X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 23 Sep 2013 18:26:34 -0400 Message-ID: X-Original-Return-Path: Received: from mail-pb0-f42.google.com ([209.85.160.42] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6487159 for lml@lancaironline.net; Mon, 23 Sep 2013 16:53:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.42; envelope-from=pjdmiller@gmail.com Received: by mail-pb0-f42.google.com with SMTP id un15so3683098pbc.15 for ; Mon, 23 Sep 2013 13:52:48 -0700 (PDT) X-Received: by 10.68.219.104 with SMTP id pn8mr15246672pbc.81.1379969549295; Mon, 23 Sep 2013 13:52:29 -0700 (PDT) X-Original-Return-Path: Received: from [192.168.1.122] (S010620aa4b008706.cg.shawcable.net. [174.0.112.194]) by mx.google.com with ESMTPSA id gh2sm6395321pbc.40.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 23 Sep 2013 13:52:28 -0700 (PDT) Subject: Re: [LML] Re: Question on Legacy MG Strut References: From: Paul Miller Content-Type: multipart/alternative; boundary=Apple-Mail-17E4702B-ED94-423F-A2BA-D143E43BEFBB X-Mailer: iPad Mail (10B146) In-Reply-To: X-Original-Message-Id: <4D193750-5487-4B29-9358-8A85CE65BABB@gmail.com> X-Original-Date: Mon, 23 Sep 2013 14:52:27 -0600 X-Original-To: Lancair Mailing List Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-17E4702B-ED94-423F-A2BA-D143E43BEFBB Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Many many thanks for those photos and outline. I wrote some years ago abou= t a click sound when turning on the ground. After tightening the vertical s= mall screws that sound disappeared. I may have some wear on that slide afte= r 700 hours and i believe thats the sound origin. Can you outline what you did to refurbish the items? It looks like seals, p= aint and all else looks in great shape. With that in mind, I may inspect mi= ne this winter. Is there any ESCO reference material? Paul On 2013-09-23, at 14:10, "Thorn, Valin B. (JSC-VA411)" wrote: > Paul, > =20 > We recently refurbished and re-sealed our Legacy=E2=80=99s gear struts to g= et them ready for flight after years of waiting to fly... Ours were made by= ESCO in Australia where later versions are made by Lancair owner Bob Wolste= nholme=E2=80=99s machining company. I don=E2=80=99t know if the designs are= exactly the same. > =20 > On the ESCO strut, the mains are much simpler than the nose gear which has= more complicated internals to allow for nose wheel pivoting on the ground b= ut straight when fully extended for landings. > =20 > Here are a few photos of the internals of the ESCO built Legacy main gear s= hock strut: > =20 > > > =20 > So, from my new familiarity with the strut design and what you described, h= ere=E2=80=99s what I think. The lower cap screws you tightened are for the p= art closing the cylinder and holding the main and scraper seals and don=E2=80= =99t affect wheel alignment. The screws running up the side of the strut ho= ld bars in place inside the cylinder that keep the strut from turning (left a= nd right). See the long bars on the table in the third photo. The large al= uminum piece, with the longitudinal slots in it, attaches to the top of the s= hock strut piston and slides up and down the cylinder -- with the bars in it= s wide slots preventing any rotation of the strut piston about its long axis= (left right alignment/toe). If they=E2=80=99re a little lose they may allo= w some very small left/right free play in the wheel alignment. When you tig= htened them up it may have change the alignment slightly. They need to be t= ight to keep oil from leaking out underneath them and there are little seals= under the screws to help with that. With the =E2=80=9Cbar screws=E2=80=9D l= ose you may have been getting a tiny bit of castoring motion where the wheel= was self-aligning when moving. With this bit of free play it was probably a= lso more vulnerable to shimmying. > =20 > With all that said, I think you just need to now realign your main wheels a= t the strut flange interface (gold dyed cadmium plating end section) to whee= l fork and you=E2=80=99ll get this problem corrected. =46rom the tire wear p= attern and turning tendency, I think it is =E2=80=9Ctoed in=E2=80=9D too far= to the right. Hope this is helpful. > =20 > Valin Thorn > Legacy Project > Boulder, Colorado > =20 > =20 > =20 > -----Original Message----- > From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Pau= l Miller > Sent: Monday, September 23, 2013 6:04 AM > To: lml@lancaironline.net > Subject: [LML] Question on Legacy MG Strut > =20 > For those with strut knowledge: My main gear was tracking well and tires w= ere wearing evenly. Recently, I noticed the 4 cap screws on the bottom of t= he strut were not tight and up along the body were smaller screws were also l= oose so I tightened them. Now, the Left Main tire is wearing dramatically o= n the outside and the plane turns constantly left during taxiing. =20 > =20 > My question is: What would that indicate inside the strut? I hesitate to= pull off the strut. If it is just normal play, I will try to re-align but= I'm not sure I want to loosen anything up on the strut at this point until I= understand what happened. Thanks. > -- > For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.htm= l --Apple-Mail-17E4702B-ED94-423F-A2BA-D143E43BEFBB Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Many many thanks for those photos and o= utline.   I wrote some years ago about a click sound when turning on th= e ground.  After tightening the vertical small screws that sound disapp= eared.  I may have some wear on that slide after 700 hours and i believ= e thats the sound origin.

