Pratt & Whitney R-985
Encyclopedia
The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder air-cooled radial
aircraft engine
s built by the Pratt & Whitney
Aircraft Company from the 1930s to the 1950s. These engines have a displacement
of 985 cu in (16.2 l); initial versions produced 300 hp, while the most widely used versions produce 450 hp. Wasp Juniors have powered numerous smaller civil and military aircraft, including small transports, utility aircraft, trainers, agricultural aircraft, and helicopters. Over 39,000 of these engines were built, and many are still in service today.
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
supercharger
. Its cylinders were smaller, however, with a bore and stroke of 5+3/16 in, giving a 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.
The U.S. military designated the Wasp Junior as the R-985, with various suffixes denoting different military engine models. However, Pratt & Whitney never adopted the R-985 designation scheme for its civil 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 ratio
s, greater RPM limits, and more effective supercharging, and they led to the "B series". The first B series model was the Wasp Junior TB, which could maintain 420 hp at sea level and could reach 440 hp 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 at altitudes up to 5000 ft (1,524 m), with 450 hp available for takeoff. A still later model, the Wasp Junior T1B2, had improved performance at low level, being able to sustain 450 hp up to 1500 ft (457.2 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 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 at altitudes as high as 9500 ft (2,895.6 m) and could produce 600 hp for takeoff. It also included reduction gearing to allow the high-revving engine to drive a propeller at suitable speeds, hence the "-G" suffix. Aviator Jacqueline Cochran
flew a special Model D17W 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.
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
amphibian
. It was also used in single-engined civil utility aircraft like the Beechcraft Staggerwing
, the Howard DGA-15
, and the Spartan Executive
.
As World War II
arrived, 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 civil 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 the British Avro Anson
and Airspeed Oxford
twin-engine trainers. The demands of World War II led to the production of many thousands of Wasp Juniors.
Up 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 the civil market. Production of the Beech 18 with the Wasp Junior engine continued until 1970. New designs based on the Wasp Junior were also introduced, such as the Sikorsky H-5
helicopter, the de Havilland Beaver
and Max Holste Broussard
bush airplanes, and agricultural aircraft
like 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 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.
Wasp Junior TB, TB2
Wasp Junior SB, SB2, SB3
Wasp Junior T1B2, T1B3
Wasp Junior B4
Wasp Junior SC-G
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
aircraft engine
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...
s built by the Pratt & Whitney
Pratt & Whitney
Pratt & Whitney is a U.S.-based aerospace manufacturer with global service operations. It is a subsidiary of United Technologies Corporation . Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut, USA...
Aircraft Company from the 1930s to the 1950s. These engines have a displacement
Engine displacement
Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...
of 985 cu in (16.2 l); initial versions produced 300 hp, while the most widely used versions produce 450 hp. Wasp Juniors have powered numerous smaller civil and military aircraft, including small transports, utility aircraft, trainers, agricultural aircraft, and helicopters. Over 39,000 of these engines were built, and many are still in service today.
Design and development
Pratt & Whitney developed the R-985 Wasp Junior as a smaller version of the R-1340 WaspPratt & Whitney R-1340
|-See also:* Pratt & Whitney Wasp series* Pratt & Whitney R-985 Wasp Junior* Pratt & Whitney R-1535 Twin Wasp Junior* Pratt & Whitney R-1830 Twin Wasp-Bibliography:...
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
Centrifugal type supercharger
The centrifugal-type supercharger is an engine-driven compressor used to increase the power output of an internal-combustion engine by increasing the amount of available oxygen by compressing air that is entering the engine...
supercharger
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
. Its cylinders were smaller, however, with a bore and stroke of 5+3/16 in, giving a 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.
The U.S. military designated the Wasp Junior as the R-985, with various suffixes denoting different military engine models. However, Pratt & Whitney never adopted the R-985 designation scheme for its civil 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 ratio
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
s, greater RPM limits, and more effective supercharging, and they led to the "B series". The first B series model was the Wasp Junior TB, which could maintain 420 hp at sea level and could reach 440 hp 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 at altitudes up to 5000 ft (1,524 m), with 450 hp available for takeoff. A still later model, the Wasp Junior T1B2, had improved performance at low level, being able to sustain 450 hp up to 1500 ft (457.2 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 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 at altitudes as high as 9500 ft (2,895.6 m) and could produce 600 hp for takeoff. It also included reduction gearing to allow the high-revving engine to drive a propeller at suitable speeds, hence the "-G" suffix. Aviator Jacqueline Cochran
Jacqueline Cochran
Jacqueline Cochran was a pioneer American aviator, considered to be one of the most gifted racing pilots of her generation...
