Nakajima Ki-44 (Ha-41/Ha109)
32-723: The Nakajima Ha5 is a twin row, 14 cylinder air-cooled radial aircraft engine built by the Japanese Nakajima Aircraft Company . The engine was a development of earlier single-row Japanese engines, the Kotobuki and Hikari , which had combined features of the Bristol Jupiter and Pratt & Whitney R-1340 Wasp designs. First introduced in a 1,000 PS prototype in 1933, about 7,000 civilian and 5,500 military Ha-5's were built during World War II . The Ha-5 had separate cam -discs for
64-564: A radial engine . He observed the English Gloster Gamecock fighter with its Bristol Jupiter engine, which was an advanced design for the era with an automatic adjustment device for tappet clearance, spiral intake piping for even charge air distribution, and a four-valve intake and exhaust system. He acquired a manufacturing license for the Jupiter in 1925. In 1927, after inviting two production engineer instructors from
96-412: A closed circuit carrying liquid coolant through channels in the engine block and cylinder head. A fluid in these channels absorbs heat and then flows to a heat exchanger or radiator where the coolant releases heat into the air (or raw water , in the case of marine engines ). Thus, while they are not ultimately cooled by the liquid, as the heat is exchanged with some other fluid like air, because of
128-430: A fluid is a function of its capacity and the difference in input and output temperatures. As the boiling point of water is reduced with lower pressure, and the water could not be efficiently pumped as steam, radiators had to have enough cooling power to account for the loss in cooling power as the aircraft climbed. The resulting radiators were quite large and caused a significant amount of aerodynamic drag . This placed
160-486: A great percentage of the heat generated, around 44%, escapes through the exhaust. Another 8% or so ends up in the oil , which itself has to be cooled in an oil cooler . This means less than half of the heat has to be removed through other systems. In an air-cooled engine, only about 12% of the heat flows out through the metal fins. Air cooled engines usually run noisier, however it provides more simplicity which gives benefits when it comes to servicing and part replacement and
192-440: A horizontal fashion as a Flat engine , while vertical Straight-four engine have been used. Examples of past air-cooled road vehicles, in roughly chronological order, include: During the 1920s and 30s there was a great debate in the aviation industry about the merits of air-cooled vs. liquid-cooled designs. At the beginning of this period, the liquid used for cooling was water at ambient pressure. The amount of heat carried away by
224-418: Is usually cheaper to be maintained. Many motorcycles use air cooling for the sake of reducing weight and complexity. Few current production automobiles have air-cooled engines (such as Tatra 815 ), but historically it was common for many high-volume vehicles. The orientation of the engine cylinders is commonly found in either single-cylinder or coupled in groups of two, and cylinders are commonly oriented in
256-583: The Lawrance A-3 two-cylinder air-cooled horizontally opposed engine. At the time the Lawrance was an oddity. Most air-cooled engines at that time were rotary engines , using cylinders that rotated together with the propeller with a fixed crankshaft, in order to improve cooling but Kimihei overheard that an engine with good cooling capability with stationary cylinders was being developed in England:
288-713: The Mitsubishi Kasei , being of smaller dimensions and displacement, yet making equivalent power levels. Nine of the Ha-219 engines where issued to the Kitai Squadron to use for the new Ki-84N. According to two surviving IJAAF mechanics in 1987, the Ki-84N had a recorded speed of 448–450 mph at a ceiling of 42,254 ft when using war emergency power. The engine required much maintenance to keep running, and it overheated when flying at low speeds. The Ha5 engine
320-402: The "AE", was innovative, with a bore of 160 mm and a stroke of 170 mm. Prototypes were made and performance tests were done, but this engine was not adopted due to its very complex engineering. Nakajima continued testing different cylinder designs. In 1929, the "AH" design, with bore and stroke of 146 × 160 mm and a total displacement of 24.1 L, was completed. This was to be
352-654: The 1900s. The first commercial production was by the New Way Motor Company of Lansing, Michigan, US. The company produced air-cooled engines in single and twin cylinders in both horizontal and vertical cylinder format. Subsequent to their initial production which was exported worldwide, other companies took up the advantages of this cooling method, especially in small portable engines. Applications include mowers, generators, outboard motors, pump sets, saw benches and auxiliary power plants and more. Nakajima Hikari Too Many Requests If you report this error to
