(US Navy)

As the United States shifts its posture away from ongoing counter-terror operations and back toward great power competition with nations like China, the U.S. is being forced to reassess it's aircraft carrier force projection strategy. If U.S. carriers find themselves on the sideline for such a conflict, it may be worth revisiting the idea of a different kind of aircraft carrier: the flying kind.

China's arsenal of hypersonic anti-ship missiles have created an area denial bubble that would prevent American carriers from sailing close enough to Chinese shores to launch sorties, effectively neutering America's ability to conduct offensive operations against the Chinese mainland. Without the ability to leverage the U.S. Navy's attack aircraft, combat operations in the Pacific would be extremely difficult. It is, however, possible (though potentially impractical) to develop and deploy flying aircraft carriers for such a conflict–the United States has even experimented with the concept a number of times in the past, and is continuing to pursue the idea today.



DARPA’s Gremlins Program

Gremlins air vehicle during a flight test at Dugway Proving Ground, Utah, November 2019 (DARPA)

The most recent iteration of a flying aircraft carrier comes from the Defense Advanced Research Projects Agency, or DARPA, and has seen testing successes as recently as January of this year.

In January, DARPA successfully launched a Dynetics' X-61A Gremlin UAV from the bay of a Lockheed Martin C-130A cargo aircraft. The program is aiming to demonstrate the efficacy of low-cost combat-capable drones that can be both deployed and recovered from cargo planes. DARPA envisions using cargo planes like the C-130 to deploy these drones while still outside of enemy air defenses; allowing the drones to go on and engage targets before returning to the airspace around the "mother ship" to be recaptured and carried home for service or repairs.

(DARPA)

The test showed that a drone could be deployed by the C-130, but the drone itself was ultimately destroyed when its parachute failed to open after the completion of an hour-and-a-half flight. A subsequent test that would include drone capture was slated for the spring of this year, but has likely been delayed to due to the outbreak of COVID-19.

Between the success of this test and other drone wingman programs like Skyborg, the concept of a flying aircraft carrier has seen a resurgence in recent years, and may potentially finally become a common facet of America's air power.

The plan to turn a Boeing 747 into a flying aircraft carrier

The Boeing 747 has already secured its place in the pantheon of great aircraft, from its immense success as a passenger plane to its varied governmental uses like being a taxi for the Space Shuttle or as a cargo aircraft. The 747 has proven itself to be an extremely capable aircraft for a wide variety of applications, so it seemed logical when, in the 1970s, the U.S. Air Force began experimenting with the idea of converting one of these large aircraft into a flying aircraft carrier full of "parasite" fighters that could be deployed, and even recovered, in mid-air.

Boeing AAC design sketch

Initial plans called for using the massive cargo aircraft Lockeed C-5 Galaxy, but as Boeing pointed out at the time, the 747 actually offered superior range and endurance when flying with a full payload. According to Boeing's proposal, the 747 could be properly equipped to carry as much as 883,000 pounds.

Sketch of a micro-fighter inside the 747 fuselage.

The idea behind the Boeing 747 AAC (Airborne Aircraft Carrier) was simple in theory, but incredibly complex in practice. Boeing would specially design and build fighter aircraft that were small enough to be housed within the 747, along with an apparatus that would allow the large plane to carry the fighters a long distance, drop them where they were needed to fight, and then recover them once again.

This graphic from Boeing's proposal shows different potential flying aircraft carrier platforms and their respective ranges. (Boeing)

Boeing's 60-page proposal discusses the ways such a program could be executed, but lagging questions remained regarding the fuel range of a 747 carrying such a heavy payload and about how the fighters would fare in a combat environment. Previous flying aircraft carrier concepts showed that the immense turbulence from large aircraft (and their jet engines) made it extremely difficult to manage the fighters they would drop, especially as they attempted to return to the aircraft after a mission.

Potential "micro-fighter" design (Boeing)

Further concerns revolved around how well these miniature "parasite" fighters would fare against the top-of-the-line Soviet fighters they would conceivable be squaring off with.

Ultimately, the proposal never made it off the page — but it did establish one important point for further discussion on this topic. According to the report, Boeing found the concept of a flying aircraft carrier to be "technically feasible" using early 1970's technology. Technically feasible, it's important to note, however, is not the same as financially feasible.

The insane Lockheed CL-1201: A massive, nuclear-powered flying aircraft carrier

(Concept illustration)

The Skunkworks at Lockheed Martin have been responsible for some of the most incredible aircraft ever to take flight, from the high-flying U-2 Spy Plane to the fastest military jet ever, the SR-71. But even those incredible aircraft seem downright plain in comparison to Lockheed's proposal to build an absolutely massive, nuclear powered, flying aircraft carrier–the CL-1201.