flew a special Model D17W Beechcraft Staggerwing
Beechcraft Staggerwing
The Beechcraft Model 17 Staggerwing is an American biplane with an atypical negative stagger , that first flew in 1932.-Development:...
with this engine in 1937, setting a speed and altitude record and placing third in the Bendix transcontinental race
Bendix trophy
The Bendix Trophy is a U.S. aeronautical racing trophy. The transcontinental, point-to-point race, sponsored by industrialist Vincent Bendix founder of Bendix Corporation, began in 1931 as part of the National Air Races. Initial prize money for the winners was $15,000...
. However, the SC-G never got past the experimental stage.
Operational history
Early versions of the Wasp Junior were used in various small civil and military utility aircraft, but only in limited numbers. The type became more popular later in the 1930s. It was selected for the Lockheed Model 10A ElectraLockheed Model 10 Electra
The Lockheed Model 10 Electra was a twin-engine, all-metal monoplane airliner developed by the Lockheed Aircraft Corporation in the 1930s to compete with the Boeing 247 and Douglas DC-2...
twin-engined airliner, as well as for other small twin-engined civil transports like the Lockheed Model 12A Electra Junior
Lockheed Model 12 Electra Junior
The Lockheed Model 12 Electra Junior, more commonly known as the Lockheed 12 or L-12, is an eight-seat, six-passenger all-metal twin-engine transport aircraft of the late 1930s designed for use by small airlines, companies, and wealthy private individuals...
, the Beechcraft Model 18
Beechcraft Model 18
The Beechcraft Model 18, or "Twin Beech", as it is better known, is a 6-11 seat, twin-engine, low-wing, conventional-gear aircraft that was manufactured by the Beech Aircraft Corporation of Wichita, Kansas...
, and the Grumman Goose
Grumman Goose
The Grumman G-21 Goose amphibious aircraft was designed as an eight-seat "commuter" plane for businessmen in the Long Island area. The Goose was Grumman’s first monoplane to fly, its first twin-engined aircraft, and its first aircraft to enter commercial airline service...
amphibian
Amphibious aircraft
An amphibious aircraft or amphibian is an aircraft that can take off and land on either land or water. Fixed-wing amphibious aircraft are seaplanes that are equipped with retractable wheels, at the expense of extra weight and complexity, plus diminished range and fuel economy compared to planes...
. It was also used in single-engined civil utility aircraft like the Beechcraft Staggerwing
Beechcraft Staggerwing
The Beechcraft Model 17 Staggerwing is an American biplane with an atypical negative stagger , that first flew in 1932.-Development:...
, the Howard DGA-15
Howard DGA-15
|-See also:-References:*Bushell, Sue J. "Some Damn Good Airplanes". Air Enthusiast, Thirty-two, December 1986-April 1987. Bromley, UK:Pilot Press. pp. 32–44.-External links:* * * *...
, and the Spartan Executive
Spartan Executive
|-Military Operators:* Royal Canadian Air Force3 Examples based in Montreal, formerly Royal Air Force examples used in California.*Chinese Nationalist Air ForceThe second prototype was exported to China and serialed 1309...
.
As World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
arrived, the U.S. military chose the Wasp Junior for the Vultee BT-13 Valiant
BT-13 Valiant
The Vultee BT-13 Valiant was an American World War II-era basic trainer aircraft built by Vultee Aircraft for the United States Army Air Corps, and later US Army Air Forces...
and North American BT-14 basic training aircraft and for the Vought OS2U Kingfisher
OS2U Kingfisher
The Vought OS2U Kingfisher was an American catapult-launched observation floatplane. It was a compact mid-wing monoplane, with a large central float and small stabilizing floats. Performance was modest, because of its light engine...
observation floatplane
Floatplane
A floatplane is a type of seaplane, with slender pontoons mounted under the fuselage; only the floats of a floatplane normally come into contact with water, with the fuselage remaining above water...
. Military versions of existing Wasp-Junior-powered civil 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 the British Avro Anson
Avro Anson
The Avro Anson is a British twin-engine, multi-role aircraft that served with the Royal Air Force, Fleet Air Arm and numerous other air forces prior to, during, and after the Second World War. Named for British Admiral George Anson, it was originally designed for maritime reconnaissance, but was...
and Airspeed Oxford
Airspeed Oxford
The Airspeed AS.10 Oxford was a twin-engine aircraft used for training British Commonwealth aircrews in navigation, radio-operating, bombing and gunnery during the Second World War.-Design and development:...
twin-engine trainers. The demands of World War II led to the production of many thousands of Wasp Juniors.
