Renesis Rotary for Aircraft?
Renesis Rotary for Aircraft?
10-04-2009, 09:03 PM
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10-04-2009, 09:04 PM
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10-04-2009, 09:08 PM
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10-04-2009, 09:10 PM
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10-05-2009, 03:40 PM
#11
Good airplane engine? No, not really (though I'll catch flak for saying so). A good aeroengine is a package deal, excelling at one aspect or another doesn't count. Porsche's attempt ~25 years ago to upstage the venerable 200 hp Lycoming IO-360 is a good example. On a test stand the ram-air cooled Lycoming was toast, with the fan-cooled, computer controlled Porsche coming out much more efficient. But then you have to add a gearbox on the nose to reduce the rpm from 6500 to 2500 for the prop. Then you have to discover when you pitch a 50 lb spinning prop, it rips the shaft in half, and beef it up (the Lycoming's front main bearing is about 4" wide!). Then you stick it in a real airplane and discover the drag from the fan cooling system at speed is much more than the el-crudo Americaner. In the end, they had to bump the power up to ~220 hp, negating the fuel consumption advantage, and only charging double the already outrageous price for the Lycoming. Dismal Failure.
Car engines in general:
a) Spin too fast (doubly so for the rotary).
b) Are rated at power outputs they cannot sustain. (Try taking your 8, flooring it, running thru the gears, and leaving it floored for the next 4 hours).
c) Have cooling systems that aren't fail-safe.
d) Depend on batteries and single ignition systems.
e) Have no provision for control of hydraulic propellors
f) Cannot take the torsional forces generated by rotating the engine sharply up or down.
g) Do not have provisions for running upside-down.
And so on. People have done the conversions, but after 30 years of trying there are only a handful of rotaries flying. The only auto engine conversions of any success have been with VW and Subaru (where the flat 4 or 6 configuration is similar to traditional light plane engines.)
Car engines in general:
a) Spin too fast (doubly so for the rotary).
b) Are rated at power outputs they cannot sustain. (Try taking your 8, flooring it, running thru the gears, and leaving it floored for the next 4 hours).
c) Have cooling systems that aren't fail-safe.
d) Depend on batteries and single ignition systems.
e) Have no provision for control of hydraulic propellors
f) Cannot take the torsional forces generated by rotating the engine sharply up or down.
g) Do not have provisions for running upside-down.
And so on. People have done the conversions, but after 30 years of trying there are only a handful of rotaries flying. The only auto engine conversions of any success have been with VW and Subaru (where the flat 4 or 6 configuration is similar to traditional light plane engines.)
10-05-2009, 03:54 PM
#12
not double so. the eccentric shaft on the renesis spins at 3000rpm at full redline.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
Last edited by kersh4w; 10-05-2009 at 03:57 PM.
10-05-2009, 04:57 PM
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10-05-2009, 05:13 PM
#14
Huge hole is huge
not double so. the eccentric shaft on the renesis spins at 3000rpm at full redline.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
Are you meaning Rotor?
10-05-2009, 05:21 PM
#15
not double so. the eccentric shaft on the renesis spins at 3000rpm at full redline.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
your tach only shows "9000" rpm because they are counting combustion cycles. 3 per rotation. so do the math.
and the renesis can very well remain floored for 4 hours. the ability to stay reliable at constant high rpms are one of its selling points.
also, someone correct me if im wrong here, but i cant imagine the renesis having problems running upside down. it doesnt really have an up or down, right? it rotates to begin with.
10-05-2009, 06:08 PM
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10-06-2009, 09:40 AM
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The rotary you are talking about in most aircraft is not the same as what we have in our cars. Those have pistons arranged in a circular manner.
See: http://en.wikipedia.org/wiki/Rotary_engine
See: http://en.wikipedia.org/wiki/Rotary_engine
10-06-2009, 12:33 PM
#20
Nonsense level quite high.
Aircraft *radial* engines used to be quite common, but are still piston engines though, just as V6 and inline 6 engines are. The WW1 vintage LeRone was called a *rotary* engine, because the crankshaft was stationary and the radially-arranged cylinders spun around instead. No modern variations on that for obvious reasons.
The 13B "crank" spins at 3x the speed of the rotors. 9000 crank/eccentric rpm is 3000 rotor rpm.
Yes there are a few wankels (dropping the term rotary for clarity's sake) flying, compared to a hundredthousandish piston engines. All are in the "experimental" category and no wankel I'm aware of has been certificated in the USA for use in "normal" category aircraft (Curtiss-Wright did build a few in the 1970's but they were never sold commercially).
It's fun to fiddle with engines, but much less so when an untimely failure results in fatal crashes. Even seemingly minor changes, propeller weight for example, to an already-throughly tested powerplant/airframe combination can have catastrophic results. A thorough test program takes either much money or much time.
Many if not most experimental planes are interesting because of the high-performance characteristics. Flying them can be a non-trivial endeavor and greatly increases the difficulties involved in executing a safe landing after engine failure. The way to play with exotic powerplants is to put them in very non-exotic (boring) airframes, with slow landing speeds and good crashworthiness. For example, I would never think of flying a Pitts S1S with an exotic engine when the fatality rate after engine failure is extremely high.
Flying is not a forgiving hobby. Most pilots would rather put their trust in a well-proven and tested engine than to get a modest, if any, increase in engine performance. Don't expect to see the skies full of Wankels anytime soon.
Aircraft *radial* engines used to be quite common, but are still piston engines though, just as V6 and inline 6 engines are. The WW1 vintage LeRone was called a *rotary* engine, because the crankshaft was stationary and the radially-arranged cylinders spun around instead. No modern variations on that for obvious reasons.
The 13B "crank" spins at 3x the speed of the rotors. 9000 crank/eccentric rpm is 3000 rotor rpm.
Yes there are a few wankels (dropping the term rotary for clarity's sake) flying, compared to a hundredthousandish piston engines. All are in the "experimental" category and no wankel I'm aware of has been certificated in the USA for use in "normal" category aircraft (Curtiss-Wright did build a few in the 1970's but they were never sold commercially).
It's fun to fiddle with engines, but much less so when an untimely failure results in fatal crashes. Even seemingly minor changes, propeller weight for example, to an already-throughly tested powerplant/airframe combination can have catastrophic results. A thorough test program takes either much money or much time.
Many if not most experimental planes are interesting because of the high-performance characteristics. Flying them can be a non-trivial endeavor and greatly increases the difficulties involved in executing a safe landing after engine failure. The way to play with exotic powerplants is to put them in very non-exotic (boring) airframes, with slow landing speeds and good crashworthiness. For example, I would never think of flying a Pitts S1S with an exotic engine when the fatality rate after engine failure is extremely high.
Flying is not a forgiving hobby. Most pilots would rather put their trust in a well-proven and tested engine than to get a modest, if any, increase in engine performance. Don't expect to see the skies full of Wankels anytime soon.
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