Transport plane

An aircraft designed to transport personnel and cargo. Aircraft used primarily for civilian passenger transport are generally called passenger aircraft. Military transport aircraft were established in the air force after World War I, prompted by the development of civilian passenger aircraft. In other words, aircraft developed as passenger aircraft were also used for military transport, and this trend continued until World War II. Most of the major transport aircraft used in the war were originally developed as civilian aircraft. However, since the original passenger transport design had problems loading and unloading cargo, full-scale military transport aircraft that were designed from the beginning for cargo transport were developed, and the shape seen worldwide today was established. It has wings placed high, landing gear attached to the fuselage, a small cargo hold above ground, and a large door opening at the rear of the fuselage. This design not only improved the efficiency of loading and unloading, but also made it possible to transport large cargo and drop it in the air.

Currently, the main force of transport aircraft is strategic transport aircraft, which transport large amounts of equipment, supplies, and personnel from the home country to the battlefield, and tactical transport aircraft, which transport within the battlefield. Strategic transport aircraft are primarily jet planes, as they are primarily used for long-distance transportation, but tactical transport aircraft are still mostly propeller planes (turboprop engines are the norm), as their flight distances are relatively short and they are required to be able to take off and land on short runways.

Other aircraft in use include small liaison and light transport aircraft (sometimes classified as utility aircraft), patient transport aircraft equipped with medical equipment, and VIP transport aircraft with airliner-like seats, but most of these are converted civilian aircraft. Transport aircraft have also been converted to serve as rescue aircraft, electronic reconnaissance aircraft, airborne command aircraft, communications relay aircraft, photogrammetry aircraft, weather observation aircraft, drone launch aircraft, and even attack aircraft, taking advantage of their large payloads and interior space. The most important derivative is the aerial refueling aircraft, and when the technology for aerial refueling was established after World War II, the range of military aircraft expanded dramatically. This can be said to be one of the most important changes in the history of military aviation.

[Katsuhiro Fujita]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

人員や貨物の輸送を目的とした航空機。民間用の旅客輸送を主体としたものは一般に旅客機とよばれている。軍用の輸送機は、第一次世界大戦後に民間旅客機の発達に促されるような形で空軍のなかに定着した。すなわち、旅客機として開発された機体が軍でも輸送用に使われたわけで、この傾向は第二次世界大戦まで続いた。大戦で活躍した主要な輸送機は、ほとんどが本来民間機として開発されたものである。しかし、もとが旅客輸送を主にした設計では貨物の積み下ろしに問題があるため、やがて最初から貨物輸送を基本に考えた本格的な軍用輸送機が開発されるようになり、今日世界的にみられる形態が確立された。それは、主翼を高い位置に配し、降着装置を胴体に取り付け、貨物室の地上高を小さくするとともに、胴体後部に大きな扉口を設けるというものである。この形式により、積み下ろしの能率が向上しただけでなく、大型貨物の輸送や空中投下も可能になった。

　現在輸送機の中心兵力は、本国から戦地まで大量の装備、補給品、人員などを空輸する戦略輸送機と、戦域内の輸送を行う戦術輸送機である。戦略輸送機は長距離輸送を主とするためジェット機が主になっているが、戦術輸送機のほうは飛行距離が比較的短く、また短距離の滑走で発着しうる能力が求められるため、まだプロペラ機（エンジンはターボプロップが主流）が多い。

　このほかに連絡・軽輸送用の小型機（雑用機として分類されることもある）、医療設備を備えた患者輸送機、旅客機のような座席をもつ要人輸送機なども使われているが、これらは民間機を転用したものがほとんどである。また輸送機はその大きな搭載量と機内スペースを生かして、救難機、電子偵察機、空中指揮機、通信中継機、写真測量機、気象観測機、無人機発射母機などに改造されたりしており、攻撃機にした例もある。もっとも重要な派生型は空中給油機で、第二次世界大戦後に空中給油の技術が確立されると、軍用機の行動範囲は飛躍的に広がった。これは軍事航空史上でもっとも重要な変革の一つといえよう。

［藤田勝啓］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例