Piper X-planes

Piper X-planes

(By Roger Peperell)

Like other general aviation manufacturers, the Piper Aircraft Corporation experimented with various designs that didn’t make it to market for one reason or another. During World War II there were designs P1 through P-10; in the 1970s there were ideas of a Navajo based jet aircraft and various pressurized twin engine designs, but some of the more notable examples that made into a prototype aircraft were Piper’s experiments with fiberglass, a pressurized single, a commuter aircraft and two twins based upon existing Piper designs.

PA-29 Papoose

In 1958 Piper announced that it was surveying the marketplace to determine whether there was a demand for a low-cost, two-place aircraft with no frills and which could be produced in a "production system that permits little or no variation from standard". A review of the 1,000 replies to a questionnaire sent out in connection with the survey indicated that there was such a demand. Piper started to design such an aircraft at Vero Beach and by March 1959 the design study was complete. It was to be a 2 place side-by-side low-wing tricycle gear training aircraft and made of plastic (fiberglass and resin). Durez Plastics Division of Hooker Chemical Corp. was to supply some of the basic material. Bob Drake, who had built the first plastic boat for the U.S.Navy some years earlier, was the Piper program manager. Piper started construction of various parts. Specimens of the paper honeycomb-fiberglass construction similar to that being used in the aircraft were placed onto the factory roof to see what would happen. In the spring of 1962 the "real" aircraft emerged, the PA-29 Papoose. The airframe was of fiberglass reinforced polyester construction with a two-shell fuselage and tail and a one-shell wing. It incorporated an all-moving horizontal tail, full span ailerons, which drooped to act as flaps (flaperons), fiberglass sprung main landing gear legs and a 108 hp Lycoming O-235 engine. Serial Number 29-01 / N2900M was first flown on 30 April 1962.

In September 1962 a major project review was held. A decision to start production of the Papoose depended on three major factors: acceptance of the configuration (flight characteristics, appearance), cost studies showing that the cost would be less than competitive materials, and that the material and type of construction would not give structural problems some time in the future. Despite various flight characteristic issues, Howard Piper, Piper’s Vice President of Research & Development, thought that they were solved or solvable in the near future. Maximum speed of 134 mph was acceptable, though not ideal. Wing fillets had solved some stability problems but a redesigned tail was required. Cost studies looked favorable and Vero Beach Engineering was confident the materials and construction would have satisfactory durability. The biggest problem appeared to be water absorption by the paper honeycomb. The honeycomb core material was made with Douglas Aircomb Kraft paper. The Weyerhaeuser Company was approached and it seemed to have a better solution for exterior exposure use. Fred Weick and the Engineering team were confident of success.

The prototype would be sent to Lock Haven for a winter exposure test. It was agreed to build the next two prototypes as close to production standard as possible. These would incorporate major changes. In addition aircraft N2900M would have some additional minor changes. None of these changes were carried out, but N2900M did spend January 1963 in Lock Haven for cold weather trials. The wings were replaced with those intended for the second prototype. Unfortunately the empty weight increased. Ed Swearingen and several Piper engineers flew the aircraft. Many comments were made, some good, others not so good. Later in May 1963, it was decided to make several changes to the design. The fuel tank would be moved from the fuselage to the wings, the vertical tail would be modified to improve directional stability and it was agreed that the horizontal tail design needed modification. Again these changes would adversely impact the empty weight. Tony Piper was brought down to Vero Beach to co-ordinate the Program. Piper's intention was to develop this new trainer to replace the PA-22-108 Colt, which was in production at Lock Haven. After Tony's review many adverse comments about the aircraft were made and further changes were discussed. One very positive point though, was the reduction in fabrication hours of the fuselage and wing as compared to the metal Cherokee by 50 to 60%. Also Piper had received a great deal of good publicity and very considerable interest and acclaim as a result of this fiberglass project.

Alternatives to the PA-29 were discussed including developing a two-place Cherokee, but Howard did not like any of them so it was decided to proceed with the PA-29. Further changes were made to N2900M including extending the wing tips. The aircraft was then flown to Lock Haven for review by Piper Senior Management. In September 1963 a questionnaire on the aircraft was issued to Piper Senior Management. Piper marketing raised many questions regarding the flying qualities, the design and the use of the resin material. Howard Piper wanted to carry out a redesign. He also questioned the willingness of Piper to take the risk of a full scale plunge into fiberglass construction. He felt that the project had been handicapped by promises and commitments that had prevented them from arriving at a completely satisfactory end product. The high level design of the redesigned PA-29 was completed by March 1964. By this time Piper had already put the two place Cherokee 140 trainer into production at Vero Beach, so there was no requirement for a new trainer at the time.

Due to the high potential development cost of a new fiberglass aircraft and other higher priority programs, the PA-29 project was quietly dropped. Aircraft N2900M was dismantled and stored at Vero Beach. Later it was restored by the Pittsburgh Institute of Aeronautics and given to the EAA Museum at Oshkosh, and now resides at Lock Haven in the Piper Aviation Museum.