Up until the end of the war, the Wasp Junior's closest competitor was Wright Aeronautical
Wright Aeronautical
Wright Aeronautical was an aircraft and aircraft engine manufacturer located in New Jersey.-History:This American company evolved from the 1909-1916 Wright Company, which merged with the Glenn L. Martin Company in 1916 to form the Wright-Martin Aircraft Corporation. Glenn Martin resigned from...
'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 the civil market. Production of the Beech 18 with the Wasp Junior engine continued until 1970. New designs based on the Wasp Junior were also introduced, such as the Sikorsky H-5
Sikorsky H-5
The Sikorsky H-5, is a helicopter built by Sikorsky Aircraft Corporation, formerly used by the United States Air Force, and its predecessor, the United States Army Air Forces, as well as the United States Navy and United States Coast Guard The Sikorsky H-5, (aka R-5, S-51, HO3S-1, or Horse) (R-5...
helicopter, the de Havilland Beaver
De Havilland Canada DHC-2 Beaver
The de Havilland Canada DHC-2 Beaver is a single-engined, high-wing, propeller-driven, STOL aircraft developed by de Havilland Canada, primarily known as a bush plane. It is used for cargo and passenger hauling, aerial application , and has been widely adopted by armed forces as a utility aircraft...
and Max Holste Broussard
Max Holste Broussard
|- See also :...
bush airplanes, and agricultural aircraft
Agricultural aircraft
An agricultural aircraft is an aircraft that has been built or converted for agricultural use - usually aerial application of pesticides or fertilizer ; in these roles they are referred to as "crop dusters" or "top dressers"...
like the Snow S-2B and S-2C
Ayres Thrush
-See also:-Bibliography:* Green, William. Aircraft Handbook. London. Macdonald & Co. Ltd., 1964.* Simpson, Rod. The General Aviation Handbook. Midland Publishing. 2005. ISBN 1-85780-222-5....
, Grumman Ag Cat
Grumman Ag Cat
-See also:-References:* Michell, Simon. Jane's Civil and Military Aircraft Upgrades 1994-95. Coulsdon, UK:Jane's Information Group, 1994. ISBN 0 7106 1208 7.-External links:*...
, and Weatherley 201
Weatherley 201
-External links:*...
.
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 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.
Variants
Wasp Junior A- U.S. military version: R-985-1.
- 300 hp at 2,000 RPM at sea level and for takeoff. First production version.
Wasp Junior TB, TB2
- U.S. military versions: R-985-9, -11, -11A, -21, -46.
- 420 hp at 2,200 RPM at sea level, 440 hp at 2,300 RPM for takeoff. Early B-series versions rated for sea-level performance.
Wasp Junior SB, SB2, SB3
- U.S. military versions: R-985-13, -17, -23, -33, -48, -50; R-985-AN-2, -4, -6, -6B, -8, -10, -12, -12B, -14B.
- 400 hp at 2,200 RPM up to 5000 ft (1,524 m), 450 hp at 2,300 RPM for takeoff. Common B-series versions rated for performance at altitude.
Wasp Junior T1B2, T1B3
- U.S. military versions: R-985-25, -27, -39, -39A; R-985-AN-1, -1A, -3, -3A.
- 450 hp at 2,300 RPM up to 1500 ft (457.2 m) and for takeoff. Common B-series versions with improved sea-level performance.
Wasp Junior B4
- U.S. military versions: R-985-AN-5, -7.
- 450 hp at 2,300 RPM up to 2300 ft (701 m) and for takeoff. Vertically mounted development of T1B3, for helicopters.
Wasp Junior SC-G
- 525 hp at 2,700 RPM up to 9500 ft (2,895.6 m), 600 hp at 2,850 RPM for takeoff. Experimental high-powered version with propeller reduction gearing.
Applications
- Airspeed OxfordAirspeed OxfordThe Airspeed AS.10 Oxford was a twin-engine aircraft used for training British Commonwealth aircrews in navigation, radio-operating, bombing and gunnery during the Second World War.-Design and development:...
(AS.46 Oxford V) - Air Tractor AT-300Air Tractor AT-300|-See also:-External links:*...
- Avro AnsonAvro AnsonThe Avro Anson is a British twin-engine, multi-role aircraft that served with the Royal Air Force, Fleet Air Arm and numerous other air forces prior to, during, and after the Second World War. Named for British Admiral George Anson, it was originally designed for maritime reconnaissance, but was...
