Fuel Burn for Rotax 914

[Vertical Tango]

The Optifuel looks at only one fuel line going from the pressure regulator to one carb only. It counts on the fact that both carbs are meant to be balanced. There is a parameter for such installation to tell the software to multiply by 2 what that carb uses.

[Learjet]

I use the Optifuel unit on my Magni (had one fitted to my previous M16 as well) and swear by it.
The sender unit is fitted "downstream" of the fuel regulator - between the fuel regulator and one carb and is therefor not affected by any return flow from the regulator to the tank. The Optfuel unit has a setting that allows you to double the measurement to compensate for the other carb (without the fuel flow sender unit), and provided that the carbs are reasonably balanced I find the accuracy to be extremely good. It may take a little bit of calibration for the first few flights - throttle settings, with pax etc . The fact that it can integrate with your GPS (I use a Garmin 495) and in so doing show you a "reserve" at destination which is very useful on cross-country trips.
Dave

[t-bird]

I burn an average 21.5 liters per hour. This is based on continues flying of 2 hours plus at 90 MPH airspeed.

[Gyronaut]

According to the Magni M16 Operators Manual:
Fuel consumption in l/h (USgal/h) 914 UL / F
at take-off performance 33,0 (8,7)
at max. continuous performance 27,2 (7,2)
at 75 % continuous performance 20,4 (5,4)
specific fuel consumption at max. continuous performance 276 g/kWh (0,458 lb/hph)

The fuel that is not used at the regulator goes back into the tank yes. The Fuel-Flow sensor/impellor should therefore be put in-line between the regulator and the carburetor. Most fuel flow devices then allow you to set up 2X on the machine, assuming that both carbs use the same amount of fuel. The MGL works the same. I know that the Optifuel comes with all the pipes and banjo-joints and instructions etc required to make it an easy job. Remember to be extra careful with cutoffs or dirt in the cut pipes - no filter between here and your jets. Also get an AP to do it for you or inspect your work and sign it off in your machines logbook - before you go fly it. please.

Len

[t-bird]

Hi Len

What is the Magni’s Manifold pressure ,RPM and airspeed at 75 % power