|Role||Blended wing body aircraft|
|National origin||United States of America|
|Manufacturer||Arup Manufacturing Corporation|
|Designer||Dr. C.L. Snyder, Raoul Hoffman|
|First flight||19 March 1935|
|Developed from||Arup S-3|
Design and development
The S-4 used a low aspect ratio, circular planform wing with a conventional landing gear and a small rudder with attached elevator on the rear of the fuselage. The aircraft was entered through a door mounted on the bottom of the aircraft.
- Hoffman Flying Wing a design based on the Arup S-4 aircraft.
- Milt Hatfield Little Bird - similar design. 
Aircraft on display
Data from Janes, Popular Aviation
- Capacity: 2
- Length: 18 ft 6 in (5.64 m)
- Wingspan: 22 ft (6.7 m)
- Wing area: 273 sq ft (25.4 m2)
- Airfoil: NACA M-6
- Empty weight: 650 lb (295 kg)
- Gross weight: 1,200 lb (544 kg)
- Fuel capacity: 18
- Powerplant: 1 × LeBlond , 70 hp (52 kW)
- Maximum speed: 100 kn; 185 km/h (115 mph)
- Service ceiling: 9,000 ft (2,700 m)
- Rate of climb: 580 ft/min (2.9 m/s)
- Avrocar: Canada's flying saucer : the story of Avro Canada's secret projects.
- "Round aircraft designs". Retrieved 7 September 2011.
- Popular Aviation: 92. August 1935.
- "Low AR-planes". Retrieved 7 September 2011.
- Experimenter. December 1957.
- Bernard L Rice (March 1987). "Milt's Little Bird". Sport Aviation: 43.
- "KSBN airport". Retrieved 7 September 2011.