Aircraft Carriers With Rubber Decks Were A Bad Idea
The British and Americans toyed with the idea of flexible aircraft carrier decks from which to operate wheelless jet aircraft.
Largely forgotten about today, the 1950s saw some extraordinary experiments involving aircraft carriers fitted with rubber flight decks, the idea being to launch and recover jet aircraft with no landing gear at all. While the thinking behind it might seem baffling in retrospect, the concept appeared to offer some key advantages at the time. However, unlike other revolutionary carrier aviation technologies that emerged in that period, the flexible deck was bound for the scrap heap.
It was in the United Kingdom where the first serious thinking about the possibility of carrier-based aircraft without landing gear took hold, in the immediate post-war period.
World War II demonstrated the primacy of the aircraft carrier as the dominant surface warship, overtaking the battleship at the center of maritime warfare. Soon after the war ended, experiments began with jet-powered carrier aircraft, which promised to bring a whole new level of performance and capability. At the same time, however, these new aircraft brought with them a new set of demands that were not necessarily compatible with operating from the carriers of the day, which were far smaller than their modern equivalents.
Clearly, there was no way that the propeller-driven carrier aircraft used operationally up till that point could recover on deck without landing gear.
The new generation of sleek jet aircraft now in development was different though. With no propeller, it was reasonable to assume that a turbine-powered aircraft could land on its belly, provided it was strong enough and that the runway provided a sufficient cushioning effect.
The first generation of jet fighters, and especially those that were intended to operate from carriers, were typically fairly compact and their engines thirsty. Aircraft designers faced a struggle to pack everything — pilot, engine, fuel, armament, etc. — into a small airframe.
Deleting the landing gear and related equipment seemed to offer a solution. It would free up internal space and remove one of the key design challenges (where to stow the retracted landing gear) and lighten the aircraft overall, promising better performance. In the case of aircraft where the landing gear previously retracted into the wing, the flying surfaces could now be made slimmer, for an aerodynamic advantage.
Doing away with landing gear also promised to improve the safety of flight deck operations. After all, landing gear collapse and other problems were a regular source of accidents in what was already a hazardous environment, and the opportunity to remove this design ‘weak spot’ appeared attractive.
Even before the end of World War II, British scientists at the Royal Aircraft Establishment (RAE) test and research unit at Farnborough, England, began to look at the broader possibilities for launching and recovering aircraft without wheels. By January 1945, suggested concepts involved the use of flexible runways floating on water, spring decks, flying from soft ground or sand, and trolleys running along tracks. The thought was also given to using wires stretched between towers aboard ships, which the aircraft could be both launched from and then snagged with a hook for recovery.
As Normal Polmar describes in an article for Naval History Magazine, the solution adopted was devised by Maj. F. M. Green and involved a wheelless jet fighter landing and taking off from a flexible rubber ‘carpet’ that was suspended on shock absorbers — made from multiple layers of pressurized fire hose. It was calculated that a carpet 150 feet long by 40 feet wide would be able to support an aircraft weighing 8,000 pounds.
Recovery was still assisted, as in a standard aircraft carrier, with the wheelless jet engaging arresting wires and a catapult would be provided for launch. Using water to lubricate the carpet would help reduce any damage, although it was predicted that wear and tear would anyway be limited.
By late 1947, the flexible deck system was ready for testing, with a prototype carpet installed at Farnborough. The test pilot for the first landing was the legendary Lt. Cdr. (later Capt.) Eric M. Brown, flying a standard Sea Vampire fighter with the wheels retracted. The first landing, on December 29, 1947, was inauspicious, with Brown experiencing a higher sink rate than anticipated. The pilot increased power to compensate, but the slow engine response left the Sea Vampire striking the ramp at the end of the carpet. The impact locked the arrestor hook shut, damaged the twin tail booms, and jammed the control surfaces. The jet continued to bounce down the carpet before coming off the end to a stop. Brown escaped serious injury.
By spring 1948, modifications had been made, and Brown was able to perform a perfect landing on the rubber deck on March 17.
After further trials at Farnborough, it was time to go to sea, aboard the light aircraft carrier HMS Warrior, now adapted with a flexible carpet deck.
The deck of Warrior was covered with a rubber-like material that extended 190 feet aft from the island structure. One arresting wire was provided, which would pull the recovering aircraft down onto the flexible carpet, after which it would come to a halt in only a few feet.
With no wheels on which to maneuver the aircraft after landing, a crane was provided to lift it onto a trolley. The jet was then winched forward to an elevator to return to the hangar deck. Alternatively, it could be taken to the catapult for launching.
Tests took place aboard Warrior between November 1948 and May 1949, with more than 200 landings ultimately completed both at sea and on land. Pilots involved came from the U.K. Royal Navy and Royal Air Force, and one U.S. Navy test pilot, Lt. Cdr. (later Vice Admiral) Donald D. Engen was also involved.
Generally, the flexible carpet deck was found to be safe. In the event of the recovering aircraft missing the wire, it would typically bounce on the rubber before the pilot flew around for another attempt.
Once all the data from the trials had been gathered, it was calculated that removing the landing gear and switching to a rubber deck should add 45 minutes to the endurance of a carrier fighter and increase speed between 17 and 23 miles per hour.
The U.S. Navy also took an interest in the trials and, following on from Lt. Cdr. Engen’s participation in the U.K. tests, a flexible deck was constructed at Naval Air Station Patuxent River, Maryland, in 1953. This measured 570 feet by 80 feet and was also fitted with a single arresting cable. The deck was roughly half an inch thick and made of Goodyear rubber.
The U.S. Navy trials involved a pair of modified F9F-7 Cougar carrier jet fighters, flown by test pilots from Grumman, the Navy, and the Marine Corps. The aircraft featured ventral bulges running along the center of the fuselage to reduce damage to the airframe.
In all, 23 Cougar landings were made on the rubber deck at Pax, but the concept was found to be generally problematic and was not taken up.
Even with the flexible deck working as planned, and aircraft launching and recovering without problem, fundamental drawbacks with the system remained.
Once an aircraft had been designed for a flexible deck, its lack of conventional landing gear would mean it could only operate from its rubber carpet, meaning it couldn’t recover to a normal runway or even a standard aircraft carrier. With early jets not being particularly reliable at the best of times, sufficient flexible decks would have to be provided, at a considerable cost.
Moving a wheelless aircraft on the ground would also always be a challenge, demanding specialist handling gear including cranes and trolleys.
There was also a question of whether this mode of operation was suitable for less-experienced naval aviators, especially since the margins for error (including a single arresting wire) were that much reduced.
It was also clear that carrier aircraft, and jets in general, were getting bigger, heavier, and more complex, and the weight savings made by deleting the landing gear would be less significant going forward.
Nevertheless, some design work did begin in the United Kingdom on carrier fighters for flexible deck operations.
The single-seat Supermarine Type 505 was designed specifically to land on rubber decks, but it was quickly reworked to become the Scimitar F1 carrier fighter, with a conventional wheeled undercarriage.
Taking all into account, it’s perhaps not surprising that rubber-decked aircraft carriers were a developmental dead-end.
At the end of World War II, it was clear that carriers would have to be adapted to keep pace with aircraft developments, especially in terms of turbine power. As it was, the United Kingdom pioneered the angled flight deck, mirror landing aids, and the steam catapult, all of which ushered in a new and much more capable era of carrier aviation.
With all those wins, the loss posted by the rubber deck concept can probably be excused.
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