Tokyo National Research Institute for Cultural Properties Center for Conservation Science
Department of Art Research, Archives and Information Systems Japan Center for International Cooperation in Conservation
Department of Intangible Cultural Heritage

Survey of jet-engine parts in the possession of International Christian University

Two exhaust nozzles of a jet engine carried into the laboratory. The right part has a cover
Process of separating the cover

 The Center for Conservation Science, under the request of International Christian University, together with Japan Aeronautic Association, conducted survey of two materials which were excavated on the university campus in 1950 and were most likely to be parts of a jet engine. A survey conducted at the university on May 20th, 2017 revealed that they were likely to be exhaust nozzles of a jet engine manufactured in Japan during World War II. In response to this result, a more detailed investigation was conducted at the Center’s laboratory from July 6th to October 26th.
 In addition to survey of the literature and visual inspection, measurement of major dimensions and weight and survey of the structure material were carried out, together with photographic recording. Furthermore, X-ray CT photography was conducted with the cooperation of the Tokyo National Museum for the purpose of investigating the composition of the material and the internal structure. One of the two surveyed materials consisted of two parts. After being carried into the Center, it was carefully separated, foreign matters such as dust and dead leaves adhering to the surface were removed, and anticorrosive treatment was provided.
 Through the investigation, it has been confirmed that there are engravings similar to those engraved on other Japanese aircrafts manufactured during the wartime, all parts are made of stainless steel and therefore heat resistant, and the shape and structure are similar to the exhaust nozzles of jet engines “ネ130” and “ネ330,” which were also developed in Japan during the wartime. As a result, it is concluded that the materials are highly likely to be exhaust nozzles of a jet engine made in Japan and that the corresponding engine is “ネ230,” developed together with Hitachi by Nakajima Aircraft Company, which existed during World War II on the grounds of International Christian University. The exhaust nozzles are considered to have been never used because of the absence of any traces that they were attached to the body of a jet engine using bolts.
 Out of the jet engines developed in Japan during the wartime, only two examples of parts have been confirmed to exist. Therefore, the materials surveyed this time are quite valuable, showing both the advancement of Japanese technology in the 1940s and the process of the aircraft development in Japan.
 On October 26th, the representatives of the survey team visited International Christian University and submitted an interim report to President Junko Hibiya. In the future, the final report will be compiled including results of the survey on the value as cultural property.

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