Kawanishi E15K

E15K Shiun
Role	Reconnaissance floatplane
Manufacturer	Kawanishi Aircraft Company
First flight	5 December 1941
Primary user	IJN Air Service
Number built	15

The Kawanishi E15K Shiun (紫雲, "Violet Cloud") was a single-engined Japanese reconnaissance floatplane of World War II. The Allied reporting name for the type was "Norm" after Squadron Leader Norman O. Clappison of the RAAF, a member of the Allied Technical Air Intelligence Unit (ATAIU).

Design and development

In 1939 the Imperial Japanese Navy instructed the Kawanishi Aircraft Company to develop a two-seat high-speed reconnaissance floatplane, which was required to have sufficient performance to escape interception by land based fighters.^[1] It was planned to equip a new class of cruisers, intended to act as a flagship for groups of submarines, operating six of the new floatplanes to find targets. The first of the new cruisers, Ōyodo was also ordered in 1939.^[2]

Kawanishi designed a single-engined low-wing monoplane, powered by a 1,460 hp (1,090 kW) Mitsubishi MK4D Kasei 14 14-cylinder radial driving two Contra-rotating two-bladed propellers, the first installation of contra-rotating propellers produced in Japan,^[3] while a laminar flow airfoil section was chosen to reduce drag. It had a single main float under the fuselage and two stabilising floats under the wing. The stabilising floats were designed to retract into the wing, while the central float was designed to be jettisoned in case of emergency, giving a sufficient increase in speed (estimated as approximately 50 knots (90 km/h)^[2]) to escape enemy fighters.^[4]

The first prototype of Kawanishi's design, designated E15K1 in the Navy's short designation system made its maiden flight on 5 December 1941.^[3] Five more prototypes followed during 1941-42. Problems were encountered with the retractable stabilising floats, resulting in several accidents when the floats could not be lowered for landing, and the system was eventually abandoned, with the stabilising floats being fixed, and a more powerful Mitsubishi MK4S Kasei 24 engine fitted to compensate for the increased drag.^[5]

Operational history

Despite these problems, the E15K1 was ordered into limited production as the Navy Type 2 High-speed Reconnaissance Seaplane Shiun Model 11.^[6] Six were sent to Palau in the South Pacific, but these were quickly shot down by Allied fighters, as the jettisonable float failed to separate on demand (although subjected to wind tunnel testing, the float separation system had never been tested on the actual aircraft). This resulted in the cancellation of production in February 1944, with only 15 Shiuns completed, including the six prototypes.^[5][7]

Variants

• E15K1 : Single-engined reconnaissance floatplane. Production version.

Operators

 Japan

• Imperial Japanese Navy Air Service

Specifications (E15K)

Data from Japanese Aircraft of the Pacific War^[7]

General characteristics

• Crew: Two
• Length: 11.59 m (38 ft 0 in)
• Wingspan: 14.00 m (45 ft 11 in)
• Height: 4.95 m (16 ft 2⅞ in)
• Wing area: 30.0 m² (323 ft²)
• Empty weight: 3,165 kg (4,978 lb)
• Loaded weight: 4,100 kg (9,039 lb)
• Max. takeoff weight: 4,900 kg (10,803 lb)
• Powerplant: 1 × Mitsubishi MK4S Kasei 24 14-cylinder air-cooled radial engine with two two-blade contra-rotating propellers, 1,159 kW (1,540 hp)at 5,500 m (18,045 ft)

Performance

• Maximum speed: 468 km/h (253 knots, 291 mph) at 5,700 m (18,700 ft) (float attached)
• Cruise speed: 296 km/h (160 knots, 184 mph)
• Range: 3,373 km (1,820 nmi, 2,095 mi)
• Service ceiling: 9,836 m (32,270 ft)
• Wing loading: 136.7 kg/m² (28 lb/ft²)
• Power/mass: 0.28 kW/kg (0.17 hp/lb)
  
• Climb to 6,000 m (19,700 ft): 10 min

Armament

• 1 × 7.7 mm (0.303 in) machine gun in rear cockpit

See also

Related lists

• List of military aircraft of Japan
• List of seaplanes and flying boats

References

Notes

1. Francillon 1979, p. 314.
2. Layman and McLaughlin 1991, pp. 77–78.
3. Francillon 1979, p. 315.
4. Green 1962, p. 127.
5. Green 1962, p. 128.
6. Francillon 1979, pp. 305–306.
7. Francillon 1979, p. 316.

Bibliography

• Francillon, PhD., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970. (2nd edition 1979, ISBN 0-370-30251-6).
• Green, William. War Planes of the Second World War: Volume Six, Floatplanes. London: Macdonald & Co. (Publishers) Ltd., 1962.
• Jackson, Robert, The Encyclopedia of Military Aircraft, Parragon, 2002. ISBN 0-7525-8130-9.
• Layman, R.D and Stephen McLaughlin. The Hybrid Warship. London: Conway Maritime Press, 1991. ISBN 0-85177-555-1.

External links

• Imperial Japanese Navy Page