Seibel S-4
Seibel Helicopter · United States · first flew 1949 · helicopter
The Seibel S-4 was a two-bladed, single-engine helicopter built by Seibel Helicopter and designed by Charles Seibel. The United States Army evaluated it as the YH-24 Sky Hawk.
Recognition (WEFT)
| W — Wings | High-mounted, rotary |
|---|---|
| E — Engines | 1 × piston, fuselage-mounted |
| F — Fuselage | 8.48 m fuselage |
| T — Tail | Conventional |
WEFT is AircraftIQ's four-point recognition method — how it works.
Spot it by:
- Two-bladed main rotor
- Welded steel-tube box frame with two decks
- Tapered monocoque tail boom carrying a two-bladed anti-torque tail rotor
A small helicopter with a two-bladed main rotor, a welded steel-tube frame, and a tapered tail boom with a two-bladed tail rotor.
Specifications
- The Seibel S-4 has a length of 8.48 m (28 ft).
- It has a wingspan of 8.88 m (29 ft).
- Its maximum speed is 105 km/h (65 mph).
- Typical crew: 1.
Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.
History
Charles Seibel formed the Seibel Helicopter Company with funding from Kansas oil investors and continued the work of his earlier S-3, with a new two-bladed rotor system and simplified transmission. The S-4 lifted off for the first time in January 1949, piloted by Johnny Gibbs, and received civil certification from the CAA on 23 April 1950.
Variants
The S-4A had an upgraded 125 hp Lycoming O-290B engine. The S-4B was a modified airframe with a two-seat cockpit and skid landing gear, and it formed the basis of the Cessna CH-1 Skyhook.
Where you'll see it
In early 1951 the US Army ordered two examples for evaluation as the YH-24 Sky Hawk. The Army decided that it did not provide sufficient payload capability, and the aircraft were returned to Seibel in 1952.
Related aircraft
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