Aerial refueling

Planes can get fuel while they fly.

One plane is the tanker. It carries the extra fuel. Another plane is the receiver. It takes the fuel. This lets planes stay in the air much longer.

There are two main ways to do this. One way uses a long pipe. This pipe moves fuel very fast. The other way uses a small tube. This tube connects to a part on the plane.

This helps planes carry more things. They can take off with less fuel. Then they get more fuel in the sky. This helps them fly very far.

People first tried this in the 1920s. It was very hard and dangerous back then. Now, only military planes use it. It is a very special way to fly.

Planes can get fuel while they are flying. This is called aerial refueling. One plane is the tanker. It carries the extra fuel. Another plane is the receiver. It takes the fuel from the tanker.

This way of flying helps planes stay in the air longer. It also lets them fly much further. Planes can take off with more cargo or people. They carry less fuel at first. Then they top off once they are in the sky.

There are two main systems. One is the flying boom. This is a long pipe that moves fuel very fast. It needs a special worker to guide it. The other is the probe-and-drogue system. The receiver uses a small tube called a probe. It connects to a part that looks like a basket.

People first tried this in the 1920s. It was a very dangerous task back then. In 1923, two planes had their first mid-air refueling. Later, a plane named Question Mark stayed up for 150 hours. Today, only military planes use this special skill.

Aerial refueling is a special way to move fuel between aircraft while they are flying. One plane is called the tanker, and the other is the receiver. This process is also known as air-to-air refueling or tanking. It is very important because it lets planes stay in the sky much longer. It also helps them fly much further distances. By refueling in the air, a plane can take off with a heavy payload of cargo or people. It carries less fuel at takeoff to stay light, then tops off once it is airborne.

There are two main ways this works. The first way uses a flying boom, which is a long pipe. This system moves fuel very quickly, but it needs a special operator to guide it. The second way is the probe-and-drogue system. In this method, the receiver plane uses a small tube called a probe. This probe connects to a basket-like part at the end of a hose. This system is often simpler to add to different types of aircraft.

People first tried this many years ago. In the 1920s, pilots used hoses to move fuel between slow planes. On June 25, 1923, two Airco DH-4B biplanes had the first mid-air refueling. Later, a plane named the Question Mark set a record in 1930. It stayed in the air for over 150 hours. In 1935, Fred and Al Key used a new nozzle to stop fuel from spilling. This made the process much safer for the pilots.

Sir Alan Cobham was a famous pioneer in this field. He helped create the first practical refueling systems. In 1949, a B-50 called Lucky Lady II made history. It flew non-stop around the whole world in about 94 hours. This huge trip was only possible because of four aerial refuelings. The plane refueled over the Azores, Saudi Arabia, the Pacific Ocean, and Hawaii.

Today, this skill is mostly used by military groups. It is very hard and expensive to do. Pilots must fly in a very close formation called "line astern." This means the planes must stay very near each other. While it was once thought to help civilian planes fly across oceans, it is now a military tool. It helps strong lands move supplies and people across the globe.

Aerial refueling is the process of transferring aviation fuel from one aircraft to another while both are in flight. The aircraft providing the fuel is known as the tanker, while the one receiving it is called the receiver. This procedure is also referred to as in-flight refueling (IFR), air-to-air refueling (AAR), or tanking.

This capability is vital because it allows receiving aircraft to remain airborne much longer. It extends their flight range or their loiter time, which is the time they can spend circling an area. In some cases, a series of refuelings can extend a flight until the crew reaches physiological limits, such as fatigue, or until engineering factors like engine oil consumption become a concern.

There are two primary technical mechanisms used to move fuel between aircraft. The first is the flying boom system. This system utilizes a rigid pipe that can be guided into the receiver. The flying boom offers a faster rate of fuel transfer, but it requires a dedicated boom operator station on the tanker to manage the connection.

The second method is the probe-and-drogue system. This system is generally easier to adapt to existing aircraft designs. In this setup, the receiver aircraft uses a probe, which is a specialized nozzle, to connect with a basket-like device at the end of a hose trailed by the tanker.

Aerial refueling also offers significant advantages for aircraft weight management and payload capacity. An aircraft can take off with a greater payload of cargo, weapons, or personnel by carrying less fuel during takeoff. This allows the plane to maintain its maximum takeoff weight while staying light enough to get airborne safely. Once the aircraft is in flight, it can be topped off with extra fuel from a tanker. Additionally, researchers have estimated that aerial refueling could reduce fuel consumption on long-haul flights by 35% to 40%, even when accounting for the fuel used by the tanker missions.

Early experiments in the 1920s involved slow-flying aircraft flying in formation. In these trials, a hose was run down from a hand-held fuel tank on one plane to the filler of another. On June 25, 1923, the first successful mid-air refueling occurred between two Airco DH-4B biplanes of the United States Army Air Service.

By August 1923, three DH-4B aircraft set an endurance record by remaining aloft for over 37 hours using nine mid-air refuels. In 1929, a Fokker C-2A named the Question Mark set a record of over 150 hours. Later, in 1930, the Hunter brothers set a record of 553 hours and 40 minutes using two Stinson SM-1 Detroiters.

Sir Alan Cobham was a key figure who revolutionized the field through his development of practical systems. In 1934, he founded Flight Refuelling Ltd (FRL) to advance in-flight refueling technology. One early method was the grappled-line looped-hose system. In this process, the receiver aircraft trailed a steel cable. The tanker then shot a line to grapple that cable, drawing it back into the tanker to connect the refueling hose. This was eventually improved into the modern probe-and-drogue system, which was demonstrated by a Gloster Meteor jet in 1949, setting a new jet endurance record.

A major milestone occurred in 1949 when the B-50 Superfortress Lucky Lady II completed the first non-stop circumnavigation of the world. The flight lasted 94 hours and 1 minute. This feat was made possible by four aerial refuelings from four pairs of KB-29M tankers. These refuelings took place over the Azores, Saudi Arabia, the Pacific Ocean near Guam, and between Hawaii and the West Coast.

This mission demonstrated how refueling could overcome the geographic limitations of early long-distance aviation.

Despite its utility, aerial refueling is currently used almost exclusively in military operations. This is due to the high cost of specialized refueling equipment and the difficulty of the maneuvers required. Pilots must perform very close "line astern" formation flying to successfully connect the aircraft. While early pioneers like Cobham saw potential for long-distance commercial transoceanic flights, the complexity of the task has kept it within the military domain.