Transport aircraft

Junkers Yu-290 with the rear ramp lowered. The tail wheel of the chassis lifted into the air is clearly visible.

Attempts to use aircraft for the transport of goods were undertaken at the dawn of aviation. In 1910, approximately 200 pounds of silk were transported by plane from the Wright brothers from a store in Dayton to a buyer in Columbus (both cities are located in Ohio , USA ), which is noted by many sources as the birth of air cargo ^[1] . In 1914, the United States Post introduced airmail service ^[2] .

The first transport aircraft were passenger aircraft adapted to the needs of cargo transportation. So, for example, on the basis of the popular passenger aircraft Douglas DC-3 , the military transport Douglas C-47 Skytrain was developed, equipped with a reinforced floor and a wide cargo hatch in the rear of the fuselage.

Standard aircraft of the first quarter of the XX century had a number of drawbacks, primarily the non-horizontal floor in the parking position due to the layout of the landing gear with a tail wheel, as well as the lateral arrangement of doors. With the growing demand for air cargo transportation and an increase in their volume, a need arose to develop aircraft specially designed for this purpose. In 1939, on the basis of a bomber that did not go into production, the Junkers Ju 90 was developed, a military transport aircraft that used an interesting technical solution: a powerful loading ramp at the tail of the aircraft opened with a hydraulic drive and lifted the plane into a horizontal “flight position”, which greatly facilitated its loading. Later, the same scheme was applied on the Ju 290 and the German Arado Ar 232 , one of the first military transport aircraft designed for this purpose from scratch.

In the 1940s - 1950s were marked by rapid growth in air traffic and, accordingly, the search for the most effective engineering solutions. There are many models of aircraft with front loading (for example, Bristol 170 , SNCAC NC 211 , Douglas C-124 ) or rear loading ramp ( Blackburn Beverley , Antonov An-12 , Breguet Deux-Ponts , Fairchild C-82 Packet ), as well as such exotic options like the Canadair CL-44 with a fully reclined tail. Many transport aircraft of the time still combined the function of passenger liners with air travel. With the growth of requirements for the safety and comfort of passengers, primarily to the noise level in the cabin, passenger and cargo aircraft were divided into two practically disjoint classes.

The need for the transportation of solid cargo, comparable in size to the largest aircraft (launch vehicles, aircraft fuselages) led to the appearance of super-heavy transport aircraft. In 1982, the An-124 Ruslan super-heavy cargo plane was launched , intended primarily for transporting intercontinental ballistic missiles and their launchers, but also widely used in civil transport aircraft for transporting bulky cargo. In 1988, the first flight was made by the An-225 , the largest transport aircraft, originally designed to transport the Buran spacecraft. In 1994, Airbus created several Airbus Beluga aircraft to transport parts of the fuselage of aircraft between the company's factories. In 2006, Boeing launched a similar aircraft, the Boeing 747 LCF Dreamlifter .

At the beginning of the 21st century, with the release of the largest passenger airliner, the Airbus A380, Airbus also planned to release a transport variant - the A380 -800F ^[3] . It would become the second (after An-225) largest transport aircraft, but in 2015 it was removed from the airline’s website and probably would not be released ^[4] .

A transport aircraft may have the following design features that distinguish it from passenger models. They are designed, first of all, to facilitate the loading and unloading of aircraft ^[5] :

• layout " vysokoplan " (allows you to position the load as close to the ground)
• reinforced chassis with lots of wheels
• cargo hatches at the bottom and top of the fuselage
• hatches in front of the fuselage (“folding nose”) and in the back (“swinging” or “folding” tail), sometimes combined with a ramp
• reduced cockpit door ^[6]
• lack of portholes

There are four fundamental approaches to the development of a transport aircraft:

Cargo version of a passenger aircraft

Due to the economic profitability of unifying the process of development, production and maintenance of aircraft, as well as significantly higher demand for passenger aircraft, most major aircraft manufacturers produce transport aircraft based on existing passenger models, for example, Airbus A330-200F , Boeing 747-8F , McDonnell Douglas MD -11F . In addition, manufacturers convert obsolete passenger aircraft that no longer meet regulatory or commercial requirements for passenger transportation to cargo aircraft. Such aircraft can be distinguished at the seams at the site of replaced portholes ^[6] .

The disadvantage of such a compromise approach is higher operating costs, since the design of the aircraft is primarily designed for the passenger function, for example, at a higher pressure in the cabin than is required for the transportation of goods. The absence of a power floor in the design of a passenger aircraft does not allow the transport of heavy single-cargo, such as trucks or subway cars. The loading height is high, which requires the use of special handling equipment at the terminals.

Extremely transport aircraft

An airplane, originally intended only for the carriage of goods and designed without regard to passenger or military functions, would be cheaper to manufacture and more economical to operate than compromise passenger-transport counterparts. In the mid-20th century, such models were produced, for example, the Fairchild C-82 , which had a fuselage of almost rectangular cross section and a double tail to facilitate loading operations. In the 1980s, by order of the US government, Douglas and Lockheed conducted a study of the economic feasibility of constructing such aircraft ^[7] . The study showed that, on the one hand, such an aircraft would achieve 20 percent savings in operating expenses, but on the other hand, in light of the relatively low demand for transport aircraft, the capital costs of developing such a model seem too high.

Military Transport Aircraft

Civil Military Transport Aircraft

The benefits of developing an aircraft that simultaneously meets the requirements of civilian and military cargo transportation are as follows:

• the design of the aircraft was originally intended for cargo transportation, which reduces the cost of production and operation compared to passenger aircraft
• development costs are shared between the civilian sector and the defense sector
• the number of aircraft required for the army is reduced, since if necessary the army can requisition civilian aircraft

At the same time, military requirements for aircraft construction - strength, maneuverability , thrust-weight ratio , etc. - can reduce the above economic advantages to nothing, except in cases of civil cargo transportation in difficult conditions, for example, in the absence of suitable runways .

Examples of military transport aircraft , civilian modifications of which are used commercially, are the Il-76 , An-124 , Lockheed L-100 Hercules . The Boeing company planned the release of a civilian version of the Boeing C-17 Globemaster III aircraft under the index MD-17 (later BC-17) ^[8] .

For the most efficient cargo placement inside round-shaped fuselages, aviation cargo is packaged in aircraft containers of a special shape - ULD ( Unit Load Device - a means of packaging goods ). The standard sizes of such containers are determined by IATA rules, their volume is from 3.4 m³ to 8.95 m³ . About 800,000 of such containers are used in the airline industry, and the annual cost of their maintenance (including losses) is 300 million US dollars ^[9] .

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  An-225

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  An-124 (Ruslan)

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  Boeing 747-400 Cargolux Airlines

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  CASA C-295

• Military transport aircraft
• Transport aviation

• Camille Allaz. History of Air Cargo and Airmail from the 18th Century . - Christopher Foyle Publishing, 2005 .-- 408 p. - ISBN 1902579828 .
• William E. O'Connor. An Introduction to Airline Economics, 6th Edition . - USA: Greenwood Publishing Group, 2001 .-- 253 p. - ISBN 0-275-96911-8 .
• RJ Burby, WH Kuhlman (McDonnell Douglas Corp.). Cargo Logistics Airlift Systems Study (CLASS). - USA: Langley Research Center, National Aeronautics and Space Administration, 1978.
• JM Norman, RD Henderson, FC Macey, RP Tuttle (Lockheed-Georgia Co.). Cargo Logistics Airlift Systems Study (CLASS). - USA: Langley Research Center, National Aeronautics and Space Administration, 1978.