Amphibian

Kawanishi N1K1 Kyofu

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Anticipation of a need for single-seat float-equipped interceptor seaplanes prompted the Japanese navy to initiate a development programme for such aircraft in 1940, the Nakajima A6M2-N floatplane adaptation of the famous Mitsubishi A6M2 Zero being intended as a stopgap until a purpose-designed aircraft could be introduced. This was to be the Kawanishi N1K Kyofu (mighty wind), whose design was started in September of that year.

Featuring a central float and twin wing-mounted stabilizing floats, the new prototype retained the same gun armament as the A6M2 but was powered by a 1089kW Kasei 14 radial engine driving two-blade contraprops in an attempt to counter the torque-induced swing on take-off. The wing-mounted floats were originally intended to be retractable but design problems led to these being fixed before the aircraft’s first flight. Persistent trouble with the contraprop gearbox resulted in a change to the Kasei 13 engine driving a single three blade propeller from the second prototype onwards.

First flown on 6 May 1942, the N1K1 went on to trials with the navy, although with tricky take-off characteristics, in the air, with its combat flaps, the Kyofu handled and manoeuvred well. The N1K1 Kyofu reached the Imperial Navy in August 1942. At a time (the end of 1942), the N1K1 was ordered into production, but the delivery rate was slow to accelerate and fortunes changed rapidly during 1943. By December 1942, with only 15 aircraft being completed each month and Japanese offensive initiative dwindling, it was decided to end production of the aircraft, and in March 1944 the last of 89 Kyofus was delivered to the service.

Codenamed ‘Rex’ by the Allies, the N1K1 was first deployed for the defence of Balikpapan in Borneo. In the final weeks of the war N1K1s flew alongside the ‘Rufes’ of the Otsu Kokutai from Lake Biwa in defence of central Honshu against the increasing American raids on Japan.

In 1941 Kawanishi was still engaged in design of the N1K1, and while their design was still in progress Kawanishi undertook a wheel-landing gear version, designated the N1K1-J Shiden (Violet Lightning).

N1K1
Engine: 1 x Mitsubishi MK4E “Kasei-15”, 1150kW / 1460 hp
Wingspan: 12 m / 39 ft 4 in
Length: 10.59 m / 34 ft 9 in
Height: 4.75 m / 15 ft 7 in
Wing area: 23.5 sq.m / 252.95 sq ft
Max take-off weight: 3500-3712 kg / 7716 – 8184 lb
Empty weight: 2752 kg / 6067 lb
Max. speed: 480 km/h / 298 mph at 18,680 ft
Cruise speed: 365 km/h / 227 mph
Ceiling: 10560 m / 34650 ft
Range w/max.fuel: 1650 km / 1025 miles
Crew: 1
Armament: 2 x 20mm cannons, 2 x 7.7mm machine-guns

Kawanishi E15K Shiun / Norm

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The first prototype flew on December 5, 1941.
The central float was jettisonable (in order to increase speed in case of being pursued by fighters), and the wing floats were retractable. In an event of jettisoning the main float, wing floats were to stay retracted during landing on water, and would then keep the plane afloat.
15 were built.

E15K1
Engine: 1 x Mitsubishi MK4S “Kasei-24”, 1390kW
Max take-off weight: 4100-4900 kg / 9039 – 10803 lb
Empty weight: 3165 kg / 6978 lb
Wingspan: 14 m / 45 ft 11 in
Length: 11.59 m / 38 ft 0 in
Height: 4.95 m / 16 ft 3 in
Wing area: 30 sq.m / 322.92 sq ft
Max. Speed: 460 km/h / 286 mph
Cruise speed: 290 km/h / 180 mph
Ceiling: 9830 m / 32250 ft
Range: 3320 km / 2063 miles
Crew: 2