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#1732782981630384-730: The Bristol company, the Jupiter Type 6 of 420 PS and Type 7 of 450 PS with a supercharger were put into production at the Nakajima factory. After studying the Pratt & Whitney Wasp 9-cylinder radial, Nakajima tried to combine the good points found in Jupiter design with the rational design of the Wasp. Nakajima then produced a series of engine types, named "AA", "AB", "AC", and "AD", as engineering exercises. The next engine design,
416-711: The Ha-109 weighed 720 kg due to its larger, twin-stage supercharger system. The Ha-41 was the primary engine of early variants of the Nakajima Ki-49 "Helen" bomber, and the Nakajima Ki-44 "Tojo" fighter, later versions of both planes using the more powerful Ha-109 engine. Early versions of the Mitsubishi Ki-21 "Sally" used the Ha-5. The Ha-41 would have been an ideal power plant in aircraft that used
448-652: The Ha-109, which featured a two-speed, single stage supercharger. The later Ha-219 was based on the same cylinder design, but was increased in size to 18 cylinders. In 1917, Chikuhei Nakajima set up the "Airplane Institute" at Ojima Town in Gunma Prefecture . In 1918 they built their first airplane; the "Nakajima Type 1" with a U.S.A. made engine. In 1920 the company sent Kimihei Nakajima to France to study European advances, and in 1922 started their own engine factory in Tokyo. This led to production of engines based on
480-474: The Ha-41 was "Ha-34". Later the engine was developed into an 18-cylinder, twin-row engine called the "Ha-219", but this never got into mass development phase before the war ended a total of 10 were built. All these engines used essentially the same cylinder heads, the differences being in supercharging systems and maximum engine revolutions per minute. The Ha-5 and Ha-41 shared the same weight of 630 kg, while
512-524: The Ha-5 and its successors. In December 1931, this engine was approved and adopted by the Navy for the Navy Type 96 Carrier fighter . The engine was named, in connection with the Jupiter engine, "Kotobuki". The "Kotobuki" engine was improved and developed into the " Hikari (light)" engine with the bore and stroke expanded to the limit of the cylinder (160 × 180 mm for a displacement of 32.6 L), with
544-690: The Light-Sport Aircraft ( LSA ) and ultralight aircraft market. Rotax uses a combination of air-cooled cylinders and liquid-cooled cylinder heads. Some small diesel engines, e.g. those made by Deutz AG and Lister Petter are air-cooled. Probably the only big Euro 5 truck air-cooled engine (V8 320 kW power 2100 N·m torque one) is being produced by Tatra . BOMAG part of the FAYAT group also utilizes an air cooled inline 6 cylinder motor, in many of their construction vehicles. Stationary or portable engines were commercially introduced early in
576-522: The Navy underwriting air-cooled engine development at Pratt & Whitney and Wright Aeronautical . Most other groups, especially in Europe where aircraft performance was rapidly improving, were more concerned with the issue of drag. While air-cooled designs were common on light aircraft and trainers, as well as some transport aircraft and bombers , liquid-cooled designs remained much more common for fighters and high-performance bombers. The drag issue
608-748: The engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled counterparts, which require a separate radiator , coolant reservoir, piping and pumps. Air-cooled engines are widely seen in applications where weight or simplicity is the primary goal. Their simplicity makes them suited for uses in small applications like chainsaws and lawn mowers , as well as small generators and similar roles. These qualities also make them highly suitable for aviation use, where they are widely used in general aviation aircraft and as auxiliary power units on larger aircraft. Their simplicity, in particular, also makes them common on motorcycles . Most modern internal combustion engines are cooled by
640-401: The final version of this basic engine design. In June 1930 the first prototype of was completed and it passed the durability test for the type approval in the summer. Then flight tests were started using a Nakajima A2N carrier plane. Nakajima had successfully designed the first original Japanese air-cooled 9-cylinder engine, the 450 PS " Kotobuki ", which would over time be developed into
672-531: The front and rear rows of cylinders like American designs, rather than using a single, front-mounted cam-disc with long and short pushrods to operate both rows of cylinder valves. The Ha-5 was a twin-row development of the Nakajima Hikari , which was itself a development of the Nakajima Kotobuki . It spawned several improved variants, namely the Ha-41, with a single stage supercharger , and