The proposal called for an aircraft that weighed 5,265 tons. In order to get that much weight aloft, the design included a 1,120 foot wingspan, with a fuselage that would measure 560 feet (or about two and a half times that of a 747). It would have been 153 feet high, making it stand as tall as a 14-story building. According to Lockheed, they could put this massive bird in the sky using just four huge turbofan engines which would be powered by regular jet fuel under 16,000 feet, where it would then switch to nuclear power courtesy of its on-board reactor. The flying aircraft carrier could then stay aloft without refueling for as long as 41 days, even while maintaining a high subsonic cruising speed of Mach 0.8 at around 30,000 feet.

The giant aircraft would carry a crew of 845 and would be able to deploy 22 multirole fighters from docking pylons installed on the wings. It also would maintain a small internal hangar bay for repairs and aircraft service while flying. Unsurprisingly, this design didn't make it past the proposal stage, but the concept itself stands as a historical anomaly that continues to inspire renewed attention to this day.

The B-36 Peacemaker

Convair GRB-36F in flight with Republic YRF-84F (S/N 49-2430). (U.S. Air Force photo)

This massive bomber weighed in at an astonishing 410,000 pounds when fully loaded with fuel and ordnance (thanks to its large fuel reserves and 86,000 weapon capacity). Development of the B-36 began in 1941, thanks to a call for an aircraft that was capable of taking off from the U.S., bombing Berlin with conventional or atomic ordnance, and returning without having to refuel. By the time the B-36 made it into the air, however, World War II had already been over for more than a year.

The B-36 had a massive wingspan. At 230 feet, the wings of the Peacemaker dwarf even the B-52's 185-foot wingspan. In its day, it was one of the largest aircraft ever to take to the sky. Despite it's incredible capabilities, the B-36 never once flew an operational mission, but the massive size and range of the platform prompted the Air Force to consider its use as a flying aircraft carrier, using Republic YRF-84F Ficon "parasitic" fighters as the bomber's payload.

The YRF-84F flying underneath its B-36 carrier aircraft. FICON modifications included installing a hook in front of the cockpit and turning down the horizontal tail so it could partially fit into the B-36 bomb bay. (U.S. Air Force photo)

The idea was similar to that of the later proposal from Boeing, carrying the fighters internally to extend their operational range and then deploying them via a lowering boom, where they could serve as protection for the bomber, reconnaissance assets, or even execute offensive operations of their own before returning to the B-36 for recovery.

View of the YRF-84F from inside the B-36 — the pilot could enter and exit the cockpit from within the bomber. (U.S. Air Force photo)

The U.S. Air Force ultimately did away with the concept thanks to the advent of mid-air refueling, which dramatically increased the operational range of all varieties of aircraft and made a flying aircraft carrier concept a less cost effective solution.

Using rigid airships as flying aircraft carriers

USS Macon (ZRS-5) Flying over New York Harbor, circa Summer 1933. (U.S. Navy)

Although we very rarely see rigid inflatable airships in service to national militaries today, things were much different in the early 20th century. Count Ferdinand von Zeppelin's airships (dubbed "Zeppelins") were proving themselves to be a useful military platform thanks to their fuel efficiency, range, and heavy payload capabilities. These massive airships were not only cost-effective, their gargantuan size also offered an added military benefit: their vast looming presence could be extremely intimidating to the enemy.

However, as you may have already guessed, it was that vast presence that also created the rigid airship's massive weakness: it was susceptible to being shot down by even the simplest of enemy aircraft. England was the first nation to try to offset this weakness by building an apparatus that could carry and deploy three Sopwith Camel biplanes beneath the ship's hull. They ultimately built four of these 23-class Vickers rigid airships, but all were decommissioned by the 1920s. The U. S. Navy's Bureau of Aeronautics took notice of the concept, however, and set about construction on its own inflatable airships, with both the USS Akron (ZRS-4) and USS Macon (ZRS-5) serving as flying aircraft carriers.

The USS Akron in flight, November 1931 (U.S. Navy)

The airships were built with an apparatus that could not only deploy F9C-2 Curtiss Sparrowhawk biplanes, they could also recover them once again mid-flight. The airships and aircraft fell under the Navy's banner, and the intent was to use the attached bi-planes for both reconnaissance (ship spotting) and defense, but not necessarily for offensive operations.

USS Akron (ZRS-4) Launches a Consolidated N2Y-1 training plane (Bureau # A8604) during flight tests near Naval Air Station Lakehurst, New Jersey, 4 May 1932. (U.S. Navy)

The biplanes were stored in hangars on the airship that measured approximately 75′ long x 60′ wide x 16′ high — or big enough to service 5 biplanes internally.

Sparrowhawk scout/fighter aircraft on its exterior rigging (U.S. Navy)

After lackluster performance in a series of Naval exercises, the Akron would crash on April 4, 1933, killing all 76 people on board. Just weeks later, on April 21, its sister ship, the USS Macon, would take its first flight. Two years later, it too would crash, though only two of its 83 crew members would die.

This article originally appeared on Sandboxx. Follow Sandboxx on Facebook.