Designed in the late 1960s as a medium transport to replace the C-46 Commando in Japanese Air Self-Defence Force (JASDF) service, the Kawasaki C-1 has a typical military transport configuration. Kawasaki flew the first example in November 1970, and delivered 31 aircraft in October 1981. Proposed tanker, reconnaissance and other military variants were abandoned, but one C-1 has been used for research into blown flying surfaces for improved field performance.

With its high wing, fuselage-mounted undercarriage sponsons and hydraulically-actuated rear loading ramp, the C-1 Asuka resembles other tactical transport aircraft. Designed to provide maximum internal cargo space for troops, vehicles and freight, it is powered by turbofan engines hut carries a smaller payload than the Lockheed C-130 Hercules or Transall C- 160.

Construction of the C-1 was a collaborative effort involving the four major Japanese aircraft manufacturers, with Fuji, Mitsubishi and Nihon all contributing major subassemblies. The Asuka was used to equip two Japanese Air Self-Defence Force (JASDF) transport squadrons, the 402nd based at Iruma and the 403rd at Miho. One C-1, known as the EC-1, was modified as an electronic warfare training aircraft, with massive bulges and radomes to house the necessary sensors. Another was used as a testbed for the T-4 trainers Ishikawajima-Harima F3 engine and the MIT1/NAL FJR710 high-bypass turbofan.

Another modified C-1, the National Aerospace Laboratory Asuka, a quiet short take-off and landing (QSTOL) research aircraft, uses the FJR710/600S powerplant. Although the C-1 was designed to a JASDI’ specification, its limited payload has ultimately restricted its versatility in service and a replacement is being sought.

For air-dropping freight or paratroops, the rear loading ramp and clamshell doors can be opened in flight. Typical loads include a 105-mm howitzer, three jeeps, a 2.54-tonne lorry or two 0.76-tonne trucks. Alternatively, three standard freight pallets may be accommodated.

Contrary to the solution adopted by Lockheed for the tail unit on its C-130, Kawasaki used a high-set horizontal surface on the C-1. This keeps the tailplane clear of the jet wash.

Although some American ECM and Elint avionics are employed by the EC-1, Elint equipment from Toshiba and the XJ/ALQ-5 ECM suite from Mitsubishi Electric are the heart of the onboard system.

Setting the wings high up on the fuselage ensures that the wing carry-through structure does not affect cabin volume. The outer wings were built by Fuji, with Nihon producing the engine pods and control surfaces.

Kawasaki C-1Large fairings fesfoon the EC-1, the most unusual being the giant radomes on the nose and beneath the tail. Kawasaki modified the 21st C-1 airframe to this standard, to meet a 1983 Defence Agency contract.

Using the upswept tail arrangement that has become characteristic of tactical transports, the C-1 offers easy loading. Three separate hydraulic units operate the aircraft’s systems, one of which is dedicated solely to the rear ramp.