Hi,

I am rebuilding a 1987 built, Viking Dragonfly, a two-place, foam-and-fiberglass plane that came with a 60 hp, 1983 era, 1835cc VW engine. In 25 years, there have a few technical improvements so I did a 'trade study' to find engine options that (1) improve useful load, and (2) preserve the 500 mile range. But when I announced the results, some of the reactions were not technical.

My trade study came up with three candidates:
  • 625 cc Hirth 3503 - two cycle, water cooled, oil injected, fuel injection, geared, two cylinders.
  • 1800 cc Jibaru - four cycle, air cooled, carb, four cylinders.
  • 680 cc HKS 700E - four cycle, air cooled, carb, geared, two cylinders.
Details about my project, requirements and study are here:
http://hiwaay.net/~bzwilson/dragonfly/

I need to find productive sources about two cycle engines and had already joined the YahooGroup Hirth group. But I suspect there may be other forums and sources with hands-on, experience with larger, two cycle engines. Any recommendations?

You know the funny thing is I can be persuaded by facts and data but I can't be brow-beaten.

Thanks,
Bob Wilson