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Archive for April, 2010

Development secret stories # 2 from “Fighter of phantom”

Posted by kikakuya on April 29, 2010


j7w1It was in 1943 that Japanese Navy ordered an experimental demand of a considerable drastic, high-speed fighter to not a private company but the relative’s Yokosuka Naval Air Technical Arsenal.
There also were some development plans of the fighter of 800 kilos per hour in the Japanese Army as a improvement idea of Ki-78 “Kensan” and “Ki-64”. However, they were plans in the calculation numerical value, a real machine hadn’t been produced. In view of the limit velocity of the propeller wing and of the piston velocity of the piston engine, 800 kilos per hour seemed to be a limit in the level flight to get on those days. Therefore, the research of the rocket and the jet plane had already been started in Germany, Britain, and the United States of America.
The speed record of 755.11 kilos per hour by Messerschmitt Bf109R in 1939 was not broken for five years. This tells us how “Wall” at speed from 700km per hour to 800km per hour had been “Thick”.

Also in Japan, the plans of some new airframe for the improvement were tried, Ki-64( Kawasaki) was the one of them. Besides relied on a engine output, it was thought that the propulsion system for airframes with the twin fuselage or the canard wing was new concept as the airframe form to decrease the wind drag. “Ki-94 I(Tachikawa Airplane)”, “Ki-98(Manshu Airplane)” and “Senden(Mitsubishi)”,etc. accommodated the engine on the back of the body, the tails was supported by two frames; “Ki-94 I” was bimotored type that had engine also in the front of body. However, Technological Captain Tsuruno judged that the canard configuration “Ente” was more advantageous than these twin fuselage types.
Tsuruno very interested in the design of the fighter had always thought about the method of designing an efficient single-seated fighter since the school days. This “Ente” fighter occurred to Tsuruno while experimenting at Yokosuka Naval Air Technical Arsenal in the autumn in 1993. It was the year when he graduated from the Tokyo empire university aeronautics department and was appointed to the naval forces arms manufacture lieutenant.
“Ente” is German. It means a “duck”. The main wing is on the backward of the body and The shape looked like the duck, which has long nose with a “canard wing”, so it came to be called “Ente”.
“Ente” is shape to put a usual airplane on the opposite direction. There is a small wing of corresponding to past tail plane on both sides of a long nose. The control compartment is in the fuselage mid-section, the main wing is on the back of the engine. And, the propeller attaches to the tail. The front of the body becomes an ideal shape by moving of the engine and the propeller backward, and the wind drag decreases, and less interference with the body improves the propeller efficiency, too. The twin fuselage type and the Ente type are the same in this point of the propeller efficiency, but the twin fuselage type needs two beams from the main wing to support the tail in the backward. This increases the surface area and grows the frictional drag. This is absolutely disadvantageous frame.
If the main wing is moved backward and if the tail plane is moved forward, two beams that become the obstructions of the wind drag and a structural weight decrease can be omitted. Moreover, there is an advantage of twin-engined aircraft level that the empty body forequarter can be equipped with the large caliber machine gun, too. Technological Captain Tsuruno insisted of this advantage of the canard configuration that was called “Ente” and insisted more strongly to the senior military official that there was no way excluding “Ente” to achieve 800 kilos per hour.
Though there were some precedents such as Wright brothers’ airframes as a canard configuration in the world, it was natural that there were a lot of voices that doubted the manoeuverability and stability for no experiences in Japan.

He produced the motor glider of the “Ente” type to prove his theory correct, and solves various problems after this.

(To be continued)

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