Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Sat, 08 Jan 2005 13:01:48 -0500 Message-ID: X-Original-Return-Path: Received: from tomts13-srv.bellnexxia.net ([209.226.175.34] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 595905 for lml@lancaironline.net; Sat, 08 Jan 2005 12:58:12 -0500 Received-SPF: none receiver=logan.com; client-ip=209.226.175.34; envelope-from=ian.crowe@sympatico.ca Received: from crowe ([69.159.73.113]) by tomts13-srv.bellnexxia.net (InterMail vM.5.01.06.10 201-253-122-130-110-20040306) with SMTP id <20050108175739.BGFV1899.tomts13-srv.bellnexxia.net@crowe> for ; Sat, 8 Jan 2005 12:57:39 -0500 X-Original-Message-ID: <009801c4f5ab$8dd27810$6721fea9@crowe> From: "Ian B. Crowe" X-Original-To: "Lancair Mailing List" Subject: LNC2 gear free fall X-Original-Date: Sat, 8 Jan 2005 12:57:43 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0095_01C4F581.A49A52E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0095_01C4F581.A49A52E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable You say the nose gear works fine so obviously the gas spring is doing = its job. As far as the mains are concerned there are two possible causes !. Is the hydraulic pressure going to zero to allow the gear to fall = freely and get into a position where the over centre spring can do its = job? As I see it the spring is there to push/lock the "knee joint " = over centre and ensure the gear stays in the down position. It is not = there to bring the gear into the down position. As a test for zero = pressure you might just crack open the connections to the cylinder one = by one to see if the gear falls correctly. If you have significant = leakage from the opened connection and the gear falls then I would think = you have some retained pressure. More scientifically you could TEE in a = pressure gauge, in a convenient place,obtainable from Vern quite cheaply = and this will tell you exactly what is going on. You might leave the T = in place and cap it for future tests. Our hydraulic pumps do strange = things if the spool valve is not fitted correctly. See the archives, = there is a lot of good stuff there. 2. Is the strut and linkage free of all binding? As I remember when = I built my A/C the amount of space available for the various components = is very small and the linkage is free to move enough to foul in some = positions. The big rod end tends to move as the gear moves. Also is = the knee joint overtightened at the fork and blade position? Check that = the out board door linkage to the strut is free at all strut positions. 3. As I remember the rat trap springs were changed at one time. = There had been a problem with their manufacture and some broke. I = believe the design was changed and the heat treat more closely = specified. However Vern would know. Good Luck Ian Crowe ------=_NextPart_000_0095_01C4F581.A49A52E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

You say the nose gear works fine so = obviously the=20 gas spring is doing its job.

As far as the mains are concerned there = are two=20 possible causes

!. Is the hydraulic = pressure=20 going to zero to allow the gear to fall freely and get into a position = where the=20 over centre spring can do its job? As I see it the spring is there = to=20 push/lock the "knee joint " over centre and ensure the gear stays = in the=20 down position. It is not there to bring the gear into = the down=20 position. As a test for zero pressure you might just crack open = the=20 connections to the cylinder one by one to see if the gear falls = correctly. =20 If you have significant leakage from the opened connection and the gear = falls=20 then I would think you have some retained pressure. More = scientifically=20 you could TEE in a pressure gauge, in a convenient place,obtainable from = Vern=20 quite cheaply and this will tell you exactly what is going on. You = might=20 leave the T in place and cap it for future tests. Our hydraulic = pumps do=20 strange things if the spool valve is not fitted correctly. See the = archives, there is a lot of good stuff there.

2. Is the strut and = linkage free=20 of all binding? As I remember when I built my A/C the amount of = space=20 available for the various components is very small and the linkage is = free to=20 move enough to foul in some positions. The big rod end tends to = move as=20 the gear moves. Also is the knee joint overtightened at the fork = and blade=20 position? Check that the out board door linkage to the strut is = free at=20 all strut positions.

3. As I remember the = rat trap=20 springs were changed at one time. There had been a problem with = their=20 manufacture and some broke. I believe the design was changed and the = heat treat=20 more closely specified. However Vern would know.

Good Luck

Ian Crowe

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