Friday, August 14, 2015

Kayaba Ka-1

The Imperial Japanese Army became interested during the late 1935 in autogyro developments taking place in the USA and, believing that such an aircraft might be developed for use as an artillery spotter, imported from America in 1939 a Kellett KD-1A. However, soon after this aircraft had arrived in Japan it was irreparably damaged during a flight test and the army arranged for the wreck to be transferred to the Kayaba Industrial Company, which had been carrying out research into the autogyro configuration. Shortly afterwards Kayaba was requested to proceed with design and development of a two-seat autogyro based on the Kellett. The resulting Kayaba Ka-1 prototype comprised a fuselage with two separate open cockpits in tandem, a tail unit incorporating a tailplane with twin inverted fins, fixed tailwheel landing gear, and an Argus As 10c engine mounted conventionally in the nose of the fuselage to drive a two-blade tractor propeller; the pylon for the three-blade unpowered rotor was incorporated in the fuselage structure, mounted just forward of the front cockpit.

First flown on 26 May 1941, the Ka-1 proved successful in early flight testing, and the type was ordered into production to serve in the originally intended role as a spotter-plane for artillery units. At the same time Japanese shipping losses were beginning to rise and it was suggested that the very short takeoff required by such aircraft would make them suitable for operation from the light escort carrier Akitsu Maru. A few production Ka-1s were modified for this role and equipped to carry two 132-lb (60-kg) depth charges, but because of their limited payload capability these had to be flown as single-seaters. Operating for some time off Japanese coastal waters they were the world's first operational armed rotary-wing aircraft, with production of both versions totalling approximately 240. This number included one Ka-1 KAI which was tested with rockets attached to the rotor tips in an attempt to improve payload capability, and a single aircraft that was evaluated with a 240-hp (179-kW) Jacobs L-4MA-7 7-cylinder radial engine, allocated the designation Ka-2.

Technical data for  Kayaba Ka-1
General characteristics
    Crew: 1-2
    Length: 9.2 m (30 ft 2⅛ in)
    Rotor diameter: 12.2 m (40 ft 0¼in)
    Disc area: 117 m² (10.9 ft²)
    Empty weight: 775 kg (1,709 lb)
    Max takeoff weight: 1,170 kg (2,574 lb)
    Powerplant: 1× Argus As 10c air-cooled inverted V8 engine, 180 kW (241 hp)
    Maximum speed: 165 km/h (89 knots, 102 mph)
    Cruise speed: 115 km/h (62 knots,71 mph)
    Range: 280 km (151 nm, 174 mi)
    Service ceiling: 3,500 m (11,500 ft)
    Rate of climb: 5 m/s (980 ft/min)
    1x 60 kg (132 lb) depth charges

Nakajima Kikka* [Kitsuka]

The Kikka (Orange Blossom), though a bit smaller than the Messerschmitt Me 262, was clearly inspired by the German jet fighter. Its primary claim to fame is that it was the very first Japanese aircraft to take off under jet power, even if it did so only once. Aside from that, it was yet again a case of too little, too late, since only the one prototype actually flew, although a second one was just a few days short of readiness when Japan capitulated.

Enthusiastic reports from the Japanese air attaché in Berlin on the development of the Me 262 led the Naval Air Staff, in September of 1944, to instruct Nakajima to design and build a similar aircraft for use as a high-speed attack bomber relying on speed to evade interceptors. The formal requirements included the following: (a) a top speed of 432 mph; (b) a range of 127 statute miles with a 1,102-lb. bombload, or 173 st. miles with a 551-lb. bombload; (c) a landing speed of 92 mph; and (d) a take-off run of just 1,150 feet when using two 992-lb. thrust RATOG bottles under the wings. Additionally, the new jet was to be easily built by semi-skilled labour, and the outer wing panels were to be foldable, enabling the aircraft to be concealed in caves and tunnels.

Designers Kazuo Ohno and Kenichi Matsumura created a plane that could be called a 2/3 rd or ¾ th-scale mimic of the Messerschmitt fighter. Whereas the Me 262 had a wingspan of about 40 feet and a length of around 34 feet, the Japanese aircraft was just a bit over 26 ½ feet long with a wingspan of just over 32 ¾ feet. Its wing was nicely swept, but the tail surfaces were not, and all control surfaces were, oddly enough, fabric-covered in an otherwise-all-metal airplane. The canopy was a three-piece sliding type, instead of the Messerschmitt’s three-piece hinged “coffin-lid” arrangement.

The twin turbojets were mounted beneath the wings in separate nacelles, allowing, with a minimum of changes, the installation of a variety of engines as they were developed. As it turned out, this feature was quite useful, as engine development fell behind that of the airframe. Initially, the plane was to have been powered by two Campini-type Tsu-11 engines, but these were replaced by a pair of 750-lb. thrust Ne-12 turbojets. But the future of the Navy Special Attacker Kikka (as it was designated) was made uncertain by the failure of the Ne-12 to develop its designed power during ground tests. By a stroke of luck, Engineer Eichi Iwaya of the Navy had obtained detailed photographs of the BMW 003 axial-flow turbojets used in the Me 262, and from those photos the Japanese were able to create a similar engine, designated Ne-20, with a theoretical power output of 1,047 pounds of static thrust. Everyone concerned felt the Ne-20 was perfect for the Kikka, and so the project’s pace was speeded up during the summer of 1945.

