Curtiss O-40 Raven

O-40 Raven
Role	Observation aircraft
National origin	United States of America
Manufacturer	Curtiss-Wright
First flight	1932
Introduction	1933
Retired	1939
Primary user	United States Army Air Corps
Number built	5

The Curtiss O-40 Raven was an American observation aircraft of the 1930s which was built and used in small numbers. A single example of the YO-40, a single-engined Sesquiplane with a retractable undercarriage was built, followed by four examples of a modified monoplane version, the O-40B, which remained in use until 1939.

Development and design

In 1931, in response to a United States Army Air Corps requirement for a new observation aircraft, Curtiss designed the Model 62, a single-engined biplane with the lower wing much smaller than the upper, known as a sesquiplane (i.e. "one-and-a-half wings"), while the outer panels of the upper wings were swept back to avoid centre-of-gravity problems. It was of all-metal construction, with a monocoque fuselage and had a retractable tailwheel undercarriage with inwards retracting mainwheels, and was powered by a Wright Cyclone radial engine. The crew of two sat in tandem in open cockpits.^[1][2][3]

A prototype, designated YO-40, flew in February 1932. Although it crashed in May that year, it was re-built with stronger wings and an enclosed cockpit as the YO-40A. A further four YO-40As were ordered, but they were redesigned as monoplanes by removing the lower wing, the resultant aircraft being designated Y1O-40B.^[2][4]

Operational history

The four Y1O-40Bs were delivered in June 1933, and after service tests, were redesignated O-40B,^[5] being operated by the 1st Observation Squadron of the USAAC.^[6] While the aircraft's performance and manoeuvrability were good, the Air Corps were disappointed with the cockpit arrangements and the low fuel capacity,^[2] and no more orders followed. The last O-40B was withdrawn from use in 1939.^[5]

Variants

YO-40

Prototype powered by 653 hp (487 kW) Wright R-1820E Cyclone engine.^[7]

YO-40A

YO-40 rebuilt with stronger wings and enclosed cockpit. Scrapped 1938.^[2][5]

Y1O-40B

Monoplane derivative with lower wing removed. Powered by 670 hp (500 kW) R-1820-27. Four built.^[5]

O-40B

Redesignation of Y1O-40B.^[5]

Operators

 United States

• United States Army Air Corps
  • 1st Observation Squadron

Specifications (O-40B)

Data from Curtiss Aircraft 1907–1947^[5]

General characteristics

• Crew: 2
• Length: 28 ft 10 in (8.79 m)
• Wingspan: 41 ft 8 in (12.70 m)
• Height: 10 ft 8 in (3.25 m)
• Wing area: 266 sq ft (24.7 m²)
• Empty weight: 3,754 lb (1,703 kg)
• Gross weight: 5,180 lb (2,350 kg)
• Powerplant: 1 × Wright R-1820-27 Cyclone 9-cylinder air-cooled radial engine, 670 hp (500 kW)

Performance

• Maximum speed: 187.7 mph (302.1 km/h; 163.1 kn)
• Cruise speed: 160.5 mph (139.5 kn; 258.3 km/h)
• Stall speed: 62 mph (54 kn; 100 km/h)
• Range: 324 mi (282 nmi; 521 km)
• Service ceiling: 23,100 ft (7,041 m)
• Rate of climb: 1,660 ft/min (8.4 m/s)

Armament

• Guns: 1× fixed forward firing .30 in machine gun and 1× .30 in machine gun in observers cockpit

Notes

1. ^ Bowers 1979, pp. 331–332.
2. ^ ^{a b c d} "Curtiss:K through Z". aerofiles. 24 January 2009. Retrieved 10 March 2010.
3. ^ Flight 4 January 1934, p.20.
4. ^ Bowers 1979, pp. 332–333.
5. ^ ^{a b c d e f} Bowers 1979, p.333.
6. ^ "Factsheets : 1 Reconnaissance Squadron (ACC)". Air Force Historical Research Agency, United States Air Force. Retrieved 10 March 2010.
7. ^ Bowers 1979, p.332.

References

• Bowers, Peter M. Curtiss Aircraft 1907-1947. London:Putnam, 1979. ISBN 0-370-10029-8.
• "A Modern American Observation Aircraft:The Curtiss "Raven" (Wright "Cyclone F") developed for the U.S. Army Air Corps". Flight, 4 January 1934, p. 20.

External links

• Photo