Drop tanks come with one notable drawback: they can degrade the F-35’s stealthy profile to the point of compromising it entirely.
Range has been a key factor in combat aircraft effectiveness since their inception during the First World War. Extending the range of fighter or strike aircraft has been particularly challenging thanks to their small size and limited internal fuel capacity. World War II aircraft addressed their fuel deficiency through external fuel tanks mounted on the wings or under the fuselage. This allowed long-range fighter escorts to accompany strategic bombers all the way to their targets. The F-35 Joint Strike Fighter is the latest aircraft to receive these upgrades, though it faces challenges that were not applicable to the P-51 Mustangs of yesteryear.
Despite being lightyears ahead in capability, the F-35A’s effective range of 670 nautical miles is almost exactly the same as the World War II-era P-51 Mustang’s. External drop tanks—so named because the pilot could jettison them for combat or when they were empty—helped extend the P-51’s range to as much as 1,600 miles. There’s more to the story behind the Mustang’s range, but those external tanks were a big part of the equation.
The three F-35 variants’ ranges are in the same ballpark as each other, with the Navy’s F-35C having a slightly longer range than the Air Force’s F-35A. The Marines’ vertical take-off/landing F-35B’s range is slightly shorter. Modern battlespace conditions have not reduced the advantages of superior range; in fact, the ever-increasing range of area denial systems, as employed by China, make effective range a vital characteristic of front-line aircraft.
F-35 External Fuel Tanks Were a Long Time Coming
External fuel tanks were envisioned for the F-35 at least as far back as 2019, even though the aircraft’s effective range was significantly greater than most fourth-generation fighters. The Israeli Air Force began working with external drop tanks and stealthier conformal fuel tanks (CFT) on their F-35I aircraft at about the same time. Those tanks reportedly increase the F-35I’s range by up to 40 percent, and are part of the F-35A’s upgrade in the Defense Department’s proposed 2026 budget. Israel wanted the capability to strike Iran without aerial refueling, thus providing more mission security. That capability was aptly demonstrated in last month’s missions against Iran’s nuclear facilities, though whether the Israelis used external or internal tanks remains unclear.
However, drop tanks come with one notable drawback: they can degrade the F-35s stealthy profile to the point of compromising it entirely. CFTs are designed to minimize that effect. But not every mission requires stealth capability, so the external drop tanks are still a viable option. Stealth-compatible external wing tanks are already being developed for the F-22 Raptor. That technology may benefit the F-35 program as well.
Finally, even with external tanks’ drawbacks, in-flight refueling can compromise a mission’s security even further. Stealthy tankers, most notably the MQ-25 Stingray tanker drone, are still in development and not yet ready for active duty deployment. Reducing the F-35’s dependence on tankers would be a distinct advantage.
The proposed budget allocates $432 million to the upcoming Block 4 upgrade, which will improve hardware and software on all three F-35 variants. External fuel tanks are certainly part of that effort. The F-35’s wings already contain the mounting pylons necessary for the extra tanks.
The F-35 Could Extend Its Range in Other Ways
Modern munitions can also affect a combat aircraft’s effective range. The Navy’s new AIM-174B missile, developed from the SM-6 surface-to-air missile, has a significantly longer range than its predecessors, and is said to be the farthest reaching missile the Navy has ever fielded. The SM-6 reportedly has a range of over 200 miles when fired from the surface, with over-the-horizon targeting capability. Its exact range remains classified. Assuming the AIM-174B has similar characteristics, firing it from altitude and speed would substantially increase its range over the surface-fired version – possibly multiple hundreds of miles.
A longer ranged missile fired from a longer ranged aircraft compounds the effect—especially when dealing with China’s new ballistic and hypersonic missile defenses, which may force the Navy to stand its ships thousands of miles off the contested area. The SM-6 has ballistic missile interception capabilities, though whether the AIM-174B shares those capabilities is not clear.
Extended range will always benefit combat aircraft and mission planners. The tried and true external fuel tank looks to be part of that equation. The funding has been proposed. But the form those tanks will take, and exactly how they will be employed, remains to be seen.
About the Author: William Lawson
William Lawson is a military historian focusing on World War II and 20th century conflicts and the American Civil War. His specialty is operational level warfare, especially American amphibious doctrine. He writes on history, politics, and firearms for multiple publications and historical journals. He serves on the editorial advisory board for the Saber & Scroll Journal and Military History Chronicles and is a member of the Society for Military History and the American Historical Association. Lawson is based in Virginia.
Image: Shutterstock.
