Wednesday, April 15, 2015

Kawasaki Ki-91

By 1943, the bombers then in service were not adequate to the task. For too long Japanese designers remained with twin engined bombers and these had reached a point where no more capability could be squeezed out of them, regardless of modifications tried. Service aircraft such as the Nakajima Ki-49 Donryu ( Storm Dragon ) and the older Mitsubishi Ki-21 "Sally" could not keep pace with and survive in the face of allied fighter power. The Mitsubishi Ki-67 Hiryu ( Flying Dragon ) proved better able to cope to a degree but it arrived in the war area much too late to make much of an impact. What was needed was something more capable with a greater range, heavier bomb load, and most importantly, something faster than those bombers in the field. And to do this required the use of more engines.

While the Navy struggled with the Nakajima G8M Renzan ( Mountain Range ) four engined bomber ( which was hampered by allied air attacks and material shortages ), Kawasaki undertook a four engined design for the Army and this was the Ki-91.

Kawasaki began investigating this design in May of 1943 but progress was slow. The Ki-91 featured a fully pressurized cabin and had a radius of action of 2,796 miles with a 8,818lb. bomb load. While this range was 436 miles more than the Ki-67 Hiryu, the bomb load able to be carried by the Ki-91 was 7,053lbs. more than the Ki-67, a substantial payload improvement. If the bomb load was less, a maximum range of 6,214 miles could have been reached. The estimated speed of 360mph for the Ki-91 was 26mph faster than the Ki-67. All around, the Ki-91 was proving to be a superior airplane to the best of the bombers then in service.

The defensive armaments for the Ki-91 were heavy, easily outgunning the weapon fits of the Ki-67. There were five power-operated turrets, all but one of them mounting two 20mm cannon. The remaining turret, mounted in the tail, was equipped with four 20mm cannon. There was a turret in the nose, one on the top of the fuselage, and two beneath the fuselage along with the tail position.

The engine array consisted of four Mitsubishi Ha-214 Ru engines, each developing 2,500hp which would drive the plane at its maximum speed of 360mph. Two engines were mounted in each wing in streamlined cowling/nacelles.

Overall, the Ki-91 would have been 108ft . and 3in. long, have a span of 157ft. and 5in., and have a loaded weight of 127,868lbs.

As mentioned, for one reason or another, progress on getting the Ki-91 from the drafting table to flying prototype lagged. The prototype was partially complete by 1945 but a bombing raid by U.S. B-29s in February of 1945 destroyed the tools and jigs needed to complete the Ki-91 and prepare the design for production. With the required materials gone, work on the Ki-91 ceased.

Kawasaki Ki-66

This aircraft was designed by Kawasaki to meet an Army specification for a twin-engined aircraft intended especially for dive-bombing attacks in support of land forces. Drawing heavily on experience acquired in designing the twin-engined Ki-45 heavy fighter and the Ki-48 light bomber, the project moved forward at Kawasaki in late 1941. Only six prototypes were completed between October 1942 and April 1943, and despite successfully completing its flight test program, it was decided that the Ki-66 was only marginally superior to the Ki-48 which was already in production. All further work was suspended by October 1943.

Technical info (Ki-66-Ib):

Type: Army experimental dive bomber
Service: Japanese Army Air Force (JAAF)
Crew: 2 (Pilot and gunner)
Armament: two 12.7 mm Ho-103 machine guns in the nose one rear-firing 7.7 mm Type 89 machine gun in the dorsal position one flexible 7.7 mm Type 89 machine gun in the ventral position up to 1102 lb (500 kg) of bombs
Reference: Francillon: 123

Specifications:  Length: 36' 9" (11.2 m) Height: 12' 1.75" (3.7 m) Wingspan: 50' 10.25" (15.5 m) Wing area: 365.972 sq. ft (34 sq. m)
Empty Weight: 9039 lbs (4100 kg)
Loaded Weight: 12677 lbs (5750 kg)
Propulsion: No. of Engines: 2 Powerplant: Nakajima Ha-315-I 14-cylinder radial Horsepower: 1360 hp each

Performance: Range: 1243 miles (2000 km)
Cruise Speed: n/a
Max Speed: 332 mph (535 km/h) at 18,370 ft (5600 m) Climb to/in: 16,405 ft (5000 m) in 7 min 30 sec
Ceiling: 32,810 ft (10,000 m)
Production: six Ki-66 prototypes total

Aichi S1A1 Denko

The Aichi S1A1 Denko (Bolt of Light) was intended to be the replacement for the Nakajima J1N1-S Gekko, filling the role of a radar-equipped night fighter to combat the American B-29 raids. Development time increased while trying to overcome the shortcomings (insufficient power) of the Navy's requested engines to be used, resulting in no aircraft being completed before the war ended. Both of the S1A1 prototypes were destroyed in separate Allied bombing raids when they were only 70-90% complete.

