Subject: [FlyRotary] Re: Fuel System (was: rotary risks. MTBE and the gospel)

 

Ian,

 

   I'm not flying my own plane yet (nor soon).  However, I

borrowed the basis of my system from Marc & Nadine Parmalee.

 

http://www.marcnadine.com/fuelvalve.html

 

   Attached is a block diagram of my implementation.  The

low pressure (debris) filter and fuel pump are below the

strake (& therefore lower than all of the fuel when in level

flight).

 

Dale;

 

I was just looking at your fuel system, and had the following comments.  A filter finer than a screen door screen upstream from the pump allows the potential for restricted flow to the pump, increasing the possibility of vapor lock. 

 

Also, why 1/4" line on the feed side and 3/8" on the return from the fuel rail.  The fuel returning will always be less than that going to the rail.  It may not matter downstream from the pump, but all you have is some gravity from the strake to the pump, and you’d not want flow restriction there.  I think a bigger line there is important.

 

Why the two ball valves?  With valves in the system, I’d want both normally open.  Do you want to rely on remote operation of those valves?  One valve downstream from the pump for maintenance or emergency shutdown, safety tied (breakable) open is something to consider.

 

I assume the sump drains are at the lowest point of the tanks; and that exit from the tank is such that there can be a bit of residual water/debris in the tank that does not get into the feed line.

 

Just some thoughts.

 

Al