X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail34.syd.optusnet.com.au ([211.29.133.218] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTPS id 2192304 for flyrotary@lancaironline.net; Sun, 22 Jul 2007 03:24:32 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.133.218; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-107-198.dsl.nsw.optusnet.com.au [211.31.107.198]) by mail34.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l6M7NeF4018328 for ; Sun, 22 Jul 2007 17:23:41 +1000 Message-ID: <003301c7cc31$3eaa23f0$c66b1fd3@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: carbs vs efi Date: Sun, 22 Jul 2007 17:23:46 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0030_01C7CC85.0F8E01F0" 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_0030_01C7CC85.0F8E01F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Does anyone know the IO/IC and size and HP of the factory P-port. Lynn, does the timing given, calculated by the rotor uncovering and = covering the port, or the side seal uncovering/covering the port = opening? I was thinking the RX8 rotor will be slightly different (bigger) = with the harased edges. George ( down under) I only have 12A stuff, but here you are: Intake port at the manifold. 1.695" Round Exhaust port at the manifold 1.645" Round IO 86 Degrees BTDC IC 75 Degrees ABDC EO 73 Degrees BBDC EC 65 Degrees ATDC A Racing Beat Street Port: IO 25 Degrees ATDC IC 60 Degrees ABDC EO 84 Degrees BBDC EC 48 Degrees ATDC In side port engines, it is the rotor closing the port. In the peripheral port engines it is the apex seal closing the port. = Actually the port is timed by the apex seal. The port never closes in the way the side port engine has the rotor = blank off the port in operation.=20 So, the Pport can flow way more than the side port, even with smaller = runners and ports.=20 Lynn E. Hanover Lynn, and Jerry Thanks and that confirms my testing, I set-up my degree wheel and = mapped out the degrees and measured the distance and sure enough 44mm=3D = 1.73. 43mm =3D 1.695. I've also confirmed the street ports (side ports) can't flow the = necessary amount for the HP required, running out of puff @ 164 KW/ = 264HP at 8,500 or about 116/117 hp at 7,500 - we can do better. So now that I have convinced myself - it's back to the P-port. As = Lynn said the P-port flows more than the street port for a number of = reasons, but one thing surprised me to hear was that the rotary can't = overcome a choked inlet to the extent a piston engine can - therefore = any restrictive inlet will result in less HP. Apparently the velocity = increase argument doesn't exist because of this reason, so a smaller = p-port inlet is out. Not only this but with a restrictive port the = engine is likely to pull exhaust( because of the overlap), causing rough = running, with a sudden decrease in RPM - so I'm led to believe. Therefore I need a carby with a inlet of 44mm or two smaller ones. I = know Bill Jepson is aiming for 1.8" P-ports ( 45.72mm) in his 20B - this = is all getting close to PL claims of 2" OD. This isn't a wasted exercise on my part, so I hope someone else got = something out of it as well. George ( down under) =20 =20 -------------------------------------------------------------------------= ----- Get a sneak peek of the all-new AOL.com. ------=_NextPart_000_0030_01C7CC85.0F8E01F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Does anyone know the IO/IC and size and HP of = the factory=20 P-port.
 
Lynn, does the timing given, = calculated by the=20 rotor uncovering and covering the port, or the side seal = uncovering/covering=20 the port opening?
I was thinking the RX8 rotor will = be slightly=20 different (bigger) with the harased edges.
George ( down=20 under)
I only have 12A stuff, but here you are:
 
Intake port at the manifold.    1.695" Round
 
Exhaust port at the manifold  1.645" Round
 
IO  86 Degrees BTDC
IC  75 Degrees ABDC
EO 73 Degrees BBDC
EC 65 Degrees ATDC
 
A Racing Beat Street Port:
 
IO  25 Degrees ATDC
IC  60 Degrees ABDC
EO 84 Degrees BBDC
EC 48 Degrees ATDC
 
In side port engines, it is the rotor closing the port.
In the peripheral port engines it is the apex seal closing the = port.=20 Actually the port is timed by the apex seal.
The port never closes in the way the side port engine has the = rotor blank=20 off the port in operation.
So, the Pport can flow way more than the side port, even with = smaller=20 runners and ports.
 
Lynn E. Hanover

Lynn, and Jerry
Thanks and that confirms my testing, I set-up my degree wheel and = mapped=20 out the degrees and measured the distance and sure enough 44mm=3D = 1.73.
43mm =3D 1.695.
 
I've also confirmed the street ports (side ports) can't flow the=20 necessary amount for the HP required, running out of puff @ 164 KW/ = 264HP at=20 8,500 or about 116/117 hp at 7,500 - we can do better.
 
So now that I have convinced myself - it's back to the = P-port.  As=20 Lynn said the P-port flows more than the street port for a number of = reasons,=20 but one thing surprised me to hear was that the rotary can't overcome = a choked=20 inlet to the extent a piston engine can - therefore  = any=20 restrictive inlet will result in less HP. Apparently the velocity = increase=20 argument doesn't exist because of this reason, so a smaller p-port = inlet is=20 out. Not only this but with a restrictive port the engine is = likely to=20 pull exhaust( because of the overlap), causing rough running, with a = sudden=20 decrease in RPM - so I'm led to believe.
 
Therefore I need a carby with a inlet of 44mm or two smaller = ones. I know=20 Bill Jepson is aiming for 1.8" P-ports ( 45.72mm) in his 20B - this is = all=20 getting close to PL claims of 2" OD.
 
This isn't a wasted exercise on my part, so I hope someone else = got=20 something out of it as well.
George ( down under)
 
 

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