Psoszegi, the cuyuna engine is very similar to the rotax 447, the one used for ultralights anyway. They are a german design that was sold to some guys in Cuyuna Minnesota,it was also manufactured by JLO and Rockwell for snomobile use. It is now made by a company called 2Si in North Carolina. They got a bad rap back in the 70's and 80's when they were pumping 43hp from them and having failures when not properly jetted and cooled. The older ones were an honest 429cc's came with a wahlbro carb with built in pulse pump and when properly maintained were reliable and put out an honest 40+hp. They weigh about 67lbs. without exhaust. A custom mtorcycle type exspansion chamber works well and newer ones have twin Mikuni's for carbureation and are rated at 35hp. It seems I read that 2SI does not warranty them for aviation purposes any longer, but I could be mistaken. I hope this enlightens you about the american made Cuyuna.
Well I put the first wingtips in there already, and wrap the core in foil and put that back into. Will see what comes out but for sure for easy work this negative has to strengthen and make some stand to work with it easy. Its just bouncing here and there... not good.
Here we go... Plaster, primer, paint. I started to calculate : 20 bucks for primer, paint, 60 bucks for the core styrofoam, 70 bucks for composite, the core was finished by a friend, the glassfibre cloth was a gift. So far all labours about boody 70-80 hours or so. If all this worth the effort and the mess ? I dont know but for sure now I learned the price behind the cured composite wingtip I need to screw this on.
Well at this very moment I would say lets cure my eye, nose and skin irritation of paint and glassfibre, than I will think about twice of doing this business. Its on, but not flight tested yet. For serial production the mould has to be strengthen with an extra layer and some stand otherwise its pain in the butt with the bouncing mould. Oh yeah weight is less than 1 kg each = 2.2 lb. I think thats very light.
I flight tested today. It was not ultimate weather for this, 7- 10 mph total crosswind on a hilly turbulent gras strip. I would not say there is a big achievement but for sure it feels better. Not only because of the extra work I put in there and to explain myself and to you, but I can support that with evidence, flight characteristic improvement. As the Vortex project failed, I thought this could as well, but it did not. First of all it feels a better ground handling, somewhat shorter takeoff distance even in that crosswind. Than it climbs better somewhere between 100-200 ft/ minute. Cruise rpm is 100-150 less, or it flies 5-7 mph faster with the same rpm. Noticeable less slipping habit. It glides better. I feel better handling in x-wind too. If we are looking at the theory of Hoerner wingtip aerodinamical wingspan increased something like 30 inches or so and that explains all that. EGT looks slightly higher than before, CHT a bit lower.. but I cant confirm that yet. Maybe because its less drag ? And for sure it looks better. If you have a Himax, landing gear change is a big "wow", hoerner wingtip is a smaller "wow" , strut farings I did not feel any difference, and Vortex was a total disappointment.
She is on the trailer awaiting to be transported to my 900 ft little runway. I Will send photos on wednesday or so if I get there.
Very nice..you certainly dont sit still for very long...Just excellent progress and workmanship.
Now can any one photoshop those tips onto a Minimax...for the change in appearance....as I'd like to see it (because it looks pretty)...and if it adds performance...or decreases drag...ALL the better.
Logged
Next step: the real wingtip.
Those are NICE! Hmmm...got to check the shipping costs from Hungary to the US 
