| 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).
 
See also
Aircraft of comparable role, configuration, and era
References
Citations
- 1 2 3 4 5 6 7 8 9 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). 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.
 
