X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from outbound-mail.vgs.untd.com ([64.136.55.15] verified) by logan.com (CommuniGate Pro SMTP 5.3.7) with SMTP id 4338859 for flyrotary@lancaironline.net; Mon, 07 Jun 2010 09:26:47 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.136.55.15; envelope-from=alwick@juno.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=juno.com; s=alpha; t=1275917170; bh=47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=; l=0; h=Message-ID:From:To:Subject:Date:Content-Type; b=lgoL2QLcwAO4RdkWV0EL0OzzeA+eXJXgigveTjVJq9pr/OMks3SC7FcKiCa4f3tWi iVG+s1v7ecP7VCfCcyWV2xz5uwHnanUrklrKz3quZW3z5jishqfW9dOZAA2SymYNOZ hNK96c9kM8AYgMGDHHPOz6at8+tM5EaV91QJ6I8Q= Received: from Penny (c-98-246-117-71.hsd1.or.comcast.net [98.246.117.71]) by smtpout03.vgs.untd.com with SMTP id AABGA364AAYVTGMA for (sender ); Mon, 7 Jun 2010 06:25:20 -0700 (PDT) Message-ID: <32DDBE88C43D489E86B272D56055E64F@Penny> From: "Al Wick" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: high/low pressure pumps question Date: Mon, 7 Jun 2010 06:25:20 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00AE_01CB060A.343C2E70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18197 X-UNTD-BodySize: 12271 X-ContentStamp: 30:15:130032668 X-MAIL-INFO:38250dd50dd519ecd5fc1978fc1945d1e815c508c8918cc5e89c889c558d91a19c192cf985f985ed398535ed5835ed05a17d6cfc0805657800fcb121414c4c0cbd3c01ddf98d8598e1f9353131f559c1e8c1e85d68e81c5d891c5d8c855c31add18c959dd9ad28dd8848486198c9dc19c1f8e86591c11c0909299115ccaca1ec68ecfc08d995695da18cd56cd58c19ecddec780845bd001d1d65ad8d65f93da11c08bd49ed99b8cd8dcd9d09583c352cf93dbc7c7c057511ed15f5b9d8 X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkD0hsAbut9t+dx7aVsl0EiGrDeJq9s/k5Q== X-UNTD-Peer-Info: 10.181.42.33|smtpout03.vgs.untd.com|smtpout03.vgs.untd.com|alwick@juno.com This is a multi-part message in MIME format. ------=_NextPart_000_00AE_01CB060A.343C2E70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I'm really concerned for your life risk. This is a very high risk fuel = design. Puts your fuel pressure at pump inlet very very close to the = vapor pressure of fuel. This suddenly makes the design sensitive to a = whole bunch of environmental factors.=20 Ask this question: Millions of automobiles. When they designed = automotive fuel systems, why did every single engineer return fuel to = tank instead of pump inlet? So much more expensive to send to tank.=20 You can bench test your design and prove how close it is to failure. = Just need to measure fuel pressure at pump inlet, measure pump temp. Use = hair dryer to force pump to higher temp. Put all the numbers in = spreadsheet, then calculate distance between vapor pressure and your = readings. Adjust for worst case, which would be high altitude airport, = hot day sitting on tarmac for 1 hour, heat soaked engine compartment, = car fuel containing ethanol.=20 Marginal designs can fly for years without failure. This is the nature = of failure. Use care, I'm concerned.=20 -al wick ----- Original Message -----=20 From: Charlie England=20 To: Rotary motors in aircraft=20 Sent: Sunday, June 06, 2010 6:47 AM Subject: [FlyRotary] Re: high/low pressure pumps question Hope this helps... On 6/6/2010 2:21 AM, Todd Bartrim wrote: > > Hi Charlie; > Hmmmnn, I gotta say a picture (or drawing) is worth a thousand = words. > Todd (sent on my new-fangled google phone with a really damn small=20 > keyboard) > >> On 2010-06-05 8:46 PM, "Charlie England" > > wrote: >> >> Hi Todd, >> >> My thought is to set up the fuel path thus: fuel source through a T = >> into injection pumps, through filters, through combining T, through = >> the regulator(in cockpit), through firewall to engine. The=20 >> regulator's bypass port (in the cockpit) would be plumbed just like = >> yours, except no heat exchanger since the bypass fuel would never = see=20 >> the heat of the engine compartment. The bypass would still T into = the=20 >> supply to the injection pumps, like your system. Obviously, a=20 >> manifold pressure line would be required through the firewall into=20 >> the cockpit to the pressure regulator. >> >> My original plan (different injection that didn't require a return=20 >> line) was similar to your selector setup: main tanks feeding stock=20 >> van's selector, with the 3rd port on it being fed by a 2nd vans=20 >> selector to select either of the 2 aux tanks. No transfer pump = would=20 >> have been required, & no crossover valve. Failure of the primary=20 >> valve could have been a 'show stopper', but the newer valves seem = to=20 >> be rock solid reliable. Going to this system using the gear type=20 >> pumps requiring a return line forced re-thinking. Using your idea = to=20 >> return the bypassed fuel at the pump inlet effectively eliminates = the=20 >> 'return' issue, & tempts me to return to the original fuel selector = >> layout, with the addition of a Facet boost pump. The fact that the=20 >> optical sensors will work looking into the side of a fuel line (the = >> T), instead of needing them in the tank & that they still give = almost=20 >> a full minute's warning, is very encouraging. I'll start looking = for=20 >> a convenient place to mount them. >> >> I hope that Tracy will chime in on how he plumbed the regulator on=20 >> his -8. >> >> Many thanks for the extra details. >> >> Charlie >> >> >> >> On 6/5/2010 12:32 PM, Todd Bartrim wrote: >> >> > >> > Hi Charlie >> > Not sure I understand correctly what you mean? Can you >> sketch it out quickly? I'... >> >> > *From*: Charlie England > >> > .. >> >> > *Subject*: [FlyRotary] Re: high/low pressure pumps question >> > *Date*: Sat, 05 Jun 2010 08:38:09 -0... >> >> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: http://mail.lancaironline.net:81/lists... >> -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_00AE_01CB060A.343C2E70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I'm really concerned for your life = risk. This is a=20 very high risk fuel design. Puts your fuel pressure at pump inlet very = very=20 close to the vapor pressure of fuel. This suddenly makes the design = sensitive to=20 a whole bunch of environmental factors.
 
