patrusso and Stephen I would not use the Geo 3 cyl as the 4 cyl is much more reliable and smoother running. I have an email address of a man that converts them for aircraft use and sells a conversion book for $60 USD. He used his in the Loehle P51 he has. It is said to be 100 hp, but I would plan on a conservative 80-85 hp continuous, with 100 hp on takeoff depending on density altitude (as with any engine). Kinda like the ratings for the Rotax family engines. Their 4 strokes are also a good choice, and are light but expensive. One netter had an engine made in Europe that was supposed to be a good engine, but ended up being his nightmare. Definitely need to use an engine with alot of parts available and local support if possible. Mail order for that kind of item is tough to service.
Also, running the radiator under the belly just at/behind the firewall will give the best airflow, aerodynamics, and shortest runs of the water lines. Other places work well, but increase the length of the water lines, or effect the frontal area in a negative way, by making the cowling wide. Scoops can be found already molded to make install easier, on the Summit Racing and Jegs Racing webpages. Colin Rainey brokerpilot9...@earthlink.net EarthLink Revolves Around You.
