This thread came from reading about the new Sonex and finding it so last century.
Piston engines for aircrafts can be directcoupled or reducted drive.
They have about the same mass to prop power ratio.The basic units for ultimate power mass ratio is piston area,mean active pressure,maximum pressure and piston speed.
One can have more or less the same mass ratio for a geared engine and direct coupled by having shorter stroke but let it run more rev.
Engine heigth is not mass enemy as much as piston area.
The sligth mass advantage for shorter stroke is very fast eaten away by gearbox mass and flywheel mass.The crank- flywheel is nessecary for everything under 8 cylinder geared installations.
The real advantage of geared installations is sexy look.
A single centerline electric propel driven from two gensets (where generators act as flywheel) can be a much safer system.
Put struts on a highwing plane and put gensets in engine pods at the junction points between strut and wing.
Lower mass, less danger from fire etc.
Whats not to like?
Piston engines for aircrafts can be directcoupled or reducted drive.
They have about the same mass to prop power ratio.The basic units for ultimate power mass ratio is piston area,mean active pressure,maximum pressure and piston speed.
One can have more or less the same mass ratio for a geared engine and direct coupled by having shorter stroke but let it run more rev.
Engine heigth is not mass enemy as much as piston area.
The sligth mass advantage for shorter stroke is very fast eaten away by gearbox mass and flywheel mass.The crank- flywheel is nessecary for everything under 8 cylinder geared installations.
The real advantage of geared installations is sexy look.
A single centerline electric propel driven from two gensets (where generators act as flywheel) can be a much safer system.
Put struts on a highwing plane and put gensets in engine pods at the junction points between strut and wing.
Lower mass, less danger from fire etc.
Whats not to like?
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