X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [64.4.51.91] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 5.0c4) with ESMTP id 760273 for flyrotary@lancaironline.net; Mon, 10 Oct 2005 09:57:45 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.4.51.91; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 10 Oct 2005 06:56:59 -0700 Message-ID: Received: from 4.174.3.128 by BAY107-DAV19.phx.gbl with DAV; Mon, 10 Oct 2005 13:56:59 +0000 X-Originating-IP: [4.174.3.128] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Carbon Build up. Date: Mon, 10 Oct 2005 09:56:52 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A5_01C5CD80.F0745170" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Mon, 10 Oct 2005 09:56:52 -0400 X-OriginalArrivalTime: 10 Oct 2005 13:56:59.0215 (UTC) FILETIME=[7B9C15F0:01C5CDA2] This is a multi-part message in MIME format. ------=_NextPart_000_00A5_01C5CD80.F0745170 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Dave, There are too many factors here to draw any firm conclusions. Possible = reasons for the broken side seal are detonation, flawed seal or = installation damage. Being sintered iron and only .7 mm thick, they are = fairly delicate. Were they fitted properly when installed? New side = seals are slightly too long as furnished and must be individually fitted = to the groove by carefully grinding to length. BTW, what apex seals were you using? These are usually the first thing = to go with detonation. RA seals will frequently not break leading many = racers to conclude that they did not have detonation. The failure mode = of our seals in detonation is heat damage which eventually causes them = to sag into the groove and have low compression when hot. Better than a = fractured seal that typically takes out a rotor and rotor housing. Lots of carbon? You call that lots of carbon? (I've seen lots of = carbon and that isn't it : ) But the really important thing about = carbon is the nature of the carbon buildup. If it is the "fluffy" type = that is easily scrapped off it is not really a problem. Typical 4 = stroke oil leaves an almost varnish like carbon deposit that is very = difficult to remove and causes seals to stick in the groove. This is = the really significant difference between 2 & 4 stroke oil. Also = remember that 99+ percent of what is being burned in the combustion = chamber is gasoline. It leaves carbon deposits especially if the = mixture is too rich. Tracy ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Monday, October 10, 2005 1:47 AM Subject: [FlyRotary] Carbon Build up. The first picture is the front rotor with the stuck and broken side = seal with a piece missing. Wouldn't fit in the last message. So the big question now is why. Note the picture of the rotor face. = There is LOTS of carbon build-up. So much for 2-stroke oil burning very = cleanly. I am mixing less than 1:100 (about 5 oz per 6 gal gas can). I = have thought of the following possible causes:=20 1 My oil may be running a little cool. It maxes out at 160 and is = usually closer to 140-150. This could keep the rotors too cool and = prevent burning of the oil. Add in the modification to the oil bypass = and this may be it, but it seems unlikely to me.=20 2 Running rich. Because it is so hard to get the engine tuned, I am = probably running very rich (the only way to keep it running), especially = at low RPM. Some of both? Poor quality 2-stroke? I have noticed that the = 2-stroke oil does accumulate in the crank case. That of course = indicates that it does not all burn, and what doe burns does not = necessarily burn cleanly. Maybe using crank-case oil would burn less, = and there would be less needed and less residue. =20 Anyone else seen this? Any ideas? --=20 Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html = http://members.aol.com/_ht_a/vp4skydoc/index.html = --=20 Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html = = http://members.aol.com/_ht_a/vp4skydoc/index.html -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_00A5_01C5CD80.F0745170 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Dave,
There are too many factors here to draw any firm conclusions.  = Possible reasons for the broken side seal are detonation, flawed = seal or=20 installation damage.  Being sintered iron and only .7 mm thick, = they are=20 fairly delicate.  Were they fitted properly when = installed?  New=20 side seals are slightly too long as furnished and must be individually = fitted to=20 the groove by carefully grinding to length.
 
 BTW, what apex seals were you using?  These are usually = the=20 first thing to go with detonation.  RA seals will frequently not = break=20 leading many racers to conclude that they did not have detonation.  = The=20 failure mode of our seals in detonation is heat damage which eventually = causes=20 them to sag into the groove and have low compression when hot.  = Better than=20 a fractured seal that typically takes out a rotor and rotor = housing.
 
Lots of carbon?  You call that lots of carbon?   = (I've seen=20 lots of carbon and that isn't it : )  But the really important = thing about=20 carbon is the nature of the carbon buildup.  If it is the=20 "fluffy" type that is easily scrapped off it is not really a = problem. =20 Typical 4 stroke oil leaves an almost varnish like carbon deposit that = is very=20 difficult to remove and causes seals to stick in the groove.  This = is the=20 really significant difference between 2 & 4 stroke oil.  Also = remember=20 that 99+ percent of what is being burned in the combustion chamber is=20 gasoline.  It leaves carbon deposits especially if the mixture is = too=20 rich.
 
Tracy
----- Original Message -----
To: Rotary motors in = aircraft
Sent: Monday, October 10, 2005 = 1:47=20 AM
Subject: [FlyRotary] Carbon = Build=20 up.

The first picture is the front rotor with the stuck and broken = side seal=20 with a piece missing. Wouldn't fit in the last message.
 
So the big question now is why.  Note the picture of the = rotor=20 face.  There is LOTS of carbon build-up.  So much for = 2-stroke oil=20 burning very cleanly.  I am mixing less than 1:100 (about 5 oz = per 6 gal=20 gas can).  I have thought of the following possible causes: =
 
1 My oil may be running a little cool.  It maxes out at 160 = and is=20 usually closer to 140-150.  This could keep the rotors too cool = and=20 prevent burning of the oil.  Add in the modification to the oil = bypass=20 and this may be it, but it seems unlikely to me.
 
2 Running rich.  Because it is so hard to get the engine = tuned, I am=20 probably running very rich (the only way to keep it running), = especially at=20 low RPM.
 
Some of both?  Poor quality 2-stroke?  I have noticed = that the=20 2-stroke oil does accumulate in the crank case.  That of course = indicates=20 that it does not all burn, and what doe burns does not = necessarily burn=20 cleanly.  Maybe using crank-case oil would burn less, and there = would be=20 less needed and less residue. 
 
Anyone else seen this?  Any ideas?

-- =
Dave=20 Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html =
http://members.aol.com/_ht_a/vp4skydoc/index.html =



--
Dave = Leonard
Turbo Rotary=20 RV-6 N4VY
http://memb= ers.aol.com/_ht_a/rotaryroster/index.html=20
http://members= aol.com/_ht_a/vp4skydoc/index.html=20 --
Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net/lists/flyrotary/
------=_NextPart_000_00A5_01C5CD80.F0745170--