|
Mark, I can certainly understand your viewpoint - I have
had experience with fire myself and it do make you a believer {:>).
Safety is a vital factor in our hobby.
That is why I always shut down the injectors first with
their power (disable) switch. That immediately cuts fuel
flow to the combustion chamber - even if you do have a leaky injector, it
certainly shuts all down but the leaky one. Then of course, I also cut my
fuel pumps - wouldn't do to leave them running on the battery for long
{:>). However, from my experience nothing stops the
engine faster than turning off the injectors. Its not 1 sec or 2 sec or 4
sec, it stops before the prop turns another revolution.
But, clearly, the vast majority (well,
maybe with the exception of Rusty and who can tell about him {:>)) prefer to
turn off their fuel pumps first. The engine will (with a couple
seconds) die of fuel starvation and stop. But, it will take a second or
two. That will of course, drain most of the fuel out of the fuel lines - but not
all. I don't know if there should be any concern about small remaining
amounts of fuel cooking and leaving gum or varnish, probably little problem if
using 100LL but could possibly be more of one with mogas.
Mark, I presume from you comment about the fire, that it
was caused by fuel dumping out the exhaust and igniting? Certainly sounds
like the engine got flooded somehow. When my first EFI a HALTECH died, it
did exactly that - all injectors went full open and fuel poured out the exhaust
like a stream of water - fortunately it did not ignite. Can be scary for
sure.
Ed
----- Original Message -----
Sent: Sunday, June 24, 2007 5:55 PM
Subject: [FlyRotary] Re: Method of
killing power??
Ed,
I am here to testify that turning off the fuel pumps, and/or the
injectors first should be considered a safety factor rather than a
personal preference. I'm not certain of the exact sequence, but on one
run I waited until the engine totally stopped before shutting off the fuel
pumps. I think I had shut off the two EC-2 switches first.
This was after a good hard ground run and it resulted in a fire.
Luckily, a fire extinguisher was close at hand or this story could have had a
much different ending. Raw fuel in a hot exhaust manifold,
plugs up or not, can result in a spontaneous combustion. I vote for
shutting off the fuel pumps first. No fuel, no fire. For me there
is no discussion, turn the fuel pumps off first... always!
Mark S.
On 6/24/07, Ed
Anderson <eanderson@carolina.rr.com>
wrote:
Thanks, Jim
That's two for fuel pump shut off.
Ed
----- Original Message -----
Sent: Sunday, June 24, 2007 10:35
AM
Subject: [FlyRotary] Re: Method of
killing power??
Ed,
I prefer the Fuel Pump shutoff method.
On my airplane the fuel system will remain pressurized for a long
time after shut down.
I don't like the idea of highly pressurized fuel inside a very hot
engine compartment.
So by turning off the fuel pumps with the engine still running it
serves to de-pressurize the fuel system.
This way if you do happen to get a stuck open injector it will not
flood the rotor housing with fuel.
It only takes a second or two for the engine to quit after fuel pump
shutoff.
To everyone running a rotary engine and particularly
flying with one - what is your normal method of killing the
engine.
1. Turning off Main
Power
2. Turning off EC2 Power
3. Turning off ignition
4. Turning off Fuel
Pumps
5. Turning off injectors
6. Other
|