Kawanishi H8K Emily

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Although only 167 examples were produced, the Kawanishi H8K was the most advanced flying-boat to achieve production status during World War II. Designed to meet a requirement issued in 1938 for a four-engine maritime reconnaissance flying-boat superior in all respects to the British Short Sunderland, the H8K1 prototype was first flown in January 1941, but initially possessed very poor water handling qualities. Extensive modifications were made and after successfully completing its service trials the aircraft was ordered into production as the Navy Type 2 Flying Boat Model 11, powered by four 1141kW Mitsubishsi Kasei 11 or 12 radials. Armament of these early aircraft was two 20mm cannon and four 7.7mm machine guns. With armour protection, selfsealing fuel tanks and a maximum speed of 433km/h, the new flying-boat was a considerable advance over the H6K.

H8K1

It carried out its first operational mission in March 1942 when two aircraft of the Yokohama Kokutai set out from Wotje Atoll in the Marshalls to bomb Oahu Island (Pearl Harbor), putting down at French Frigate Shoals to refuel from a submarine. Arriving over the American base, the Japanese crews found heavy cloud and the raid was ineffective. As a longrange maritime reconnaissance aircraft, the H8K1 (codenamed ‘Emily’ by the Allies) with its 7,200km range, heavy armament and good performance proved a highly competent aircraft. 112 improved H8K2, with 1380kW Kasei 22 radials and armament increased to five 20mm cannon and four 7.7mm machine-guns, were built between 1943 and 1945. It was also equipped with ASV radar, being responsible for the sinking of at least three American submarines in the area north of the Philippines during the last 18 months of the war.

Additional to the maritime reconnaissance version, 36 H8K2-L boats were built in the last two years of the war, these being equipped as naval staff and troop transports capable of accommodating either 29 staff passengers or 64 fully armed troops. The progressively deteriorating war situation for Japan led to a run-down in production of flying boats during 1945 in favour of fighters for home defence, and later versions of the H8K were accordingly abandoned. Nevertheless this excellent aircraft saw considerable service, being flown by the 14th, 801st, 851st, 1001st, 1021st, Takuma, Toko, Yokohama and Yokosuka Chinjufu Kokutais.

H8K2
Engine: 4 x Mitsubishi MK4Q “Kasei-22”, 1380kW / 1850 hp
Max take-off weight: 24500-32500 kg / 54014 – 71651 lb
Empty weight: 18380 kg / 40521 lb
Wingspan: 38 m / 124 ft 8 in
Length: 28.13 m / 92 ft 3 in
Height: 9.15 m / 30 ft 0 in
Wing area: 160 sq.m / 1722.22 sq ft
Max. Speed: 460 km/h / 286 mph at 15,485 ft
Cruise speed: 290 km/h / 180 mph
Ceiling: 8850 m / 29050 ft
Range w/max.fuel: 7050 km / 4381 miles
Crew: 9
Armament: 3 x 20mm cannons, 4 x 7.7mm machine-guns, 2 x 800-kg torpedos or 2000kg of bomb

Kawanishi H6K Mavis

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Owing much to American and French flying-boat design of the mid-1930s, the large four engine Kawanishi Type 97 parasol monoplane flying boat. When first flown in July 1936, The Type 97 was Japan’s only in-service long-range reconnaissance flying-boat when that nation went to war in December 1941. The H6K1 initial military version entered limited service with the Imperial Japanese Navy in 1938, and was followed by 10 H6K2 flying-boats.

The first major production version, the H6K4, was powered by four Mitsubishsi Kinsei 43 radiais and armed with four 7.7mm machine-guns in bow and midships positions and a 20mm cannon in a tail turret, and was capable of carrying two 800kg bombs or torpedoes. A total of 66 were in service at the time of Pearl Harbor, later aircraft powered by Kinsei 46 engines. These boats were widely employed, although the initial heavy defeats inflicted on the Allies in the Pacific rendered maritime reconnaissance duties subordinate to the need for air transportation of Japanese troops during the swift conquests in the East Indies and elsewhere. A number of aircraft, designated H6K4-L, were converted for transport duties and were each able to accommodate about 18 fully-armed troops. Lacking armour and self-sealing fuel tanks, they were extremely vulnerable to fighter attacks and, after a number had been shot down, a new version entered production as the H6K5 in August 1942. By that time the maritime reconnaissance version had been given the reporting codename ‘Mavis’ by the Allies, the transport derivative being named ‘Tillie’.

