A Look At The Aerial Refueling Tankers Of The USAF

In its massive fleet, the United States Air Force (USAF) currently operates four types of tanker aircraft for air-to-air refueling. Before we look at these four aircraft in-depth, let’s first look at why the ability to refuel aircraft in the air is essential, how it is done, and how it has evolved over the years.

Since the end of the Cold War, the focus of the United States military has changed from one that relies on nuclear weapons. While nuclear weapons remain a deterrent, the military needs to defend American interests everywhere on the planet.

The USA cut spending and closed bases

Since the Soviet Union no longer posed the threat it did, the United States was able to cut military spending and close many bases overseas. Rather than projecting its power from a regional base thanks to air-to-air refueling, aircraft based in the United States can reach any corner of the globe.

Photo: USAF

The ability to refuel planes in the air allows fighter aircraft to have an extended range and remain on station for longer periods. Refueling while airborne allows planes operating from smaller runways to take off with a full combat payload and then take on enough fuel to complete the mission when airborne.

The history of aerial refueling

On October 5, 1922, two airmen, Lt. John A. Macready and Lt. Oakley G. Kelly, set a world endurance record when their Fokker T-2 remained airborne for 35 hours and 18 minutes. Later, the pair realized they could have stayed in the air longer if not for personal fatigue and running out of fuel.

To eliminate planes from running out of fuel, aviators at Rockwell Field, San Diego, developed a system to pass fuel from one plane to another while in the air. Using two British WWI Airco DH.4 two-seat biplane bombers, Lts. Virgil Hine and Frank W. Seifert passed gasoline through a hose to another Airco DH.4 flying below them. Thus, the first air-to-air refueling of an aircraft occurred on June 27, 1923.

For the rest of the decade, aviators worldwide used aerial refueling to set endurance and long-distance records. After witnessing aerial refueling at barnstorming events in the United States, Royal Air Force officer Richard Atcherley developed and patented a system for aerial refueling. Others later improved upon it but still relied on gravity to transfer fuel from one aircraft to another.

After the war, engineers started investigating other methods of transferring fuel between planes and devised two systems: probe-and-drogue air-to-air and the flying-boom system.

The flying boom: A rigid, telescoping tube with movable flight control surfaces that a boom operator on the tanker aircraft extends and inserts into a receptacle on the receiving aircraft.

Probe-and-drogue: The probe-and-drogue refueling method employs a flexible hose that trails from the tanker. Sometimes called a basket, what looks like a badminton shuttlecock is a funnel into which the aircraft receiving fuel inserts its nozzle.

United States Air Force (USAF) tankers

Boeing KC-135 Stratotanker

Photo: USAF

Still, the backbone of the USAF tanker fleet, the Boeing KC-135 Stratotanker, was developed from the Boeing 367-80 and Boeing 707 airliners. When it replaced the 135 Stratotanker, it became the first jet-powered USAF tanker.

Used extensively during the Vietnam War and Operation Desert Storm, the KC-135 was used to extend a fighter aircraft’s range and endurance. During its production run between 1955 and 1965, Boeing manufactured 800 KC-135 Stratotanker, of which 377 remain operational. The KC-135 is expected to remain in service with the USAF until 2030. The newer Boeing KC-46 Pegasus will replace it.

McDonnell Douglas KC-10 Extender

Photo: USAF

The McDonnell Douglas KC-10 Extender is an American air-to-air refueling tanker based on the civilian three-engine DC-10 airliner. Following lessons learned in Southeast Asia and the Middle East, the McDonnell Douglas KC-10 Extender was developed to supplement the KC-135 Stratotanker.

Related

History: The USAF KC-135 Stratotanker Whose 20-Degree Dive Saved A Fighter Jet

One of the two jets had already flamed out.

During the Vietnam War, Pentagon planners began to question the ability of the Air Force’s existing fleet of KC-135 Stratotankers to meet the US military’s global commitment. Because of this, the Air Force sent two DC-10s to Edwards Air Force Base in California for trials. The tests went well and included fitting the aircraft with a McDonnell Douglas Advanced Aerial Refueling Boom and additional fuel tanks. By adding fuel tanks below the main deck, the KC-10 had nearly double the fuel capacity of the KC-135.

The first KC-10 to be delivered to the Air Force entered service with the Strategic Air Command (SAC) in March 1981 and was stationed at Barksdale Air Force Base in Louisiana. After serving in the military for over 40 years, 20 KC-10s remain in service at Travis AFB, California, and McGuire AFB, in New Jersey.

Lockheed MC-130

Photo: USAF

Based on the Lockheed C-130 Hercules transport, the Lockheed MC-130 is an extended-range tanker used to replace older KC-130 tankers. The KC-130 first entered service with the United States Navy (USN) in 1962 and was designed to refuel United States Marine Corps jet fighters. It could also be used for the refueling of helicopters and the rapid ground refueling of other planes. The USAF currently has 57 KC-130J aircraft and a further four on order.

Boeing KC-46 Pegasus

Photo: USAF

Developed from the Boeing 767 airliner, the Boeing KC-46 Pegasus was selected by the USAF to replace its existing Boeing KC-135 Stratotankers. In 2001, the USAF began a procurement program to replace its older KC-135s. After numerous delays and problems with aerial refueling, the Boeing KC-46 Pegasus eventually entered service with the USAF on January 10, 2019, three years later than anticipated.

The Boeing KC-46 Pegasus is currently stationed at the following USAF bases:

• The 97th Air Mobility Wing at Altus AFB in Oklahoma
• The 157th Air Refueling Wing at Pease Air National Guard Base in New Hampshire
• The 916th Air Refueling Wing at Seymour Johnson Air Force Base in North Carolina

Related

How The USAF Overcame Issues With The Boeing KC-46 Pegasus

A main problem with the KC-46 was the refueling boom vision system.

Currently, the USAF has 72 Boeing KC-46 Pegasus listed as operational and plans to have 179 by 2027.