I've heard they have a reasonably good safety record. The plans seem quite thorough, and are supposed to have been drawn by some engineers from Cessna. Sky Pups are supposed to come out at 190 lbs empty, but I seem to recall from discussion groups that they usually come out heavier. Controls are only rudder, elevator, and throttle. They're intended for relatively low power. As I recall, the instructions say no more than 20 hp, though I think sometimes people use a bit more. I recall you're not supposed to have more than 60 lbs or so for the engine, prop, redrive etc. It does have some AN hardware and some welded bits, but in general the materials are fairly basic. For instance, you're supposed to cover it in dress lining! Mostly it's wood and Styrofoam insulation that you can get at lumber places. The wheels are from BMX bikes! If I recall correctly, the gross is supposed to be 400 lbs. The fuselage isn't all that wide, either, so if you're big and/or heavy, you may have a problem. The wings are in 3 pieces, with the center section permanently attached.What's the good bad and ugly of it?
The only negative I can think of is there are not more of them.What's the good bad and ugly of it?
You will find more articles by Dan and others on http://machnone.com and several experienced Sky Pup builders and pilots participating in https://groups.yahoo.com/neo/groups/Skypup-club/info.I have been asked to share my thoughts about the Skypup in crosswinds compared to spoiler equipped ultralights and 3-axis ultralights so here goes. Compared to all other 2-axis ultralights, it is far better for two or three reasons. It is comparable to many 3-axis ultralights for reasons you might not realize. I flew mine in the 80's and 90's along with many other types and I did just fine.
1. A higher landing speed than almost all others means the crosswind component is less. In practice it lands faster than any quicksilver.
2. The VERY low CG and wide gear with large wheels can make successful landings in conditions that wreck other ultralights (even 3-axis). They are very hard to tip over, drag a wingtip, or ground loop. The key is to land on grass, not pavement. Those big wheels will slide sideways when you land in a crab. A witness once said my wheels threw up big rooster tails of dirt as they turned and slid sideways in an extreme crosswind landing. On pavement you would pull the rubber off the wheels doing that.
3. Crosswind potential of 3-axis ultralights is just that. "Potential". You must have the skill to use it and be willing to risk the airframe. I flew with ultralights that had great crosswind potential, but the average pilot didn't want to risk it. It has been 20 years, but I estimate my max comfortable crosswind at about 12mph on grass. Have landed successfully in much more without damaging anything but the sod. In strong conditions you come to a stop at 90 degrees to the runway.
4. The choice of ultralight depends on where you fly, and what you want to do. I hangared at an airport with a wide grass runway and at one with two paved runways at 90 degrees. It takes a wide runway to land a Skypup in a crosswind. You don't want to have to hit a narrow pavement and miss the landing lights.
5. The length of runway is also a factor. I can get a quicksilver or a trike in or out of a 600-800 foot runway (some with obstacles). The Pup needs more, especially for landing.
For very short tight spots I would want a quicksilver. If you have just one paved runway it's best to have tricycle gear and full 3-axis. The Skypup can go farther on 3 gallons than any Quick can go on 5 gal. I did cross country flights up to 70 miles on my Pup. You can buy used 3-axis Quicks nowadays for $5-6 but they will be sucking fumes after 70 miles.
The biggest advantages of the Pup are; elegant design, low cost,fun to build, and VERY SAFE compared to many others. I started out with almost no training and it probably saved my life more than a few times.