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240 Landmarks of Japanese Automotive Technology
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240 Landmarks TopPassenger Cars, Part 1 > Otomo
 Otomo
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Junya Toyokawa, the eldest son of Ryohei Toyokawa, a board member of the Mitsubishi Zaibatsu conglomerate, had loved building and tinkering with machines since his childhood. This led him to establish the Hakuyosha Company with Keishin Tsuji at the age of 26. He also loved inventing, and a patent that he took out for a ship that could be steered automatically using gyroscopes led him to the US to open negotiations with the famous Sperry Corporation. He was still deeply attached to automobiles, and stayed for two years in America, during which time he entered university to study not just automotive engineering, but also factory management and mechanical engineering. He started a machinery import business in 1917, and directed Tetsushi Makita to begin designing and building an automobile. The first vehicle manufactured by this collaboration was the Ares, of which the Otomo was a smaller version. Originally featuring an air-cooled engine, the Ares was given a water-cooled engine and enlarged from a small to a medium-sized vehicle. The smaller version was then renamed the Otomo. A restored water-cooled Otomo is on display at the Toyota Automobile Museum.
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Storage location:TOYOTA AUTOMOBILE MUSEUM (41-100, Yokomichi, Nagakute, Nagakute-cho, Aichi-gun, Aichi-ken 480-1131)
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Year manufactured:1923
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Manufacturer:Hakuyosha, Ryohei Toyokawa
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Classification:Mass-production vehicle
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Current status:On public display: operational
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Vehicle name / Manufacture
Vehicle name:Otomo (Ares)
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Model name:S (M)
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Company name:Hakuyosha Company
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Year manufactured:1923 (1926)
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Designed by:Junya Toyokawa
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Collaboration:Higuma Ikenaga
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Vehicle type/usage:Small car
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Location of actual vehicle/replica:Toyota Automobile Museum
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Model / Weight
Style:Phaeton
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Number of doors:2
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Passenger capacity:4 (5)
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Vehicle weight:450 (600) kg
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Points of interest, topicality:Manufactured units: 230 units (Otomo), 500 units (Ares)
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Body / Size
Structure:Wood frame and steel sheets
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Bumpers:None
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Step:Provided
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Overall length:3030 (3600) mm
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Overall width:1210 (1300) mm
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Overall height:1300 (1600) mm
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Tire size:3.50-20 (26)
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Features:Handmade sheet metal body
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Body / Axle / Driving / Others
Frame:Steel sheets, ladder type
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Front axle:Rigid, longitudinal 1/2 leaf
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Rear axle:Rigid, longitudinal leaf
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Wheelbase:2200 (2600) mm
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Front tread x rear tread:1010 (1100) mm
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Vehicle height adjustment:None
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Steering:Round steering wheel
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Dampers:None
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Stabilizer:None
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Driving stability devices:None
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Engine / Size / Power
Cooling/cylinder arrangement:Air (water)/inline 4-cylinder
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Valve train:OHV (SV)
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Carburetor:Zebra
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Bore x stroke:59×86 (70×115) mm
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Displacement:945 (1770) cc
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Ignition system:Sawafuji, magneto type
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Max. power/r.p.m.:9/12 hp/2600 rpm(12/20 hp/2600 rpm)
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Exhaust emissions treatment:Noise reduction muffler only
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Supercharger:None
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Variable ignition system:Manual ignition timing
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Fetures:First OHV engine, initially air cooled by cooling fan, later changed to water-cooled type
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Hybrid
Hybrid system type:None
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Drive-train
Transmission:MT3
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Drive system:FR
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Performance
Mode fuel efficiency:-
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Reference materials:San-ei Shobo Publishing Co., Ltd., Kokusan-sha 100 Nen No Kiseki (1978); Documents of the Toyota Automobile Museum
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