----- Original Message -----
Sent: Wednesday, March 02, 2005 8:11
PM
Subject: [FlyRotary] Re: fuel cutoff
valve necessary?
I don't doubt that it is so, Ed, but putting the edicts from
Federal
agencies aside, I'd like to raise the question of whether it is
safer.
Indeed, how many
crashes have resulted from people taking off with the fuel valves off?
Granted, that won't happen with fuel injection, but with a big carb bowl it
does.
Assuming that connections will be the weakest spot in any system,
and
that there actually is a pump that blocks flow when there's no
power
applied (I haven't tried to determine if there is), I would
argue that
the pump IS the cutoff valve,
This is another one of those
questions I've never seen a good answer for, so out to the garage I just
went. I grabbed one of the Walbro in-tank pumps, and tried with all my
might to blow through it, and could not. With the exception of my
cheeks, I feel better now. My RV-3 has no fuel shutoff valves.
Rusty (forgot what I was going to put
here)
I guess in Experimental there goes a
lot that would be impossible on a certified plane.
If you get distracted and fumble
around in an emergency for the fuel shut off you are way behind on your
emergency procedure practise anyway! That should be one of those items in your
flying career that should go automatic even if you are in a coma!
If you don't use the fuel shut off
regularly you still should be able to get at it and actuate it
blind/sleeping/dumbfounded/etc.!!
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!
If I ever get to build my plane it
will have at a minimum a emergency fuel shut off. Most likely
safety-wired open with a big red handle on it, in a easy reachable spot, but
still out of the way: eg. for a side throttle just forward of the throttle
lever - so you can let go of the throttle grab the shut off and pull. For
a center throttle, put it on the roof - reach up, grab it and pull. Use a
flexcable to actuate the valve (or valves) as close to the tanks as
possible.
The safety wire keeps it from
accidental actuation, but a serious yank will brake the wire and cut the fire!
(The only reason you really would want to cut the fuel, ....or maybe a runaway
engine...)
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!
Back lurking!
Thomas J. (Curious about Rusty's EWP
tests!)