Yokosuka K5Y1 / K5Y2

The Yokosuka K5Y, also known as the Type 93 Intermediate Training Aircraft, was a biplane trainer with unequal-span wings that served in the Imperial Japanese Navy during World War II.

Its bright orange paint scheme, which was applied to all Japanese military trainers for visibility, earned it the nickname “aka-tombo” or “red dragonfly”, after a common insect in Japan.

One K5Y, belonging to the Kamikaze Special Attack Corps 3rd Ryuko Squadron, was credited with sinking the USS Callaghan destroyer on July 28, 1945, marking the last US warship lost to kamikaze attack during the war.

Originally based on the Yokosuka Navy Type 91 Intermediate Trainer, the K5Y underwent a redesign by Kawanishi in 1933 due to stability issues.

It entered service in 1934 as the Navy Type 93 Intermediate Trainer K5Y1, equipped with fixed tail-skid landing gear, and remained in use throughout the war.

Floatplane versions, the K5Y2 and K5Y3, were also produced.

These planes were the primary aircraft used for flight training in the Imperial Japanese Navy Air Service, and as intermediate trainers, they were capable of performing demanding aerobatic manoeuvres.

Although two further land-based versions, the K5Y4 with a 358 kW (480 hp) Amakaze 21A engine and the K5Y5 with a 384 kW (515 hp) Amakaze 15, were projected, they were never built.

Variants

K5Y1 

Two-seat intermediate trainer for the Imperial Japanese Navy.

K5Y2 

Floatplane version, with Amakaze 11 engine.

K5Y3 

Floatplane, with 384 kW (515 hp) Amakaze 21.

K5Y4 

Projected land-based version with 358 kW (480 hp) Amakaze 21A. Never built.

K5Y5

Projected land-based version with 384 kW (515 hp) Amakaze 15. Never built.

Specifications

Crew

2

Length

8.78 m (28 ft 10 in)

K5Y1

8.05 m (26 ft)

Wingspan

11 m (36 ft 1 in)

Height

3.68 m (12 ft 1 in)

K5Y1

3.2 m (10 ft)

Wing area

27.7 m2 (298 sq ft)

Empty weight

1,130 kg (2,491 lb)

K5Y1

1,000 kg (2,205 lb)

Gross weight

1,650 kg (3,638 lb)

K5Y1

1,500 kg (3,307 lb)

Powerplant

1 × Hitachi Amakaze 11 9-cylinder air-cooled radial piston engine,

250 kW (340 hp) for take-off

300 hp (224 kW) normal at sea level

Propellers

2-bladed wooden fixed-pitch propeller

Performance

Maximum speed

200 km/h (120 mph, 110 kn) at sea level

K5Y1

213 km/h (132 mph; 115 kn)

Cruise speed

139 km/h (86 mph, 75 kn) at 1,000 m (3,281 ft)

Range

702 km (436 mi, 379 nmi)

K5Y1

1,018 km (633 mi; 550 nmi)

Service ceiling

4,330 m (14,210 ft)

K5Y1

5,700 m (18,701 ft) in

Time to altitude

3,000 m (9,843 ft) in 19 minutes 35 seconds

K5Y1

3,000 m (9,843 ft) in 13 minutes 32 seconds

Wing loading

59.6 kg/m2 (12.2 lb/sq ft)

Power/mass

0.1537 kW/kg (0.0935 hp/lb)

Armament

Guns

1× fixed, forward-firing 7.7 mm (.303 in) Type 97 aircraft machine gun

&

1× flexible, rearward-firing 7.7 mm (.303 in) Type 92 machine gun

Bombs

Up to 100 kg (220 lb) of bombs on external racks.

Sources
Japanese Aircraft, 1910-1941-Robert Mikesh & Shorzoe Abe
The Mainichi Newspapers Co Ltd
Yushukan War Memorial Museum
Japanese Aircraft of the Pacific War-Rene Francillon,
Japanese Aircraft-John Stroud,
Japanese Military Aircraft Illustrated.