Mailing List flyrotary@lancaironline.net Message #53388
From: <bktrub@aol.com>
Subject: Re: [FlyRotary] Re: Fuel rail pressure
Date: Tue, 28 Dec 2010 00:10:07 -0500
To: <flyrotary@lancaironline.net>
Tracy,
did you ever find a suitable replacement fuel pressure sender? What are you using now?
 
Thanks,
Brian Trubee



-----Original Message-----
From: Tracy <tracy@rotaryaviation.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Dec 27, 2010 4:30 pm
Subject: [FlyRotary] Re: Fuel rail pressure

Just for another data point:

I installed the fuel pressure regulator prior to the fuel rails in my 20B installation so there is no fuel flow to flush vapor from the rails on hot startups.  This arrangement is now used on most new cars.  Even with this arrangement I have had no trouble with vapor lock.   Even if it should happen, the EC2/3  primer function would be able to vent the vapor from the rails.

This setup allows the use of a Floscan type fuel flow sensor with the EM2/3 since there is no return flow from the fuel rails.  No big advantage other than being much easier to calibrate.

Tracy

On Mon, Dec 27, 2010 at 6:53 PM, <bktrub@aol.com> wrote:
It seems to me that the fuel would have to be pretty hot for the vapor pressure to exceed 40 psi and cause vapor lock. Running the fuel pump in such a case would cause coller fuel to flow through the rail and back to the tank.
 
Brian Trubee



-----Original Message-----
From: Al Gietzen <ALVentures@cox.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Dec 27, 2010 3:49 pm
Subject: [FlyRotary] Fuel rail pressure

 
Also remember that when you are starting the engine you are starting it under a load.  This is different then in a car config where in a car you are starting it with no load attached to the crankshaft.  If the fuel rails are getting so hot that they are vaporizing I would think this would cause an excess pressure in the fuel system and be very dangerous.  This is not a problem I have ever had in a car.  What is causing this besides poor ventilation?
The pressure in the fuel rail can never exceed the setting of the pressure regulator; which should bear about 40 psi engine off. That’s true even if you call the e-shaft a crankshaftJ.
Al
 

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