Powered by either Kinsei 51 or 53 radials, the H6K5 was intended to eliminate the shortcomings of the earlier versions, but although the open bow gun position was replaced by a single-gun turret immediately aft of the pilot’s cockpit, the overall armament was not increased. Only 36 H6K5s were completed by 1943, when production gave place to the greatly superior H8K.

H6K4

Kawanishi H6K Article

H6Ks served with the 8th, 14th, 801st, Toko and Yokohama Kokutais, and some of the H6K5s were employed as naval staff transports throughout the Pacific in 1943. Eighteen aircraft served on the quasicommercial courier services in South East Asia, a number of them being destroyed by Allied aircraft both in the air and at their moorings.

H6K5
Engine: 4 x Mitsubishi “Kinsei-51”, 975kW
Take-off weight: 17500-23000 kg / 38581 – 50707 lb
Empty weight: 12380 kg / 27293 lb
Wingspan: 40 m / 131 ft 3 in
Length: 25.63 m / 84 ft 1 in
Height: 6.27 m / 20 ft 7 in
Wing area: 170 sq.m / 1829.86 sq ft
Max. Speed: 380 km/h / 236 mph
Cruise speed: 255 km/h / 158 mph
Ceiling: 9560 m / 31350 ft
Range: 4870 km / 3026 miles
Range w/max.fuel: 6670 km / 4145 miles
Crew: 10
Armament: 1 x 20mm cannon, 4 x 7.7mm machine-guns, 2 x 800-kg torpedos or 1000kg of bombs

H6K5
Engines: 4 x Mitsubishi Kinsei 46, 1070 hp
Span: 131 ft 3 in
Max speed: 211 mph at 13,120 ft
Range: 3107 miles
Max bombload: 3527 lb

Kawanishi E7K Alf / Navy Type 94

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In 1932 the Imperial Japanese Navy sought a replacement for the Navy Type 90-3 Reconnaissance Seaplane which had been built as the Kawanishi E5K. The resulting three-seat Kawanishi E7K1 was an equal-span biplane, powered by a 462kW HiroType91 engine. First flown on 6 February 1933, the prototype was handed over to the Japanese navy three months later for service trials, being flown in competition against the Aichi AB-6 developed to meet the same requirement. The E7K1 was ordered into production as the Navy Type 94 Reconnaissance Seaplane in May 1934, entering service in early 1935. However, its Hiro engine was unreliable, and although late production E7K1s had a more powerful version of the Hiro 91, this offered no improvement.
During 1938 Kawanishi built an E7K2 prototype which, generally similar to the E7K1, replaced the Hiro engine with a Mitsubishi Zuisei 11 radial. Flown for the first time in August 1938, the E7K2 was ordered into production three months later under the designation Navy Type 94 Reconnaissance Seaplane Model 2, the original version then becoming the Navy Type 94 Reconnaissance Seaplane Model 1. Production of the E7K1 totalled 183 (57 built by Nippon), and of the E7K2 about 350 (some 60 built by Nippon).
As a type, the E7Ks saw extensive use from 1935 until the beginning of the Pacific war, when the E7K1s were relegated to second-line duties. The E7K2s continued in first-line service until 1943, and both versions were used in kamikaze operations in the closing stages of the war. When, in the second half of 1942, Allied code names were allocated to Japanese aircraft, the E7K2 became known as ‘Alf’.

