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Model 33 Little Dipper
Role	Single-seat utility monoplane
National origin	United States
Manufacturer	Lockheed
Designer	John Thorp
First flight	August 1944
Number built	1
Developed into	Thorp T-211

The Lockheed Model 33 Little Dipper, also known as Air Trooper, was an American single-seat monoplane, designed by John Thorp and built by Lockheed at Burbank, California. Flown in 1944 and offered to the Army as a "flying motorcycle", it was evaluated as a potential entry for Lockheed into the civilian market, but the program was cancelled before the second prototype was completed.

Design and development

The design of the Model 33 originated with a private venture for a two-seat light aircraft by John Thorp, a Lockheed engineer.^[1] In April 1944, the company agreed to build the aircraft as the Lockheed Model 33.^[1] Due to wartime restrictions on materials,^[1] the company gained the interest of the United States Army in the aircraft as an "aerial flying motorcycle" to equip a "flying cavalry" under the name Air Trooper.^[2] The Army, willing to entertain the concept, authorized Lockheed to build two prototypes of the Model 33.^[1]

The Model 33 was of ordinary light-aircraft design, with a low-mounted cantilever monoplane wing and conventional empennage; powered by a 50 hp (37 kW) Franklin 2A4-49 engine, it was fitted with a fixed tricycle landing gear and proved to have STOL performance.^[1]

Operational history

The Model 33 prototype first flew in August 1944.^[1] The handling characteristics of the aircraft were considered satisfactory,^[3] but the Army had lost interest in the concept,^[1] despite the prototype demonstrating its performance by landing and taking off again in the courtyard of the Pentagon.^[4] Lockheed had intended to market the type as an inexpensive light aircraft on the civilian market as the Little Dipper; with the military interest having evaporated, the prototype and the partially completed second aircraft were scrapped in January 1947 for tax reasons.^[1]

Thorp, the aircraft's designer, would go on to develop the Thorp T-211 with lessons learned from the Little Dipper project.^[5]

Specifications

Data from Francillion 1982^[1]

General characteristics

Crew: One (pilot)
Length: 17 ft 6 in (5.33 m)
Wingspan: 25 ft 0 in (7.62 m)
Height: 7 ft 0 in (2.13 m)
Wing area: 104 sq ft (9.7 m²)
Empty weight: 425 lb (193 kg)
Gross weight: 725 lb (329 kg)
Powerplant: 1 × Franklin 2A4-49 two-cylinder air-cooled horizontally opposed piston engine, 50 hp (37 kW)

Performance

Maximum speed: 100 mph (161 km/h, 87 kn)
Cruise speed: 91 mph (146 km/h, 79 kn)
Range: 210 mi (340 km, 180 nmi)
Service ceiling: 16,000 ft (4,900 m)
Rate of climb: 900 ft/min (4.6 m/s)
Takeoff run: 100 feet (30 m); with clearance of 50-foot (15 m) obstacle, 400 feet (120 m).

References

Citations

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Francillon 1982, pp. 256-257.
^ Ingalls 1973, p. 108.
^ Badrocke and Gunston 1998, p.36.
^ "Designer John Thorp Dies". Flying. Vol. 119, no. 7. New York: Hatchette Magazines. July 1992. p. 26. Retrieved 16 December 2017.
^ "The Thorp Sky Skooter". Flying. Vol. 41, no. 2. Chicago: Ziff-Davis Publishing. August 1947. p. 44. Retrieved 16 December 2017.

Bibliography

Badrocke, Mike; Bill Gunston (1988). "Model 33 Little Dipper - Standard Issue?". Lockheed Aircraft Cutaways: The History of Lockheed-Martin. Oxford, England: Osprey Publishing. ISBN 978-1-8553-2775-7.
Francillon, René J. (1982). Lockheed Aircraft since 1913. London: Putnam & Company. ISBN 0-370-30329-6.
Ingells, Douglas J. (1973). L-1011 TriStar and The Lockheed Story. Fallbrook, CA: Aero Publishers. ISBN 978-0-8168-6650-2.