Aichi S1A Denko
Type: advanced nightfighter
Service: Japanese Navy Air Force (JNAF)
Crew: two
Armament: two fuselage-mounted forward-firing 30mm Type 5 cannons
                   two fuselage-mounted forward-firing 20mm Type 99 cannons
                   two dorsal turret-mounted 20mm Type 99 Model 2 cannons
                   one 551 lb (250 kg) bomb externally

        Length: 49' 6.5" (15.1 m)
        Height: 15' 1.5" (4.61 m)
        Wingspan: 57' 5" (17.5 m)
        Wing area: 505.902 sq. ft (47 sq. m)
        Empty Weight: 16138 lbs (7320 kg)
        Loaded Weight: 22443 lbs (10180 kg)
        Max Weight:25375 lbs (11510 kg)

        No. of Engines: 2
        Powerplant: Nakajima NK9K-S Homare 22 18-cylinder radial
        Horsepower: 2000 hp each

        Normal Range: 1054 st miles (916 naut miles)
        Max Range: 1580 st miles (1373 naut miles)
        Cruise Speed: 276 mph at 13125 ft (240 kt at 4000 m)
        Max Speed: 366 mph  at 26245 ft (318 kt at 8000 m)
        Climb to/in: 29530 ft (9000 m) in 14 min 45 sec
        Ceiling: 39370 ft (12000 m)

Production: No aircraft completed by the end of the war.

Additional color schemes for this aircraft can be found here.

Aichi E16A1 Zuiun

The design of a twin-float reconnaissance seaplane, to supersede the E13A1 in service, was initiated by Aichi in October 1940. This had the company designation AM-22, and in early 1941 the Imperial Japanese navy drew up a specification based upon this design. The first of three prototypes was flown for the first time during May 1942, but the resolution of stability problems, and of buffeting from the dive brakes occupied 15 months, the navy ordering the E16A1 into production in August 1943 as the Navy Reconnaissance Seaplane Zuiun Model 11.

Of low-wing monoplane configuration, the E16A1 had wings that incorporated trailing-edge flaps, and which could be folded for shipboard stowage. Basic structure was of metal, but the tailplane and wingtips were of wood, and all control surfaces were fabric covered. The single-step floats each included a controllable rudder to assist in on-water operation, and the forward mounting strut of the floats incorporated by hydraulically-actuated dive brakes to allow the E16A1 to operate as a dive-bomber. Accommodation for the crew of two was provided in tandem cockpits, enclosed by a long transparent canopy. Powerplant of the prototype and of early production Zuiun (auspicious cloud) aircraft consisted of a 1,300-hp (969-kW) Mitsubishi Kinsei 51 radial engine, driving a three-blade propeller. A single prototype of an improved E16A2 was being flight tested at the time of the Japanese surrender, powered by a 1,560-hp (1163-kW) Mitsubishi MK8P Kinsei 62 radial engine.

Production totalled 193 by Aichi and 59 by Nippon. Unfortunately for the navy, by the time the E16A1 entered service the Allies had gained air superiority and in consequence these aircraft, allocated the Allied codename 'Paul', suffered very heavy losses during 1944. The majority which survived were used for kamikaze operations in the Okinawa area.

Aichi E16A1 (late production)
Type: long-range reconnaissance floatplane
Powerplant: one 1,300-hp (969-kW) Mitsubishi MK8D Kinsei 54 14-cylinder radial piston engine
Performance: maximum speed at 18,045 ft (5500 m) 273 mph (440 km/h); cruising speed at 16,405 ft (5000 m) 208 mph (335 km/h); service ceiling 32,810 ft (10000 m); maximum range, 1,504 miles (2420 km)
Weights: empty 6,4931b (2945 kg); maximum take-off 10,038 lb (4553 kg)
Dimensions: span 42 ft 0 ¼ in (12.81 m); length 35 ft 6 ½ in (10.83 m); height 15 ft 8 ½ in (4.79 m); wing area 301.40 sq ft (28.00 m2)
Armament: two 20-mm wing-mounted Type 99 Model 2 cannon and one 13-mm (0.51-in) Type 2 machine-gun on flexible mount in aft position, plus one 551-lb (250-kg) bomb on under fuselage mounting
Operator: Japanese navy

    Main production version.
    Single prototype with Kinsei 62 piston engine.