(Mk V) - Barkley-Grow T8P-1Barkley-Grow T8P-1|-References:NotesBibliography* Gerritmas, Joop and Hazewinkel Harm. "The Barkley-Grow T8P-1." AAHS Journal 50 , 2005.* Taylor, J.H. Jane's Encyclopedia of Aviation. London: Studio Editions, 1989, p. 121. ISBN 0-51710-316-8....
- Beechcraft Model 18Beechcraft Model 18The Beechcraft Model 18, or "Twin Beech", as it is better known, is a 6-11 seat, twin-engine, low-wing, conventional-gear aircraft that was manufactured by the Beech Aircraft Corporation of Wichita, Kansas...
and military derivatives - Beechcraft StaggerwingBeechcraft StaggerwingThe Beechcraft Model 17 Staggerwing is an American biplane with an atypical negative stagger , that first flew in 1932.-Development:...
D17S, D17W, G17S - Bell XV-3Bell XV-3|-See also:- References :NotesBibliography*Markman, Steve, and William G. Holder. Straight Up: A History of Vertical Flight. Schiffer military/aviation history. Atglen, PA: Schiffer Pub, 2000....
- Bellanca 300-WBellanca CH-300-References:NotesCitationsBibliography* Szurovy, Geza. Bushplanes. St. Paul, Minnesota: Zenith Press, 2004. ISBN 0-7603-1478-0.* Taylor, Michael J.H. Jane's Encyclopedia of Aviation. London: Studio Editions, 1989, p. 149.-External links:* *...
- Berliner-Joyce OJBerliner-Joyce OJ|-See also:-References:...
- Boeing-Stearman Model 75 (in aftermarket conversions)
- Bratukhin G-3BratukhinBratukhin, or OKB-3, was a Soviet aircraft design bureau created in 1940 from within TsAGI to develop helicopters. Headed by Ivan Pavlovich Bratukhin, the bureau built several experimental helicopters over the next decade. Each model had the same basic design of two rotors with separate engines...
- CAC WinjeelCAC Winjeel|-See also:-External links:* http://www.warbirdalley.com/winjeel.htm* http://www.dropbears.com/f/felix_noble/winjeel.htm* http://www.raafmuseum.com.au/raaf2/html/body_winjeel.htm...
- de Havilland Canada DHC-2 BeaverDe Havilland Canada DHC-2 BeaverThe de Havilland Canada DHC-2 Beaver is a single-engined, high-wing, propeller-driven, STOL aircraft developed by de Havilland Canada, primarily known as a bush plane. It is used for cargo and passenger hauling, aerial application , and has been widely adopted by armed forces as a utility aircraft...
and L-20/U-6 military versions - Douglas C-26 Dolphin
- Fleetwings BT-12Fleetwings BT-12|-See also:-References:* John Andrade, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, ISBN 0-904597-22-9 * The Illustrated Encyclopedia of Aircraft , 1985, Orbis Publishing...
- Grumman G-164 Ag CatGrumman Ag Cat-See also:-References:* Michell, Simon. Jane's Civil and Military Aircraft Upgrades 1994-95. Coulsdon, UK:Jane's Information Group, 1994. ISBN 0 7106 1208 7.-External links:*...
(some models) - Grumman G-21 GooseGrumman GooseThe Grumman G-21 Goose amphibious aircraft was designed as an eight-seat "commuter" plane for businessmen in the Long Island area. The Goose was Grumman’s first monoplane to fly, its first twin-engined aircraft, and its first aircraft to enter commercial airline service...
- Howard DGA-11Howard DGA-11|-See also:-Notes and references:*...
- Howard DGA-15PHoward DGA-15|-See also:-References:*Bushell, Sue J. "Some Damn Good Airplanes". Air Enthusiast, Thirty-two, December 1986-April 1987. Bromley, UK:Pilot Press. pp. 32–44.-External links:* * * *...
- Koolhoven F.K.51 (some models)
- Lockheed Model 10-A ElectraLockheed Model 10 ElectraThe Lockheed Model 10 Electra was a twin-engine, all-metal monoplane airliner developed by the Lockheed Aircraft Corporation in the 1930s to compete with the Boeing 247 and Douglas DC-2...
- Lockheed Model 12-A Electra JuniorLockheed Model 12 Electra JuniorThe Lockheed Model 12 Electra Junior, more commonly known as the Lockheed 12 or L-12, is an eight-seat, six-passenger all-metal twin-engine transport aircraft of the late 1930s designed for use by small airlines, companies, and wealthy private individuals...