Can you outline what you d= id to refurbish the items?  It looks like seals, paint and all else loo= ks in great shape.  With that in mind, I may inspect mine this winter. &= nbsp;Is there any ESCO reference material?

Paul

On 2013= -09-23, at 14:10, "Thorn, Valin B. (JSC-VA411)" <valin.b.thorn@nasa.gov> wrote:

=

Paul,

 

We recently refurbished and re-sealed our Legacy=E2= =80=99s gear struts to get them ready for flight after years of waiting to f= ly...  Ours were made by ESCO in Australia where later versions are mad= e by Lancair owner Bob Wolstenholme=E2=80=99s machining company.  I don=E2=80=99t know if the designs are exactly the same.

 

On the ESCO strut, the mains are much simpler than= the nose gear which has more complicated internals to allow for nose wheel p= ivoting on the ground but straight when fully extended for landings.

 

Here are a few photos of the internals of the ESCO= built Legacy main gear shock strut:

 

<i= mage007.jpg>

<i= mage008.jpg><image009.jpg>

 

So, from my new familiarity with the strut design a= nd what you described, here=E2=80=99s what I think.  The lower cap scre= ws you tightened are for the part closing the cylinder and holding the main a= nd scraper seals and don=E2=80=99t affect wheel alignment.  The screws running up the side of the strut hold bars in place inside the c= ylinder that keep the strut from turning (left and right).  See the lon= g bars on the table in the third photo.  The large aluminum piece, with= the longitudinal slots in it, attaches to the top of the shock strut piston and slides up and down the cylinder --= with the bars in its wide slots preventing any rotation of the strut piston= about its long axis (left right alignment/toe).  If they=E2=80=99re a l= ittle lose they may allow some very small left/right free play in the wheel alignment.  When you tightened them u= p it may have change the alignment slightly.  They need to be tight to k= eep oil from leaking out underneath them and there are little seals under th= e screws to help with that.  With the =E2=80=9Cbar screws=E2=80=9D lose you may have been getting a tiny bit of c= astoring motion where the wheel was self-aligning when moving.  With th= is bit of free play it was probably also more vulnerable to shimmying.<= /o:p>

 

With all that said, I think you just need to now r= ealign your main wheels at the strut flange interface (gold dyed cadmium pla= ting end section) to wheel fork and you=E2=80=99ll get this problem correcte= d.  =46rom the tire wear pattern and turning tendency, I think it is =E2=80=9Ctoed in=E2=80=9D too far to the right.&nbs= p; Hope this is helpful.

 

Valin Thorn

Legacy Project

Boulder, Colorado

 

 

 

-----Original Message-----
From: Lancair Mailing List [mailto:= lml@lancaironline.net] On Behalf Of Paul Miller
Sent: Monday, September 23, 2013 6:04 AM
To: lml@lancaironline.net
Subject: [LML] Question on Legacy MG Strut

 

For those with strut knowledge:  My main gear= was tracking well and tires were wearing evenly.  Recently, I noticed t= he 4 cap screws on the bottom of the strut were not tight and up along the b= ody were smaller screws were also loose so I tightened them.  Now, the Left Main tire is wearing dramatically o= n the outside and the plane turns constantly left during taxiing.  = ; 

 

My question is: What would that indicate inside th= e strut?   I hesitate to pull off the strut.   If it is j= ust normal play, I will try to re-align but I'm not sure I want to loosen an= ything up on the strut at this point until I understand what happened.  Thanks.

--

For archives and unsub http://mail.lancaironline= .net:81/lists/lml/List.html

= --Apple-Mail-17E4702B-ED94-423F-A2BA-D143E43BEFBB--