FT-60 Fuel Flow Transducer on 912ULS

Hi James, thanks for your reply.  Do you have an electric backup fuel pump?  If so, where is the Red Cube in relation to that pump?  I would prefer to install my Red Cube in the cockpit after my electric backup pump but EI says to install it after all fuel pumps (including the mechanical one on the engine.  I guess I could try it in the cockpit--with my filters before the fuel selector valve I am comfortable that it will not "plug up"...  I guess the worst case would be an incorrect reading?

Hi John, thank for your reply.  In my case the fuel return is to the gascolator and the Red Cube would be before the gascolator; therefore there would be no need for a second Red Cube.

My system does not have an electric back-up fuel pump.

John, regarding the need for two red cubes to subtract the return flow (if necessary), I have posted this several times before on this forum so I hope not to beat a dead horse too badly, but I totally disagree. If your return line is installed per Rotax instructions it contains a very small orifice (I believe about 0.014" diameter if my memory serves) for the 912 UL/ULS. With a fuel pressure of about 4 psi this orifice only passes about 0.5 gph of fuel flow. This is an extremely small amount and can be easily corrected (subtracted) from the readout by tweaking the "K" factor. I have been flying this way for 8 years with good fuel accuracy. I contacted EI, the cube manufacturer, and told them what I was doing and they responded that this was acceptable. If you have a fuel injected engine or even a 912 UL series with a larger return flow orifice, then this method may not be so good.

Hello Brian!

Just for curiosity , the manufacturer of the ft 60 RED CUBE specify that it should be installed down stream of the last pump.

i wonder why they mentioned it , because you said you installed it actually up stream and it works....?

Thanks for your help!

Regards,

Barak. 

Hello Brian!

Just for curiosity , the manufacturer of the ft 60 RED CUBE specify that it should be installed down stream of the last pump.

i wonder why they mentioned it , because you said you installed it actually up stream and it works....?

Thanks for your help!

Regards,

Barak.