- Max Holste MH.1521 BroussardMax Holste Broussard|- See also :...
- McDonnell XHJH Whirlaway
- North American BT-14North American BT-9|-See also:-References:NotesBibliography* Davis, Larry. T-6 Texan in Action . Carrollton, Texas: Squadron/Signal Publications, Inc., 1989. ISBN 0-89747-224-1....
- PWS-24PWS-24- See also :-References:*Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939" , WKiŁ, Warsaw 1977 -External links:*...
bis - Seversky BT-8Seversky SEV-3|-See also:-References:NotesBibliography* Green, William and Gordon Swanborough. "The end of the beginning...The Seversky P-35". Air Enthusiast, Ten, July–September 1979, pp. 8–21....
- Sikorsky H-5Sikorsky H-5The Sikorsky H-5, is a helicopter built by Sikorsky Aircraft Corporation, formerly used by the United States Air Force, and its predecessor, the United States Army Air Forces, as well as the United States Navy and United States Coast Guard The Sikorsky H-5, (aka R-5, S-51, HO3S-1, or Horse) (R-5...
helicopter (and S-51 civil version) - Sikorsky S-39Sikorsky S-39The Sikorsky S-39 was a smaller, single-engine version of the S-38 light amphibious aircraft, built in the USA by aviation firm Sikorsky Aircraft during the early 1930s.-Postwar usage:...
amphibian - Snow S-2B and S-2CAyres Thrush-See also:-Bibliography:* Green, William. Aircraft Handbook. London. Macdonald & Co. Ltd., 1964.* Simpson, Rod. The General Aviation Handbook. Midland Publishing. 2005. ISBN 1-85780-222-5....
- Spartan Executive 7WSpartan Executive|-Military Operators:* Royal Canadian Air Force3 Examples based in Montreal, formerly Royal Air Force examples used in California.*Chinese Nationalist Air ForceThe second prototype was exported to China and serialed 1309...
- Stinson ReliantStinson ReliantThe Stinson Reliant was a popular single-engine four to five seat high-wing monoplane manufactured by the Stinson Aircraft Division of the Aviation Manufacturing Corporation of Wayne, Michigan.-Design and development:...
SR-9F and SR-10F - Vought OS2U Kingfisher
- Vultee BT-13 Valiant
- Waco S3HD
- Waco SRE Aristocrat
- Weatherly 201 series
- Weatherly 620Weatherly 620-External links:*...
Engines on display
Some museums which have Wasp Junior engines on display:- The National Air and Space MuseumNational Air and Space MuseumThe National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...
's Steven F. Udvar-Hazy CenterSteven F. Udvar-Hazy CenterThe Steven F. Udvar-Hazy Center is the Smithsonian National Air and Space Museum 's annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia, United States....
near Washington Dulles International AirportWashington Dulles International AirportWashington Dulles International Airport is a public airport in Dulles, Virginia, 26 miles west of downtown Washington, D.C. The airport serves the Baltimore-Washington-Northern Virginia metropolitan area centered on the District of Columbia. It is named after John Foster Dulles, Secretary of...
in VirginiaVirginiaThe Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. (This engine has been sectioned and motorized for display.) - EAA AirVenture MuseumEAA AirVenture MuseumThe EAA AirVenture Museum is a museum dedicated to the preservation and display of historical and experimental aircraft located in Oshkosh, Wisconsin adjacent to the Wittman Regional Airport. Paul Poberezny proposed the idea of the EAA Air Museum-Air Education center in August 1958. The current...
in Oshkosh, WisconsinOshkosh, WisconsinAs of the census of 2000, there were 62,916 people, 24,082 households, and 13,654 families residing in the city. The population density was 2,662.2 people per square mile . There were 25,420 housing units at an average density of 1,075.6 per square mile...
. - Hill Aerospace MuseumHill Aerospace MuseumHill Aerospace Museum, located near Ogden, Utah, is a U.S. Air Force museum that is part of the United States Air Force Heritage Program.The museum, founded in 1981 and moved to its current location in 1991, displays over 90 aircraft from around the world, in addition to a variety of munitions,...
near OgdenOgden-Surname:* Aaron Ogden, governor of New Jersey* Bud Ogden, American professional basketball player* Carlos C. Ogden, American Medal of Honor recipient* Charles Ogden * Charles Kay Ogden, Cambridge University linguist, inventor of Basic English...
