The Kawanishi K-3 was a Japanese, fast, multi-purpose civil transport aircraft from the early 1920s. Despite its good performance it was eclipsed by the release of Army surplus machines and only one was built.

Design and development

The K-3, completed in October 1921, was designed as a fast civil transport able to carry two passengers or mail and other cargo. It was a development of the

Kawanishi K-1 Kawanishi's first aircraft, the Kawanishi K-1, was designed as a mail carrier. It was the first Japanese aircraft to receive a Certificate of Airworthiness from the Aviation Bureau. It won a prize in a national contest but was not a commercial ...

completed in December 1920 and was more powerful, aerodynamically cleaner and faster. Like most aircraft of its period it had a wooden structure and was fabric-covered. It was a single bay biplane with rectangular plan wings braced by parallel pairs of interplane struts. The upper wing was joined to the upper fuselage by a cabane formed by pairs of transverse outward-leaning inverted V- struts to the forward wing spar and similar but longitudinal V's to the rear. The lower wing was joined as usual to the lower fuselage

longerons In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

. At the end of World War I Japan received a large number of Maybach engines, designed to power airships, as part of its war reparations. The K-3 was the first Japanese aircraft to use one, a Maybach Mb.IVa six cylinder, water-cooled, upright

straight engine The straight or inline engine is an internal combustion engine with all cylinders aligned in one row and having no offset. Usually found in four, six and eight cylinder configurations, they have been used in automobiles, locomotives and aircraft ...

producing . Its

radiator Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

was mounted horizontally in the upper wing centre section to reduce drag. It was nose-mounted and smoothly faired into the fuselage behind. An open, underwing cockpit seated two passengers side-by-side, with the pilot in a second open cockpit well behind the wing trailing edges. The K-3 had a fixed, conventional

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

with mainwheels on a single axle with pairs of faired landing legs and rearward drag struts mounted on the lower fuselage longerons. There was a short tailskid.

Operational history

The K-3 first flew in the early winter of 1921. It was the fastest civil aircraft in Japan, with the speed of a fighter and the load-carrying ability of a light bomber. Kawanishi had hopes of commercial success but instead the light civil transport market was filled by the lower-powered and slower Nakajima Type 5 Trainers released by the Army and no more K-3s were built. In 1926 the sole K-3 was modified to take a straight six, Benz Bz.IIIaV (

Benz Bz.IV The Benz Bz.IV was a German six-cylinder, water-cooled, inline engine developed for aircraft use. Deliveries began in 1916, and some 6,400 were produced. Design and development The Bz.IV was a dual-camshaft design, with two intake and two exhau ...

) engine as well as other changes to become the Kawanishi K-3B.

Variants

;Kawanishi K-3: Prototype with Maybach Mb.IVa. ;Kawanishi K-3B: Prototype with

and airframe modifications.

Specifications (K-3)

Notes

References

{{Kawanishi aircraft Biplanes Single-engined tractor aircraft 1930s Japanese civil utility aircraft Kawanishi aircraft