Karlis Irbitis's earliest design activity was to help Nikolajs Pulins with the design of the Spriditis
The 1926 vintage Irbitis I-2 Ikars (Icarus) is shown here with a temporary fairing over the front cockpit, YL-AAA was rebuilt in 1930 and emerged as the I-5. The original 45-h.p. Anzani was replaced by a 77-h.p. Siemens Sh 5 radial.
Karlis Irbitis's I-4 design was a two-seater built by A S Backman.
The Irbitis I-1 "Spriditis", powered by a 25-h.p. three-cylinder Anzani engine
The I-2 "Ikars" two-seater, powered by a 45-h.p. Anzani;
The I-5 was developed from the I-2, but was powered by a 77-h.p. Siemens & Halske Sh.5 engine;
The I-9 was based on the experience gained with the I-5.
