|Histoire résumée||A development of the O-2 but for Open Class competition, the O-3 featured a longer span of higher aspect ratio, with trailing-edge airbrakes and a retractable gear. One was flown in several Nationals and made a flight of 694 km./ 431 miles. Two O-3’s were built, and both were subsequently motorized. A two-cylinder, in-line, two-cycle Yamaha snowmobile engine was mounted inside the fuselage behind the wing spar driving a pylon-mounted pusher propeller via belts.|
The original 0-3 single-seat sailplane was designed and built by Mr Vernon W. Oldershaw of Bakersfield, California, in 15 months for a cost of $4,000, and it made its first flight in June 1967. He then began to develop a retractable powerplant installation which was added to a second 0-3 completed in 1975, the engine being used primarily for take-off and climb to soaring height. It is a 31 hp Yamaha Snowmobile SW433 two-stroke 'flat twin' driving a two-blade fixed-pitch wooden pusher propeller, the pylon mounted propeller retracting forwards into the fuselage behind closed doors to lie over the engine, which is behind the cockpit. There is a single aluminium fuel tank in the fuselage of 2.5 US gallons capacity. The 0-3 is of all-wood construction with cantilever shoulder wings and a V-tail; the wings have a spruce spar and plywood ribs and skins, with wooden ailerons and air brakes on the trailing edges. The ellipitcal-section fuselage is built up from plywood bulkheads, the front portion from the nose to the wing trailing edge having a glassfibre outer shell and the remainder being plywood-covered. The tail surfaces, which are slightly swept back, are
of similar construction to the wings. There is a retractable rubber-sprung monowheel and a tail skid. The pilot sits under a one-piece flush-fitting cockpit canopy.