Established early 1948. Seibel had worked with Bell Helicopters,
but joined the Boeing company in 1946.
With two collaborators built in 1947 S-3 light helicopter
(lateral and longitudinal control effected by changing center
of gravity). S-4A of 1948 had special blade-attachment
system patented for S-3. Followed by S-4B with more
powerful engine and side-by-side seats. In March 1952
company taken over by Cessna.
