If You Want To Win At Aviation Trivia You’d Best Study the Skyshark
The Douglas A2D Skyshark is the answer to several aviation trivia questions. What aircraft came between the Douglas AD Skyraider and the A3D Skywarrior? The A2D Skyshark of course. What was the first gas turbine-powered prototype built for use on escort carriers? Also the A2D Skyshark. What Douglas product broke the streak of highly successful Navy and Marine Corps attack aircraft from the Skyraider to the Skyhawk? You guessed it- the Skyshark. But the Skyshark wasn’t a total waste…
The A2D was developed in response to a Navy Bureau of Aeronautics (BuAer) request for a turbine-powered, propeller-driven attack aircraft. The request, put forth on June 25th 1945, came in part because BuAer realized that the jet engine designs of the day were far from fuel efficient enough to make operation of aircraft powered by them from aircraft carriers practical. June 11th 1947 was the next significant date in the Skyshark’s development- the Navy gave Douglas an initial order for a total of 12 A2D Skysharks. There was a plan in place to order 331 more of them…but the aircraft had to prove itself first.
Another reason for BuAer’s insistence on turboprop power was the requirement for the aircraft to operate from Casablanca-class escort carriers. The AD Skyraider was underpowered and large for deployment aboard escort carriers. The biggest practical difference between piston engines and gas turbine or turboprop power was power-to-weight ratio. When compared to reciprocating engines like the R-3350, the turboprop engine itself ran at near full power and RPM all the time with delivered thrust being controlled by propeller pitch.
There was certainly a family resemblance to the Skyraider from which the Skyshark was developed, but the Allison XT-40-A2 engine in the A2D, which consisted of two T38 engines linked to a common gearbox, produced more than twice the horsepower of the R-3350 in the Able Dog. The dual 14 foot contra-rotating propellers were required to handle all the additional horsepower and turn it into thrust. The thickness of the A2D wing root actually decreased by five percent and the tail surface area and height increased substantially. The A2D ended up being an almost entirely new aircraft.
It took until May 26th 1950 to get the development of the engine and propeller worked out. On that date the XA2D-1 flew for the first time at Edwards Air Force Base. But only 14 flights totaling 20 hours later the aircraft crashed, killing Navy test pilot Commander Hugh Wood. It would take sixteen months to work through the cause of the crash and engineer fixes for the remaining XA2D-1s. At that time sixteen months was forever in aerospace engineering, and the jet powered aircraft being developed by then effectively shot down the Skyshark.
But development of the A2D went on for a time. Allison finally delivered a production-spec engine in 1953. But while testing another XA2D-1 with the production-spec engine installed that Skyshark shed its propellers due to a gearbox failure. When the Navy started mothballing the escort carriers there was no longer any need for the A2D. Work on the Skyshark still continued but when Douglas rolled out a ready-to-fly turbojet-powered A4D Skyhawk in 1954 it spelled the end for the Skyshark program.
Douglas built 12 A2D Skysharks– the two prototypes and 10 preproduction aircraft. Most were scrapped or destroyed in accidents, and only one has survived. But the Skysharks flew for many months after the Navy formally terminated the A2D program in August of 1954- the same month that saw the first flight of a new turboprop airlifter- Lockheed C-130 Hercules. The following year the Army was watching a demonstration of the first (of many to come) gas turbine-powered helicopter, the XH-40. You know that helicopter today as the Bell UH-1 Huey. And of course Allison went on to produce turboprop power plants for thousands of aircraft.