X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 24 Sep 2013 06:19:29 -0400 Message-ID: X-Original-Return-Path: Received: from argon.lunarpages.com ([216.97.227.30] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6487440 for lml@lancaironline.net; Tue, 24 Sep 2013 00:09:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=216.97.227.30; envelope-from=thorn@starflight.aero Received: from 65-128-94-248.hlrn.qwest.net ([65.128.94.248]:65165 helo=VAlien2) by argon.lunarpages.com with esmtpa (Exim 4.77) (envelope-from ) id 1VOJvl-0005Tq-L1 for lml@lancaironline.net; Mon, 23 Sep 2013 21:08:58 -0700 From: "Valin & Allyson Thorn" X-Original-To: "'Lancair Mailing List'" X-Original-Cc: "Valin & Allyson Thorn" References: In-Reply-To: Subject: RE: [LML] Re: Question on Legacy MG Strut X-Original-Date: Mon, 23 Sep 2013 22:08:51 -0600 X-Original-Message-ID: <016c01ceb8db$c751d2a0$55f577e0$@starflight.aero> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_016D_01CEB8A9.7CBC1D90" X-Mailer: Microsoft Outlook 15.0 Content-Language: en-us Thread-Index: AQFZpXSUlydQvi67GhwIBDKnE/EvAZq+ZcFg X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - argon.lunarpages.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - starflight.aero X-Get-Message-Sender-Via: argon.lunarpages.com: authenticated_id: thorn@starflight.aero This is a multipart message in MIME format. ------=_NextPart_000_016D_01CEB8A9.7CBC1D90 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Paul, =20 Normally this work is done by Lancair and that is their strong = preference. We wanted to do it ourselves for its educational value. = After some deliberations, Lancair agreed and required us signing a = liability waiver and they would provide absolutely no instructions but = would sell us the seals. We were brave enough to risk doing it = ourselves because a maintenance shop at our airport routinely reseals = shock struts and we had them as consultants to rescue us if needed. =20 =20 Fortunately, we didn=E2=80=99t need any rescuing and we handled it with = just one call for help where we determined we had to build some special = tools to get the nose gear internals disassembled. We had the cylinders = powder coated, and the shock piston wheel fork attachment flanges = re-plated with cadmium. The replacement seals were fairly expensive. = We didn=E2=80=99t look into getting them directly from Esco in = Australia. =20 A quick outline of how to change out the oleo-pneumatic shock strut = seals is to be sure to let the pressure out of the shock strut before = disassembly. Remove the fasteners. Take photos of how it all comes out = of the cylinder. Change out seals. Reassemble. Compress the strut = completely and fill with oil. Pressurize with nitrogen to a level that = results in about a 25% compression of the strut under the static weight = of the airplane. =20 Hope that helps, =20 Valin Thorn Legacy Project Boulder, Colorado =20 =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Paul Miller Sent: Monday, September 23, 2013 4:27 PM To: lml@lancaironline.net Subject: [LML] Re: Question on Legacy MG Strut =20 Many many thanks for those photos and outline. I wrote some years ago = about a click sound when turning on the ground. After tightening the = vertical small screws that sound disappeared. I may have some wear on = that slide after 700 hours and i believe thats the sound origin. =20 Can you outline what you did to refurbish the items? It looks like = seals, paint and all else looks in great shape. With that in mind, I = may inspect mine 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 get 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 Wolstenholme=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 but straight when fully extended for landings. =20 Here are a few photos of the internals of the ESCO built Legacy main = gear shock strut: =20 =20 So, from my new familiarity with the strut design and what you = described, here=E2=80=99s what I think. The lower cap screws you = tightened are for the part 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 hold bars in place inside the cylinder = that keep the strut from turning (left and right). See the long 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 little lose they may allow = some very small left/right free play in the wheel alignment. When you = tightened them up it may have change the alignment slightly. They need = to be tight 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 lose 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 also more vulnerable to shimmying. =20 With all that said, I think you just need to now realign your main = wheels at the strut flange interface (gold dyed cadmium plating end = section) to wheel fork and you=E2=80=99ll get this problem corrected. = From the tire wear pattern 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 = Paul Miller Sent: Monday, September 23, 2013 6:04 AM To: lml@lancaironline.net =20 Subject: [LML] Question on Legacy MG Strut =20 For those with strut knowledge: My main gear was tracking well and = tires were wearing evenly. Recently, I noticed the 4 cap screws on the = bottom of the strut were not tight and up along the body were smaller = screws were also loose so I tightened them. Now, the Left Main tire is = wearing dramatically on 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.html ------=_NextPart_000_016D_01CEB8A9.7CBC1D90 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Paul,

