The Thaden T-4 Argonaut was a 1930s American four-seat all-metal cabin monoplane built by the Thaden Metal Aircraft Company of San Francisco, California.

[1] The T-4 was the third and last design of the Thaden Metal Aircraft Company which had been formed by Herbert von Thaden, a former United States Army Signal Corps pilot and engineer, to work on developing the first American all-metal aircraft.

The T-4 was a high-wing monoplane powered by a 300 hp (224 kW) Wright Whirlwind radial engine.

[1] It had a fixed conventional landing gear with a tailwheel.

[3] Data from Jane's all the World's Aircraft 1931,[4] Aerofiles[3]General characteristics Performance