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#1732782981630704-575: The liquid-coolant circuit they are known as liquid-cooled . In contrast, heat generated by an air-cooled engine is released directly into the air. Typically this is facilitated with metal fins covering the outside of the Cylinder Head and cylinders which increase the surface area that air can act on. Air may be force fed with the use of a fan and shroud to achieve efficient cooling with high volumes of air or simply by natural air flow with well designed and angled fins. In all combustion engines,
736-506: The much smaller radiators and less fluid in the system, the weight and drag of these designs was well below contemporary air-cooled designs. On a weight basis, these liquid-cooled designs offered as much as 30% better performance. In the late- and post-war era, the high-performance field quickly moved to jet engines . This took away the primary market for late-model liquid-cooled engines. Those roles that remained with piston power were mostly slower designs and civilian aircraft. In these roles,
768-510: The power was increased to 720 PS. The "Hikari" was used in Type 95 carrier fighters and Type 96 Carrier Attack Plane . Nakajima knew that engines of higher power would be needed and began work on the Ha-5, a new 14-cylinder, twin-row design that was based on the 160 × 180 mm cylinder of the Hikari. The Ha-5 prototype engine was completed in 1933, producing 1,000 PS. An improved Ha-5
800-529: The radiator size by 50% compared to water cooled designs. The experiments were extremely successful and by 1932 the company had switched all future designs to this coolant. At the time, Union Carbide held a monopoly on the industrial process to make glycol, so it was initially used only in the US, with Allison Engines picking it up soon after. It was not until the mid-1930s that Rolls-Royce adopted it as supplies improved, converting all of their engines to glycol. With
832-454: The simplicity and reduction in servicing needs is far more important than drag, and from the end of the war on almost all piston aviation engines have been air-cooled, with few exceptions. As of 2020 , most of the engines manufactured by Lycoming and Continental are used by major manufacturers of light aircraft Cirrus , Cessna and so on. Other engine manufactures using air-cooled engine technology are ULPower and Jabiru , more active in
864-458: The steam through tubes located just under the skin of the wings and fuselage, where the fast moving outside air condensed it back to water. While this concept was used on a number of record-setting aircraft in the late 1930s, it always proved impractical for production aircraft for a wide variety of reasons. In 1929, Curtiss began experiments replacing water with ethylene glycol in a Curtiss D-12 engine. Glycol could run up to 250 C and reduced
896-459: The two designs roughly equal in terms of power to drag, but the air-cooled designs were almost always lighter and simpler. In 1921, the US Navy , largely due to the efforts of Commander Bruce G. Leighton , decided that the simplicity of the air-cooled design would result in less maintenance workload, which was paramount given the limited working area of aircraft carriers . Leighton's efforts led to
928-590: The volume of water required and the size of the radiator by as much as 30%, which opened the way to a new generation of high-powered, relatively low-drag liquid cooled inline engines such as the Rolls-Royce Merlin and Daimler-Benz DB601 , which had an advantage over the unpressurized early versions of the Jumo 211 . This also led to development work attempting to eliminate the radiator entirely using evaporative cooling , allowing it to turn to steam and running
960-499: Was developed as a 1,500 PS engine. In all about 5,500 Ha-5 engines were produced for the military. Later on, as the weights of aircraft rose and higher speeds were required, Nakajima continued to improve the Ha-5 design, creating the "Ha-41" and "Ha-109", which shared the same 146mm x 160mm bore and stroke as the Ha-5, but were increased from the 950 hp of the Ha5 to 1,260 hp and 1,440 hp, respectively. The unified code for
992-493: Was upset by the 1929 introduction of the NACA cowl , which greatly reduced the drag of air-cooled engines in spite of their larger frontal area, and the drag related to cooling was at this point largely even. In the late 1920s into the 1930s, a number of European companies introduced cooling system that kept the water under pressure allowed it to reach much higher temperatures without boiling, carrying away more heat and thus reducing
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1024-437: Was used to power: The Ha41 engine was used to power: The Ha109 engine was used to power: Data from Engine development at Nakajima 1923–1945 , Engine History of Nakajima Aircraft . Related development Comparable engines Related lists Air-cooled engine Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep
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