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24-514: The Navy's experience with the F2F revealed issues with stability and unfavorable spin characteristics, prompting the 15 October 1934 contract for the improved XF3F-1, placed before F2F deliveries began. The contract also required a capability for ground attack, in addition to the design's fighter role. Powered by the same Pratt & Whitney R-1535-72 Twin Wasp Junior engine as the F2F, the fuselage

48-510: A 27% lesser total displacement. The Wasp Junior used many parts from the Wasp and even had the same mounting dimensions, allowing an aircraft to easily use either the smaller or the larger engine. The first run of the Wasp Junior was in 1929, and sales began in 1930. The initial version, the Wasp Junior A , produced 300 hp (224 kW). The U.S. military designated the Wasp Junior as

72-704: The Boeing-Stearman Model 75 , which originally used other engines, have had them replaced with the Wasp Junior to provide more power or for easier maintenance, since parts for the Wasp Junior are readily available. Some museums which have Wasp Junior engines on display: Data from FAA type certificate data sheet for the Wasp Junior SB; dimensions from Pratt & Whitney (1956), p. A2. Related development Comparable engines Related lists The following Federal Aviation Administration type certificate data sheets, all available from

96-582: The Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of 985 in (16 L); initial versions produced 300 hp (220 kW), while the most widely used versions produce 450 hp (340 kW). Wasp Juniors have powered numerous smaller civil and military aircraft, including small transports, utility aircraft, trainers, agricultural aircraft, and helicopters. Over 39,000 engines were built, and many are still in service today. Pratt & Whitney developed

120-552: The R-985 , with various suffixes denoting different military engine models. However, Pratt & Whitney never adopted the R-985 designation scheme for its civilian Wasp Juniors, identifying them simply by name and model (e.g. "Wasp Junior A"). Pratt & Whitney followed the Wasp Junior A with more powerful models in the "A series". These had higher compression ratios , greater RPM limits, and more effective supercharging, and they led to

144-672: The Wasp Junior T1B2 , had improved performance at low level, being able to sustain 450 hp (340 kW) up to 1,500 ft (460 m) while still matching the SB's power at high altitudes. The SB and T1B2, and later versions of these with similar performance, were the most popular Wasp Junior models. One later development of the T1B2, the Wasp Junior B4 , was especially designed for vertical mounting in helicopters. During

168-625: The "B series". The first B series model was the Wasp Junior TB , which could maintain 420 hp (310 kW) at sea level and could reach 440 hp (330 kW) for takeoff. The TB was tuned for best performance at sea level; it was soon joined by the Wasp Junior SB , which was tuned for best performance at altitude and could sustain 400 hp (300 kW) at altitudes up to 5,000 ft (1,500 m), with 450 hp (340 kW) available for takeoff. A still later model,

192-446: The 10th dive, the aircraft's pullout at 8,000 ft (2,400 m) registered 14 g on the test equipment. The aircraft broke up in midair, crashing in a cemetery and killing Collins. A second, strengthened prototype was built, but it crashed on 9 May of the same year following the pilot's bailout during an unsuccessful spin recovery. The second prototype was rebuilt in three weeks, flying on 20 June 1935. An order for 54 F3F-1 fighters

216-830: The 1930s. It was selected for the Lockheed Model 10A Electra twin-engined airliner, as well as for other small twin-engined civil transports like the Lockheed Model 12A Electra Junior , the Beechcraft Model 18 , and the Grumman Goose amphibious aircraft . It was also used in single-engined civilian utility aircraft like the Beechcraft Staggerwing , the Howard DGA-15 , and the Spartan Executive . As World War II arrived,

240-618: The British Avro Anson and Airspeed Oxford twin-engined trainers. The demands of World War II led to the production of many thousands of Wasp Juniors. Until the end of the war, the Wasp Junior's closest competitor was Wright Aeronautical 's R-975 Whirlwind . However, during the war, the Wasp Junior was far more widely used in aircraft than the R-975, and Wright ceased production of the R-975 in 1945. After World War II, many military-surplus aircraft with Wasp Junior engines entered

264-709: The Grumman demonstrator G-32A, all which were restored by Herb Tischler's Texas Airplane Factory in Fort Worth. The restorations took four years and consisted of rebuilding the G-32A from original blueprints with tooling built at the Texas Airplane Factory. The wreckage of three -2 aircraft which had originally crashed in Hawaii were utilized to complete the other restorations. Data from Great Aircraft of

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288-537: The R-985 Wasp Junior as a smaller version of the R-1340 Wasp to compete in the market for medium-sized aircraft engines. Like its larger brother, the Wasp Junior was an air-cooled, nine-cylinder radial, with its power boosted by a gear-driven single-speed centrifugal type supercharger . Its cylinders were smaller, however, with a bore and stroke of 5 + 3 ⁄ 16  in (132 mm), giving

