In 1918, the japanese Army purchased from France some of the most highly regarded military aeroplanes of the First World War, among them Nieuport 24 fighter. This and others were evaluated at the newly established Kagamigahara Army Airfield. At that time, 27 October, 1918, Tomotari Inagaki, a long-time friend of the company, and still studying in Tokyo Polytechnical School, became engineer of Itoh Aeroplane Research Studio. By chance, he had an opportunity to visit Kagamigahara and was able to rationalize the design and manufacture of a small aerobatic aircraft similar to the designs he had just seen. Beginning on 8 January, 1919, Inagaki started his first design as a company employee. It was to be a single-seat single bay biplane, light in weight, rugged, and easy to fly.

Logically, the design followed that of the Nieuport, but to obtain sufficient lift with the low powered 50hp Gnome engine Inagaki increased the total wing area, yet retained the same overall wing span and chord of the upper wing, by enlarging the lower wing to conform to that of an equal-span biplane rather than the sesquiplane arrangement of the Nieuport. The appearance of this aeroplane was considered radical when compared to other Japanese aircraft at that time.

The front half of the fuselage was ply-covered. To enhance the aeroplane’s appearance and resemble a fighter aircraft after which it was patterned, Itoh himself painted a white crane like a unit insignia on the sides of the fuselage similar to those often used by the French Air Force. This aeroplane was completed on 21 April, 1919, and made its first flight on 25 April.

Although Yamagata began teaching himself the skills of aerobatic flying, much had to be learned from an English-language book he had bought. His efforts included being suspended upside down while strapped in a chair to visualize control movements while in inverted flight. On 5 May, using this aeroplane, he became the first civil pilot in Japan to complete a loop.

Engine: Gnome, 50hp
Propeller: two-blade wood
Span: 7.21m (23ft 8in)
Wing area: 14.58sq m (156.942sq ft)
Length: 5.77m (18ft 11.25in)
Height: 2.38m (7ft 9.5in)
Empty weight: 204kg (450Ib)
Loaded weight: 340kg (749Ib)
Maximum speed: 74kt (85mph)
Climb to 1,000m (3,280ft): 4min 30 sec

After the move caused by the destruction after the tsunami, ltoh Hikoki Kenkyusho built its first aircraft under the designation Tsurubane No.1 (“crane wing”). Its design was started by Ito’s assistant, The Tsurubane’s design was the result of the retrieval of a 50 hp (37 kW) Gnome rotary engine from the crashed Tamai No.3 by a relative of Itoh’s talented assistant, Toyotaro Yamagata, and given to him to create his own aircraft. This engine was purchased by Yamagata’s uncle to allow his nephew to finish the project. Yamagata made some initial sketches but Itoh was asked to take on the detailed design.

The aircraft that emerged was a wooden-structured, fabric covered two bay biplane. Its wings were rectangular in plan, with bays separated by pairs of upright, parallel interplane struts. The considerable overhang of the upper, greater span, wing was wire braced and a cabane of parallel struts held the central upper wing high above the fuselage. As on Itoh’s earlier aircraft there were ailerons only on the upper wings, with chords that increased outwards.

Its rotary engine was shrouded with a standard, open-bottomed cowling intended to collect oil spray. Behind it the fuselage became slender and flat-sided, as with Itoh’s earlier designs. Its pilot had an open cockpit near the wing trailing edge. The tail was like that of the Itoh Emi 2 with the horizontal tail mounted on the top of the fuselage carrying elevators that had a cut-out for rudder movement. The fin and rudder had upright, parallel edges but a sloping top.

Though its landing gear was a conventional, single axle design, Itoh was aware of the need to make it robust. It had large wheels and was taller than those of his earlier landplanes, with landing legs and rearward drag struts doubly cross-braced.

The Tsurubane was completed on 8 May 1918 and flown soon after.

The Tsurubane No.1, like several other early Japanese civil aircraft, initially paid its way with demonstration flights. Yamagata began with flights around Hiroshima. These attracted support from the Asahi Shimbun newspaper resulting in a tour of Korea, at that time part of the Japanese empire, throughout November 1918. In the following spring the Tsurubane gave many exhibition flights in Osaka. World-wide, early aircraft demonstrators included risky tricks to swell audiences: on one occasion the Tsurubane carried a passenger astride the fuselage.

When it was retired from demonstration flights, the Tsurubane was used as a trainer by Itoh’s flying school. It is not known how long it remained airworthy but it was eventually privately purchased, then donated to the Aki-Itsukushima Shrine near Hiroshima.

Tsurubane No.1
Powerplant: 1 × Gnome, 37 kW (50 hp)
Propeller: 2-bladed
Wingspan: 10 m (32 ft 10 in)
Wing area: 30 m2 (320 sq ft)
Length: 6.5 m (21 ft 4 in)
Height: 2.6 m (8 ft 6 in)
Empty weight: 380 kg (838 lb)
Gross weight: 520 kg (1,146 lb)
Maximum speed: 80 km/h (50 mph, 43 kn)
Cruise speed: 65 km/h
Crew: one