New Ideas
Ross and Low Pass,
I hear what you guys are saying, but if you are after a free exchange of ideas, you must be prepared for answers that don't support your hypothesis.
For example: Somebody says "Install a supercharger in the alternator drive position on your Lycoming, and put the alternator on the vacuum pump pad".
To the casual observer, Ross sounds like an optimist when he says "great idea, take pictures and share it with the group".
Trouble is, the vacuum pump drive is limited to fractional horsepower, and turns too slow to properly operate a stock alternator. B&C builds a custom backup alternator for the vacuum pad, but it is 8 or 20 amps, much short of the 60 amps we usually install. They produce this power at 3500 rpm, so at the 1.30 to 1 drive ratio of the vacuum pad, that means you will not charge when idling on the ground. That's why the stock alternator installation has a 5 to 1 pully ratio, so the alternator will charge on the ground.
Dragsters use superchargers...........but can't think of one current production airplane using a supercharger. Must be a good reason! Lack of turbo lag is the only reason I know of for a supercharger, but that is of no consequence
in aircraft. If you look at Eggenfellner's supercharged 4, it could barely compare to Van's 160 hp Lycoming, at 34 inches of MP.
Superchargers consume shaft horsepower that otherwise would be driving the prop, so most performance experts do infact seem to opt for the turbo.
If Egg's move from superchargers to turbos is any indication, I would think you would be headed down the wrong road.
So if you are looking to tinker, go for it, but you will most likely end up with a
marginal result. In which case you should take Ross's advise and "post some pictures when you are done"!
Ross and Low Pass,
I hear what you guys are saying, but if you are after a free exchange of ideas, you must be prepared for answers that don't support your hypothesis.
For example: Somebody says "Install a supercharger in the alternator drive position on your Lycoming, and put the alternator on the vacuum pump pad".
To the casual observer, Ross sounds like an optimist when he says "great idea, take pictures and share it with the group".
Trouble is, the vacuum pump drive is limited to fractional horsepower, and turns too slow to properly operate a stock alternator. B&C builds a custom backup alternator for the vacuum pad, but it is 8 or 20 amps, much short of the 60 amps we usually install. They produce this power at 3500 rpm, so at the 1.30 to 1 drive ratio of the vacuum pad, that means you will not charge when idling on the ground. That's why the stock alternator installation has a 5 to 1 pully ratio, so the alternator will charge on the ground.
Dragsters use superchargers...........but can't think of one current production airplane using a supercharger. Must be a good reason! Lack of turbo lag is the only reason I know of for a supercharger, but that is of no consequence
in aircraft. If you look at Eggenfellner's supercharged 4, it could barely compare to Van's 160 hp Lycoming, at 34 inches of MP.
Superchargers consume shaft horsepower that otherwise would be driving the prop, so most performance experts do infact seem to opt for the turbo.
If Egg's move from superchargers to turbos is any indication, I would think you would be headed down the wrong road.
So if you are looking to tinker, go for it, but you will most likely end up with a
marginal result. In which case you should take Ross's advise and "post some pictures when you are done"!
