Toyota G1

Kiichiro Toyoda's desire was to produce automobiles. Unfortunately, the A1 passenger car that was under development in 1935 was unlikely to sell well due to Japan's underdeveloped economy. Work still progressed on the A1 but emphasis was shifted to a truck derived from the same engine and chassis (slightly lengthened).[2]

The financial resources of the parent company, Toyoda Automatic Loom Works, were stretched almost to breaking point and large loans were required to put the G1 into production at the Kariya loom factory. The total cost of the G1 development was well several times the annual profits of Toyoda.

The G1 was sold as a Toyoda. The company changed its name from Toyoda to Toyota at the introduction of the G1's successor, the GA.

Since this was Toyoda's first production vehicle at the loom works factory, there were still many problems to be solved. When the first production examples were driven to Tokyo for the motor show, they were packed with many spare parts. These spare parts were in case something broke during the trip - luckily only a few replacement parts were required. Early sales were mostly to people who were sympathetic to local manufacturers and who were willing to endure many failures. To support them, design engineers from the factory were often sent to do repairs in order to learn which parts needed the most attention. For example, broken rear axle housings were common until new welding methods were developed. Repairs were done for free and sometimes entire trucks were replaced for free. Rectifications were then applied as running changes on the production line, reflecting Toyota's "5 Whys" problem solving philosophy.

A bus based on the G1 chassis, with a lowered floor. Bus bodies were built by several manufacturers; one manufacturer's body seated 21 passengers.[4] (The DA bus should not be confused with the much later DA truck line introduced in the later 1950s.)

A minor update to the G1.

A version of the GA with the wheelbase shortened to 3,300 mm (129.9 in).[8]

Improved version of the GA, introduced in December 1938, with a redesigned front end, greater length, a slightly longer wheelbase of 3,609 mm (142.1 in), and a new 75 PS (55 kW) Type B engine, a more powerful version of the Type A engine with a higher compression ratio. In January 1940 the engine was further upgraded to 78 PS (57 kW) and the chassis was refined.[9]

A bus based on the GB chassis, otherwise similar to the previous DA bus.[11] (This DB bus should not be confused with Toyota's much later DB line of diesel buses introduced in the later 1950s.)

A version of the GB with the wheelbase shortened to 3,300 mm (129.9 in). A bus was also built on this chassis.[12]

Sunken Toyota KB truck in Chuuk Lagoon, Micronesia

Introduced in March 1942, the KB was the replacement for the GB. Designed to meet the military's demand for heavier trucks, its payload was increased to four tons, and its wheelbase was extended to 4,000 mm (157.5 in).[13] The body was still made from steel but was of a simpler design with fewer curves.

A version of the KB with the wheelbase shortened to 3,594 mm (141.5 in), the same as that of the preceding GB. This shorter chassis was also intended to be used for buses and specialized trucks.[16]

Scale model of a Toyota KC aircraft starter truck, minus the starting equipment.

Scale model of a Toyota KC aircraft starter truck, minus the starting equipment. This is a very early version that still has curved guards over the wheels. Later versions had flat guards and a single headlight.

The KC was an update to the KB in response to official government specifications for a wartime truck. Nicknamed the "Toyota To-Ki", the KC used about thirty percent less steel, which was in short supply in Japan during the war, than preceding trucks.[17] Former Toyota trucks had a torque tube driveshaft mount, but this required steel components that were difficult to obtain under wartime conditions, so the KC switched to a Hotchkiss drive.[18] The engine cover was still metal but other body panels were made from plywood. The body design was extremely boxy, with only simple curves used on the engine cover and a flat radiator with no grill. As the war dragged on and material shortages grew worse, more of the body was built from wood, the headlamps were reduced to one, and only rear brakes were used.[18][2][10][15] However, once the war ended in August 1945, Toyota continued production of the KC without these former material restrictions.[19]

One special use for the KC truck was to start aircraft engines on Japanese military airfields. A power take-off was taken from after the gearbox. It rose behind the cabin and then projected forward. This was mated to the spinner on an aircraft's propeller to start the aircraft engine. Because this version of the KC wasn't used for heavy cargo, its cargo bed was narrow and the rear wheels were singles instead of the normal doubles. Also, the cabin was very basic, having plywood sides, no doors and a canvas roof. The starter truck was unique in having running boards, due to its narrow cargo bed. Hasegawa made a 1:72 scale plastic model of the KC starter truck labelled as "Starter Truck Toyota GB", even although the real GB had a curved radiator grill and more complex bodywork.

A military amphibious vehicle using a metal boat style hull and KC truck mechanicals.

• "75 Years of TOYOTA - Vehicle Lineage" (PDF). Toyota. 2012.
• Toyoda, Eiji (1987). Toyota: fifty years in motion. Tokyo: Kodansha International. ISBN 9780870118234.</ref>
• Togo, Yukiyasu; Wartman, William (1993). Against all odds. New York: St. Martin's Press. pp. 56–73. ISBN 0-312-09733-6.