X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4195301 for flyrotary@lancaironline.net; Sun, 04 Apr 2010 17:25:39 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id BA992173712 for ; Mon, 5 Apr 2010 05:25:04 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 1078DBEC00C for ; Mon, 5 Apr 2010 05:25:03 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Multipal throats Date: Mon, 5 Apr 2010 07:25:06 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01CAD491.1D67F8A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100404-0, 04/04/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0009_01CAD491.1D67F8A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lynn, I was thinking higher velocities for both idle and high end ( to 7,500 = rpm) for PP, but like you said complexity and possible energy losses. George (down under) Bill, On researching the Weber carb it seems it was originally developed = to=20 provide different chokes, one for low rpm and one for high rpm. That would be good if we had siamesed PP with different sized = runners -=20 sounds complicated. George ( down under) The single throat for each housing is ideal for reducing complexity = and limiting energy loss.=20 The Webers with multipal throat sizes are for econemy at low speeds on = the street. Very effective, and Ford and GM licensed the Weber DMSA-100 = carb (one 23MM choke and one 27MM choke) for the Pinto and the Vega. Of = course the Americans redesigned that carb instead of just buying it, and = both were useless. Too many cooks you know.......... There is little need of a strong mid range for aircraft use. The = airplane is stuck in 2nd gear in effect by the reduction ratio. The prop = loads build exponentially with RPM so, you need best power by 6,500 or = 7,000 RPM tops, and best torque around cruise RPM. A big deal for a = piston engine, nothing at all for a rotary if it is cooled and oiled = properly. Lynn E. Hanover ------=_NextPart_000_0009_01CAD491.1D67F8A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Lynn,
I was thinking higher velocities = for both=20 idle and high end ( to 7,500 rpm) for PP, but like you said = complexity=20 and possible energy losses.
George (down under)
Bill,
On researching the Weber carb it seems it was = originally=20 developed to
provide different chokes, one for low rpm and one = for high=20 rpm.
That would be good if we had siamesed PP with different = sized=20 runners -
sounds complicated.
George ( down = under)
The single throat for each housing is ideal for reducing = complexity=20 and limiting energy loss.
 
The Webers with multipal throat sizes are for econemy at low = speeds=20 on the street. Very effective, and Ford and GM licensed the Weber = DMSA-100=20 carb (one 23MM choke and one 27MM choke) for the Pinto and the Vega. = Of course=20 the Americans redesigned that carb instead of just buying it, and = both=20 were useless. Too many cooks you know..........
 
There is little need of a strong mid range for aircraft use. = The=20 airplane is stuck in 2nd gear in effect by the reduction ratio. The = prop loads=20 build exponentially with RPM so, you need best power by 6,500 or 7,000 = RPM=20 tops, and best torque around cruise RPM. A big deal for a piston = engine,=20 nothing at all for a rotary if it is cooled and oiled = properly.
 
Lynn E. Hanover
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