, UtahUtahUtah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
. - Museum of FlightMuseum of FlightThe Museum of Flight is a private non-profit air and space museum at King County International Airport , south of downtown Seattle, Washington. It was established in 1965 and is fully accredited by the American Association of Museums...
in Seattle, Washington. - National Museum of Naval AviationNational Museum of Naval AviationThe National Museum of Naval Aviation is a military and aerospace museum located at Naval Air Station Pensacola, Florida. The museum opened in 1962....
near PensacolaPensacolaPensacola is a city in the western part of the U.S. state of Florida.Pensacola may also refer to:* Pensacola people, a group of Native Americans* A number of places in the Florida:** Pensacola Bay** Pensacola Regional Airport...
, FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. - National Museum of the United States Air ForceNational Museum of the United States Air ForceThe National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
near DaytonDaytonDayton is a city in Ohio and the county seat of Montgomery County, Ohio, United States.Dayton may also refer to:-United States:*Dayton, Alabama*Dayton, California, in Butte County*Dayton, Lassen County, California*Dayton, Idaho*Dayton, Indiana...
, OhioOhioOhio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
. - New England Air MuseumNew England Air MuseumThe New England Air Museum is located at Bradley International Airport, Windsor Locks, Connecticut, USA. The museum is housed in three large display buildings consisting of more than of exhibit space...
in Windsor Locks, ConnecticutConnecticutConnecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...
. - Pima Air & Space MuseumPima Air & Space MuseumThe Pima Air & Space Museum features a display of nearly 300 aircraft spread out over 80 acres on a campus occupying 127 acres . Located in Tucson, Arizona, it is one of the world's largest, non-government funded aerospace museums...
in Tucson, ArizonaArizonaArizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
. - Southern Museum of FlightSouthern Museum of FlightThe Southern Museum of Flight is an aviation museum located three blocks east of the Birmingham-Shuttlesworth International Airport in Birmingham, Alabama. It features a valuable collection of aviation artifacts spanning the 20th century in the various areas of aviation. It explores eight decades...
in BirminghamBirmingham, AlabamaBirmingham is the largest city in Alabama. The city is the county seat of Jefferson County. According to the 2010 United States Census, Birmingham had a population of 212,237. The Birmingham-Hoover Metropolitan Area, in estimate by the U.S...
, AlabamaAlabamaAlabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
. - Strategic Air and Space MuseumStrategic Air and Space MuseumThe Strategic Air and Space Museum is a museum focusing on United States Air Force military aircraft and nuclear missiles located near Ashland, Nebraska, along Interstate 80 southwest of Omaha, Nebraska. The objective of the museum is to preserve and display historic aircraft, missile, and space...
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. - Canada Aviation and Space Museum in OttawaOttawaOttawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...
, OntarioOntarioOntario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
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. - Cincinnati State
- South African Air Force Museum, A.F.B. Ysterplaat, Cape Town (Wasp Junior B4).
Specifications (R-985 Wasp Junior SB)
| Engine | Power, continuous | Critical altitudeThis is the highest altitude at which the engine can achieve its full continuous power rating. Above this altitude, power falls off with height as with a naturally aspirated engine. See Supercharger#Altitude effects for details. | Power, takeoff | Compression ratio | Supercharger gear ratio | Octane rating | Dry weight |
|---|---|---|---|---|---|---|---|
| Wasp Jr. A | 300 hp at 2,000 RPM | sea level | same | 5.0:1 | 7:1 | 68 | 565 lb (256 kg) |
| Wasp Jr. TB | 420 hp at 2,200 RPM | sea level | 440 hp at 2,300 RPM | 6.0:1 | 8:1 | 80 | 640 lb (290 kg) |
| Wasp Jr. SB | 400 hp at 2,200 RPM | 5000 ft (1,524 m) | 450 hp at 2,300 RPM | 6.0:1 | 10:1 | 80/87 | 640 lb (290 kg) |
| Wasp Jr. T1B2 | 450 hp at 2,300 RPM | 1500 ft (457.2 m) | same | 6.0:1 | 10:1 | 80/87 | 653 lb (296 kg) |
| Wasp Jr. B4 | 450 hp at 2,300 RPM | 2300 ft (701 m) | same | 6.0:1 | 10:1 | 80/87 | 684 lb (310 kg) |
| Wasp Jr. SC-G | 525 hp at 2,700 RPM | 9500 ft (2,895.6 m) | 600 hp at 2,850 RPM | 6.7:1 | 10:1 | 100 | 864 lb (392 kg) |