The aircraft was designed to comply with the European Fédération Aéronautique Internationale microlight category, including the category's maximum gross weight of 4500NaN0. It was also marketed in the United States as a kit only for the US homebuilt category.
The Piper UL is based on early Piper Aircraft designs, such as the Piper PA-15 Vagabond, which it resembles. It features a strut-braced high-wing, a two-seats-in-side-by-side configuration enclosed cockpit accessed via doors, fixed conventional landing gear with wheel pants and a single engine in tractor configuration.
The aircraft fuselage is made from welded steel tubing, with the whole aircraft covered in doped aircraft fabric. Its 9.41NaN1 span wing, mounts flaps, has a wing area of 12.7m2 and is supported by "V" struts and jury struts. The standard engine used is the 500NaN0 Rotax 503 two-stroke powerplant.
The Piper UL has a typical empty weight of 250kg (550lb) and a gross weight of 450kg (990lb), giving a useful load of 200kg (400lb).
The manufacturer estimated the construction time from the supplied kit as 800 hours.
By 1998 the company reported that 25 aircraft were completed and flying.
In September 2014 no examples were registered in the United States with the Federal Aviation Administration.[2]