Erich Zussmann Terrier (1899-1961) was a self-taught Swiss engineer and one of the most eccentric figures in European aviation between the wars. Born in Lucerne, he began his career as a mechanic in railway workshops before transitioning to aeronautical engineering. In the 1920s, he worked on small experimental projects, including the EZ-3 "Falke", a short-winged metal glider, and the T-502 "Sternflug", a prototype biplane with a makeshift engine.

Terrier became known for his perfectionism and for working alone, refusing sponsorship or outside interference. His notes reveal his keen interest in structural lightness and high-speed aerodynamics—themes that culminated in his most ambitious project, the Erich-Z Model T-789 G.1.

Erich-Z Model T-789 G.1 (1932).

Built entirely by Terrier in a shed on the outskirts of Zurich, the T-789 was a single-engine touring and test aircraft. Weighing approximately four tons and made with Swiss metal alloys and a French 12-cylinder radial engine, the aircraft reached a remarkable top speed of 460 km/h.

The aircraft had a closed cockpit, an elegant shape, and exceptional performance; however, it was highly unstable during landings. During initial testing, Erich almost lost control, which led him to reject invitations to air races.

The T-789 was used in experiments with propellers and control surfaces and served as the basis for later concepts, but it was never reproduced. The only example was damaged in 1947 and disappeared years later, leaving only the engine and part of the wings.

Though not widely recognized during his lifetime, Terrier is remembered as a pioneering figure whose dedication to lightness and efficiency anticipated ideas that would not be revisited for decades.