Before I launch into this, let me state I am finishing up a BD-4 with a Continental 0-470 that I eventually chose over auto conversions because of all the issues in coming up with a reliable install.
Having said that (and having read old threads here about this) I think that the Japanese monster bikes offer serious potential. These motors-Honda, Kawasaki, Suzuki, Yamaha- were brewed in the high stakes world of motorcycle racing and they are brutally strong, so much so that they spawned the mini-sprint racing categories--in case the reader is unaware, these cars run full bore with essentially stock long blocks and are seriously reliable under racing conditions.
I own a ZX1100 that is stupidly powerful and it has been run HARD AT SPEEDS MOST HOMEBUILT AIRPLANES WON'T SEE and still purrs like a kitten. Don't ask for details...but with new tires I can state that the 180 mph speedometer is not on there for show.
Dyno charts on these bikes show horsepower in the 140-180 range at rpms anywhere from 10-12K. The Kawasaki ZX 10R for example is a 160 hp engine at 12000 rpm and is race tested with HOURS at full throttle. These engines geared to run in the 6500 rpm range will produce 65-70 horsepower and be running at a little more than half their designed max rpm. And get this, the Suzuki 1300 Hayabusa engine produces 53.9 horsepower at a STUNNING 3500 rpm.
These motors weigh 140-170 lbs without coolant and that is in the Rotax 912 range and can be bought for $1000-1500 all day long. They have altitude compensating EFI and as far as I can determine there are no "limp home" modes. Those drive sprockets are designed for heavy shock loads (wheelies) and for high speed loading as well; chain drive psrus come to mind here.
Torsional resonance issues would need to be engineered through. Serious consideration but not impossible.
"too heavy", "weren't designed for heavy loads over long periods" etc don't really apply to the motors referenced here as they all have a racing heritage for durability and power/weight ratio.
My next airplane may well be a Kitfox type with one of these hanging on the nose.....
Thoughts?
Having said that (and having read old threads here about this) I think that the Japanese monster bikes offer serious potential. These motors-Honda, Kawasaki, Suzuki, Yamaha- were brewed in the high stakes world of motorcycle racing and they are brutally strong, so much so that they spawned the mini-sprint racing categories--in case the reader is unaware, these cars run full bore with essentially stock long blocks and are seriously reliable under racing conditions.
I own a ZX1100 that is stupidly powerful and it has been run HARD AT SPEEDS MOST HOMEBUILT AIRPLANES WON'T SEE and still purrs like a kitten. Don't ask for details...but with new tires I can state that the 180 mph speedometer is not on there for show.
Dyno charts on these bikes show horsepower in the 140-180 range at rpms anywhere from 10-12K. The Kawasaki ZX 10R for example is a 160 hp engine at 12000 rpm and is race tested with HOURS at full throttle. These engines geared to run in the 6500 rpm range will produce 65-70 horsepower and be running at a little more than half their designed max rpm. And get this, the Suzuki 1300 Hayabusa engine produces 53.9 horsepower at a STUNNING 3500 rpm.
These motors weigh 140-170 lbs without coolant and that is in the Rotax 912 range and can be bought for $1000-1500 all day long. They have altitude compensating EFI and as far as I can determine there are no "limp home" modes. Those drive sprockets are designed for heavy shock loads (wheelies) and for high speed loading as well; chain drive psrus come to mind here.
Torsional resonance issues would need to be engineered through. Serious consideration but not impossible.
"too heavy", "weren't designed for heavy loads over long periods" etc don't really apply to the motors referenced here as they all have a racing heritage for durability and power/weight ratio.
My next airplane may well be a Kitfox type with one of these hanging on the nose.....
Thoughts?
