to half the original length.=A0 This restores a =0Amore favorab= le ratio between door length and moment arm of the actuator.=A0 The =0Ashor= ter door is the one nearer the camera in the video above.=0AHopefully this = helps.=A0 If not, please elaborate on the details of your =0Aobservations.= =A0 I'm sure someone on the list will have a good solution.=0A=0AChris Zava= tson=0AN91CZ=0A360std=0Awww.N91CZ.com=A0=0A=0A=0A=0A=0A____________________= ____________=0AFrom: JON ADDISON =0ATo: lml@lancaironlin= e.net=0ASent: Tue, October 12, 2010 5:47:07 PM=0ASubject: [LML] LNC 2 inner= gear doors vibrate=0A=0ADoes anyone have experience stabilizing the inner = gear doors on Lancair 360??=A0 =0AHindges were already replaces with a stou= t carbon fiber pair.=0A=A0=0AThe actrator end appears to allow some up/down= motion.=0A=A0=0AJack Addison=A0 jraddison@msn.com=A0=A0 541-419-2502=0AN36= 0JS=0A=0A=0A --0-1826328728-1287072898=:34234 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable

Jack,
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Based on some Barnstormer photos, it would appear you have = the outback gear.  I am not completely sure which issue you are descri= bing.  I'll take a stab at a few possibilities. Relative to rigid= ity, the outback gear has some inherent drawbacks simply due to geomet= ry.  The moment arm on the the actuator when compared to the= increased length of the door is problematic. Tolerances in joints and= simple flexing of components leads to the doors visibly shaking when = extended on the ground with the engine running.
=0A
DoorShake.wmv  (white door is the o= riginal)
=0A
(http://www.n91cz.com/Outback-Gear/DoorShake.wmv) 
You mention changing= the hinge.  The original was prone to cracking near the actuation poi= nt.  The with the actuation arm attached beyond the hinge, a dispropor= tionate load is applied to the very first link.  I first discovered cr= acking during instrument training several years ago.  The doors spend = much more time hanging out in the breeze during instrument approaches that = they do in the traffic pattern.  Extending the hinge forward, beyond t= he actuator, distributes the load across the hinge sections more evenl= y.  This solved the cracking issue.   
=0A
htt= p://www.n91cz.com/misc/gear_hinge_small.JPG
=0A
The final rigidity= solution stems from a redesign tackling a different issue.  In r= esolving the problem of the outback doors deforming under aerodynamic = loads and the trailing edges subsequently being pulled down in flight,= the inboard gear door was shortened to half the original length.  Thi= s restores a more favorable ratio between door length and moment arm of the= actuator.  The shorter door is the one nearer the camera in the video= above.
=0A
Hopefully this helps.  If not, please elaborate o= n the details of your observations.  I'm sure someone on the list will= have a good solution.
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Chris Zavatson=0A
N91CZ
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360std
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=0AFrom: JON ADDISON <j= raddison@msn.com>
To:= lml@lancaironline.net
Sent:= Tue, October 12, 2010 5:47:07 PM
Subject: [LML] LNC 2 inner gear doors vibrate

= =0A=0ADoes anyone have experience stabi= lizing the inner gear doors on Lancair 360??  Hindges were already rep= laces with a stout carbon fiber pair.
 
The actrator end appears= to allow some up/down motion.
 
Jack Addison  jraddison@msn.com   541-419-2502
N360JS<= BR>


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