WWII Fighters on Floats

By: Norm Goyer

The United States Military had a history of modifying a front-line fighter into a float plane. In fact, Jimmy Doolittle, flew an Army Curtiss biplane on floats to a victory in the 1925 Schneider Cup Races. Supermarine of England also entered these prestigious races, and won the overall Schneider Cup in 1932 with their Supermarine Model S-6. This aircraft was later extensively modified by Supermarine, and it became the WWII Spitfire. Italy and France were also competitors in these races, which started in 1914, and,with a few years off to fight WWI, they continued until 1932. Italy’s Macchi Castoldi M.C. 72 was the fastest aircraft, which still holds the seaplane record of 424 mph, which exceeded many speeds attained ten years later during WWII. Seaplanes were looked upon as very viable platforms by most countries.

This huge RC Rufe, (Zero on floats) built by Ray Hinds, shows the sleek lines of the float-equipped Rufe, a favorite of model builders.

Japan did not enter these races, but did find themselves in need of seaplane fighters, due to their island nation, and the occupation of small islands, dominated by the Japanese, prior to Pearl Harbor, in 1941. The problem, once troops had landed and taken over an island, the military felt they needed some form of aircraft protection. Most of these small islands had difficult terrain for an airfield, and Japan did not have trained troops capable of building landing strips almost overnight. The solution? Fighter planes adapted to floats.

Grumman also installed floats on their F4F Wildcat for testing purposes. The formation of the Seabees eliminated that need.

\r\nJapan had a number of single-engine fighters that were fitted with floats, including the famous Zero/Zeke. Japan favored using a large single float with streamlined struts attached beneath the fuselage for the main floatation, and two small wing tip floats to keep aircraft upright. The main reason was that a single float was much lighter and easier to adapt to a catapult-launch system. Most of Japan’s battleships and cruisers had liaison aircraft, and the catapults were available. Besides the Mitsubishi Zero, there was the Aichi E13A-1 and Kawanishi E1K, all highly effective fighters that were based in lagoons near the troop encampments.

Meanwhile, in England, Supermarine added floats to their Spitfire.

At the time of the Pearl Harbor attack, the USN only had a small number of Grumman Wildcat fighters to defend its fleet and ground installations. The US Navy was faced with the same problem as that of the Japanese; no airfields were available on newly-acquired island bases. Grumman attached a set of twin floats to a small number of F4F Wildcat fighters, so they could be assigned to help the ground troops. United States military leaders knew that there would be an island-hopping offensive leading our troops closer and closer to Japan for an invasion.
Japan also had a very powerful float-fighter in their Kawanishi N1K1. This plane was so effective as a float-fighter, it was redesigned for wheel operation.

\r\nTheir answer was a new highly-trained military construction unit called the Seabees who were provided with heavy earth moving equipment. Their job was to build airfields almost overnight, so land-based fighters could be flown in for protection in anticipation of the upcoming offensives. Many credit the Seabees with shortening the war by many months, if not years. At this point, the USN dropped all experiments with float-equipped-fighters and concentrated on liaison and observation float planes. The Vought Kingfisher and Curtiss Sea Mews, catapult-launched, single-float-aircraft based aboard battleships and cruisers, were effective in providing long range “eyes” for the fleet. Now, the helicopter takes on these duties far more effectively.\r\n\r\n The Grumman F4F Wildcat is pictured during a water-takeoff. Note the small auxiliary fins on the horizontal stabilizer to offset the added lateral area caused by the floats. \r\n\r\n

In England, Supermarine was busy installing double floats on their Spitfire for use in outlying areas of their water-surrounded homeland. There is very little research on this aircraft and its accomplishments during WWII. Naval ships of all countries used catapult-launched observation aircraft. The Germans even experimented with small aircraft and towed rotary-wing kites. These unmanned gyrocopters were towed to great heights to increase the submarine’s radio transmission range. These were the beginning of the Benson type of sport gyroplanes that are still popular today. All navies also depended on a fleet of multi-engine flying boats to supply remote areas with troops and supplies. Such aircraft, like the outstanding Consolidated PBY Catalina, saved hundreds of pilots who were forced down at sea. Huge four-engine Martin and English Short flying boats labored throughout the war, with many of them still flying or in museums.

The Vought Kingfisher, carried by many battleships and cruisers, was a very effective observation aircraft. It was launched via catapult, after landing in the water alongside the vessel, it was recovered with a crane.

For those of you wondering why the Schneider Cup Trophy races were held on water? The answer is quite simple, but still complicated. Not one of these later seaplane racers could take off from any available airport at that time; none had runways long enough. The aircraft had high wing loadings, huge engines and propellers that were pitched extremely high. This caused the aircraft to slowly gather speed over the water until the high pitched props could operate with the most efficiently. The takeoff run could be measured in miles, not feet. It is best illustrated by trying to start a racing car in high gear. In later years, the constant-speed propeller would address this problem. This type of propeller acts in a way similar to that of automatic transmissions that start your car off in low gear, then shifts into higher ranges automatically, when needed. Most of the Schneider Cup racers used machine-carved, hand-finished, wood propellers. A prop has two critical dimensions, the diameter and the pitch. The diameter, or the length of the prop, is determined by ground clearance or horsepower requirements of the engine; while the pitch is the theoretical distance the propeller will screw itself into the air for each 360-degree turn. It is the pitch that creates the speed of the aircraft, coordinated with the weight and hp of the aircraft and engine. It was the aeronautical knowledge obtained during World War II, the Thompson Trophy Air Races and the Schneider Cup Trophy races that accelerated the development of aircraft so rapidly from 1932 to 1945.\r\n
The Curtiss Sea Hawk was designed to offer more range and speed than the current Kingfisher. Both the Curtiss and Vought were delivered on wheels and converted to floats by EDO.