In 1932 Harold A Wagner built a single place open cockpit high wing monoplane powered by a 30hp Szekely and registered N12738 c/n 1.

It was sold to Marvin Wright (Beaverton) for $200 on 16 November 1936, sold then to L S Wilson (Beaverton) on 13 February 1937, then to C M Smock & N E Day (Portland) on 8 June 1938, who wrote CAA on 22 August 1939 that “it was necessary to discontinue flying our aircraft due to natural depreciation of materials used in its construction.” It was dismantled and the registration canceled on 15 June 1939.

Stanisław Wacyk and Tadeuz Tyrala designed the high performance sports WT-1 aircraft during 1930 and they largely financed the construction of its fuselage at the Aviation Circle of the Industrial School at Kraków and wings in the workshops of the Kraków Air Regiment. It was completed in the summer of 1931.

The aircraft was an aerodynamically clean cantilever wing monoplane. Its high-mounted, one piece wing was built around two spars, with a plywood covered leading edge and fabric covering. Narrow chord ailerons occupied the whole of the trailing edges.

The WT-1’s borrowed 67–73 kW (90–98 hp) de Havilland Gipsy I four cylinder upright inline engine was mounted largely exposed, though with a fairing behind it. The ply-covered fuselage had rounded decking; the fuel tank was in the forward fuselage and its two seat, side-by-side cockpit was behind the wing trailing edge. The fuselage tapered rearwards, with the tailplane mounted on top. A tall triangular fin carried a rounded rudder, which reached down to the keel. Its fixed landing gear was conventional, though details are not known.

An initial first flight was abandoned due to a fuel supply problem. The system was modified and a new fuel pump fitted, after which Stanisław Szubka piloted its first flight, finding the WT-1 hard to fly because of a misplaced centre of gravity (c.g.), and damaging it on landing. After accident repair and c.g. adjustment the WT-1 was flown by Jerzy Bajan. The take-off run was short and performance high, but Bajan found its handling dangerous. At this point the loaned Gipsy engine had to be returned to the Kraków Air Regiment and the development of the WT-1 was abandoned.

Engine: 1 × de Havilland Gipsy I, 67–73 kW (90–98 hp)
Propeller: 2-bladed Schwartz
Wingspan: 8.5 m (27 ft 11 in)
Wing area: 10 sq.m (110 sq ft)
Length: 6.2 m (20 ft 4 in)
Height: 2.0 m (6 ft 7 in)
Empty weight: 260 kg (573 lb)
Gross weight: 410 kg (904 lb)
Maximum speed: 210 km/h (130 mph; 113 kn)
Cruise speed: 180 km/h (112 mph; 97 kn)
Stall speed: 90 km/h (56 mph; 49 kn) minimum speed
Range: 700 km (435 mi; 378 nmi)
Service ceiling: 3,000 m (9,800 ft)
Rate of climb: 2.5 m/s (490 ft/min)
Crew: One
Capacity: One passenger