Return-Path: Received: from access.aic-fl.com ([204.49.76.2] verified) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 792361 for flyrotary@lancaironline.net; Mon, 14 Mar 2005 08:54:15 -0500 Received-SPF: none receiver=logan.com; client-ip=204.49.76.2; envelope-from=unicorn@gdsys.net Received: from b9k4u9 (unverified [204.49.76.118]) by access.aic-fl.com (Rockliffe SMTPRA 4.5.6) with SMTP id for ; Mon, 14 Mar 2005 07:48:09 -0600 Message-ID: <002301c528ad$77942d20$764c31cc@b9k4u9> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: peripheral ports Date: Mon, 14 Mar 2005 07:49:49 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01C5286A.663C4F00" 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 This is a multi-part message in MIME format. ------=_NextPart_000_0020_01C5286A.663C4F00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: WRJJRS@aol.com=20 To: Rotary motors in aircraft=20 Sent: Sunday, March 13, 2005 9:41 PM Subject: [FlyRotary] Re: peripheral ports In a message dated 3/13/2005 6:29:35 PM Pacific Standard Time, = jesse@jessfarr.com writes: Years ago, I was buying something from some feller and he was kind = of high. When I asked for a little better deal and said I was used to = buying 'em from this other fellow for a lot less but he was out; he told = me real quick like that he could even sell 'em cheaper than the other = fellow when he didn't have 'em either. I guess price is not something = to even gripe about if you can't get 'em. And, I will admit that the = price might not seem too bad when/if you need housings anyway. Oh well, = I 'll just stay happy with my junker, as long as it lasts; then I can = worry about some of that kind of stuff. But, let's face it, if the pp = engines don't keep running at low rpms and/or idle well, even though = their high rpms can be right down our aircraft use alley with proper = psru gearing, they will not be much good to us; it seems aircraft = actually do have to have an engine that keeps running on/in slow flight, = too. Group,=20 I really would like to know where the idea that the PP rotary won't = idle came from?=20 This is total baloney. Lynn Hanover has commented several times that = his PP 12A idles just fine. Some carburated engines with unusual = manifolds sometimes have problems. This is true for both PP and side = port engines. Many of the earlier rotary engines used P ports.=20 If and engine is radically ported in either port type, (just like a = radically cammed piston engine), it can be difficult to make idle. If = you keep the port timing reasonable the engine ?WILL IDLE FINE, = especially a EFI engine. The throttle plates being close to the housings = makes things work better. The MB C111 used various rotary = configurations. Most of the engines were peripheral ported. There was no = problem with idle, but the sealing problems of that era prevented a = production version. If your engine is set up carefully without radical = timing idle won't be a problem. The real problems encountered by many = people are caused by large ports and extended port timings.=20 Bill Jepson Bill, I have been asking that question myself, and the group at last years = rotary meeting in Lake City. Initially I believed it and started out = with the combination port on the one-rotor. Total disaster! Than I made = a beautiful close up butterfly only to find out that it had no impact on = controlling the engine. Now, with a carburetor that has not been tuned = for the engine in any way it idled at 1200 RPM rightaway. That will be a = lower prop speed than a LIC on a 3.3:1 gear box.Throttle response is = also as good as good as it could be. As long as the mixture is rich enough, it will idle. Richard Sohn N-2071U ------=_NextPart_000_0020_01C5286A.663C4F00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 WRJJRS@aol.com
Sent: Sunday, March 13, 2005 = 9:41=20 PM
Subject: [FlyRotary] Re: = peripheral=20 ports

In a message dated 3/13/2005 6:29:35 PM Pacific Standard Time, jesse@jessfarr.com = writes:
Years ago, I was buying something = from some=20 feller and he was kind of high.  When I asked for a little = better deal=20 and said I was used to buying 'em from this other fellow for a lot = less but=20 he was out; he told me real quick like that he could even sell = 'em=20 cheaper than the other fellow when he didn't have 'em = either.  I=20 guess price is not something to even gripe about if you can't get = 'em. =20 And, I will admit that the price might not seem too bad when/if you = need=20 housings anyway. Oh well, I 'll just stay happy with my junker, as = long as=20 it lasts; then I can worry about some of that kind of stuff. But, = let's face=20 it, if the pp engines don't keep running at low rpms and/or idle = well, even=20 though their high rpms can be right down our aircraft use alley = with=20 proper psru gearing, they will not be much good to us; it seems = aircraft=20 actually do have to have an engine that keeps running on/in = slow=20 flight, too.
 Group,
 I really would like to know where the idea that the PP = rotary won't=20 idle came from? 
This is total baloney. Lynn Hanover has commented several times = that=20 his PP 12A idles just fine. Some carburated engines with unusual=20 manifolds sometimes have problems. This is true for both PP and = side port=20 engines. Many of the earlier rotary engines used P ports.
 If and engine is radically ported in either port type, = (just like a=20 radically cammed piston engine), it can be difficult to make idle. If = you keep=20 the port timing reasonable the engine ?WILL IDLE FINE, especially a = EFI=20 engine. The throttle plates being close to the housings makes = things work=20 better. The MB C111 used various rotary configurations. Most of = the=20 engines were peripheral ported. There was no problem with idle, but=20 the sealing problems of that era prevented a production version. = If your=20 engine is set up carefully without radical timing idle won't =  be a=20 problem. The real problems encountered by many people are caused by = large=20 ports and extended port timings.
Bill Jepson
 
Bill,
I have been asking that question myself, and the group at last = years=20 rotary meeting in Lake City. Initially I believed it and started out = with the=20 combination port on the one-rotor. Total disaster! Than I made a = beautiful=20 close up butterfly only to find out that it had no impact on = controlling the=20 engine. Now, with a carburetor that has not been tuned for the engine = in any=20 way it idled at 1200 RPM rightaway. That will be a lower prop = speed than=20 a LIC on a 3.3:1 gear box.Throttle response is also as good as good as = it could be.
As long as the mixture is rich enough, it will idle.
 
Richard Sohn
N-2071U
 
 
 
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