It is probably the highest power to weight propeller driven aircraft to
have ever flown.

This is due entirely to the fact that the Mazda rotary engine is such a
high power
to weight ratio engine. 650 HP at under 200 pounds is remarkable.

High power to weight ratio aircraft engines have been essential from the
very beginning of flight. Prior to the Wright Brothers flying professor
Langley
of the Smithsonian Institution appreciated the need for a high power to
weight ratio engine.

Quote  Aircraft Piston Engines Herschel Smith

"Charles M. Manly, then a recent Cornell graduate, was assistant to
Prof. Samuel P. Langley of the Smithsonian Institution, the best-known
and best-financed aerial experimenter in the world at the time.  As
early as 1898, only the lack of a suitable engine seemed to stand
between Langley and success. However, overcoming this lack proved to be
a formidable task. No engine builder in Europe or America could supply a
light enough engine of sufficient power, and so Manly reluctantly took
on the task of designing one. Building on the work of Stephen M. Balzer
of New York, he turned out a 5-cylinder radial engine of 540 cu in.
(8.85 L) that gave a reliable 52 hp at 950 rpm. Despite being
water-cooled, it weighed only 136 lb exclusive of water and radiator. To
make such a big engine so light, Manly went to remarkable extremes. The
cylinders, made with a steel shell for strength and a cast-iron liner
for good lubrication, had a total wall thickness of only one eighth of
an inch.    The sheer workmanship required to machine closed-end steel
shells 5 in. in diameter, 9 in. long, and 1/16 in.  thick on 1900
equipment is staggering. On top of this, Manly and his staff had to make
equally thin cast-iron sleeves accurately enough to be a shrink fit in
these shells. The water jackets were made of sheet steel 0.020 in.
thick, brazed to the cylinders. This, too, was a formidable job;  it is
extremely hard to bring two pieces of metal of very different
thicknesses to red heat without having the lighter piece burn before the
heavier one gets up to temperature. "

This type engine went on to  dominate the aircraft engines used in World
War I.

  Essential to the Wright brothers success was their designing and
building their own high power to
weight ratio (at the time) 4 cylinder in-line engine.

Since that time billions of dollars have been spent by the aircraft
engine industry world wild in the
search  for higher and higher power to weight ratio engines. The TTC
Mazda Wankel is the beginning of
the end for aircraft piston engines and the small aircraft turbo prop
engine. Only a small
gain in BSFC remains to be invented.


Paul Lamar


Paul,

650 HP at near 200 lbs engine weight really is remarkable.

Following below is a quote from Wikipedia on the Formula 1 engine of 2006 that were used till 2013. V8, 2,4 liter. 19,000 rpm, 750 hp, 95 kg minimum weight.

I am not sure what the actual weight really was. Anyway, 95 kg is close to 210 lbs. 2.4 liter is close to the 2.6 liter Mazda RX8, the weight compares close too. In other words the Mazda is as good or better than the F1 of 2006 that needed 1900 rpm to get the 750 hp. By linear deduction 650/750 hp *19,000 means 16,500 or near there would be needed for 650 HP. Including the somewhat higher displacement 15,200 rpm are required for to get 650 HP.

The life of the F1 was some 2 races or roughly 1000 km or there abuts. No comparison really regarding endurance, and really in fuel use too as the F1 had an efficiency near or under 10% as far as I am aware of. If someone has more accurate numbers please let us know.

The difference really is the high mean effective pressure the Wankel can tolerate. As Paul always puts it, the RPE is a 'hand grenade' and such pressures or would explode.

At equal combustion pressures to the RPE the Wankel is just loafing. It's strength really is high speed and high combustion pressure tolerance. An ideal aircraft engine that is low on fuel use compared to turbines. As aircraft engine for up to 500 hp or perhaps more nothing is better. A twin engine of total 1000 - 1200 hp would serve many business aircraft.


From Wiki: (http://www.formula1-dictionary.net/engine_rule_changes_history.html)
*For 2006*, 2400cc engine with 8 cylinders in a 90° V bank, each one with 2 inlet and 2 outlet valves with a 98 mm maximum circular bore, which imply a 39.7 mm minimum stroke. An engine must weigh at least 95kg. Limited to be built with Aluminium alloys (with ceramics, metal matrix and magnesium alloys forbidden). Variable geometry intake and output systems forbidden. Each cylinder can have only one fuel injector and a single plug spark ignition. This is leading to a power reduction of around 20% from the three litre engines. Gearbox must last 4 consecutive races.
750 hp at 19000+ rpm (Toyota)

Rolf Pfeiffer.


95 Kg is 202 pounds. Two pounds heavier than ours with that 100 million dollar engine.
Assume our engine cost $20,000 that is only 2% of the cost of the F1 engine.

These F1 engines  are not suitable for aircraft  as they are running at up to  19,000 RPM.
It takes a very very heavy gear box indeed  to reduce the prop RPM to 2500.

With expensive beryllium aluminum rotors we could run at only 16,000 RPM and double
the HP  to  1,300 HP.

Paul Lamar

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