Fuel Consumption

John, I don't think you've said how you are getting your fuel consumption figure (I'm confused by the 2nd post by Rick - is that a question, or is it a statement from someone connected with you?) Is it calculated or flow measurement? If it's by flow measurement, have you got an oversized return line that you aren't compensating for? Have you calibrated the system?

I can't imagine you could be losing it through a leak without smelling it.

If you're really putting 20lph through the engine at low power, you should be getting a filthy black stain behind the exhaust and lots of soot in the pipe. In fact I'd be surprised if the engine would run decently.

I have a Europa XS with 912ULS and Airmaster/WarpDrive. My economy cruise around 90kts uses (by calculation not flow measurement) around 12lph. To use near 20lph I would be at 130kts or so which would be something like 5400rpm @ 26-27".

As a side issue, by manifold vacuum 2500 do you mean 25" pressure or something else? I wouldn't pull 25" at less than 5000rpm personally even if the Rotax curves say you can. Doesn't feel right.

Hi Mike,

"I have a Europa XS with 912ULS and Airmaster/WarpDrive. My economy cruise around 90kts uses (by calculation not flow measurement) around 12lph. To use near 20lph I would be at 130kts or so which would be something like 5400rpm @ 26-27".

I had an idea that the Europa XS was more "slippery" than what your comment would suggest. Is your Airmaster a constant speed?

I spent at least two years trying to find/purchase a suitable Europa XS/912ULS Mono - came close a couple of times. In the end settled for a Sonex Legacy  - see earlier comment for usual performance/fuel consumption.😈

I

Hi,

I compute the amount of fuel by measuring the exact amount of fuel of fuel I put in the tank and compare that with the actual time flying. Over several flights it gives a pretty precise number of liters per hour.
I have no leaks, the needle is in the third groove from top (as per default by Rotax).
The exhaust is nasty black and I get black soot spots on the wheel fairing nearest the exhaust pipe after each flight.

The carbs are fully synchronized. 

Hi,
The needle is in the 3rd notch from top - I was just wondering if I could change that, there might be variations carbs in between.
The vent tubes are installed into a camber as per the installation manual.
I don't use a flow meter for measuring. All measurement are made by measuring the exact  amount of fuel I fill in the tank and exactly recording the flight hours and the tacho hours. All flights in 2500 ft.
I'm concerned about the fuel consumption, but have no problems in how to measure it.

Mike,
I wrongly wrote 2500.  My MAP setting is 24".