Fellow  Bearhawk Builder is looking at various engine options:

When I  suggest a Rotary is the response:

They consume too much fuel, as  there was a Kit Plane article
that said they had much worse  consumption than a 180hp 0-360.

Looking for solid fuel  consumption evidence to post up.  RX8 vs RX7 also a
plus.

Thanks,

Tom Walter

Not true.  Ask anybody flying them. They are about 5% worse and they will
burn  auto fuel which is a 25% savings.

Paul  Lamar


Paul,
I believe Tom lives in the Austin area.  In  Austin 100LL is about
$3.75/gallon at present time and 87UL is approx.  $2.55/gallon, or $1.20
less.  That is a 47% savings.  Kinda makes  the 5% higher fuel burn look
insignificant in my book.  My Lancair  holds 94 gallons; which works out to
$112 savings per tank.

And take  into account that we can use $5 spark plugs and $3.00 oil filters,
and the  savings really begin to add up.

There I go again... preaching to the  choir.  ;-)

Mark S.


From a dyno sheet for a bridgeported 12-A.. How about 6,500 RPM, 139.6
torque, 173.3 HP, EGTs 1515 and 1491, BSFC .666,  Oil temp 162, oil  pressure
99.9, AF 12.3. This would give you a very fuel hungry answer, but a  start.

That should be enough data to come up with your answer..

Lynn E. Hanover

That is fine and it is very typical of any piston engine as well
as a rotary. When you are running 12.5 to one the engine is full power
mixture and the BSFC is about 20% to 30% higher than it would be at cruise
mixtures depending on how well you lean the engine. The rotary will
still run at 20:1 lean mixtures.

A turbo Lycoming at full take off power is .65.

Paul Lamar