Return-Path: Received: from frontend3.cwpanama.net ([201.225.225.169] verified) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 769489 for flyrotary@lancaironline.net; Thu, 03 Mar 2005 22:28:05 -0500 Received-SPF: none receiver=logan.com; client-ip=201.225.225.169; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend3.cwpanama.net (CommuniGate Pro SMTP 4.2.1) with SMTP id 36011284 for flyrotary@lancaironline.net; Thu, 03 Mar 2005 22:49:30 -0500 Message-ID: <016701c5206a$051d5dc0$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: fuel cutoff valve necessary? Date: Thu, 3 Mar 2005 22:26:57 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0163_01C52040.1C12D840" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_0163_01C52040.1C12D840 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit MessageReaching? ----- Original Message ----- From: Russell Duffy To: Rotary motors in aircraft Sent: Thursday, March 03, 2005 9:53 PM Subject: [FlyRotary] Re: fuel cutoff valve necessary? When your electric system starts to act up, you might not be able to shut down your pumps! You still can stop your engine by cutting the fuel! You're reaching a bit here. A fuel pump is an on/off device. It's not like we have a bank of CPU's running the pumps :-) Not at all!! I fly quite a few hours every month in a machine that has an electric clutch engagement. It happens quite often that something in that installation goes dead (microswitches in the tension adjustment system) and the system stays "on" or "off" - point is, it can keep a circuit open/closed - eg. your pumpswitch brakes and the pump stays on via the relay (if so installed) or what if the master solenoid "freezes" - happens also quite a lot. But keeping it to a part that is not really a shut off valve, like the fuel pump, no way! What if the pump shortens out/gets hot/leaks/etc. I want to be able to cut the fuel at the source! What if your fuel valve connections leak, or the shaft of the valve? Then you're sucking air, which is a much more ominous problem. If it is just used as a emergency shut off, there should be no leaks as you hardly ever move it. My point is, I want a system that I can shut down no matter if I have electric power or not or if it is shortening out somewhere. Have a look at the shut offs Robinson uses, never saw one leaking. Though the tank drains start to leak frequently, especially when they get rather dated.... Everyone has their comfort level, so feel free to install a cutoff valve. There are certainly situations where it could be needed, but for every one of those, I can come up with one where it's an extra danger :-) As a point of trivia, Van's specifically recommends against using braided hose in place of the normal aluminum tubing from the wing tanks. The theory is that in an accident, the wings will be pulled back, and the fuel line will be torn loose. The aluminum line will tend to pinch itself closed when it bends and breaks, but the braided hose will stay open when it breaks. The difference is a big leak vs a small leak. Van's not so dumb :-) Sounds like good advice, did they ever test it by ripping some nive RV wings of a nice RV-body? :)) Cheers, Rusty (my beer's empty) Saludos, Thomas J. (no beer allowed for another 3 weeks :(() ------=_NextPart_000_0163_01C52040.1C12D840 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Reaching?
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Thursday, March 03, 2005 = 9:53=20 PM
Subject: [FlyRotary] Re: fuel = cutoff=20 valve necessary?

When your=20 electric system starts to act up, you might not be able to shut down = your=20 pumps! You still can stop your engine by cutting the fuel! 
 
You're reaching a bit here.  A fuel = pump is an=20 on/off device.  It's not like we have a bank of CPU's running the = pumps=20 :-)  Not at all!! I fly quite a few hours = every month=20 in a machine that has an electric clutch engagement. It happens quite = often=20 that something in that installation goes dead (microswitches in the = tension=20 adjustment system) and the system stays "on" or "off" - point is, it = can keep=20 a circuit open/closed - eg. your pumpswitch brakes and the pump stays = on via=20 the relay (if so installed) or what if the master solenoid "freezes" - = happens=20 also quite a lot.
 
But = keeping it to a=20 part that is not really a shut off valve, like the fuel pump, no way! = What if=20 the pump shortens out/gets hot/leaks/etc. I want to be able to cut the = fuel at=20 the source! 
 
What if your=20 fuel valve connections leak, or the shaft of the valve?  Then = you're=20 sucking air, which is a much more ominous problem.  If it is just used as a emergency shut off, there = should be no=20 leaks as you hardly ever move it. =
My point is, I want a system that I can = shut down no=20 matter if I have electric power or not or if it is shortening out = somewhere.=20 Have a look at the shut offs Robinson uses, never saw one leaking. = Though the=20 tank drains start to leak frequently, especially when they get rather=20 dated....
 
Everyone has their comfort level, so feel = free to=20 install a cutoff valve.  There are certainly situations where it = could be=20 needed, but for every one of those, I can come up with one where it's = an extra=20 danger :-) 
 
As a point of trivia, Van's = specifically=20 recommends against using braided hose in place of the normal aluminum = tubing=20 from the wing tanks.  The theory is that in an accident, the = wings=20 will be pulled back, and the fuel line will be torn loose.  = The=20 aluminum line will tend to pinch itself closed when it bends and = breaks, but=20 the braided hose will stay open when it breaks.  The difference = is a big=20 leak vs a small leak.  Van's not so dumb=20 :-)
Sounds like good advice, did they ever test = it by=20 ripping some nive RV wings of a nice RV-body? = :))
 
Cheers,
Rusty (my beer's=20 empty)
Saludos,
Thomas J. (no beer allowed for another 3 = weeks=20 :(()
 
------=_NextPart_000_0163_01C52040.1C12D840--