The design of the ST-12 dates back to the mid-1920s with the development of a single-spar wing. In 1931 GAL was formed to develop the patented Monospar Co wing design. The ST-12 was a fixed undercarriage variant of the ST-10, re-engined with two 120 hp Gipsy Majors.
A production run of ten ST 12s (reverting to fixed undercarriage) was undertaken.
Engine: 2 x Gipsy Major, 130 hp
Wingspan: 40 ft 2 in
Length: 26 ft 4 in
AUW: 2875 lb
Max speed: 158 mph
Undercarriage: fixed
All Aero 