From the Planes You’ve (Probably) Never Heard Of Department of Wingspan, we bring you the Douglas XA2D Skyshark (and friends).
Wars are a catalyst for rapid technological development, and at the same time that piston-powered aircraft design was reaching its zenith towards the end of the Second World War, the jet engine entered the scene. Germany was the first to field an operational jet fighter, and they were soon followed by Great Britain and the US. While jet performance was impressive, miles per gallon was not. The gas guzzling turbojets of the era could fly fast, but not that far, and fixing a propeller to a spinning jet engine to create a turboprop seemed to be the best way to get the most from jet power while taking advantage of the range of a propeller plane.
Back in 1941, the Douglas Aircraft Corporation had begun work on a dive bomber for the US Navy, an aircraft that eventually took the form of the BTD Destroyer. The Destroyer was a large, three-man dive bomber and torpedo bomber, but by the time it entered service in 1944 the war was drawing to a close, the dedicated torpedo bomber had become an anachronism, and the Navy expressed a preference for aircraft with a single pilot. Ed Heinemann and his team at Douglas had already been working on a single-seat Destroyer known as the BTD-2, and that aircraft served as the basis for the remarkable Douglas AD Skyraider, a master-of-all-trades workhorse that served the US into the 1970s. But was there room to improve the Skyraider?
With the inexorable push toward jet power, the Navy wanted to know what would happen if Douglas gave the Skyraider a turboprop engine instead of the Wright R-3350 Duplex-Cyclone it came with from the factory. Along with improved performance, the Navy hoped to fly the new turboprop from their Casablanca-class escort carriers. After all, the Navy had 50 of them left over from the war, and it would be easier for a turboprop-powered aircraft to take off from a shorter deck. So Douglas engineers started with the Skyraider and took an experimental Allison XT40 dual turbine engine, mounted it under the cockpit, and fixed massive three-bladed fully-reversible contra-rotating propellers to it. The XT40 provided 5,500 shaft horsepower, a maximum speed just shy of 500 mph, and a combat range of over 500 miles.
The Skyshark took its maiden flight on March 26, 1950, but the new turboprop engine proved problematic. So much so that US Navy test pilot Cdr. Hugh Wood was killed when a clutching mechanism in the engine malfunctioned during a flight of the first prototype. Delays to correct the problems with the engine stretched into 1953, and then the first production engine to fly suffered the loss its propellers. By this time, jet engine technology was maturing, the Skyshark was no longer deemed necessary, and the project was canceled. Of the two prototypes and 10 pre-production Skysharks Douglas built, just one aircraft remains, and it is on display at the San Diego Air and Space Museum.
While the Skyshark did not catch on in US service, the idea of using a turboprop in what was essentially a single-engine aircraft did find success in other countries, particularly in naval aviation. The arrangement works well because the turboprop provides better range at medium altitudes, and the propeller provides more power at takeoff, making it easier to get off the deck of the carrier without burning large amounts of fuel. The British and French fielded a few such aircraft, mainly in the antisubmarine warfare (ASW) role.
The Westland Wyvern (the Brits have the coolest airplane names), first flown in 1946, was a single-seat strike aircraft that operated from Royal Navy carriers and was designed to carry rockets, bombs, or a single torpedo. The Wyvern was powered by a single Armstrong Siddeley Python turboprop and had a top speed of 383 mph. A total of 127 Wyverns were built, and the type saw action during the 1956 Suez Crisis where they flew 79 sorties from the carrier HMS Eagle.
The Fairey Gannet was another British contra-rotating turboprop, but where the Wyvern was powered by a single turboprop engine, the Gannet received an Armstrong Siddeley Double Mamba engine. Like the XT40, the Double Mamba was two engines side-by-side and joined through a gearbox, though each engine drove a separate propeller (on the Skyshark, the two engines drove both propellers simultaneously). The Gannet first flew on September 19, 1949, was was designed for ASW and ground attack (303 built), and was later covered into an electronic countermeasures platform (45 built). The Gannet was retired by 1978.
The Short Seamew has been called, for obvious reasons, a camel amongst race horses for both its shape and its relative plodding pace. It was designed as a replacement for Britain’s Grumman Avengers, and took its maiden flight in 1953. The Seamew was originally designed to be powered by a Rolls-Royce Merlin piston engine, but the Royal Navy was phasing out all piston engines and ordered Shorts to use the Armstrong Siddeley Mamba turboprop engine instead. The Seamew took its maiden flight on August 23, 1953, but only 26 were built and the type was retired after only four years of service.
The sole French entrant into the turboprop parade is the Bréguet 1050 Alizé. Like its British counterparts, the Alizé, which translates as “Tradewind,” was developed for the carrier-borne ASW role. It had a three-man crew, with pilot and navigator seated side-by-side in front while the radar operator sat behind. Power came from a single Rolls-Royce Dart turboprop which gave the Alizé a top speed of 322 mph. The Alizé took its first flight on October 6, 1956, and served in the navies of both France and Pakistan. Pakistani aircraft took part in the Indo-Pakistani War of 1971 flying from the carrier INS Vikrant, and French Alizés took part in the NATO air campaign over the former Yugoslavia as late as 1999 flying from the French carrier Foch.
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