Don,
We had a kit built BALSA NOVA 120 last Summer that fell victim to a brand new bad battery. It had an MVVS 160 gasser with a tuned pipe that was mounted inverted style. We started with 15-8, 16-8 and 16-10 APC props but ultimately went with 17-8 and 17-10 APC's. It seemed like no matter what prop we ran it wanted to over-speed and make a lot of prop tip noise. We also ran an 18-6. I take it back............. I remember some standard Zinger props on it too. I guess it's all going to depend on your plane, weight, etc. It flew great. Several of our TRI-COUNTY BARNSTORMER members got to twiddle the sticks and everyone liked it. The installation was simple to do. We used a tank from an ARF kit and changed out the rubber stopper to accomodate the gas fuel. I'll be in the office on Monday after lunch CDT. Give me a buzz.
Thanks,
Terry