1943: (Charles W) Seibel,
Kenmore NY
USA
(while working for Bell Co).
1946:
Wichita KS
USA
(while working for Boeing Co on XL-15).
In 1943 designed the Seibel S-1 twin-tilt rotor. Preliminary first design, patented in March 1944.
With two collaborators built in 1947 S-3 light helicopter (lateral and longitudinal control effected by changing center of gravity).
The S-2 of 1947 was a single-place open coaxial design study. No specs or data found.
Established early 1948 Seibel Helicopter Co Inc, Wilson Field, Wichita.
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.
1949: 5613 N Broadway,
Wichita
USA
1951; 3400 N Broadway,
Wichita.
USA
In March 1952 company taken over by Cessna.
All Aero 