Pratt & Whitney R-1340 Wasp

Last updated
R-1340 Wasp
Pratt and Whitney Wasp.jpg
The first Pratt & Whitney Wasp
Type Radial engine
National originUnited States
Manufacturer Pratt & Whitney
First run29 December 1925
Major applications Boeing 247
Boeing P-26 Peashooter
de Havilland Canada DHC-3 Otter
North American T-6 Texan
Sikorsky H-19
Sikorsky S-38
Number built34,966
Developed into Pratt & Whitney R-985 Wasp Junior

The Pratt & Whitney R-1340 Wasp is an aircraft engine of the reciprocating type that was widely used in American aircraft from the 1920s onward. It was the Pratt & Whitney aircraft company's first engine, and the first of the famed Wasp series. It was a single-row, nine-cylinder, air-cooled, radial design, and displaced 1,344 cubic inches (22 L); bore and stroke were both 5.75 in (146 mm). A total of 34,966 engines were produced. [1]


As well as numerous types of fixed-wing aircraft, it was used to power helicopters, the Agusta-Bell AB.102 and the Sikorsky H-19, and a class of airship, the K-class blimp.

In 2016, it received designation as a Historic Engineering Landmark from the American Society of Mechanical Engineers. [2]


Note:R for Radial and 1340 for 1340 cubic inch displacement.

450 hp (340 kW), 600 hp (450 kW)
425 hp (317 kW)
450 hp (340 kW), 525 hp (391 kW)
550 hp (410 kW)
525 hp (391 kW)
600 hp (450 kW)
600 hp (450 kW)
550 hp (410 kW)
550 hp (410 kW)
575 hp (429 kW)
550 hp (410 kW)
550 hp (410 kW)
600 hp (450 kW)
600 hp (450 kW)
600 hp (450 kW)
550 hp (410 kW), 600 hp (450 kW)
550 hp (410 kW), 3:2 geared prop shaft
450 hp (340 kW)
500 hp (370 kW)
525 hp (391 kW)
550 hp (410 kW), 600 hp (450 kW)
600 hp (450 kW)
520 hp (390 kW)


R-1340 powered Curtiss SOC Seagull Curtiss SOC-1.jpg
R-1340 powered Curtiss SOC Seagull

Engines on display

Specifications (R-1340-S1H1-G)

Pratt & Whitney R-1340 installed in a T-6 Texan Pratt & Whitney R-1340.jpg
Pratt & Whitney R-1340 installed in a T-6 Texan

Data fromJane's. [8]

General characteristics



See also

Related development

Related lists

Related Research Articles

Lockheed Model 9 Orion

The Lockheed Model 9 Orion is a single-engined passenger aircraft built in 1931 for commercial airlines. It was the first airliner to have retractable landing gear and was faster than any military aircraft of that time. Designed by Richard A. von Hake, it was the last wooden monoplane design produced by the Lockheed Aircraft Corporation.

Wright R-3350 Duplex-Cyclone

The Wright R-3350 Duplex-Cyclone is a twin-row, supercharged, air-cooled, radial aircraft engine with 18 cylinders displacing nearly 55 L. Power ranged from 2,200 to over 3,700 hp, depending on the model. Developed before World War II, the R-3350's design required a long time to mature before finally being used to power the Boeing B-29 Superfortress. After the war, the engine had matured sufficiently to become a major civilian airliner design, notably in its turbo-compound forms, and was used in the Lockheed L-1049 Super Constellation airliners into the 1990s. The engine is now commonly used on Hawker Sea Fury and Grumman F8F Bearcat Unlimited Class Racers at the Reno Air Races. Its main rival was the Pratt & Whitney R-4360 Wasp Major, first run some seven years after the Duplex-Cyclone's beginnings.

Pratt & Whitney R-4360 Wasp Major R-28 piston aircraft engine family

The Pratt & Whitney R-4360 Wasp Major is an American 28-cylinder four-row radial piston aircraft engine designed and built during World War II, and the largest-displacement aviation piston engine to be mass-produced in the United States. It was the last of the Pratt & Whitney Wasp family, and the culmination of its maker's piston engine technology, but the war was over before it could power airplanes into combat. It did, however, power many of the last generation of large piston-engined aircraft before turbojets, and equivalent horsepower turboprops, supplanted it. Its main rival was the twin-row, 18-cylinder, nearly 55-litre displacement Wright R-3350 Duplex-Cyclone, first run some seven years earlier.

Pratt & Whitney R-2800 Double Wasp

The Pratt & Whitney R-2800 Double Wasp is an American twin-row, 18-cylinder, air-cooled radial aircraft engine with a displacement of 2,800 cubic inches (46 L), and is part of the long-lived Wasp family of engines.

Pratt & Whitney R-1830 Twin Wasp

The Pratt & Whitney R-1830 Twin Wasp is an American aircraft engine widely used in the 1930s and 1940s. Produced by Pratt & Whitney, it is a two-row, 14-cylinder, air-cooled radial design with seven cylinders on a row. It displaces 1,830 cu in (30.0 L) and its bore and stroke are both 5.5 in (140 mm). A total of 173,618 R-1830 engines were built, and from their use in two of the most-produced aircraft ever built, the four-engined B-24 heavy bomber and twin-engined DC-3 transport, more Twin Wasps may have been built than any other aviation piston engine in history. A "bored-out" version with a slightly higher power rating and other slight changes in detail design was produced as the R-2000. Mostly retired today, it is still used on Douglas DC-3 and various museum aircraft and warbirds seen at airshows. It is not manufactured anymore, but spares are still available and there exists a wide market for second-hand engines and parts.

