On Tue, 21 Oct 2003 14:47:32 GMT, David Hill
wrote:

The project I'm working on (1924 Epps Light Monoplane replica) motivated
me to learn about modern motorcycle engines. The original engine in the
original plane was an Indian Chief motorcycle engine. From photos it
looked like he initially had it set up as a direct drive, then
subsequently built a chain drive PSRU.

At some point before the plane was sold, it was converted to a Lawrance
A-3 engine. I've heard two stories about why he changed the engine.
One is that he wanted more power (28 hp for the Lawrance vs. 17 hp for
the Indian). The other story is that he got tired of the chain breaking.

Hey, cool. But forget those period motorcycle engines. Use a nice
reliable aircraft engine, like a Szekely. :-)

(For those who don't get it: The Szekely 3-cylinder radial has an AD note
calling for a cable running around the outside of the cylinders. To
prevent the parts from flying too far away when they break....)


One interesting motor I found is the Honda series of V-4 engines.
Though they have only one plug per cylinder, they have dual spark boxes.
Some riders I know have lost half their ignition system and had a hard
time telling something was wrong; they just seemed to be down a bit on
power, even though they were running on only two cylinders out of four.

My 1984 Nissan pickup has a straight four with two plugs per cylinder. As
I recall, it has two coils but fires all the plugs via one distributor.

Ron Wanttaja