Dave,

I have been following your thread. I'm not particularly interested in building the plane you are talking about but I did see that you are gonna use an RCV 91CD. I have one of those engines and just to make you feel better it is really, really good. It does take some time for breakin though. I ran about 3/4 of a gallon thru it before I put it on a plane (a 60 size Sig Twist). Breakin will continue from that point until you get 8-10 10minute flights. At that point you can get it to idle very good at around 2000rpm. It does like 15% nitro but will run well on 10%. I have not mounted it inverted so cannot say from experience how it would run mounted that way. The glow plug is mounted on the side (why am I telling you this? you have one to look at) which makes me believe it would run good. So, there is my .02 cents worth.

sonnytex