X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-it0-f53.google.com ([209.85.214.53] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9605660 for flyrotary@lancaironline.net; Fri, 24 Mar 2017 14:22:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.53; envelope-from=ceengland7@gmail.com Received: by mail-it0-f53.google.com with SMTP id 190so9448352itm.0 for ; Fri, 24 Mar 2017 11:22:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to; bh=n+nvIDlrCOXufMHlbqZf7Z9EmiMb+cwS3q1X9YiJZ9w=; b=HokB5umynbVbx7KWv5sL/Bi/3QMBaGy79t1Yy4zo2XQfHkTEbzAI53cXWobzEufZ7E 7OUViqq9n/TF8Vy4vzZpO06De3Sa1Sd7XVmYcLofAQzfTdMU0rT0uDn7gCeRXvmychLe z3AzkmrH3m9ceGOVH7tE8xsSuBK6DYTwmeelkjKTsUpGO4UBzEhb4D4wSt52+Mt4OcmS JELaeYI2+BRbDxeig5A9VEDL27b/BN5bgq9YjpM68se2xu4jTf9ULcNAp32Uj1l6a8SK v3LQsyG5d9NXwot5KnC4kLtd3sFm508amfTrkYM0UxQUXyLrRkX1L3sHvPss7Hv3rnsD pT7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to; bh=n+nvIDlrCOXufMHlbqZf7Z9EmiMb+cwS3q1X9YiJZ9w=; b=YTs3BNrJX6JLK2TJkFimlcblrCptkiqD76ic8bLhlqZaGo+3wqAj7y6pkLbQCVB/K8 F5xSL5rsBvvhf10h/xheXpU6WN90hWc2v+EJvVeC90Enh3MgeHuNKns8opq3IVzfkAUA QsFrr5m91YwT6409uiZ2dAt+qk2lNahcFb7QwcDgr0LTZd5bU5x6IfXEUscS6hgz2OTM 0ENJOBe0ylAw/1DC0y4nGUmubu+rYJgRIpkRu+XJQHBMm3cse3bifGQlh+MHnFjpV7Ym rnfIOwy8ie+R5zLB2pj683vmx4ipLP957qnCblHuwM6jHMTL/oguVNJ2ku6d/Tte0yWN JjEw== X-Gm-Message-State: AFeK/H3q6hfmaWNwjRitHyiVBzFaA89nNybOHWLE8wsSceqmRagETcwxbXoGUSzaajBSiQ== X-Received: by 10.107.6.157 with SMTP id f29mr9502500ioi.205.1490379727650; Fri, 24 Mar 2017 11:22:07 -0700 (PDT) Return-Path: Received: from ?IPv6:2602:306:25fb:1599:8474:643d:896b:cbd8? ([2602:306:25fb:1599:8474:643d:896b:cbd8]) by smtp.googlemail.com with ESMTPSA id e20sm2583727itc.3.2017.03.24.11.22.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Mar 2017 11:22:06 -0700 (PDT) Subject: Re: [FlyRotary] Re: Fuel Pump current and pressures To: Rotary motors in aircraft References: Message-ID: <437b2ec8-33ab-b78d-45d3-1566d8ff3610@gmail.com> Date: Fri, 24 Mar 2017 13:24:02 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------2A1EC8E09699E7FEF13B28AF" This is a multi-part message in MIME format. --------------2A1EC8E09699E7FEF13B28AF Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Hey Steve, Just re-read your post with the measurements, & I'm not sure which had higher current draw. It was the bottom pump, right? Thanks, Charlie On 3/24/2017 8:06 AM, Stephen Izett wrote: > Good idea Charlie. > That would clear it up as far as the manifold flow characteristics. > Just a pain in the but to get to. > Thanks > Steve > > > >> On 24 Mar 2017, at 8:56 pm, Charlie England >> > wrote: >> >> Have you tried swapping the position of the pumps & making the same >> measurements? It's hard to imagine it making that much difference, >> but the bottom pump does have a tight right turn and then a sharp >> edged 'T' turn to the left. I couldn't guess how much, but that would >> account for at least some pressure increase. >> >> Charlie >> >> On Fri, Mar 24, 2017 at 4:14 AM, steve Izett >> > wrote: >> >> Hi Guys >> Hi Peoples >> >> Here is a photo of our parallel pumps plumbed with 3/8 aluminium >> lines feed from a 28 gallon header tank above to the right. >> Fuel then passes through the firewall and race filter before >> feeding the rail and returning via the pressure regulator (4cyl >> toyota reg) >> back through the firewall to the header tank, again in 3/8. >> >> I did further measurements today. >> >> 1. Bottom Pump only ~8A and 48psi - Turning both pumps on this >> pump draws 9.9A and produces a rail pressure of 65psi >> 2. Bottom Pump only ~9.9A and 44psi - Turning both pumps on this >> pump draws 14.8A and produces the same rail pressure of 65psi >> >> So bottom pump goes from 8.0 -> 9.9A (1.9A increase) under higher >> head pressure >> Top pump goes from 9.9A -> 14.8A (5.1A increase) under same head!! >> >> Clearly Pressure Reg bypass capacity is inadequate for both >> pumps, perhaps with even one pump running. >> (I don’t have data of fuel pressure under load to see if it drops >> as power is applied) >> I think I modelled the pump layout/manifold after seeing someone >> else’s and not sure if it causes any problems? >> The pumps came from eBay stating that they were genuine Walbro >> and now I’m wondering. >> >> Cheers >> >> Steve Izett >> Glasair Super II RG Renesis 4 port RD1C EC3 EM3 >> >> >> >> >> >> >> >> > --------------2A1EC8E09699E7FEF13B28AF Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
Hey Steve,

