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