X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from aspensprings.uwyo.edu ([129.72.10.32] verified) by logan.com (CommuniGate Pro SMTP 5.4c2o) with ESMTPS id 4881778 for flyrotary@lancaironline.net; Thu, 24 Feb 2011 19:14:29 -0500 Received-SPF: none receiver=logan.com; client-ip=129.72.10.32; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht1.uwyo.edu (ponyexpress-ht1.uwyo.edu [10.84.60.208]) by aspensprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id p1P0DLHY021945 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Thu, 24 Feb 2011 17:13:51 -0700 (MST) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-mb5.uwyo.edu ([fe80::9813:248c:2d68:a28b]) by ponyexpress-ht1 ([10.84.60.208]) with mapi; Thu, 24 Feb 2011 17:13:30 -0700 From: "Steven W. Boese" To: Rotary motors in aircraft Date: Thu, 24 Feb 2011 17:13:29 -0700 Subject: RE: [FlyRotary] Re: Fwd: Fuel injector pump cooling?? Thread-Topic: [FlyRotary] Re: Fwd: Fuel injector pump cooling?? Thread-Index: AcvUeTWs3QB1wTV0SF6xWUURgGTJXQAAI91Q Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_E1AA3B1AF41D8049B1E3FBD5E225626008872D2143ponyexpressmb_" MIME-Version: 1.0 --_000_E1AA3B1AF41D8049B1E3FBD5E225626008872D2143ponyexpressmb_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Charlie, I transferred fuel to a T in the return line from the regulator. The regul= ator return was connected to the side branch of the T. I suspect that the = back pressure from this connection adversely affected the flow rate from th= e Facet pump. A separate line to the main tank or a different connection a= rrangement at the T might have been better. The high pressure pump had a h= igher and predictable flow rate. While returning the fuel to only the main tank would work, it seems to leav= e the possibility for a couple of undesirable situations. One would be in the event that the supply from the main tank were compromis= ed, fuel would have to be drawn from the aux tank while the returned fuel w= ould accumulate in the main tank where it would be inaccessible and possibl= y vented. A second possibility would be to draw fuel from the aux tank and return it = to an operational but full main tank where it would be vented. I'm sure yo= u would not do this. Me?... I'm not so sure. Steve From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Charlie England Sent: Thursday, February 24, 2011 4:18 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Fwd: Fuel injector pump cooling?? Ouch; I hadn't thought about that. But I suspect that even a low pressure p= ump would damage the tank if the vent is blocked. Thanks for the data point= on the fact that a high pressure pump can be used effectively as a transfe= r pump. Were you using a separate port on the main tank for your transfer point? My= tentative plan is to T into either the regulator return, or (assuming an e= ffective back/anti-siphon setup), into the main supply between tank & engin= e pump. Obviously, the anti-siphon feature would need to be bullet proof to= tap the supply line. One option I've considered is to use the fuel selector 'normally', but have= all regulator bypass return to a single 'main' tank. This arrangement is a= ctually used in some certified planes with injected Continentals, but I'm l= eery of having my primary engine pump run dry for even a very short interva= l as I empty an aux tank. I suppose that with that arrangement, it would on= ly run dry for a couple of seconds ( :-> ), so maybe it would work out fine= . Any thoughts? Charlie --_000_E1AA3B1AF41D8049B1E3FBD5E225626008872D2143ponyexpressmb_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

= Charlie,<= /o:p>

 

I transferred fue= l to a T in the return line from the regulator.  The regulator return = was connected to the side branch of the T.  I suspect that the back pr= essure from this connection adversely affected the flow rate from the Facet= pump.  A separate line to the main tank or a different connection arr= angement at the T might have been better.  The high pressure pump had = a higher and predictable flow rate.

 =

While returning the fuel to only the main tank woul= d work, it seems to leave the possibility for a couple of undesirable situa= tions.

 

One w= ould be in the event that the supply from the main tank were compromised, f= uel would have to be drawn from the aux tank while the returned fuel would = accumulate in the main tank where it would be inaccessible and possibly ven= ted.

 

A secon= d possibility would be to draw fuel from the aux tank and return it to an o= perational but full main tank where it would be vented.  I’m sur= e you would not do this.  Me?... I’m not so sure.

 

Steve

 

 = ;

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.n= et] On Behalf Of Charlie England
Sent: Thursday, February = 24, 2011 4:18 PM
To: Rotary motors in aircraft
Subject:= [FlyRotary] Re: Fwd: Fuel injector pump cooling??

 

Ouc= h; I hadn't thought about that. But I suspect that even a low pressure pump= would damage the tank if the vent is blocked. Thanks for the data point on= the fact that a high pressure pump can be used effectively as a transfer p= ump.

Were you using a separate port on the main tank for your transf= er point? My tentative plan is to T into either the regulator return, or (a= ssuming an effective back/anti-siphon setup), into the main supply between = tank & engine pump. Obviously, the anti-siphon feature would need to be= bullet proof to tap the supply line.

One option I've considered is = to use the fuel selector 'normally', but have all regulator bypass return t= o a single 'main' tank. This arrangement is actually used in some certified= planes with injected Continentals, but I'm leery of having my primary engi= ne pump run dry for even a very short interval as I empty an aux tank. I su= ppose that with that arrangement, it would only run dry for a couple of sec= onds ( :-> ), so maybe it would work out fine. Any thoughts?


=
Charlie

 

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