Ryan YO-51 Dragonfly

YO-51 Dragonfly
Role	Army observation and liaison
Manufacturer	Ryan Aeronautical
First flight	1940
Primary user	United States Army Air Corps
Number built	3

The Ryan YO-51 Dragonfly was an observation aircraft designed and built by Ryan Aeronautical for the United States Army Air Corps (USAAC). A single-engined parasol wing monoplane, it was designed for optimum STOL capability, but although three prototypes proved highly successful in testing, the Stinson YO-49 was judged superior and no production contract was placed.

Design

The design of the YO-51 Dragonfly was typical for aircraft of its type, being optimised for the observation and liaison role, with emphasis on the ability to operate out of the smallest possible airfields. ^[1] The Dragonfly was a high-wing braced parasol monoplane with fixed tailwheel landing gear, a two-seat open cockpit, and full-span slots and Fowler flaps for STOL capability. ^[2] It was powered by a single Pratt & Whitney R-985-21 Wasp Junior radial engine. ^[3]

At gross weight, the YO-51 could, without flaps, take off after a run of 400 feet, while with full flaps the takeoff run would be only 75 feet, or just four feet more than twice its own length. ^[4] The Dragonfly was capable of maintaining level flight at speeds as low as 30 miles per hour (48 km/h), ^[5] and was claimed as being capable of landing in a distance shorter than the length of the aircraft itself. ^[6]

Operational history

Nicknamed the "flying motorcycle", ^[7] three YO-51 aircraft were acquired by the United States Army Air Corps to take part in a fly-off evaluation against the Stinson YO-49 and Bellanca YO-50 to supply a new observation and liaison aircraft for use by the USAAC. ^[8] The YO-51 was the heaviest of the three aircraft evaluated. ^[9]

Although the Dragonfly was considered satisfactory during its flight testing, ^[10] conducted at Wright Field in Ohio, ^[11] the Stinson machine won the production contract, and no further YO-51s were built. ^[12]

Specifications

YO-51 on the ground

Data from Donald 1997 ^[3]

General characteristics

• Crew: two (pilot and observer)
• Length: 35 ft 6 in (10.82 m)
• Wingspan: 52 ft (16 m)
• Height: 11 ft 1 in (3.38 m)
• Gross weight: 4,206 lb (1,908 kg)
• Powerplant: 1 × Pratt & Whitney R-985-21 Wasp Junior radial, 440 hp (330 kW)

Performance

• Maximum speed: 129 mph (208 km/h, 112 kn)
• Cruise speed: 107 mph (172 km/h, 93 kn)
• Stall speed: 30 mph (48 km/h, 26 kn)

Armament

• None

See also

Aircraft of comparable role, configuration, and era

• Bellanca YO-50
• Fieseler Fi 156 Storch
• Henschel Hs 126
• Kokusai Ki-76
• Polikarpov Po-2
• Repülőgépgyár_Levente_II
• Stinson L-1 Vigilant

Related lists

• List of military aircraft of the United States

References

Notes

1. Penfield 1941, p.31.
2. Foottit, H. R. (February 1942). "The Fowler Flap". Flying and Popular Aviation . 30 (2). Chicago: Ziff-Davis Publishing Co.: 71.
3. Donald 1997, p.794.
4. Fowler 1948, p.79.
5. Rowe 2006, p.22.
6. Wilson, Gill Robb (July 1954). "Genealogy of American Aircraft". Flying . 55 (1). Chicago: Ziff-Davis Publishing Co.: 23.
7. "U. S. Army's "Flying Motorcycle"". The Boston Globe . Boston, MA. May 25, 1941. p. C1.
8. Pattillo 2001, p.137.
9. Adcock 2005, p.5.
10. "The Dragonfly---Army's Newest Observation Plane". The Milwaukee Sentinel . Milwaukee, WI. February 23, 1940. p. 2.
11. "Army Tests New B-17C". The New York Times . New York. November 17, 1940. Retrieved 2012-08-11.
12. Merriam 2002, p.26.

Bibliography

• Adcock, Al (2005). US Liaison Aircraft in action. Aircraft in Action. Vol. 195. Carrollton, TX: Squadron/Signal Publications. ISBN   978-0897474870.
• Donald, David (1997). Complete Encyclopedia of World Aircraft. London: Orbis Publishing Ltd. ISBN   0760705925.
• Fowler, Harlan Davey (1948). Fowler Flaps for Airplanes: An engineering handbook. Los Angeles: Wetzel Publishing Co. ASIN   B0007EA17Q.
• Merriam, Ray, ed. (2002). World War II Journal #15: U.S. Military Aircraft of World War II. Bennington, VT: Merriam Press. ISBN   1576381676.
• Pattillo, Donald M. (2001). Pushing the Envelope: The American Aircraft Industry. Ann Arbor, MI: University of Michigan Press. ISBN   978-0472086719.
• Penfield, Thomas (1941). Wings for America: Fighting Planes of the U. S. A. Chicago: Rand McNally & Co. ASIN   B004BVUSC4.
• Rowe, Frank Joseph (2006). The Helio Courier Ultra C/stol Aircraft: An Illustrated Developmental History. Jefferson, NC: McFarland & Company. ISBN   978-0786422890.

External links

• O-51 Dragonfly at Dave's Warbirds