Unable to produce in sufficient quantity such advanced interceptors as the Kawasaki Ki-100 (396 of all models built), the Kawasaki Ki-102 (“Randy”; 238 built) and the Mitsubishi A7M3-J Reppu (Hurricane; “Sam”; prototype only), or to bring to operational status the Funryu (“Raging Dragon”) surface-to-air guided missiles, Japan sought German aid. Plans, and in some cases completed models, were acquired of the Bachem Natter, the Reichenberg piloted-bomb (built as the Baika), and the Messerschmitt Me 262 twin-engined jet fighter-bomber. A prototype based on the latter, the IJN’s Nakajima Kikka (“Orange Blossom”), flew on 7 August 1945; if production had been attained it was to have been deployed in concealed revetements as a “special attack” bomber.
A major effort at a point-defence interceptor was the joint IJN/IJA project for the Mitsubishi J8M1 (Navy) or Ki-200/202 (Army) Shusui (“Swinging Sword”), a near-identical version of the Luftwaffe’s Messerschmitt Me 163 Komet. Rights to produce a version of the Komet’s airframe and Walter HWK 509A bi-propellant (T-Stoff and C-Stoff, which the Japanese called Ko and Otsu liquids respectively) rocket engine, with a completed example of the aircraft itself, were purchased as early as March 1944; but only one Walter unit and an incomplete set of blueprints reached Japan. Germany’s final effort to provide her ally with more material on the Komet and other “special weapons” was made on 2 May 1945, when U.234 (Cdr Johann Fehler) sailed from Norway for Japan with high-ranking Luftwaffe officers, technicians, and two Japanese scientists aboard. En route, Fehler received the news of Germany’s collapse and, as he headed for the USA to surrender his boat, both Japanese committed seppuku.
In Japan, training with the Komet-replica MXY8 Akigusa (“Autumn Grass”) glider began in December 1944. The first powered flight was attempted on 7 July 1945 at Yokoku airfield, Yokosuka. Successfully jettisoning the takeoff trolley, LtCdr Toyohiko Inuzuka had reached c.1,300ft (400m) when, probably because of a fuel line blockage caused by the steep climb, the engine flamed out and the Shusui stalled and crashed, mortally injuring Inuzuka. Later that month, an explosion of the volatile fuel mixture during ground testing killed another of the project’s officers. Many similar fatalities – especially during the hard skid-landings that often brought the liquid propellants violently together – had occurred in Germany, where the “Devil’s Egg” was regarded by many Luftwaffe personnel as semi-suicidal at best.
The Japanese rocket interceptor differed little from its German pattern. The J8M1 had a span of 31.2ft (9.5m), a length of 19.86ft (6.05m) and a height on its jettisonable trolley of 8.86ft (2.7m). Powered by a Toko Ro.2 motor giving 3,307lb (1500kg) thrust for up to c.5.3 minutes, it was estimated to be capable of a maximum 559mph (900kmh) at 32,810ft (10,000m); thus probably having a range at optimum flight profile of less than 60 miles (96km). Its armament was to be two wing-mounted 30mm cannon – although if the planned production of more than 1,000 examples by August 1945 had been achieved, it is likely that many would have been expended in ramming attacks after exhausting their ammunition of 50 rounds per gun. In the event, only seven Shusui, which were to have been operated by the 312th Naval Air Group, were completed by the war’s end.