At this point, a note about the aircraft’s designation would be in order. Although it was dubbed a "Special Attacker", this writer believes that the Kikka was not actually intended for kamikaze attacks, except in extremis (i.e., if the pilot were wounded or the airplane was damaged, and could not return to base). It seems very foolish to go to the trouble to design a very expensive jet-powered plane and then assign it to one-way missions. The Me 262 was notorious for requiring a skilled pilot to fly it, and even then the pilot, if he had previous experience in aircraft with reciprocating engines, had to unlearn a lot of habits which were all right for flying conventional fighters but which could be fatal in the 262. For example, the Me 262’s throttles could not be “chopped”, i.e., quickly brought from high power to a lower-power setting, or shoved forward swiftly, “balls to the wall” as American flying slang put it.
Jet throttles had to manipulated carefully and slowly, or else the jet engines would flame out, either from fuel starvation or fuel satiation. Thus, by analogy, only skillful pilots could fly the Kikka. 

Undoubtedly the Japanese were aware, from reports from their air attaché in Germany, of the unique problems involved in flying a jet as opposed to flying a more conventional aircraft. Thus, the Kikka could not have been intended as a kamikaze aircraft. Indeed, it was intended for other roles besides being a fast attack bomber, as will be seen. The term “Special Attacker” refers, in this writer’s opinion, to the special way the Kikka was powered (by jets) rather than to its being intended for “special”, i.e., suicide, attacks.

With its Ne-20 engines installed, the Kikka prototype was given its first ground tests on June 30, 1945. Late in July, it was dismantled and taken to Kisarazu Naval Airfield, where after re-assembly it was flown for the first time on August 7, with Lt. Cdr. Susumu Takaoka as test pilot. The Kikka taxied for a long time before it gained enough speed to lift off the ground; the flight itself lasted just 20 minutes, and the aircraft was never taken above 2000 feet. The slowness with which it gained take-off speed delayed the second flight until August 11, when it attempted to lift off with RATOG bottles beneath the wings. Unfortunately, the rocket bottles were not installed at the correct angle to lift the Kikka off the runway, and after the rockets burned out, the pilot aborted the take-off and crashed into the rough ground beyond the runway’s end. The second prototype was almost ready for its own first flight when the war ended on August 15. Eighteen additional prototypes and pre-production examples were left in various stages of construction on that date.

Aside from the basic attack bomber, there was a projected unarmed two-seat trainer, and the third Kikka was to be the prototype for this variant. An unarmed two-seat reconnaissance version and a cannon-armed single-seat fighter were also under development at the war’s end. The fighter variant was to have been powered by either a pair of 1,984-lb. thrust Ne-130 or a pair of 1,951-lb. thrust Ne-330 axial-flow turbojets, and armed with a pair of nose-mounted 30mm cannon.

Nakajima Kikka Technical Data
Single-seat twin-jet attack bomber, of all-metal construction with fabric-covered tail surfaces.
Pilot in enclosed cockpit.
Two Ne-20 axial-flow turbojets, rated at 1,047-lb. of static thrust.
Armament: One 1,102-lb. or 1,764-lb. bomb under the fuselage centre section.
Dimensions, weights, and performance:
Wingspan: 32 ft. 9 11/16 in.;
length, 26 ft. 7 7/8 in.;
height, 9 ft. 8 5/32 in.;
wing area, 142.083 sq. ft.;
empty weight, 5,071 lb.;
loaded weight, 7,716 lb.;
maximum weight, 8,995 lb.;
wing loading, 54.3 lb./sq. ft.;
power loading, 3.7 lb./lb. s. t.;
maximum speed, 387 mph at sea level, (estimated) 433 mph at 32,810 ft.;
(estimated) climb to 32,810 ft., 26 minutes;
(estimated) service ceiling, 39,370 ft.;
(estimated) range, 586 statute miles.

In the section devoted to this aircraft he refers to the aircraft as the Nakajima Kitsuka (I had always thought it the Kikka).

At the end of the section he says this .....

'A note about the use of the name Kitsuka as opposed to the more commonly used Kikka. Kitsuka is the proper translation of the kanji characters. However, it is pronounced 'kikka'. Kikka was used in post-war reports as phonetically it approximated to Kitsuka and thus has become the accepted name of the aircraft. Neither name is incorrect.'

Now, quite apart from the fact that our high school teachers would be aghast at the last sentence containing a double negative, I would have thought that the translation of kanji characters in an English language book would be phonetic (the same as Russian words and names are) with perhaps slight differences in spelling.

So how then do you get Kitsuka pronounced Kikka if it isn't Kikka......As I see it Kitsuka has 3 syllables and Kikka has 2? 

If Kitsuka is pronounced Kikka, then if someone asks me what this aircraft is then should I say Nakajima Kikka, but write down Nakajima Kitsuka?