Return-Path: Received: from imf24aec.mail.bellsouth.net ([205.152.59.72] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3060648 for flyrotary@lancaironline.net; Wed, 03 Mar 2004 08:12:51 -0500 Received: from TOSHIBAjhr ([209.215.55.115]) by imf24aec.mail.bellsouth.net (InterMail vM.5.01.06.05 201-253-122-130-105-20030824) with SMTP id <20040303131250.ZZJE1860.imf24aec.mail.bellsouth.net@TOSHIBAjhr> for ; Wed, 3 Mar 2004 08:12:50 -0500 From: "John Slade" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: 13B smooth running issues Date: Wed, 3 Mar 2004 08:12:50 -0500 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: > I purchased a 5/8 heater nipple from > CarQuest that had a 1/2"NPT fitting... We must be talking about different holes. This one's almost 1/8 NPT, but the same theory should apply. By the way - I discovered an "interesting" failure mode yesterday.... I took her out for her first taxi test. First impression was that the engine was running MUCH smoother with the prop in place. Still rich, but much more responsive. There was a metallic noise I hadn't heard before, so I swung her around and taxied straight back. As I shut her down I noticed a prop vibration that didnt seem right. There was a LOT of lag on the prop. Buly peered down into the flywheel area and spotted a bolt lying at the bottom of the case, just waiting for the best opportunity to jump up and attack the expensive and really important piece of wood right behind the redrive. :( Wiggling the prop a bit more I noticed that the flywheel was moving a little with respect to the counterweights behind it. I removed the redrive. The entire damper plate / flywheel assembly was loose. I removed the damper plate and found, behind it, the 6 small bolts and one very large central bolt that hold the flywheel in place were all loose. I said 6. Actually there were 5. The other one, the one Buly found, had already come out. This situation could have taken a very serious bite out of my ass if the remaining bolts had come out during the first flight. Can you say "catastrophic failure"? I know what happened. Three years ago, when we were making the engine mount, we had assembled the redrive to the engine. We'd mounted the flywheel and damper plate, probably finger tight, at that time. For three years the engine had sat around with that damper plate in place hiding the loose bolts. When it finally came time to install the redrive properly I had forgotten that the flywheel had never been torqued down. It had been "part of the engine" for all that time, and I'd ASSumed that it had been correctly installed when the engine was built. I guess this is why we do taxi testing. Today I'll pick up a new bolt from NAPA and a new bottle of locktite.