Just re-read your post with the measurements, & I'm not sure which had higher current draw. It was the bottom pump, right?

Thanks,

Charlie

On 3/24/2017 8:06 AM, Stephen Izett wrote:
Good idea Charlie. 
That would clear it up as far as the manifold flow characteristics.
Just a pain in the but to get to.
Thanks
Steve



On 24 Mar 2017, at 8:56 pm, Charlie England <flyrotary@lancaironline.net> wrote:

Have you tried swapping the position of the pumps & making the same measurements? It's hard to imagine it making that much difference, but the bottom pump does have a tight right turn and then a sharp edged 'T' turn to the left. I couldn't guess how much, but that would account for at least some pressure increase. 

Charlie

On Fri, Mar 24, 2017 at 4:14 AM, steve Izett <flyrotary@lancaironline.net> wrote:
Hi Guys
Hi Peoples

Here is a photo of our parallel pumps plumbed with 3/8 aluminium lines feed from a 28 gallon header tank above to the right.
Fuel then passes through the firewall and race filter before feeding the rail and returning via the pressure regulator (4cyl toyota reg) 
back through the firewall to the header tank, again in 3/8.

I did further measurements today. 

1. Bottom Pump only ~8A and 48psi - Turning both pumps on this pump draws 9.9A and produces a rail pressure of 65psi
2. Bottom Pump only ~9.9A and 44psi - Turning both pumps on this pump draws 14.8A and produces the same rail pressure of 65psi

So bottom pump goes from 8.0 -> 9.9A (1.9A increase) under higher head pressure
Top pump goes from 9.9A -> 14.8A (5.1A increase) under same head!!

Clearly Pressure Reg bypass capacity is inadequate for both pumps, perhaps with even one pump running. 
(I don’t have data of fuel pressure under load to see if it drops as power is applied)
I think I modelled the pump layout/manifold after seeing someone else’s and not sure if it causes any problems?
The pumps came from eBay stating that they were genuine Walbro and now I’m wondering.

Cheers

Steve Izett
Glasair Super II RG Renesis 4 port RD1C EC3 EM3 





<Fuel Pres Pumps.JPG>



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