Johansen CAJO 59

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CAJO 59 (0001) D-GDFH

The CAJO 59 was designed by Carl Johansen (hence the name) as a general purpose 3-4 seat amphibious flying boat. It was a high-gull winged twin-engine monoplane with a wooden structure, mostly wooden skinned, apart from glass fibre/foam sandwich panels in the fuselage and fabric covered control surfaces. The wings inboard of the engines were built around two spars and had high dihedral (8.8°), which raised the engines well above the water. Outboard of the engines the wings had a single spar and were without dihedral. They carried full span slotted flaps and ailerons which were lowered when the flaps were fully extended.

The fuselage was flat sided with rounded decking, with the cabin under the wings. Its conventional flying boat V-shaped planing bottom had a change of curvature near midpoint but no discrete step. The vertical tail was straight-tapered, the rudder fitted with a trim tab. The cantilever variable incidence tailplane, with elevators, was mounted above the fuselage at about one third fin height.

The CAJO 59 was powered by two 65 hp (49 kW) Walter Mikron III inverted inline engines. Two fixed floats, mounted well outboard on single struts, stabilised flights off water. It had a manually retractable tricycle wheeled undercarriage, with main legs mounted on the fuselage and retracting into it above the waterline.

The first flight was made from water on 25 July 1967 and the first from land on 17 April 1968. Certification facilities were lacking in Denmark, so the CAJO 59 was taken to Germany and flew as D-GDFH during 1970.

It achieved certification but did not go into production.

Engines: 2 × Walter Mikron III, 48 kW (65 hp)
Propellers: 2-bladed , wooden
Length: 6.95 m (22 ft 10 in)
Wingspan: 9.80 m (32 ft 2 in)
Height: 2.75 m (9 ft 0 in)
Wing area: 12.80 m2 (137.8 sq ft)
Empty weight: 580 kg (1,279 lb)
Max takeoff weight: 900 kg (1,984 lb)
Maximum speed: 215 km/h (134 mph; 116 kn)
Cruising speed: 200 km/h (124 mph; 108 kn)
Range: 1,000 km (621 mi; 540 nmi) with maximum fuel
Rate of climb MAUW: 4.5 m/s (890 ft/min)
Crew: one
Capacity: two-three passengers

Jannus 1915 Flying Boat

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A new and efficient design for rough water, ready assembly and disassembly, inherent stability, wide range of flying speed, waterproof construction of wings, enormous margin of safety, comfort for pilot and three passengers, and a dry, clean place for them to sit, this 1915 model is ideal.
The rough water ability is obtained in two principal ways: first, all the wing attachments are independent of the motor and propeller shaft; and. second, the low centre of gravity. Of special interest are the tapering end floats that never pound or jerk the wings. These taper from three inches wide across the bottom to a foot across the top. The taper has the advantage of reducing the planing surface, which at high speed would be sufficient to pound the wings badly, but when called upon as floats are quickly displacing water at an increased rate, easily combating the heaviest side lurching or listing or yawing tendency.
The removability of the tail for shipment has many advantages in construction and in simplicity of shipment for compactness. The motor remains in the front half of the hull with all controls intact. The control cables going to the tail and rudder all pass through individual leads in a conduit that is made of heavy steel as a protection against the propeller breaking or throwing anything with sufficient force to sever them.
Between the conduit and the controls the cables are supplied with the Jannus type sister hook, which locks the cables together in a permanent fashion quickly, and without additional safety wire or other auxiliary being necessary.
The wings are assembled in their entirety before being attached to the hull and, when on, cannot fail to align properly if reasonable care is taken. Where desirable they can he put on half at a time. To April 1915 the best record showed a total load of 2.200 lbs. carried in flight at 22-55 mph with an indicated 60 h.p.
Tests in the lee of large vessels, along windward shores and in other extreme conditions of gusty wind and treacherous obstacles prove that the new struts and the staggered planes are serious contenders for the inherent stability honors. The pilots reported that in no case was there any rapid inequality developed nor did the machine make any appreciable variation from its course due to these unfavourable conditions.
The tests have been conducted by Mr. Fritz G. Ericson and Mr. Antony Jannus.
The designers did not stagger the planes in this model for other than structural advantage.
The internal construction of the wing is free from ordinary glue and is amply strong without any adhesives, although liquid marine glue is used in all joints to maintain rigidity under severe stress and to prevent rotting. All bolts go on each side of the beams, through end grain blocks that are brass covered outside of the fabric.
The pilot is seated in front, leaving a seat behind for three large passengers. The ample foot space is well above the ribs of the bottom and made in the form of a grating that is removable for cleaning the bilge scuppers or any other purpose.
The motor compartment is segregated from all other parts of the boat, so that no oil or grease can be distributed.

