X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pa0-f48.google.com ([209.85.220.48] verified) by logan.com (CommuniGate Pro SMTP 6.0.10) with ESMTPS id 7247132 for flyrotary@lancaironline.net; Fri, 31 Oct 2014 09:53:22 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.220.48; envelope-from=ceengland7@gmail.com Received: by mail-pa0-f48.google.com with SMTP id ey11so7753863pad.21 for ; Fri, 31 Oct 2014 06:52:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=IUuxcpyF0+X2SIksVrgCNuykha1559mjGaj6zq9GxbI=; b=ySWkx+G1r4s2x/NpFK4D3MNY40uO1Qs09nj6NBPfStEyuWXvbRzOve1DeDK9seFVja akZHFwMx396o0Cle/WDCltQUZUX6+9F4c5jD075DqxyGrpgUAP7BHeH78UinmWXxaVDC 2dqH9AtR7GFnuqUqQGOVgvMcR6+m4URqDtZtmKoUtBfmE3AH1YEulZsXWF6MG5E/S3xH TLUgdDlLK+bmK3By4WtQU7oo7lN19aI//X+xYnx2Ig5jovfeWV/gpi3uAS8IILMjuc3Q uQeh6TsHmrrraufqGKMfu+0FVq/0ksXvx+NY5CjLrsnR+RnY9gZa28D+/Ju0WE6mx0ix 92tg== X-Received: by 10.68.168.100 with SMTP id zv4mr25083956pbb.132.1414763566232; Fri, 31 Oct 2014 06:52:46 -0700 (PDT) Return-Path: Received: from ?IPv6:2602:306:25fb:99:6c8f:29d:3147:5709? ([2602:306:25fb:99:6c8f:29d:3147:5709]) by mx.google.com with ESMTPSA id ez4sm10054724pab.36.2014.10.31.06.52.43 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 31 Oct 2014 06:52:44 -0700 (PDT) Message-ID: <545394AC.9080803@gmail.com> Date: Fri, 31 Oct 2014 08:54:52 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Fw: Rotary Engine & Fuel Valves References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------070606090301080005090709" This is a multi-part message in MIME format. --------------070606090301080005090709 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 10/31/2014 8:09 AM, Ernest Christley wrote: > > > > On Friday, October 31, 2014 12:57 AM, Charlie England > wrote: > > >But...Didn't you mention 6psi fuel pressure? If that's correct, then > why have a return line at all? If it's a carb engine, > >just use Facet 'solid state' (interrupter style) pumps. No return > line needed. > > Good point, Charlie, but the engine came with one of those AeroVee > carbs on it. It's basically a throttle body with a drip feed for > fuel. It gets upset with more that 2psi of pressure, and there are > very few regulators that are accurate down that low. They're > basically designed to be gravity fed, and the 601XL doesn't have a > header tank. > > I'm now seriously considering the transfer pump configuration. Now > that I've been reminded, I remember that Tracy has been flying with > that setup for years. I've got to think about it more. > > But what can you use for a bypass style regulator that's accurate at 2 psi, anyway? Facet makes cube ('solid state') pumps rated as low as 2.0 psi max. Here's a list; the window scrolls for more models. http://www.facet-purolator.com/cube-fuel-pumps.php That page mentions 'optional check valve' (CV) but doesn't explain the PSO column. That's basically a 'positive shutoff' or anti-siphon that prevents fuel from flowing through the pump if it's not running. Whether you want that depends on how you plumb the installation. 2 in parallel, you could potentially eliminate valves. 2 in series, twice the pressure but no flow unless both are running. The .pdf link in the page has a better description. --------------070606090301080005090709 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
On 10/31/2014 8:09 AM, Ernest Christley wrote:



On Friday, October 31, 2014 12:57 AM, Charlie England <flyrotary@lancaironline.net> wrote:

>But...Didn't you mention 6psi fuel pressure? If that's correct, then why have a return line at all? If it's a carb engine,
>just use Facet 'solid state' (interrupter style) pumps. No return line needed.

Good point, Charlie, but the engine came with one of those AeroVee carbs on it.  It's basically a throttle body with a drip feed for fuel.  It gets upset with more that 2psi of pressure, and there are very few regulators that are accurate down that low.  They're basically designed to be gravity fed, and the 601XL doesn't have a header tank.

I'm now seriously considering the transfer pump configuration.  Now that I've been reminded, I remember that Tracy has been flying with that setup for years.  I've got to think about it more.


But what can you use for a bypass style regulator that's accurate at 2 psi, anyway?

Facet makes cube ('solid state') pumps rated as low as 2.0 psi max. Here's a list; the window scrolls for more models.

http://www.facet-purolator.com/cube-fuel-pumps.php

That page mentions 'optional check valve' (CV) but doesn't explain the PSO column. That's basically a 'positive shutoff' or anti-siphon that prevents fuel from flowing through the pump if it's not running. Whether you want that depends on how you plumb the installation. 2 in parallel, you could potentially eliminate valves. 2 in series, twice the pressure but no flow unless both are running. The .pdf link in the page has a better description.

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