 

Normally this work is done by Lancair and that is = their strong preference.=C2=A0 = We wanted to do it ourselves for its educational value.=C2=A0 After some deliberations, = Lancair agreed and required us signing a liability waiver and they would = provide absolutely no instructions but would sell us the seals.=C2=A0 We were brave enough to risk = doing it ourselves because a maintenance shop at our airport routinely = reseals shock struts and we had them as consultants to rescue us if = needed.=C2=A0 =

 

Fortunately, we didn=E2=80=99t need any rescuing = and we handled it with just one call for help where we determined we had = to build some special tools to get the nose gear internals = disassembled.=C2=A0 We had the = cylinders powder coated, and the shock piston wheel fork attachment = flanges re-plated with cadmium.=C2=A0 = The replacement seals were fairly expensive.=C2=A0 We didn=E2=80=99t look into = getting them directly from Esco in = Australia.

 

A quick outline of how to change out the = oleo-pneumatic shock strut seals is to be sure to let the pressure out = of the shock strut before disassembly.=C2=A0 Remove the fasteners.=C2=A0 Take photos of how it all comes = out of the cylinder.=C2=A0 = Change out seals.=C2=A0 = Reassemble.=C2=A0 = Compress the strut completely and fill with oil.=C2=A0 Pressurize with nitrogen to a = level that results in about a 25% compression of the strut under the = static weight of the airplane.

 

Hope that helps,

 

Valin Thorn

Legacy Project

Boulder, Colorado

 

 

From: Lancair Mailing List [mailto:lml@lancaironline.net] On = Behalf Of Paul Miller
Sent: Monday, September 23, 2013 = 4:27 PM
To: lml@lancaironline.net
Subject: [LML] Re: = Question on Legacy MG Strut

 

Many many thanks for = those photos and outline.   I wrote some years ago about a click = sound when turning on the ground.  After tightening the vertical = small screws that sound disappeared.  I may have some wear on that = slide after 700 hours and i believe thats the sound origin.

 

Can you outline what you did to refurbish the items?  It = looks like seals, paint and all else looks in great shape.  With = that in mind, I may inspect mine this winter.  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 fly...  Ours = were made by ESCO in Australia where later versions are made 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 pivoting 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:

 

<image007.jpg>

<image008.jpg><image009.jpg>=

 

So, from my new familiarity with the strut design = and what you described, here=E2=80=99s what I think.  The lower cap = screws you tightened are for the part 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 hold bars = in place inside the cylinder that keep the strut from turning (left and = right).  See the long 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 little lose they may allow some very small left/right = free play in the wheel alignment.  When you tightened them up it = may have change the alignment slightly.  They need to be tight 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 lose 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 also more vulnerable to = shimmying.

 

With all that said, I think you just need to now = realign your main wheels at the strut flange interface (gold dyed = cadmium plating end section) to wheel fork and you=E2=80=99ll get this = problem corrected.  From the tire wear pattern and turning = tendency, I think it is =E2=80=9Ctoed in=E2=80=9D too far to the = right.  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
Subjec= t: [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 the 4 cap screws on = the bottom of the strut were not tight and up along the body were = smaller screws were also loose so I tightened them.  Now, the Left = Main tire is wearing dramatically on the outside and the plane turns = constantly left during taxiing.   

 

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://m= ail.lancaironline.net:81/lists/lml/List.html

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