Return-Path: Received: from out009.verizon.net ([206.46.170.131] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 573056 for flyrotary@lancaironline.net; Sun, 19 Dec 2004 10:04:13 -0500 Received-SPF: pass receiver=logan.com; client-ip=206.46.170.131; envelope-from=finn.lassen@verizon.net Received: from verizon.net ([4.12.145.173]) by out009.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20041219150341.IPFG24088.out009.verizon.net@verizon.net> for ; Sun, 19 Dec 2004 09:03:41 -0600 Message-ID: <41C5984B.1050301@verizon.net> Date: Sun, 19 Dec 2004 10:03:39 -0500 From: Finn Lassen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Engine damage thoughts References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------010203030501060400070108" X-Authentication-Info: Submitted using SMTP AUTH at out009.verizon.net from [4.12.145.173] at Sun, 19 Dec 2004 09:03:41 -0600 This is a multi-part message in MIME format. --------------010203030501060400070108 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit So did I. The thing is that without a prop (load) the engine can rev up pretty high very quickly. In my situation it was obvious that the bearings were gone: I could no longer turn the engine by hand. What looked like drops of solder were hanging from the main bearing - visible behind the output shaft counterweight. In Rusty's case he had a well lubricated engine. In my case not. I still think that Rusty's plan of running the engine and staying within glide distance for some hours is sound. Still must run the engine, tied down, at full takeoff power for the time it takes to reach pattern altitude. Repeat a couple of times. Finn Steve Brooks wrote: > Rusty, > A friend of mine is building a Lancair with a 20B. He ran the engine > on a test stand, gearbox, but no prop. He had a problem with the oil > flow, and the bearings were destroyed within a few seconds of running. > > He would have only had whatever assembly lubrication was present, but > it surprised me that the bearings would go so fast. > > In your case, and if you were running synthetic oil.....who knows, > they may be fine...maybe > > Steve Brooks > > -----Original Message----- > From: Rotary motors in aircraft > [mailto:flyrotary@lancaironline.net]On Behalf Of Russell Duffy > Sent: Sunday, December 19, 2004 12:15 AM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: Engine damage thoughts > > Something I will ask is at what rpm and power setting did the > engine seize at?? > > The engine did NOT seize. As I stated before, it quit because I > tried to throttle up with the mixture set way lean. I have no > reason to believe the engine is damaged, aside from what feels > like a bit less compression than normal. > > As for the bearings, Bruce also said the bearings would be the > first to go, but I have to wonder now if that isn't a car vs > airplane experience. He sees car engines that have run for some > time without oil, but at very low power settings. In that case, > the bearings may be the first to go. In your case, you ran at > high power, which would probably generate enough heat to seize the > engine, possibly before the bearings got damaged. > > I still find it very hard to believe the engine ran without oil > pressure for more than about 30 seconds, and did so at very lean > mixture, and idle power. I can't see how this is any more > damaging than cranking the engine several times. Maybe I'll learn > something from the oil filter tomorrow. > > Cheers, > > Rusty > > > --------------010203030501060400070108 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit So did I. The thing is that without a prop (load) the engine can rev up pretty high very quickly.
In my situation it was obvious that the bearings were gone: I could no longer turn the engine by hand. What looked like drops of solder were hanging from the main bearing - visible behind the output shaft counterweight. In Rusty's case he had a well lubricated engine. In my case not.

I still think that Rusty's plan of running the engine and staying within glide distance for some hours is sound.

Still must run the engine, tied down, at full takeoff power for the time it takes to reach pattern altitude. Repeat a couple of times.

Finn

Steve Brooks wrote:
Message
Rusty,
A friend of mine is building a Lancair with a 20B.  He ran the engine on a test stand, gearbox, but no prop.  He had a problem with the oil flow, and the bearings were destroyed within a few seconds of running. 
 
He would have only had whatever assembly lubrication was present, but it surprised me that the bearings would go so fast. 
 
In your case, and if you were running synthetic oil.....who knows, they may be fine...maybe
 
Steve Brooks
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Russell Duffy
Sent: Sunday, December 19, 2004 12:15 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Engine damage thoughts

   Something I will ask is at what rpm and power setting did the
engine seize at??

The engine did NOT seize.  As I stated before, it quit because I tried to throttle up with the mixture set way lean.  I have no reason to believe the engine is damaged, aside from what feels like a bit less compression than normal. 

As for the bearings, Bruce also said the bearings would be the first to go, but I have to wonder now if that isn't a car vs airplane experience.  He sees car engines that have run for some time without oil, but at very low power settings.  In that case, the bearings may be the first to go.  In your case, you ran at high power, which would probably generate enough heat to seize the engine, possibly before the bearings got damaged.  

I still find it very hard to believe the engine ran without oil pressure for more than about 30 seconds, and did so at very lean mixture, and idle power.  I can't see how this is any more damaging than cranking the engine several times.  Maybe I'll learn something from the oil filter tomorrow.

Cheers,

Rusty 



--------------010203030501060400070108--