Burning 50,000 pounds of fuel per hour: Aerial refueling from a fighter pilot
The development of aerial refueling was one of the greatest leaps in fighter lethality. A fighter, just like any aircraft, consists of hundreds of tradeoffs—cost, payload, speed, stealth, size, weight, maneuverability, the list goes on and on. But, the Achilles heel of fighters has always been their fuel consumption.
At the heart of a modern jet like the F-16 or F-35 is an afterburning turbofan engine. The turbofan part is similar to an airliner, however the afterburner is a special section fitted to the aft-tailpipe that injects fuel and ignites it, similar to a flame thrower. This rapidly increases thrust, however the tradeoff is that it burns fuel at an incredible rate.
Members of the 18th Component Maintenance Squadron engine test facility, run an F-15 Eagle engine at full afterburner while checking for leaks and any other issues. (U.S. Air Force photo by Senior Airman Omari Bernard)
I remember flying in an F-16 in afterburner while supersonic over the Yellow Sea and looking down to see a fuel-flow rate of over 50,000 lbs per hour. To put that into perspective, that's similar to a fire-hose operating fully open—and that's just a single engine, a twin-engine jet such as the F-15 or F-22 can double that. The problem is, topped off, I could only carry 7,000 pounds of fuel which was enough for me to fly at that fuel-setting for less than 10 minutes.
The reason we're able to sacrifice fuel for incredible speed and maneuverability is because we can refuel in the air. The Air Force has over 450 airborne tankers, which are specially modified passenger aircraft that are filled with fuel. The backbone of our tanker fleet, the KC-135 Stratotanker is based on the Boeing 707, which amazingly has been flying aerial refueling operations since the 1950's.
A 401st Tactical Fighter Wing F-16C Fighting Falcon aircraft refuels from a KC-135 Stratotanker aircraft as another F-16 stands by during Operation Desert Storm. (USAF Photo)
When we need fuel, we'll pull up slightly behind and below the tanker. The tanker will then extend it's boom, which is a 50 foot long tube with small flight control surfaces on it. The boomer, who sits in the back of the aircraft, then steers the boom using those control surfaces into the refueling receptacle of our aircraft.
Once contact is made, a seal forms and fuel starts transferring at several thousand pounds per minute. We'll then continue to maintain that precise position using director lights on the bottom of the tanker until we're topped off. The amount of time it takes depends on how much fuel is transferred, but generally takes about 5 to 10 minutes.
A U.S. Air Force pilot navigates an F-35A Lightning II aircraft assigned to the 58th Fighter Squadron, 33rd Fighter Wing into position to refuel with a KC-135 Stratotanker assigned to the 336th Air Refueling Squadron over the northwest coast of Florida. (USAF photo by MSgt John Nimmo Sr.)
Aerial refueling is a common part of most missions. When we take our jets to different exercises around the country, we'll use tankers so we can fly nonstop. Tankers also allow us to double our training during a flight—we'll fly our mission, refuel, and then fly it again. When we deploy, tankers allow us to cross vast swaths of ocean in one hop—I remember topping off 10 times on my way to Afghanistan. But, the most critical benefit of air refueling is it allows us to project and sustain air power.
Tankers allow us to fly indefinitely. Even if I was running my power settings as efficiently as possible, I could only stay airborne for about two hours, which translates into a combat radius of just a few hundred miles. That's not nearly enough range to project power into another country and return home. With a tanker though, our combat radius can extend into the thousands of miles—we're primarily limited by pilot fatigue.
By breaking the fighter range problem into two components—a fighter and a tanker— engineers were able to massively increase the performance and relevance of fighters in combat. A single formation of fighters can have a near strategic level impact on the battlefield.
Make sure to check back in two weeks for an in-cockpit play-by-play of how we rejoin with the tanker and refuel at 350 mph.
Want to know more about life as a fighter pilot? Check out Justin "Hasard" Lee's video about a day in the life of a fighter pilot below: