Allison V-1710-3
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The Allison V-1710
aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbin ...
designed and produced by the
Allison Engine Company The Allison Engine Company was an American aircraft engine manufacturer. Shortly after the death of James A. Allison, James Allison in 1929 the company was purchased by the Fisher Body, Fisher brothers. Fisher sold the company to General Motors ...
was the most common US-developed V-12 liquid-cooled engine in service during
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
. Versions with a
turbocharger In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into th ...
gave excellent performance at high altitude in the twin-engined
Lockheed P-38 Lightning The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps (USAAC) by the Lockheed Corporation, the P-38 incorporated a distinc ...
, and turbo-superchargers were fitted to experimental single-engined fighters with similar results. The
United States Army Air Corps The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical ri ...
(USAAC) preference for turbochargers early in the V-1710's development program meant that less effort was spent on developing suitable mechanically driven centrifugal
supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...
s for the Allison V-12 design, as other V-12 designs from friendly nations like the British
Rolls-Royce Merlin The Rolls-Royce Merlin is a British Coolant#Liquids, liquid-cooled V12 engine, V-12 Reciprocating engine, piston aero engine of 27-litre (1,650 cu in) Engine displacement, capacity. Rolls-Royce Limited, Rolls-Royce designed the engine an ...
were already using. When smaller-dimensioned or lower-cost versions of the V-1710 were desired, they generally had poor performance at higher altitudes.


Design and development

The
Allison Allison may refer to: People * Allison (given name) * Allison (surname) (includes a list of people with this name) * Eugene Allison Smith (1922-1980), American politician and farmer * Allison family, a family of RMS Titanic passengers Compan ...
Division of
General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...
began developing an
ethylene glycol Ethylene glycol ( IUPAC name: ethane-1,2-diol) is an organic compound (a vicinal diol) with the formula . It is mainly used for two purposes: as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odo ...
-cooled engine in 1929 to meet a USAAC need for a modern, , engine to fit into a new generation of streamlined bombers and fighters. To ease production, the new design could be equipped with different propeller gearing systems and superchargers, allowing a single production line to build engines for various fighters and
bomber A bomber is a military combat aircraft that utilizes air-to-ground weaponry to drop bombs, launch aerial torpedo, torpedoes, or deploy air-launched cruise missiles. There are two major classifications of bomber: strategic and tactical. Strateg ...
s. The
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
(USN) hoped to use the V-1710 in its rigid airships ''Akron'' and ''Macon'', but both were equipped with German-built
Maybach VL II The Maybach VL II was a type of internal combustion engine built by the German company Maybach in the late 1920s and 1930s. It was an uprated development of the successful Maybach VL I, and like the VL I, was a 60° V-12 engine. History Five of ...
engines as the V-1710 was still in testing when the ''Macon'' was lost in February 1935 (the ''Akron'' having been lost in April 1933). The USAAC purchased its first V-1710 in December 1932. The
Great Depression The Great Depression was a severe global economic downturn from 1929 to 1939. The period was characterized by high rates of unemployment and poverty, drastic reductions in industrial production and international trade, and widespread bank and ...
slowed development, and it was not until December 14, 1936, that the engine next flew in the Consolidated XA-11A testbed. The V-1710-C6 successfully completed the USAAC ''150 hour Type Test'' on April 23, 1937, at , the first engine of any type to do so. The engine was then offered to aircraft manufacturers where it powered the prototype Curtiss XP-37s. All entrants in the new pursuit competition were designed around it, powering the Lockheed P-38, Bell P-39 and
Curtiss P-40 The Curtiss P-40 Warhawk is an American single-engined, single-seat, all-metal fighter-bomber that first flew in 1938. The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time and enabled a rapid entry ...
. When war material procurement agents from the United Kingdom asked
North American Aviation North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F- ...
to build the P-40 under license, NAA instead proposed their own improved aircraft design, using the V-1710 in their NA-u73, which became the famed
P-51 Mustang The North American Aviation P-51 Mustang is an American long-range, single-seat fighter aircraft, fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in 1940 by a team headed ...
.


Technical description

The V-1710 has 12 cylinders with a bore and stroke of in 60° V format, for a
displacement Displacement may refer to: Physical sciences Mathematics and physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
of , with a
compression ratio The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine. A fundamental specification for such engines, it can be measured in two different ways. Th ...
of 6.65:1. The
valvetrain A valvetrain is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) into the combu ...
has a single
overhead camshaft An overhead camshaft (OHC) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustio ...
per bank of cylinders and four valves per cylinder.


Versatility and reversibility of rotation

The engine design benefited from General Motors’ adoption of
modular design Modular design, or modularity in design, is a design principle that subdivides a system into smaller parts called ''modules'' (such as modular process skids), which can be independently created, modified, replaced, or exchanged with other modules ...
that provided built-in aviation powerplant production and installation versatility. The engine was constructed around a long block, which could meet various design requirements by fitting the appropriate accessories section at the rear, and an appropriate power output drive at the front. A turbo-supercharger could be used, if desired. The P-39, P-63, and Douglas XB-42 Mixmaster used V-1710-Es, exchanging the integral reduction gear for an extension shaft driving a remotely located reduction gear and propeller. Aircraft such as the P-38, P-40, P-51A, and North American P-82E used close-coupled propeller reduction gears, a feature of the V-1710-F series. The accessory end had a one- or two-speed engine-driven supercharger that might have a second stage with or without an
intercooler An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines. Internal combustion engines Mo ...
, the ignition magnetos and the customary assortment of oil and fuel pumps, all dictated by the application requirements. The front of the engine could have one of a number of different output drives. The drive might be a "long-nose" or close coupled propeller reduction gear, an extension drive to a remote gearbox, or a gearbox that could drive two wing-mounted propellers from a fuselage-mounted engine. Another key feature of the V-1710 design was its ability to turn the output shaft clockwise or counter-clockwise by assembling the engine with the crankshaft turned end-for-end, by installing an idler gear in the drive train to the supercharger, camshafts, and accessories, installing a starter turning the proper direction, and re-arranging the ignition wiring on the right side to accommodate a changed firing order. No change to the oil pump nor coolant pump circuits was needed. The ability to reverse the direction of rotation with a minimum of extra parts allowed the use of either a "tractor" or "pusher" propeller. This approach allowed easy changes of the supercharger(s) and supercharger drive-gear ratio. That gave different critical altitude (the maximum altitude at which the engine could produce full power) ratings ranging from .


Supercharger

The V-1710 has often been criticized for not having a "high-altitude" supercharger. The comparison is usually to the later, two-stage, versions of the
Rolls-Royce Merlin The Rolls-Royce Merlin is a British Coolant#Liquids, liquid-cooled V12 engine, V-12 Reciprocating engine, piston aero engine of 27-litre (1,650 cu in) Engine displacement, capacity. Rolls-Royce Limited, Rolls-Royce designed the engine an ...
60-series engines also built by Packard as the V-1650 and used in the P-51B Mustang and subsequent variants. The USAAC had specified that the V-1710 was to be a single-stage supercharged engine and, if a higher altitude capability was desired, the aircraft could use their newly developed turbo-supercharger as was featured in the XP-37(YP-37), P-38, and XP-39. The benefits of a two-stage supercharger eventually became so clear that Allison did make some efforts in this direction. Allison attached an auxiliary supercharger in various configurations to the existing engine-mounted supercharger and carburetor. Early versions of these two-stage supercharger engines were used on the P-63. No intercooler, aftercooler, or backfire screen (flame trap) were incorporated into these two-stage V-1710 engines (except for the V-1710-119 used on the experimental P-51J, which had an aftercooler and Flame Traps). The two-stage Merlin engines had all of these features, which were designed to prevent detonation from charge heating and backfire into the supercharger. The G-series V-1710s installed on the F-82 E/F/G models had only anti-detonation injection (ADI) to deal with these problems, and not surprisingly had severe reliability and maintenance problems. In one record, it was stated that the F-82 required 33 hours of maintenance for each hour of flight.Wagner, Ray. ''Mustang Designer: Edgar Schmued and the P-51'' Although the early V-1710 powered P-39, P-40 and P-51A were limited to combat operations at a maximum of about they were available in comparatively large numbers and were the mainstay of some Allied Air Forces in all but the
European theater The European theatre of World War II was one of the two main Theater (warfare), theatres of combat during World War II, taking place from September 1939 to May 1945. The Allies of World War II, Allied powers (including the United Kingdom, the ...
of war. The engines proved to be robust and little affected by machine-gun fire. In total, over 60 percent of the post-June 1941
USAAF The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
's pursuit aircraft operated during WWII were powered by the V-1710. Allison slowly but continuously improved the engine during the war. The initial rating of was incrementally increased; the final V-1710-143/145(G6R/L) was rated for . By 1944, the War Emergency Power rating on the P-38L was . The most powerful factory variant was the V-1710-127, designed to produce dry at low altitude and at . This engine was static tested at wet War Emergency Power and was planned for installation in an XP-63H aircraft. The end of the war ended this development, so this promising experiment never flew. The extra power of this version was derived from using exhaust turbines, not to drive a turbo-supercharger, but to return that energy to turning the crankshaft, called a
turbo-compound engine A turbo-compound engine is a reciprocating engine that employs a turbine to recover energy from the exhaust gases. Instead of using that energy to drive a turbocharger as found in many high-power aircraft engines, the energy is instead sent to ...
. (From Aerospace Engineer Jim Leonard's Monograph dated 2010.) Improvements in manufacturing brought the cost to produce each engine from $25,000 down to $8,500 and allowed the installed lifetime of the engine to be increased from 300 hours to as much as 1,000 hours for the less-stressed power-plants. Weight increases needed to accomplish this were minimal, with the result that all models were able to produce more than 1 hp/lb (1.6 kW/kg) at their takeoff rating. There was also a high degree of commonality of parts throughout the series. The individual parts of the Allison series were produced to a high degree of standardization and reliability, using the best technology available at the time. Even after the war, racing Merlins used Allison connecting rods. As stated previously, General Motors' policies regarding versatility meant that their Allison division would also employ modular design features on the V-1710 from its "long block" core V-12 unit outwards, so that it was capable of being mated to many different styles of turbo-superchargers and various other accessories, although the variety of turbo-superchargers available for installation was limited due to the constraints of single-engine fighter design. Since it was produced in large numbers and was highly standardized, the engine has been used in many postwar racing designs. Its reliability and well-mannered operation allowed it to operate at high rpm for extended periods. Following the war, North American built 250 P-82E/F for air defense roles into the early 1950s. This was the final military role for the V-1710.


Turbo-supercharger

The USAAC had earlier decided to concentrate on
turbo-supercharger In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the ...
s for high altitude boost, believing that further development of turbo-superchargers would allow their engines to outperform European rivals using crankshaft driven superchargers. Turbo-superchargers are powered by the engine exhaust and so do not draw much power from the engine crankshaft, whereas displacement superchargers are coupled directly by shafts and gears to the engine crankshaft. Turbo-superchargers do increase the exhaust back-pressure and thus do cause a very small decrease in engine power, but the power increase due to increased induction pressures more than makes up for that decrease. Crankshaft-driven superchargers require an increase in directly driven percentage of engine power as altitude increases (the two-stage supercharger of the Merlin 60 series engines consumed some at . General Electric was the sole source for research and production of American turbo-superchargers during this period, from its four decades worth of
steam turbine A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Par ...
engineering experience. Turbo-superchargers were highly successful in U.S. bombers, which were exclusively powered by radial engines. The P-47 fighter had the same combination of radial engine ( R-2800) and turbo-supercharger and was also successful, apart from its large bulk, which was caused by the need for the ductwork for the aft-mounted turbo-supercharger. However, mating the turbocharger with the Allison V-1710 proved to be problematic. As a result, designers of the fighter planes that used the V-1710 were invariably forced to choose between the poor high-altitude performance of the V-1710 versus the increased problems brought on by addition of the turbo-supercharger. The fates of all of the V-1710 powered fighters of World War II would thus hinge on that choice. The original XP-39 was built with a V-1710 augmented by a General Electric Type B-5 turbo-supercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville.Bodie 1991, p. 19. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers,
NACA The National Advisory Committee for Aeronautics (NACA) was a United States federal agency that was founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its ...
aero-dynamic specialists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie.Bodie 1991, p. 20. The production P-39 was thus stuck with poor high-altitude performance and proved unsuitable for the air war in Western Europe which was largely conducted at high altitudes. The P-39 was rejected by the British, but used by the U.S. in the Mediterranean and the early Pacific air war, as well as shipped to the Soviet Union in large numbers under the Lend Lease program. The Soviets were able to make good use of P-39s because of its excellent maneuverability and because the air war on the Eastern Front in Europe was primarily short ranged, tactical, and conducted at lower altitudes. In the P-39, Soviet pilots scored the highest number of individual kills made on ''any'' American, or British fighter type. The P-40, which also had only the single-stage, single-speed-supercharged V-1710, had similar problems with high-altitude performance. The P-38 was the only fighter to make it into combat during World War II with turbo-supercharged V-1710s. The operating conditions of the Western European air war – flying for long hours in intensely cold weather at – revealed several problems with these engines. They had a poor manifold fuel-air distribution and poor temperature regulation of the turbo-supercharger air, which resulted in frequent engine failures (
detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with ...
occurred as the result of persistent uneven fuel-air mixture across the cylinders caused by the poor manifold design). Specially formulated fuels were a necessity for the P-38 as were specific spark plugs needed for specific cylinders. The turbo-supercharger had additional problems with getting stuck in the freezing air in either high or low boost mode; the high boost mode could cause detonation in the engine, while the low boost mode would be manifested as power loss in one engine, resulting in sudden fishtailing in flight. These problems were aggravated by sub-optimal engine management techniques taught to many pilots during the first part of WWII, including a cruise setting that ran the engine at high RPM and low manifold pressure with a rich mixture. These settings can contribute to over-cooling of the engine, fuel condensation problems, accelerated mechanical wear, and the likelihood of components binding or "freezing up." Details of the failure patterns were described in a report by General Doolittle to General Spatz in January 1944. In March 1944, the first Allison engines appearing over Berlin belonged to a group of P-38Hs of 55th Fighter Group, engine troubles contributing to a reduction of the force to half strength over the target. It was too late to correct these problems in the production lines of Allison or GE, and as the numbers of Merlin-engined P-51 Mustangs based in England mounted up through the end of 1943 and into 1944, the P-38s were steadily withdrawn from Europe until October 1944 when they were no longer used for bomber escort duty with the
Eighth Air Force The Eighth Air Force (Air Forces Strategic) is a numbered air force (NAF) of the United States Air Force's Air Force Global Strike Command (AFGSC). It is headquartered at Barksdale Air Force Base, Louisiana. The command serves as Air Forces S ...
. A few P-38s would remain in the European theater as the F-5 for photo reconnaissance. The P-38 had fewer engine failures in the Pacific Theater, where operating techniques were better developed (such as those recommended by
Charles Lindbergh Charles Augustus Lindbergh (February 4, 1902 – August 26, 1974) was an American aviator, military officer, and author. On May 20–21, 1927, he made the first nonstop flight from New York (state), New York to Paris, a distance of . His aircra ...
during his development work in the theater),) and the Japanese did not operate at such high altitudes. Using the same P-38Gs which were proving difficult to maintain in England, Pacific-based pilots were able to use the aircraft to good advantage including, in April 1943,
Operation Vengeance Operation Vengeance was the American military operation to kill Admiral Isoroku Yamamoto of the Imperial Japanese Navy on 18 April 1943 during the Solomon Islands campaign in the Pacific Theater of World War II. Yamamoto, commander of the Combine ...
, the interception and downing of the Japanese bomber carrying Admiral
Isoroku Yamamoto was a Marshal Admiral of the Imperial Japanese Navy (IJN) and the commander-in-chief of the Combined Fleet during World War II. He commanded the fleet from 1939 until his death in 1943, overseeing the start of the Pacific War in 1941 and J ...
. New P-38 models with ever-increasing power from more advanced Allisons were eagerly accepted by Pacific air groups. When Packard started building Merlin V-1650 engines in America in 1942, certain American fighter designs using the Allison V-1710 were changed to use the Merlin. The P-40F, a Lend Lease export to Britain, was one of the first American fighters to be converted to a Packard-Merlin engine. However, the installed engine was the V-1650-1 (a Packard-produced Merlin XX) with a slightly improved single-stage, two-speed supercharger, yielding only modest gains over the Allison V-1710. The last Allison powered P-51, the Mustang I(II)/P-51A, used the single-stage, single-speed Allison V-1710-81, with a 9.6:1 blower ratio. This allowed the P-51A to reach a maximum speed of at and maintain at . This was more than faster than the Merlin 45-powered Spitfire V at , and more than faster at . Its speed impressed the British, and the RAF quickly realized the airplane would possess excellent high altitude performance if the Allison V-1710 engine were replaced by the 60-Series Merlin. A similar proposal to cure the P-38's problems by replacing its Allisons with Merlins was quashed by the USAAF, after protests from Allison. Starting with the V-1710-45 around 1943 (after the P-51 had been fitted with a Merlin 61 by Rolls-Royce), Allison attached an auxiliary supercharger to some of its engines in an effort to improve high-altitude performance. The two-stage supercharged Allison was essentially developed as an "add on" to the single-stage engine, and required minimal changes to the base engine. While it lacked the refinement, compactness and after-cooler of the two-stage Merlin, the Allison used a pressure-altitude governed variable-speed first stage. Various configurations of this auxiliary supercharger were used in production versions of the V-1710 that powered aircraft such as the Bell P-63 and North American P-82E/F/G series. In addition, it was tried or studied as the powerplant for many experimental and test aircraft such as the Curtiss XP-55 Ascender, North American XP-51J "lightweight Mustang", Boeing XB-38 Flying Fortress, and Republic XP-47A (AP-10), both of the latter with turbo-superchargers.


Post-war

The V-1710-powered F-82 did not arrive in time for World War II, but did see brief action in the
Korean War The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
, although the type was completely withdrawn from Korea by the end of 1950. It had a short service life that was probably due to a combination of factors: poor reliability from the G-series V-1710 engines, low numbers of F-82s produced, and the arrival of jet fighters. The initial production P-82B had Merlin engines, but North American was forced to use the Allison V-1710 for the E/F/G models when Rolls Royce required a "Royalty" of $6,500.00 per engine and the U. S. Government stopped buying the Merlin engine because of the excessive cost.


Production total

In total, 69,305 V-1710s were built by Allison during the war, all in
Indianapolis, Indiana Indianapolis ( ), colloquially known as Indy, is the List of capitals in the United States, capital and List of municipalities in Indiana, most populous city of the U.S. state of Indiana and the county seat of Marion County, Indiana, Marion ...
.


Other uses

The V-1710's useful life continued, as thousands were available on the surplus market. In the 1950s, many drag racers and land speed racers, attracted by its reliability and good power output, adopted the V-1710;
Art Arfons Arthur Eugene Arfons (February 3, 1926 – December 3, 2007) was the world land speed record holder three times from 1964 to 1965 with his ''Green Monster'' series of jet-powered cars, after a series of ''Green Monster'' piston-engine and j ...
and brother
Walt Walt is a masculine given name, generally a short form of Walter (name), Walter, and occasionally a surname. Notable people with the name include: People Given name * Walt Anderson (American football) (born 1952), American football official * Walt ...
in particular used one, in an early dragster version of their ''Green Monster''. It proved unsuccessful in the 1/4 mile, being unable to accelerate rapidly, but "could taxi all day at 150". Unlimited
hydroplane racing Hydroplane racing (also known as hydro racing) is a sport involving racing hydroplanes on lakes, rivers, and bays. It is a popular spectator sport in several countries. Racing circuits International professional outboard hydroplane racing The ...
also became a big sport across the U.S. at this time and V-1710s were often tuned for racing at up to —power levels that were beyond design criteria and significantly reduced durability. Later, as purpose-built V8 engines became available for drag racing and unlimited boats shifted to
turboshaft A turboshaft engine is a form of gas turbine that is optimized to produce shaft horsepower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the ex ...
power,
tractor pull Truck and tractor pulling, also known as power pulling, is a form of a motorsport competition in which antique or modified tractors pull a heavy drag or sled along an , track, with the winner being the tractor that pulls the drag the farth ...
ers began using the Allison engine, again developing unimagined power. Finally, the
warbird A warbird is any vintage military aircraft now operated by civilian organizations and individuals, or in some instances, by historic arms of military forces, such as the Battle of Britain Memorial Flight, the Royal Australian Air Force's No. 100 ...
movement began to restore and return to the air examples of the classic fighters of the war and many V-1710-powered pursuit airplanes began to fly again, with freshly overhauled engines. The reliability, maintainability, and availability of the engine has led others to use it to power flying examples of aircraft whose original engines are unobtainable. This includes newly manufactured
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n Yak-3 and
Yak-9 The Yakovlev Yak-9 (; NATO reporting name: Frank) is a single-engine, single-seat multipurpose fighter aircraft used by the Soviet Union and its allies during World War II and the early Cold War. It was a development of the robust and successful ...
airplanes, originally powered by
Klimov UEC-Klimov () is a Russian manufacturer of gas turbine engines, main gearboxes and accessory drive gearboxes for transport aircraft. Originally established as ''Kirill Klimov Experimental Design Bureau'' in Saint-Petersburg under the directio ...
V-12s in World War II and the two (so far) airworthy examples of the Ilyushin Il-2, taking the place of the Mikulin V-12 it originally used, as well as ambitious projects such as a replica Douglas World Cruiser and
Focke-Wulf Fw 190 The Focke-Wulf Fw 190, nicknamed ''Würger'' (Shrike) is a German single-seat, single-engine fighter aircraft designed by Kurt Tank at Focke-Wulf in the late 1930s and widely used during World War II. Along with its well-known counterpart, the ...
D by Flug Werk of
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.


Variants

Allison's internal model designation for the V-1710 started with the letter A and proceeded to the letter H. Each letter designated a family of engines that shared major components, but differed in specific design details. Each of these designs were identified by a number, starting with number 1. The last letter, which was introduced when both right hand turning and left hand turning engines were built, identified by the letter R or L respectively. The military model numbers were identified by a "dash number" following the engine description "V-1710". The USAAC/USAAF models were the odd numbers, starting with "-1" and the USN models were the even numbers, starting with "-2". ;: "A" series engines were early development engines for the USN and USAAC. The first military model was a single V-1710-2, which was first sold to the USN on June 26, 1930. The "A" engines had no counterweights on the crankshaft, 5.75:1 compression ratio, 2:1 internal spur gear-type reduction gear boxes, 8.77:1 supercharger ratio, impeller, SAE #50 propeller shaft, a float-type carburetor, and produced at 2800 rpm on 92 octane gasoline. ;: "B" series engines were designed for USN airships. The military model was V-1710-4. They differed from the "A" series engines in that they did not have a supercharger, had two float-type down-draft carburetors were mounted directly to the intake manifold, an SAE #40 propeller shaft, and could be brought from full power to stop and back to full power in the opposite rotation in less than 8 seconds. They produced at 2400 rpm. ;: "C" series engines were developed for highly streamlined pursuit aircraft for the USAAC, and are easily identified by the long reduction gear case. The military models were V-1710-3, -5, -7, -11. -13, -15, -19, -21, -23, -33, producing between at 2600 rpm. These engines came in two groups, one group rated at full power at sea level, the other rated at full power at high altitude. The altitude rating difference was in the supercharger gear ratio, four of which were used: 6.23:1, 6.75:1, 8.0:1 and 8.77:1. These engines received heavier crankcases, a stronger crankshaft, SAE #50 propeller shaft, and Bendix pressure carburetors. ;: "D" series engines were designed for pusher applications using propeller-speed extension shafts and remote thrust bearings mounted to the airframe. The military models were V-1710-9, -13, -23, and -41, producing at 2600 rpm. Supercharger ratios were 6.23:1, 8.0:1 or 8.77:1, depending on altitude rating. These engines had the compression ratio increased to 6.65:1. Marvel MC-12 fuel injection, which was unsatisfactory and quickly replaced by a float-type carburetor on -9 and -13 models. Later dash number engines used Bendix pressure carburetors. These engines were being designed at the same time as the V-3420 engine, and shared many assemblies as they were developed. The "D" series engines were the last of the "early" V-1710 engines. ;: "E" series engines were designed for remote gearbox applications using crankshaft-speed extension shafts and remote 1.8:1 gearboxes with SAE #60 hollow propeller shafts. The military models were V-1710-6, -17, -31, 35, -37, -47, -59, -63, -83, -85, -93, -103, -109, -117, -125, -127, -129, -133,-135 and -137, producing at 3000 rpm. Supercharger gear ratios were: 6.44:1, 7.48:1, 8.10:1, 8.80:1 and 9.6:1 depending on altitude rating. These engines were a complete redesign, and did not share many components with the earlier engine series. Almost all components were interchangeable with later series engines and the V-3420, and could be assembled as right hand or left hand turning engines in either pusher or tractor applications. ;: "F" series engines were designed for late model pursuit aircraft, and are identified by the compact external spur gear-type reduction gear box. Military models were V-1710-27, -29, -39, -45, -49, -51, -53, -55, -57, -61, -75, -77, -81, -87, -89, -91, -95, -99, -101, -105, -107, -111, -113, -115, -119, producing at 3000 rpm. The V-1710-101, -119 and -121 models has an auxiliary supercharger, some with a liquid-cooled aftercooler. Supercharger gear ratios were: 6.44:1, 7.48:1, 8.10:1, 8.80:1 and 9.60:1 depending on altitude rating. These engines had either a six or twelve weight crankshaft, revised vibration dampeners that combined to allow higher engine speeds, SAE #50 propeller shaft, and higher horsepower ratings. The "E" series and "F" series engines were very similar, the primary difference being the front crankcase cover, which was interchangeable between the two series engines.Whitney 1998, Chapter 12 ;: "G" series engines were designed for high-altitude pursuit aircraft, and are identified by the auxiliary supercharger with a Bendix "Speed-Density" fuel control. Military models were V-1710-97, -131, -143, -145, and -147, producing at 3000 rpm. Supercharger gear ratios were: 7.48:1, 7.76:1, 8.10:1, 8.80:1 and 9.60:1 depending on altitude rating. These engines were equipped with an SAE #50 propeller shaft and a single power lever to regulate engine performance, reducing the pilot's workload when managing this very complex engine.Whitney 1998, Chapter 13 ;: "H" series engines were to use a two-stage supercharger driven by a two-stage air-cooled power recovery turbine. The engine was to have an aftercooler and port-type fuel injection. This variant, however, was never built.Whitney 1998, Chapter 13


Applications

* Bell FM-1 Airacuda * Bell FL Airabonita *
Bell P-39 Airacobra The Bell P-39 Airacobra is a fighter produced by Bell Aircraft for the United States Army Air Forces during World War II. It was one of the principal American fighters in service when the United States entered combat. The P-39 was used by th ...
* Bell P-63 Kingcobra * Boeing XB-38 Flying Fortress *
Curtiss P-40 Warhawk The Curtiss P-40 Warhawk is an American single-engined, single-seat, all-metal fighter-bomber that first flew in 1938. The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time and enabled a rapid entry ...
*
Curtiss-Wright XP-55 Ascender The Curtiss-Wright XP-55 Ascender (company designation CW-24) is a 1940s United States prototype fighter aircraft built by Curtiss-Wright. Along with the Vultee XP-54 and Northrop XP-56, it resulted from United States Army Air Corps proposal ...
* Curtiss XP-60A * Curtiss P-37 * Douglas XB-42 Mixmaster *
Douglas DC-8 The Douglas DC-8 (sometimes McDonnell Douglas DC-8) is an early long-range Narrow-body aircraft, narrow-body jetliner designed and produced by the American Douglas Aircraft Company. Work began in 1952 towards the United States Air Force's (USA ...
*
Lockheed P-38 Lightning The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps (USAAC) by the Lockheed Corporation, the P-38 incorporated a distinc ...
*
North American A-36 Apache The North American A-36 (company designation NA-97, listed in some sources as "Apache" or "Invader", but generally called Mustang) is the Attack aircraft, ground-attack/dive bomber version of the North American P-51 Mustang, from which it coul ...
*
North American F-82 Twin Mustang The North American F-82 Twin Mustang is an American long-range escort fighter aircraft, fighter. Based on the North American P-51 Mustang, the F-82 was designed as an escort for the Boeing B-29 Superfortress in World War II, but the war ended ...
* North American P-51A Mustang * T29 Heavy Tank (trial)


Engines on display

*An Allison V-1710-51 is on public display at the
Aerospace Museum of California The Aerospace Museum of California is a private non-profit aviation museum located in McClellan, California, outside of Sacramento, California, on the grounds of the former McClellan Air Force Base. History Founded as the Air Force Logistics Mus ...


Specifications (V-1710-F30R / -111)


See also


References


Notes


Bibliography

*Bodie, Warren M. ''The Lockheed P-38 Lightning: The Definitive Story of Lockheed's P-38 Fighter''. Hayesville, North Carolina: Widewing Publications, 2001, 1991. *''Jane's Fighting Aircraft of World War II''. London. Studio Editions, 1998. *Kirkland, Richard. ''War Pilot: True Tales of Combat and Adventure.'' New York: Ballantine Books, 2003. *Ludwig, Paul. ''P-51 Mustang – Development of the Long Range Escort Fighter''. Walton-on-Thames, Surrey, UK: Classic Publications, 2003. *Smith, Richard K. ''The Airships Akron & Macon, Flying Aircraft Carriers of The United States Navy''. Annapolis, Maryland: United States Naval Institute, 1965. *White, Graham. ''Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced By Great Britain and the United States during World War II''. Warrendale, Pennsylvania: Society of Automotive Engineers, 1995. *Whitney, Daniel. ''Vee's for Victory!: The Story of the Allison V-1710 Aircraft Engine 1929–1948''. Atglen, Pennsylvania: Schiffer Publishing, 1998.


External links


''Popular Science'', October 1940, ''Streamline Motors For Streamline Airplanes''
a 1942 ''Flight'' article {{US military piston aeroengines V-1710 1930s aircraft piston engines V12 aircraft engines