Itoh Emi 31

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The development of the Emi 31 began in 1922 when the fledgling Japan Air Transport Research Society bought a Curtiss Seagull flying boat as their first passenger aircraft, intended for a service between Tokyo and Yokohama Bay. This was seriously damaged before it could be delivered so the airline’s founders, Sun-ichi Bando and Yukichi Goto who had earlier owned the Emi 16 racer, turned to Itoh for a replacement flying boat. In response Tomotari Inagaki designed the Itoh Emi 28, which was strongly influenced by the Seagull and powered by a 150 hp (110 kW) Hispano-Suiza engine, but this design was never built. Another passenger company, Choichi Inoue’s Japanese Air Transport Research Association (JATRA) that had provided Japan’s first regular airline service using floatplanes between Sakai to Takamatsu and Tokushima, was looking for a suitable passenger flying boat. Aware of the Emi 28 he placed an order for a more powerful development, resulting in the Emi 31.

The Emi 31 was a wooden-structured, pusher configuration biplane. Its unequal span, fabric covered, two bay wings were braced by parallel pairs of interplane struts. The shorter lower wing was mounted on top of the hull and the upper centre section, high above the water, was strengthened by the struts that supported the pusher engine. There were ailerons on the upper wings.

Its 220 hp (160 kW), pusher configuration, water-cooled V-8 Hispano-Suiza 8B engine was pylon-mounted just below the upper wing with two long, upright, rectangular radiators mounted edge-on ahead of the upper leading edge. The Emi 31’s plywood-covered hull was essentially the same as that of the single step Seagull. On the water it was stabilized by small, strongly up-pitched floats mounted below the outer interplane struts. It had two open, side-by-side seat cockpits in tandem. Initially the pilot and flight engineer occupied the forward cockpit with two passengers behind but in service the engineer was often displaced by a third passenger.

The Emi 31’s fabric-covered tail was also similar to that of the Curtiss, with a tailplane and elevator held well clear of the water on top of an abbreviated fin. Its large, comma-profile rudder moved in a deep elevator cutout and had a forward balance area overhanging the tailplane.

The Emi 31 was completed in mid-1922. The date of its first flight is not known but, after test flights at Itoh’s Tsudanuma base, it went to the JATRA base at Sakai to fly the planned route. It was also used by The Asahi Shimbun newspaper to report army manoeuvres, catching the attention of the Prince Regent. There were frequent, poorly recorded modifications; after only a few months of use it had been significantly improved twice. It remained in use with JATRA into 1924, after which it was retired to the water surface, further modified for use as a water taxi and sightseeing-boat.

Powerplant: 1 × Hispano-Suiza 8B, 160 kW (220 hp)
Propeller: 2-bladed wooden
Wingspan: 14.66 m (48 ft 1 in)
Wing area: 26 m2 (280 sq ft)
Length: 7.65 m (25 ft 1 in)
Height: 3 m (9 ft 10 in)
Empty weight: 780 kg (1,720 lb)
Gross weight: 1,350 kg (2,976 lb)
Maximum speed: 121 km/h (75 mph, 65 kn)
Endurance: 2 hr 30 min
Crew: one, with option of a flight engineer
Capacity: three, or two with engineer