Mailing List flyrotary@lancaironline.net Message #38076
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Favored Method 8/9 - Fuel Pump Shut off was [FlyRotary] Re: Method of killing power??
Date: Sun, 24 Jun 2007 16:16:03 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

 Ok, heard from one more, the count now is  out of 9 respondents (including yours truly), it looks like the methods of engine shut down are:
 
8 - turn off fuel pump
 
1- Disable injector
 
So, I think it fairly clear with this "statiscally valid" sampling that  88.9 % use Fuel pump shut-off and 11.1%  remove power from the injectors. 
 
Of those reporting "run time" after shutting off the fuel pumps it appears it can take anywhere from 1 - 4 seconds for the engine to stop.  Presumably depending primarily on how much volume of fuel contained in each particular fuel system. 
 
The primary advantage to the pump shut off approach appears to be to minimize the amount of fuel in the line at shut down - which in case of a leaking injector - would minimize the protential for flooding.  Only possible down side suggested was residue heat causing any fuel left in lines to evaporate/boil and possibly result in residue "gum/varnish" build up.
 
As David mentioned - with the old sneak circuit turning off power to the EC2 would not shut down the engine (as I also discovered) so another method was required.  Most chose to shut off their fuel pumps, I chose to turn off power to the injectors.  With the new snubber modification, the "sneak circuit" no longer exists, so shutting off power to the EC2 should now do the job as well.
 
 
 
 Ed
 
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