|
|
Paul wrote:
----- Original Message ----- From: "Ernest Christley" <echristl@cisco.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, March 04, 2005 9:01 AM
Subject: [FlyRotary] Re: fuel cutoff valve necessary?
Even my home plumbing has a shutoff valve for the sinks, toilets, refrigerator ice-maker, washer connection, etc. If something starts leaking downstream, it's nice to be able to shut it off for repairs, as well as to minimize the damage from water, fuel or whatever. I would not feel comfortable without a fuel shutoff. They're really not that heavy, and mighty handy if you need to shut off the flow of fuel to work on anything downstream. When I had my forced landing recently, fuel and ignition was shut off at 100 feet of altitude. Maybe I'm too cautious, but I am still somewhat comforted knowing that I can shut off the flow of fuel in an emergency. Paul Conner
Paul, you're mixing two seperate things here. A maintenance shutoff valve and an emergency shutoff valve. I'm only really considering the latter.
Consider this objectively. Once the pump stopped, did turning an extra vavle actually make you safer, or did it just make you feel safer? If there was no flow through the pump without the electrons driving it, what additional benefit does the valve offer?
One point that I should clarify, so that my ruminations here would not seem so pointless. I've been considering a returnless system. A single tank is located high in the back of the airplane. If I locate the pumps, filters and gascolator back under the tank (advantageous for W&B and positive head to the pumps), and just run the single supply line up front, then I would have to find a valve that would reliably operate under elevated pressures. But having a pump that blocks flow when it isn't running immediately begs the question of, "What is the point of the valve?" Not thinking for a moment that I know it all, I present the question here.
|
|