Arup S-2

https://en.wikipedia.org/wiki/Arup_S-2

The Arup S-2 was the first commercial development of Cloyd Snyder's Arup S-1 low
aspect ratio wing aircraft.

The Arup S-2 featured a straight leading edge wing with a trailing edge that
tapered to the rear of the aircraft giving it a guitar pick shape when viewed
from above. An M6 airfoil was chosen over its predecessor's sharp edged,
modified Clark-Y airfoil. The large trailing edge control surfaces were mixed
for pitch and roll control, but were assisted by small, movable, semi-circular
wingtips that could provide additional roll control. Conventional landing gear
was used, faired with wheel pants. The access to the cockpit was from a belly
mounted hatch. Visibility was enhanced with celluloid panels on the aircraft's
belly.

Role

National origin
United States

Manufacturer
Arup Manufacturing Corporation

Designer
Raoul Hoffman

First flight
April 1933

Number built
1

Developed from
Arup S-1

The prototype S-2 was test flown by Glen Doolittle. The STOL aircraft could fly
at up to 35 degrees angle of attack without stalling. The aircraft was
demonstrated across the country at events like the Indianapolis 500 and the 1933
National Air Races. Later it was demonstrated to the Army, NACA and CAA in
Washington. D.C. Raoul Hoffman left Arup after the development of the S-2 to
create his own design, the Hoffman Flying Wing. Engineer Charles H. Zimmerman
viewed the S-2 trials in Washington and later applied the principles to the
Vought XF5U program.

The S-2 was sold without an engine to a stuntman, F.F. Bowser Frakes, who
performed air crashes at fairs. A Szekely radial engine removed from an American
Eaglet was installed on the S-2, but did not perform well. A propeller was
acquired from Milt Hatfield, who sourced the landing gear for the first S-1.
Hatfield demonstrated how to fly the aircraft and it was eventually crashed in a
show.

Specifications (Arup S-2)

General characteristics
Length: 17 ft (5.2 m)
Wingspan: 19 ft (5.8 m)
Wing area: 211 sq ft (19.6 m2)
Airfoil: NACA M6
Empty weight: 780 lb (354 kg)
Powerplant: 1 × Continental A-40 , 36 hp (27 kW)

Performance
Maximum speed: 84 kn; 156 km/h (97 mph)
Stall speed: 20 kn; 37 km/h (23 mph)
Maximum glide ratio: 3 to 1




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