312-620: The U.S. military chose the Wasp Junior for the Vultee BT-13 Valiant and North American BT-14 basic training aircraft and for the Vought OS2U Kingfisher observation floatplane . Military versions of existing Wasp Junior-powered civilian aircraft were also produced, such as the military derivatives of the Beech 18, Beech Staggerwing, Grumman Goose, and Howard DGA-15. The Wasp Junior also powered some versions of

336-467: The World General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Pratt %26 Whitney R-1535 The Pratt & Whitney R-1535 Twin Wasp Junior is an American aircraft engine developed in the 1930s. The engine was introduced in 1932 as a 14-cylinder version of the 9-cylinder R-985 , and

360-676: The civilian market. New designs based on the Wasp Junior were also introduced, such as the Sikorsky H-5 helicopter, the de Havilland Canada DHC-2 Beaver , and Max Holste Broussard bush airplanes , and agricultural aircraft such as the Snow S-2B and S-2C , Grumman Ag Cat , and Weatherley 201 . Pratt & Whitney ceased production of the Wasp Junior in 1953, having built 39,037 engines. Many Wasp Junior engines are still in use today in older bush planes and agricultural planes, as well as in antique aircraft. Some antique aircraft, such as

384-632: The end of 1941, though 117 were assigned to naval bases (Mainly NAS Miami and NAS Corpus Christi) and used for training and utility duties until December 1943. The G-32 and G-32A two-place aircraft were used by the U.S. Army Air Force as ferry-pilot trainers, under the designation UC-103/UC-103A . A civilian aerobatic two-seat variant, the G-22A "Gulfhawk II," was constructed in 1936 and flown by Major Alford "Al" Williams , head of Gulf Oil 's aviation department. Data from: Aerofiles - Grumman Today, there are four flying aircraft, three F3F-2 models and

408-621: The fuselage skinning forward of the aft cabane strut in order to improve aerodynamics and reduce carbon monoxide intrusion. On 21 June 1938, the Navy ordered 27 F3F-3s, as new monoplane fighters like the Brewster F2A and Grumman's own F4F Wildcat were taking longer to develop than had been planned. With the introduction of the Brewster F2A-1, the Navy's biplane fighter days were numbered. All F3Fs were withdrawn from squadron service by

432-618: The high-revving engine to drive a propeller at suitable speeds, hence the "-G" suffix. Aviator Jacqueline Cochran flew a special Model D-17W Beechcraft Staggerwing with this engine in 1937, setting a speed and altitude record and placing third in the Bendix transcontinental race . However, the SC-G never got past the experimental stage. Early versions of the Wasp Junior were used in various small civilian and military utility aircraft, but only in limited numbers. The type became more popular later in

456-479: The mid-1930s, Pratt & Whitney developed a still greater improvement of the Wasp Junior, the "C series", with an even higher compression ratio and RPM limit. The only type produced in this series, the Wasp Junior SC-G , could sustain 525 hp (391 kW) at an altitude of 9,500 ft (2,900 m) and could produce 600 hp (450 kW) for takeoff. It also included reduction gearing to allow

480-530: The powerful new 950 hp (708 kW) Wright R-1820 supercharged radial engine, began work on the F3F-2 without a contract; the order for 81 aircraft was not placed until 25 July 1936, two days before the type's first flight. The engine's larger diameter changed the cowling's appearance, making the aircraft look even more like a barrel, though top speed increased to 255 mph (410 km/h) at 12,000 ft (3,700 m). The entire F3F-2 production series

504-423: Was a two-row, air-cooled radial design. Displacement was 1,535 cu in (25.2 L); bore and stroke were both 5 + 3 ⁄ 16  in (132 mm). Data from Related development Comparable engines Related lists Pratt %26 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

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528-516: Was delivered in between 1937 and 1938; when deliveries ended, all seven Navy and Marine Corps pursuit squadrons were equipped with Grumman single-seat fighters. Further aerodynamic improvements were made to an F3F-2 (BuNo 1031) based on wind tunnel studies in the NACA Langley 30' x 60' full-scale wind tunnel and became the XF3F-3 . It featured a larger-diameter propeller, and a complete revision of

552-399: Was lengthened and wing area increased over the earlier design. A reduction in wheel diameter allowed greater fuselage streamlining, eliminating the prominent bulge behind the cowling of the F2F. The prototype, BuNo. 9727, was delivered and first flown on 20 March 1935 with company test pilot Jimmy Collins making three flights that day. Two days later, six dive-recovery flights took place; on

576-521: Was placed on 24 August of that year, following the conclusion of the flight test program. The first production F3F-1 (BuNo 0211) was delivered on 29 January 1936 to the test group at Naval Air Station Anacostia , with squadron service beginning in March to VF-5B of Ranger and VF-6B of Saratoga . Marine squadron VF-4M received the last six in January 1937. Grumman, wanting to take advantage of

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