Aerial Lifelines: Tracing the History of Air-to-Air Refuelling
Category: AirTanker Released: 15 July 2023
In the realm of aviation, air-to-air refuelling stands out as a remarkable feat of engineering and a critical technique that has transformed the capabilities of military and civilian aircraft. With the ability to transfer fuel between aircraft mid-flight, air-to-air refuelling has extended flight endurance, expanded operational range, and enhanced the overall effectiveness of missions.
Air-to air refuelling is at the core of what we do today. However, knowing where this fantastic capability started, 100 years ago, is something we cannot take for granted. This article takes you on a journey through the fascinating history of air-to-air refuelling, highlighting its origins, significant milestones, and its pivotal role in shaping modern aviation.
The concept of air-to-air refuelling can be traced back to the early days of aviation. As early as the 1920s, visionaries like the Italian engineer and aviation pioneer, Giovanni Caproni, proposed the idea of mid-air fuel transfers. It was in June 1923 that the first successful recorded refuelling flight was completed with US Army Air Service aircraft.
The military had developed a successful system for midair refuelling between DH-4B bi-planes, following previous endurance attempts that were limited mainly by fuel supply. However, it was not until the 1930s that tangible progress was made in developing practical methods for in-flight refuelling.
Development and World War II
In the late 1930s, the United States Army Air Corps (predecessor to the United States Air Force) initiated experiments to further explore the potential of air-to-air refuelling. In 1941, the first successful demonstration of air-to-air refuelling took place when a modified Boeing B-18 Bolo bomber transferred fuel to another B-18 in flight. This achievement laid the groundwork for further advancements in the field.
During World War II, air-to-air refuelling emerged as a crucial technique for long-range bombing missions. The British Royal Air Force (RAF) used a system called the "Looped Hose" for refuelling their Short Stirling bombers, while the United States employed the "Probe and Drogue" system, which featured a refuelling probe on the receiving aircraft and a flexible hose trailed by the tanker aircraft. These early systems, though rudimentary, provided valuable experience and set the stage for future developments.
Advancements in the Cold War Era
The Cold War era witnessed significant advancements in air-to-air refuelling technology. The United States Air Force introduced the "Flying Boom" system in the 1950s, which involved a rigid pipe with movable surfaces (the boom) extending from the tanker aircraft to make contact with the receiving aircraft's receptacle. This method allowed for faster and more efficient fuel transfer, leading to increased operational flexibility and range for military aircraft.
The 1960s brought further innovations, such as the development of the "Probe and Drogue" system used by NATO allies, including the United Kingdom and France. This system employed a flexible hose with a stabilising drogue at its end, which the receiving aircraft would connect to using a refuelling probe. The "Probe and Drogue" system proved to be versatile and compatible with a wide range of aircraft.
Modernisation and current day application
As technology advanced, air-to-air refuelling systems became increasingly sophisticated and reliable. The beginning of computerised flight controls, advanced sensors, and improved aircraft designs further enhanced the efficiency and safety of the process. Introducing, Voyager’s predecessors…
In 1978 the RAF announced that instead of converting yet another bomber, which they didn't have, it would form a squadron of nine dedicated tanker aircraft.
Although designed as a civil airliner, the VC10 proved to be an excellent platform for Air to Air Refuelling (AAR), and in this role served the Royal Air Force (RAF) for almost twenty years. The VC10 was never designed as a tanker and it took quite a bit of work to convert the different airframes for their new role.
In 1977, studies began into converting redundant commercial VC10s into aerial refuelling tankers; the RAF subsequently contracted British Aerospace to convert nine former civilian airliner VC10s to the K2 and K3 variants. Both variants featured a pair of wing-mounted refuelling pods and a single centreline refuelling point, known as a Hose Drum Unit (HDU), installed in the rear freight bay; nose-mounted refuelling probes were also fitted.
In 1982, VC10 C.1s formed a part of the airbridge between RAF Brize Norton and Wideawake Airfield on Ascension Island during Operation Corporate, the campaign to retake the Falkland Islands.
The VC10 completed its final flights in RAF service on 20 September 2013.
The Lockheed TriStar entered service with the RAF in 1984 as an air-to-air tanker and transport aircraft; a converted civilian Lockheed L-1011-500 TriStar airliner previously operated by British Airways and Pan American World Airways.
The RAF purchased these aircraft following the Falklands War, after a requirement for additional air-to-air refuelling (AAR) operations had been identified.
The Tristar operated a centre line refuelling hose which provided fuel to receiving aircraft one at a time.
The TriStar fleet was operated by No. 216 Squadron at RAF Brize Norton. No. 216 Squadron was officially disbanded on 20 March 2014 and flew its last sorties with the TriStar on 24 March 2014.
With both the VC10 and TriStar aircraft nearing their retirement, the RAF needed to source a replacement that would support the future requirements of AAR, Air Transport and Aeromedical Evacuation.
Enter the Voyager
In 2008, AirTanker were award the Future Strategic Tanker Aircraft contract by the MOD. With the fantastic flexibility of the aircraft, the Airbus A330 MRTT was a clear contender from the start and has proven to be the RAF’s most reliable and versatile aircraft. With the fuel capacity of the aircraft greater than those of its predecessors, and using the capacity already provided by the aircraft, Voyager can comfortably transport passengers, carry our air-to-air refuelling and carry out aeromed capabilities simultaneously.
The current day capabilities of the Voyager are possible, due to the groundbreaking and blue sky thinking of those now 100 years before us, and all the subsequent research and developments that have taken place.
Air-to-air refuelling has evolved from a visionary concept into a critical capability that has shaped the face of modern aviation. From its humble beginnings in the early 20th century to its pivotal role in military operations today, this remarkable technique has extended the reach and endurance of aircraft, enabling missions that were once deemed impossible.
As technology continues to advance, air-to-air refuelling systems are likely to become even more efficient, reliable, and versatile. With its ability to push the boundaries of flight, there is no doubt that air-to-air refuelling will remain a vital lifeline for aviation, facilitating global mobility, military operations, and humanitarian endeavours for years to come.