Ask this question: Millions of = automobiles. When=20 they designed automotive fuel systems, why did every single engineer = return fuel=20 to tank instead of pump inlet? So much more expensive to send to tank.=20
 
You can bench test your design and = prove how close=20 it is to failure. Just need to measure fuel pressure at pump inlet, = measure pump=20 temp. Use hair dryer to force pump to higher temp. Put all the numbers = in=20 spreadsheet, then calculate distance between vapor pressure and your = readings.=20 Adjust for worst case, which would be high altitude airport, hot day = sitting on=20 tarmac for 1 hour, heat soaked engine compartment, car fuel containing = ethanol.=20
 
Marginal designs can fly for years = without failure.=20 This is the nature of failure. Use care, I'm concerned.
 
-al wick
 
 
----- Original Message -----
From:=20 Charlie=20 England
Sent: Sunday, June 06, 2010 = 6:47 AM
Subject: [FlyRotary] Re: = high/low=20 pressure pumps question

Hope this helps...

On 6/6/2010 2:21 AM, Todd = Bartrim=20 wrote:
>
> Hi Charlie;
> Hmmmnn, I gotta say a = picture (or=20 drawing) is worth a thousand words.
> Todd (sent on my = new-fangled=20 google phone with a really damn small
> = keyboard)
>
>>=20 On 2010-06-05 8:46 PM, "Charlie England" <ceengland@bellsouth.net =
>>=20 <mailto:ceengland@bellsouth.net>>=20 wrote:
>>
>> Hi Todd,
>>
>> My = thought is=20 to set up the fuel path thus: fuel source through a T
>> = into=20 injection pumps, through filters, through combining T, through =
>>=20 the regulator(in cockpit), through firewall to engine. The =
>>=20 regulator's bypass port (in the cockpit) would be plumbed just like=20
>> yours, except no heat exchanger since the bypass fuel = would never=20 see
>> the heat of the engine compartment. The bypass would = still T=20 into the
>> supply to the injection pumps, like your system. = Obviously, a
>> manifold pressure line would be required = through the=20 firewall into
>> the cockpit to the pressure=20 regulator.
>>
>> My original plan (different = injection that=20 didn't require a return
>> line) was similar to your = selector setup:=20 main tanks feeding stock
>> van's selector, with the 3rd = port on it=20 being fed by a 2nd vans
>> selector to select either of the = 2 aux=20 tanks. No transfer pump would
>> have been required, & = no=20 crossover valve. Failure of the primary
>> valve could have = been a=20 'show stopper', but the newer valves seem to
>> be rock = solid=20 reliable. Going to this system using the gear type
>> pumps=20 requiring a return line forced re-thinking. Using your idea to =
>>=20 return the bypassed fuel at the pump inlet effectively eliminates the=20
>> 'return' issue, & tempts me to return to the original = fuel=20 selector
>> layout, with the addition of a Facet boost pump. = The=20 fact that the
>> optical sensors will work looking into the = side of=20 a fuel line (the
>> T), instead of needing them in the tank = &=20 that they still give almost
>> a full minute's warning, is = very=20 encouraging. I'll start looking for
>> a convenient place to = mount=20 them.
>>
>> I hope that Tracy will chime in on how = he=20 plumbed the regulator on
>> his -8.
>>
>> = Many=20 thanks for the extra details.
>>
>>=20 Charlie
>>
>>
>>
>> On 6/5/2010 = 12:32 PM,=20 Todd Bartrim wrote:
>>
>>    =20 >
>>     > Hi=20 Charlie
>>     >    Not = sure I=20 understand correctly what you mean? Can=20 you
>>     sketch it out quickly?=20 I'...
>>
>>     > *From*: = Charlie=20 England <ceengland@bellsouth.net
&g= t;>    =20 <mailto:ceengland@bellsouth.net>
>>    =20 <mailto:Charlie%= 20England%20%3cceengland@bellsout.
>>    = ;=20 <mailto:Ch= arlie%2520England%2520%253cceengland@bellsout.>..
>>
&= gt;>    =20 > *Subject*: [FlyRotary] Re: high/low pressure pumps=20 question
>>     > *Date*: Sat, 05 Jun = 2010=20 08:38:09 -0...
>>
>>
>>
>> = --
>>=20 Homepage: http://www.flyrotary.com/
>&= gt;=20 Archive and UnSub: http://mail.lancaironline= .net:81/lists...
>>

--
Homepage:  http://www.flyrotary.com/
Archi= ve and=20 UnSub:   http:= //mail.lancaironline.net:81/lists/flyrotary/List.html
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