Return-Path: Received: from hawk.prod.itd.earthlink.net ([207.217.120.22]) by truman.olsusa.com (Post.Office MTA v3.5.1 release 219 ID# 0-52269U2500L250S0V35) with ESMTP id com for ; Tue, 23 Mar 1999 01:43:14 -0500 Received: from bigfoot.com (pool042-cvx.ds55-ca-us.dialup.earthlink.net [209.179.158.42]) by hawk.prod.itd.earthlink.net (8.8.7/8.8.5) with ESMTP id WAA24563 for ; Mon, 22 Mar 1999 22:45:16 -0800 (PST) Message-ID: <36F7388C.C4932F7D@bigfoot.com> Date: Mon, 22 Mar 1999 22:45:32 -0800 From: Bob Belshe To: Lancair Subject: LC-20 GM-6 casting failed X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Has anyone ever had the compression donut cap casting (GM-6) break? These are the castings that go on the top and bottom of the GM-33A compression donuts on the main gear and are held together by a bolt and nut. Preflighting on Saturday, I discovered the lower GM6 on my right main had fractured just below the nut which holds the compression donut assembly together and was turned 90 degrees, with the compression donut sitting on the edge. The bolt inside the donut remained attached to the broken piece of the GM6. Today I took it apart and found that the bottom of the donut was dinged pretty well from contact with the edge of the broken GM6. I believe I must have made at least one landing in this condition. With the weight off the wheels, the right main falls straight down, so I can only conclude that wind pressure held the gear against the bottom of the donut. Also it could not retract fully because the wheel would not align with the well, so I assume it just went up until the tire contacted the bottom of the wing. No damage to the bottom of the wing. This seems to be a good argument for having "gear up" microswitches, which I do not have. If the donut assembly, which was just hanging on the upper pivot, had swung back a couple of inches there would have been no support for the wheel and would certainly resulted in an exciting landing. About 2 weeks ago I replaced the compression donuts with new ones. The new ones required slightly more compression force. I wonder if this is a coincidence? Today I called Lancair and was told that they had not seen this problem before, and they asked me to send the broken part in for examination. They also volunteered to send a new GM6 at no charge, and this is for a kit that was delivered in 1986! Lancair has always given me first-class treatment, even though I am not the builder. (Lucky) Bob Belshe N19BJ Lancair 235/320