Pratt & Whitney R-1535 Twin Wasp Junior

The Pratt & Whitney R-1535 Twin Wasp Junior was an engine used in American aircraft in the 1930s. The engine was introduced in 1932 as a 14-cylinder version of the 9-cylinder R-985. It was a two-row, air-cooled radial design. Displacement was 1,535 in³ (25.2 L); bore and stroke were both 5-3/16 in (131.8 mm).

Pratt & Whitney R-985 Wasp Junior

The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder, air-cooled, radial aircraft engines built by the Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of 985 in3 (16 L); initial versions produced 300 hp (220 kW), while the most widely used versions produce 450 hp (340 kW).

Pratt & Whitney R-1690 Hornet

The Pratt & Whitney R-1690 Hornet was a widely used American aircraft engine. Developed by Pratt & Whitney, 2,944 were produced from 1926 through 1942. It first flew in 1927. It was a single-row, 9-cylinder air-cooled radial design. Displacement was 1,690 cubic inches. It was built under license in Italy as the Fiat A.59. In Germany, the BMW 132 was a developed version of this engine. The R-1860 Hornet B was an enlarged version produced from 1929.

Douglas Dolphin

The Douglas Dolphin was an American amphibious flying boat. While only 58 were built, they served a wide variety of roles including private air yacht, airliner, military transport, and search and rescue.

The P-1 Hawk was a 1920s open-cockpit biplane fighter aircraft of the United States Army Air Corps. An earlier variant of the same aircraft had been designated PW-8 prior to 1925.

Consolidated P-30 American two-seat fighter

The Consolidated P-30 (PB-2) was a 1930s United States two-seat fighter aircraft. An attack version called the A-11 was also built, along with two Y1P-25 prototypes and YP-27, Y1P-28, and XP-33 proposals. The P-30 is significant for being the first fighter in United States Army Air Corps service to have retractable landing gear, an enclosed and heated cockpit for the pilot, and an exhaust-driven turbo-supercharger for altitude operation.

Lockheed Altair

The Lockheed Altair was a single-engined sport aircraft of the 1930s. It was a development of the Lockheed Sirius with a retractable undercarriage, and was the first Lockheed aircraft and one of the first aircraft designs with a fully retractable undercarriage.

Vought O2U Corsair

The Vought O2U Corsair was a 1920s biplane scout and observation aircraft. Made by Vought Corporation, the O2U was ordered by the United States Navy (USN) in 1927. Powered by a 400 hp (298 kW) Pratt & Whitney R-1340 Wasp engine, it incorporated a steel-tube fuselage structure and a wood wing structure with fabric covering. Many were seaplanes or amphibians.

Boeing P-29 Fighter aircraft prototype series by Boeing

The Boeing P-29 and XF7B-1 were an attempt to produce a more advanced version of the highly successful P-26. Although slight gains were made in performance, the U.S. Army Air Corps and U.S. Navy did not order the aircraft.

Wright R-975 Whirlwind

The Wright R-975 Whirlwind was a series of nine-cylinder air-cooled radial aircraft engines built by the Wright Aeronautical division of Curtiss-Wright. These engines had a displacement of about 975 cu in (15.98 L) and power ratings of 300–450 hp (220–340 kW). They were the largest members of the Wright Whirlwind engine family to be produced commercially, and they were also the most numerous.

Thomas-Morse O-19

The Thomas-Morse O-19 was an American observation biplane built by the Thomas-Morse Aircraft Company for the United States Army Air Corps.

Fiat G.49

The Fiat G.49 was an Italian two-seat basic trainer designed by Giuseppe Gabrielli and built by Fiat.

Lockheed XC-35

The Lockheed XC-35 is a twin-engine, experimental pressurized airplane. It was the second American aircraft to feature cabin pressurization. It was initially described as a 'supercharged cabin' by the Army. The distinction of the world's first pressurized aircraft goes to a heavily modified Engineering Division USD-9A which flew in the United States in 1921. The XC-35 was a development of the Lockheed Model 10 Electra that was designed to meet a 1935 request by the United States Army Air Corps for an aircraft with a pressurized cabin.

Wright Whirlwind series

The Wright Whirlwind was a family of air-cooled radial aircraft engines built by Wright Aeronautical. The family began with nine-cylinder engines, and later expanded to include five-cylinder and seven-cylinder varieties. Fourteen-cylinder twin-row versions were also developed, but these were not commercially produced.

The C-8 Eightster was a single-engine airliner developed by Granville Brothers Aircraft that did not go into production.



  1. Pratt&Whitney R-1340 page Retrieved: 25 October 2008
  2. "Pratt’s first engine gets historic designation" from Hartford Business Journal, published February 1st Retrieved: 7 April 2016
  3. "Knoll KN-3". Western Flying. August 1929.
  4. "Pratt & whitney R-1340 Wasp A"
  5. "Pratt & Whitney R-1340 Wasp C Cutaway"
  6. "Pratt & Whitney R-1340-0 Wasp C"
  7. "Pratt & Whitney Roscoe Turner R-1340 Wasp Engine"
  8. Bridgman 1994, p. 81d.