karel wrote:

Out of curiosity I started to look for fuel consumption figures for the
Jabiru 3300.
I found a figure of 0.46 lbs/HP/hr which is not particularly meaningful to
me.
Moreover it said "at cruise power" without further specification.
So I started to assume 65% powser for cruise, calculating from
the rated power of 120HP this gives some 78 HP.
So 78*0.46 gives me 3.6 lbs/hour, or 6 USG per hour or close to 23
liters/hour.

Is this way of calculating correct and do the numbers seem reasonable?
I had expected this engine to be less fuel hungry than the Lycomings &C...
Do not Rotax claim something like 15 liters/hour?

TIA

PS do not tell me that the rated power of 120 HP is not for
continued application, I knew that. Seems similar to the Rotax 914S.


According to the Zenair web site: (seems a bit optimistic)



Specifications: Jabiru 3300 A
Displacement: 3300 cc. (200 cu.in.)
Bo 97.5 mm.
Stroke: 74 mm.
Compression: 8.3 : 1
Prop Rotation: Clockwise
Firing Order: 1 - 4 - 5 - 2 - 3 - 6
Power Rating: 100 hp @ 2750 rpm (see above)
Fuel Consumption @ 75%: 5.0 US Gal/Hour (gph)
Fuel: 100/130 Avgas or 92+ octane Mogas
Oil: Aeroshell W100 (or equivalent)
Oil Capacity: 3.5 qts. (3.75 l.)
Spark: NGK D9EA (common automotive)


My Cessna 150 manual (for a continental o-200) shows a spc of .448 for 75%
(75 HP) operation. The above table works out to a SFC of .4 which looks
low.( note they derate the J 3300 to 100 HP) your figure of .46 looks more
real. Hey but who knows unless you've flown one!
John