"Pete" wrote in message
...
I am toying with teh idea of using a single-rotor turbo-normalized mazda
with reduction-drive and was wondering if there are any builders out there
who have checked out the same possibility? I'm only looking for around
100-120 hp, with weight an obvious consideration.

I've looked at the idea of using a single rotor in the past, and I know that
Dave Atkins has made them. I've only heard of one flying, but can't recall
who that was, but I know Dave has one in his lawnmower :-) I'm thinking
about a single for a future project, but I'm trying to get the current
project done first (taking my 13B turbo RV-3 to the airport for final
assembly tomorrow).

Unfortunately, going from 2 rotors to 1 gives up half the power, but it
doesn't give up half the weight. Also, I think your quest for 100-120 HP is
a little optimistic for a single rotor, unless you turn the boost above sea
level pressure. For example, a well tuned and optimised 2 rotor
installation will make about 190 HP, which is 95 HP for a single if you're
lucky. On the other hand, there are 2 rotor turbo RX-7 engines producing
more than 425 HP at the rear wheels, though they won't last very long.

How much engine weight can you allow for your plane? I'd guess that a
single rotor, with all the trimmings will weigh over 200 lb. That's just a
guess though. There's a lot that could be done to cut that down, but it
wouldn't be cheap, or easy.

Good luck. I'll be interested in hearing anything else you find out.

Cheers,
Rusty