X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail14.syd.optusnet.com.au ([211.29.132.195] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTPS id 2199137 for flyrotary@lancaironline.net; Wed, 25 Jul 2007 17:56:45 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.132.195; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-107-198.dsl.nsw.optusnet.com.au [211.31.107.198]) by mail14.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l6PLu0KU022603 for ; Thu, 26 Jul 2007 07:56:01 +1000 Message-ID: <001001c7cf06$98548da0$c66b1fd3@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: carbs vs efi Date: Thu, 26 Jul 2007 07:56:02 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C7CF5A.692ECEB0" 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_000D_01C7CF5A.692ECEB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Re your analysis comparing side ports with p ports, I wonder if such an = analysis is even possible as they are quite different.? Anyway, I doubt = that a standard port can deliver 100 hp or a street port 130 hp. per = rotor, certainly not when limited to 7500 rpm.? Of course I am only = guessing.? No real knowledge or experience.?? From a Daryl Drummond dyno sheet for a 12A bridge ported running 36MM = chokes. One per housing. 6,500 RPM 139.6 Torque 173.3 HP 7,000 RPM 147.6 Torque 196.9 HP 7,500 RPM 152.6 Torque 218.2 HP Front EGT 1518/ Rear EGT 1492/ BSFC = .671 oil 164/ pressure 100.1 F/A 12.1 Main 210/ air .80. A Pport with a slightly larger choke would better. = A 13B Pport would do still better. A 13B Pport injected would do much better.=20 Lynn E. Hanover Lynn, Good stuff! For comparison, using my trusty hand made degree wheel, I revisited = the bridge port and found it really opens very early 115 BTDC and closes = quite late 72 ABDC. These figures could be played with depending upon = the length and placement of the bridge. I saw one bridge made up of holes ( about 1/4" I suppose), these holes = had a bridge between them, which I thought was a good idea. Who ever = made the holes also ground in recessed flutes to the holes on the = inside, at the time I wondered how well that worked. I also felt one = could vary the timing with the number and placement of the holes. Similar variations can be also done with the street port, by varying = the length. The distance between IO/IC in the bridge port is something like 62mm = and would represent a P-P of 2.44" dia ( 4.98 sq") - if you could fit it = in!!=20 Would need a monster inlet tube to feed that sucker! I say this tongue = in cheek of course as you couldn't fit a round PP this large in the = housing. The Factory PP is large enough with an opening of 50mm x 43mm, about = 3sq" ( 50mm dia), which is fed by a 43mm inlet tube, about a 16% = reduction in diameter. I can't for the life of me figure out why the port opening has to be = so much larger than the inlet tube. It may be the duration of the open = inlet they are looking for. Do you know what sort of power they found with the 13B stock PP? Any how for those interested, I've settled on a 44mm inlet straight = tube with a late opening and late closing - same a stock PP IO 86 BTDC = and 75 BBDC. I can buy 41mm and 44mm tube and have opted for the 44mm ID inlet = tube, only 2.35sq" area. George ( down under) -------------------------------------------------------------------------= ----- Get a sneak peek of the all-new AOL.com. ------=_NextPart_000_000D_01C7CF5A.692ECEB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Re your=20 analysis comparing side ports with p ports, I wonder if such an analysis = is even=20 possible as they are quite different.? Anyway, I doubt that a standard = port can=20 deliver 100 hp or a street port 130 hp. per rotor, certainly not when = limited to=20 7500 rpm.? Of course I am only guessing.? No real knowledge or=20 experience.??
From a Daryl Drummond dyno sheet for a 12A bridge ported running = 36MM=20 chokes. One per housing.
 
6,500 RPM 139.6 Torque 173.3 HP
7,000 RPM 147.6 Torque  196.9 HP
7,500 RPM 152.6  Torque  218.2 HP Front EGT 1518/ Rear = EGT=20 1492/ BSFC .671 oil 164/ pressure 100.1
 
F/A 12.1
 
Main 210/ air .80. A Pport with a slightly larger choke would = better. A=20 13B Pport would do still better.
 
A 13B Pport injected would do much better.
 
Lynn E. Hanover

 
Lynn,
Good stuff!
For comparison, using my trusty hand made degree wheel, I = revisited the=20 bridge port and found it really opens very early 115 BTDC and=20 closes quite late 72 ABDC. These figures could be played = with=20 depending upon the length and placement of the bridge.
 
I saw one bridge made up of holes ( about 1/4" I suppose), these = holes=20 had a bridge between them, which I thought was a good idea. Who ever = made the=20 holes also ground in recessed flutes to the holes on the inside, at = the time I=20 wondered how well that worked. I also felt one could vary the timing = with the=20 number and placement of the holes.
 
Similar variations can be also done with the street port, by = varying the=20 length.
 
The distance between IO/IC in the bridge port is something like = 62mm and=20 would represent a P-P of 2.44" dia ( 4.98 sq") - if you could fit it=20 in!! 
Would need a monster inlet tube to feed that sucker! I say this = tongue in=20 cheek of course as you couldn't fit a round PP this large in the=20 housing.
 
The Factory PP is large enough with an opening of 50mm x = 43mm, =20 about 3sq"  ( 50mm dia), which is fed by a 43mm inlet tube, about = a 16%=20 reduction in diameter.
 
I can't for the life of me figure out why the port opening has to = be so=20 much larger than the inlet tube. It may be the duration of the open = inlet they=20 are looking for.
 
Do you know what sort of power they found with the 13B stock = PP?
 
Any how for those interested, I've settled on a 44mm inlet = straight tube=20 with a late opening and late closing - same a stock PP IO 86 BTDC and = 75=20 BBDC.
 
I can buy 41mm and 44mm tube and have opted for the 44mm ID inlet = tube,=20 only 2.35sq" area.
 
George ( down under)


Get a sneak peek of the all-new AOL.com.
------=_NextPart_000_000D_01C7CF5A.692ECEB0--