10/31/2023. Remarks by
Johan Visschedijk: "All previous Ryan trainers had employed metal construction, but the Ryan Model S-T-4, or YPT-25, was built almost entirely of plastic-bonded plywood, and, apart from the engine cowling, its airframe used no aluminum alloys, forgings, castings or extrusions.
42-8703) (
Johan Visschedijk Collection)
The YPT-25 was produced in answer to a request made by the USAAF to the Ryan Aeronautical Company for the rapid development of a new primary training monoplane which would make no demands on supplies of strategic materials.
42-8703) APS No. 3253 (
Johan Visschedijk Collection)
The tandem two-seat YPT-25 was powered by a Lycoming O-435-1 six-cylinder horizontally-opposed engine rated at 185 hp for take off and with a normal maximum rating of 175 hp.
(42-8703 to 42-8707) (
Johan Visschedijk Collection)
Ryan built a service test quantity of five YPT-25s (serialed 42-8703 to 42-8707, c/n 1775 to 1779), which were flown in 1942. However, by that time the anticipated shortage of aluminum had not materialized, and therefore no production orders were placed for Ryan's wooden trainer.
