X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from mail01.syd.optusnet.com.au ([211.29.132.182] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTPS id 1905665 for flyrotary@lancaironline.net; Tue, 06 Mar 2007 17:15:01 -0500 Received-SPF: none receiver=logan.com; client-ip=211.29.132.182; envelope-from=lendich@optusnet.com.au Received: from george (d58-109-7-14.dsl.nsw.optusnet.com.au [58.109.7.14]) by mail01.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l26ME4aq000839 for ; Wed, 7 Mar 2007 09:14:06 +1100 Message-ID: <004f01c7603c$c31cb050$0e076d3a@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Engine choice for BD-4 (changed from "Hard Landing ") Date: Wed, 7 Mar 2007 08:14:06 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004A_01C76090.93468D20" 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 X-Antivirus: avast! (VPS 0657-0, 12/12/2006), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_004A_01C76090.93468D20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable What is the difference between "early 13B" and "late(??) 13B"? The early 13Bs had the compression and water seals in the rotor = housing just like the 12As. Later this was changed to the seal grooves being cut into the irons, = and the sides of the rotor housings being flat. The irons often break = through the bottom of the seal groove when run too hot. There is not = enough material (cast iron) around the outside of that groove.=20 When left sitting for ages, they can even rust through that groove and = fail sitting still. The Renesis engine has the grooves in the rotor housings again, where = God intended them to be all along.=20 There are a number of options, where you can mix and match irons and = housings to achieve differing outcomes. For example a 12A center iron to = get the biggest primary ports and turbo end irons to get the biggest = secondary ports. So, you could run two throttle bodies, and at lower = power and on the ground have a docile quiet tame engine, and at full = song with two throttle bodies have the end irons bridge ported and doing = over 200 HP when flat out. Race engines have all irons bridge ported because there is no need for = full power below 7,000 RPM.=20 You cannot build up anything with no seals but you can run two seals = facing each other. Racers do it anyway with no problems. I would dyno = that one a lot before installing it in a plane. Lynn E. Hanover Right-on Lynn, The Local lads use 12 Housings and early 13B rotor housings( Cosmo) = which has the biggest exhaust port. I've taken that one step further and = purchased a RX8 rotor for the single development. I don't like the idea of using groove to groove surfaces, but if their = using them and it works! - I would be concerned that something ( like = part of a seal) might move. Wouldn't recommend it for aviation. Also a Cosmo rear Iron and the Cosmo BH and starter would be a good = 'mix& match' . The extra mount point at 11.30 on the BH doesn't go = astray either. George ( down under) ------=_NextPart_000_004A_01C76090.93468D20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
What is=20 the difference between "early 13B" and  "late(??)=20 13B"?

 
 
The early 13Bs had the compression and water seals in the rotor = housing=20 just like the 12As.
 
Later this was changed to the seal grooves being cut into = the irons,=20 and the sides of the rotor housings being flat. The irons often break = through=20 the bottom of the seal groove when run too hot. There is not enough = material=20 (cast iron) around the outside of that groove.
 
When left sitting for ages, they can even rust through that = groove and=20 fail sitting still.
 
The Renesis  engine has the grooves in the rotor housings = again,=20 where God intended them to be all along. 
 
There are a number of options, where you can mix and match irons = and=20 housings to achieve differing outcomes. For example a 12A center iron = to get=20 the biggest primary ports and turbo end irons to get the biggest = secondary=20 ports. So, you could run two throttle bodies, and at lower power and = on the=20 ground have a docile quiet tame engine, and at full song with two = throttle=20 bodies have the end irons bridge ported and doing over 200 HP when = flat=20 out.
 
Race engines have all irons bridge ported because there is no = need for=20 full power below 7,000 RPM. 
 
You cannot build up anything with no seals but you can run two = seals=20 facing each other. Racers do it anyway with no problems. I would dyno = that one=20 a lot before installing it in a
plane.
 
Lynn E. Hanover

Right-on Lynn,
The Local lads use 12 Housings and  early 13B = rotor=20 housings( Cosmo) which has the biggest exhaust port. I've taken that = one step=20 further and purchased a RX8 rotor for the single = development.
 
I don't like the idea of using groove to groove = surfaces,=20 but if their using them and it works!  - I would be concerned = that=20 something ( like part of a seal) might move. Wouldn't = recommend it=20 for aviation.
 
Also a Cosmo rear Iron and the Cosmo BH and = starter would be=20 a good 'mix& match' . The extra mount point at 11.30 on the BH = doesn't go=20 astray either.
George ( down=20 under) 
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