X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail10.syd.optusnet.com.au ([211.29.132.191] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTPS id 2355985 for flyrotary@lancaironline.net; Thu, 27 Sep 2007 17:25:06 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.132.191; envelope-from=lendich@optusnet.com.au Received: from george (d58-108-77-165.dsl.nsw.optusnet.com.au [58.108.77.165]) by mail10.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l8RLOKcM017811 for ; Fri, 28 Sep 2007 07:24:22 +1000 Message-ID: <000d01c8014c$ccf74ac0$a54d6c3a@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Carbs Date: Fri, 28 Sep 2007 07:24:27 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000A_01C801A0.9A3BBAE0" 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_000A_01C801A0.9A3BBAE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable That's OK Ed, Thanks anyway! George (down under) George, you're going to have to ask someone who has experience with = carburetors - I went with fuel injection because of the very frustrating = experience I had trying to tune a Webber carburator with all its = different size air bleeds and jets. I just found EFI was much easier = to know what I was getting. Not against carburetors, they obviously = work quite well - if you know what you are doing with all the jets and = air bleeds - which I clearly did not. Perhaps Bill J can help. Ed ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Thursday, September 27, 2007 3:12 AM Subject: [FlyRotary] Carbs Ed, I have another one for you! I am currently copying some of the parts of different carbs to = cobble together my own design. I found info that the slide carbs with = the flat ground needle - have a needle size of 1/8" ( 3.175mm) and are = ground to what appears to be 'half' their original size at WOT. My = needle stock is 3.18mm, with sliding tolerance, the needle seat/ jet is = 3.23mm That is the sized used for a 38mm carb and I was wondering if the = 44mm carb might need a bigger needle, but I don't know how to calculate = the main jet size/ fuel flow. I have 13.1936 lbm (min of air) and 1.043lbm (min of fuel) at = 12.65:1 fuel ratio, at 7,500 rpm (WOT). Can you show me how to work out the main jet size please, I just = need to know if I'm in the ballpark or need to go up in needle size, if = the depth of the grind exceeds 'half' the needle size at WOT. George (down under) -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.488 / Virus Database: 269.13.32/1032 - Release Date: = 26/09/2007 8:20 PM ------=_NextPart_000_000A_01C801A0.9A3BBAE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

That's OK Ed,

Thanks anyway!

George (down under)

George, you're going to have to ask someone = who has=20 experience with carburetors - I went with fuel injection because of = the very=20 frustrating experience I had trying to tune a Webber carburator with = all its=20 different size air bleeds and jets. I just found EFI was = much=20 easier to know what I was getting. Not against carburetors, they = obviously work quite well - if you know what you are doing with all = the jets=20 and air bleeds - which I clearly did not.

Perhaps Bill J can help.

Ed

----- Original Message -----
From:=20 George Lendich
To: Rotary motors in = aircraft=20

Sent: Thursday, September 27, = 2007 3:12=20 AM

Subject: [FlyRotary] = Carbs

Ed,

I have another one for = you!

I am currently copying some of the = parts of=20 different carbs to cobble together my own design. I found info that = the=20 slide carbs with the flat ground needle - have a needle size of 1/8" = (=20 3.175mm) and are ground to what appears to be = 'half' their=20 original size at WOT. My needle stock is 3.18mm, with sliding=20 tolerance, the needle seat/ jet is 3.23mm

That is the sized used for a 38mm = carb and I=20 was wondering if the 44mm carb might need a bigger needle, but I = don't know=20 how to calculate the main jet size/ fuel flow.

I have 13.1936 lbm (min of air) and = 1.043lbm=20 (min of fuel) at 12.65:1 fuel ratio, at 7,500 rpm = (WOT).

Can you show me how to work out the = main jet=20 size please, I just need to know if I'm in the ballpark or need to = go up in=20 needle size, if the depth of the grind exceeds 'half' the needle = size at=20 WOT.

George (down under)

No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.488 / Virus Database: 269.13.32/1032 - = Release Date:=20 26/09/2007 8:20 PM
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