by K+B.91 » Fri May 15, 2009 5:42 am
To answer your question simply, the 'through the crankshaft' type of induction is very primitive and doesn't lend itself to high RPM efficiency.
The drum rotor is far more efficient than through the crankshaft, and the disc rotor is even more efficient again over the drum rotor.
The carbs on both my rotor/drum engines have low end adjustment, even the older style barrel carbs with the large interchangable venturi's.
The reason that all plane engines have through the crankshaft induction is because they don't rev like a ducted fan or marine engine, so they don't need the more efficient form of induction.
You will also notice that plane engines have somewhat smaller carbs than marine/ducted fan engines, because that's all they need.
Cheers.
K+B.91.