The Rotax 912 does appear to use less fuel at altitude, keeping RPM
constant, (though I know I'm not comparing 'like with like', so my
situation isn't relevant for you). I think this is due mostly to the
altitude compensation feature built into the carbs.
I always reckon on a ballpark 17 1/2 litres/hr at 1000ft and 5200RPM or
so. My prop. is a traditional W.D. ground adjustable (slightly coarsely
adjusted; runs about 4900RPM static) and my aircraft is a 'classic'.
17 1/2 litres would be 3.8 Imperial gallons or 4.6 US gallons.
(approx: 4.55 litres = 1 Imp. gallon = 1.2 US gallon)
At, say 10,000ft AGL (yes, I really do get up there ;) there is a
noticeable decrease in fuel burn and consequent improvement in range.
(possibly reducing to 15 l/hr or less, but I've never accurately
measured). TAS increases too, but I think that the biggest benefit is in
straight 'point to point' flying with fewer performance degrading
course/altitude changes. I have about 70 litres useable in my main tank,
so I think I could make the Med. in one hop from S. England with fair
wind and empty bladder ;)
Less seriously..
.. not a patch on Singapore Airlines new A340-500, non-stop Singapore -
New York service though. (10,300 statute in 18 hours). I think London -
Sydney is only 10,500 by the shortest route.
...I just hammered my figures into the flight planning section of
www.flightcalc.com. I get 75 hours and 264 Imp gallons for the same
journey !
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Paul
McAllister
Subject: Europa-List: Setting the mixture - 914 Rotax
<paul.mcallister@qia.net>
Hi all,
I was wondering how the correct air / fuel ratio is set for a 914. I
suspect that mine is running a bit rich. I see black soot on the
cowling
and on the under side of the wing. I think that the fuel flows are on
the
high side. I am seeing the following numbers.
- 4500' @ 30' x 5000 rpm = 6.2 US Gallons per hour.
- 4500' @ 28' x 5000 rpm = 5.5 US Gallons per hour
- 4500' @ 26' x 5000 rpm = 4.5 US Gallons per hour
I am also suspicious that it uses more fuel at the same power settings
at
higher altitudes. I will connect my laptop to my EIS latter this week
and
collect a larger data set to verify my measurements.
I'd appreciate anyone's opinion as to what I am seeing so far.
Thanks, Paul
==
==
==
==
|