TOM PITTENDREIGH wrote:

I've read a lot of messages and seen a lot of beautiful color diagrams

all

on this problem of returning unused [presurized] fuel from the injector

fuel

rail to the supply tank(s). IMHO folks are missing some of the basic

laws of

fluid dynamics or even simple "seat of the pants" hydraulics. This

higher

pressured fuel can be returned to the supply side of the fuel system at

any

place the pressure is lower than what it is at the "overflow" side of

the

fuel rail relief valve. This means that you can "tee" it back into the
supply hose right at the input side of the fuel pump. It doesn't have to

be

piped all the way back to the tank(s) and "poured" back in.

Paul Wrote:

I think you are forgetting about the excess heat in the return fuel Tom.
You don't want it right at the intake of the pump as the fuel supply could
get hotter and the pump vapor lock. Also for vapor lock reasons one would
like to have the pump buried in the fuel tank.

Tracy Crook wrote:

PLEASE DON'T  "T" the return line.   More than one pilot has died to prove
the error of this practice.  I think the most recent fatality was in an S51
Mustang here in Florida a few months ago.  Paul correctly identified one
good reason not to do this.  We could spend a lot of time discussing all the
reasons this is bad practice.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

 
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