Faireyâ€™s Strike Fighter Concept: 1944

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In late August 1944, the Fairey Corporation was asked to asses the feasibility of adapting its original tandem, twin engine research studies to a new naval strike platform. The British Royal Navy issued a verbal requirement statement in October asking for a twin tandem aircraft fitted with a Tandem Merlin power plant, codenamed Project A, and alternative Twin Griffon platform, known as Project B. Either design was intended to be a single seated fighter, although there was the possibility of adding a rear compartment for a navigator.

The initial single seated platform design was very similar in form to the Fairey’s O-21-44 Torpedo Bomber. The main difference was a contra-rotating propeller system. Two heavy caliber cannons were fitted underneath each wing nacelles, the structure that also housed the main undercarriage. One torpedo or a 2,000lb bomb load could be carried on the plane’s centerline. The wings can also carry up to one thousand pound bomb load under each inner wing. Project A was designed to carry a 300 gal fuel load internally and additional 520 gal on drop fuel tanks.

The plane projected top speed at a 20,000′ operational ceiling was estimated at 460 mph. Top service ceiling was 36,000′, but with a torpedo load it felt to 29,600′. With drop fuel tanks, the aircraft was able to operate at a distance of 820 miles. Project B or Griffon carry a similar profile. Top speed was determinate at 397 mph with a top ceiling of 38,000′. Bomb load capacity was the same as the A program. The only other variant visa-vise the Merlin centered project was that the Griffon projected an 860-870 miles operational range, between forty to fifty miles longer than the Merlin. Nevertheless, it was the Merlin in which the company pitted their hopes for a new, huge production contract. But the fact of the matter was that Project A did not measured up to the concurrent Westland N-11-44 design.

During the first weeks of March 1945, Fairey redesigned the “A”‘s overall specifications. The plane would still employ the Merlin RM-17sm power plant, but the new version was streamlined and compacted. The new concept was a welcome sight to many inside the Ministry of Aircraft Production (MAP) who were unease about the path the whole program was directed to. The new version of Project A had a better climb rate than the Westland and a more robust undercarriage, a most ion naval operations. Still, the Westland was considerable faster than the “A”. One factor will change the dynamics of the “A”. By the middle of 1945, engineers at Fairey and other British aircraft manufacturing companies were in the adapting to a new kind of engine, the gas turbine. The Merlin has achieved its peak of aerodynamic design and now it was time to replace it with a more flexible unit.

Fairey was quickly to adapt to the new realities and promptly began to design the “A” with a turbine propeller alignment. With MAP consent, Fairley field officials commences informal discussion with Rolls-Royce engineers regarding the availability of the Clyde engine as well as other jet propeller gas turbine power plants under development. Rolls-Royce gave the company advance data research information for three top secret turboprop engines, RB-52 (an improved Clyde), RB-52-30 and RB-52-50. After redesigning the “A” program with each of the three prototypes, Fairey determined that the twin Merlin configuration gave a better overall performance, thus prompting the company to conclude that the expected high cruising fuel consumption of the single turbine power plant running in a throttle environment was the main culprit of the “A” poor showing in contrast to the Westland. The project managing team at Fairey decided to implement a small twin turbine configuration which would drive a contra-rotating propeller in a similar manner to the tandem piston system. It was envisioned that this alignment would give the “A” a better overall profile that a single turbine of equal aggregate power.

Soon after the engine configuration decision was achieved, the company commenced work on two new strike fighters. The first would utilize a single RB-52-50 turboprop with a contra-rotating propeller. The other sample was fitted with two B-52-30 arranged in tandem with a separated contra-propeller gearbox with each propeller driven by its own turbine system. A specification and profile paper was submitted to the MAP in June 30th 1945 featuring three planes. Each had a 52 feet wing span, four 20mm heavy caliber cannons and a torpedo arrangement. The piston configuration (RB-52-30) offered a total weight of 23,900lb, with a maximum speed of 410 mph at a 10,000′ ceiling. The RB-52-50 weighted at 24,400lb with a top speed of 395 mph and the same armament arrangement. The Clyde’s profile was similar to the other two, only its airspeed (413 mph) and total weight (23,300lb) was different.

Following Fairey’s paper the MAP concluded that a single Clyde system was inferior to the twin Merlin arrangement on almost all areas. But the higher achieved power gave the Project A an overall systematic quality that exceeded, albeit not by much, the one profiled on the Westland (now known as the N-11-44 project). The Admiralty gave the company the official ‘go ahead’ to start pre-production development on the strike fighter in September 1945. The Royal Navy made it official on June 20th 1946 when it issued Specification N-16-46.

With the end of the war in May 1945, the MAP began to review all incomplete aircraft programs. All Rolls-Royce engines designs were also reviewed. The company was asked to issue its views regarding the standing of their twin-tandem piston engine in regards to the new turboprops. In October, Rolls-Royce stated that it was in favor of utilizing the Fairey’s twin turboprop arrangement for navalized version of the strike fighter project. At the same meeting, Rolls executives told the Ministry members and Fairey senior staff that eventually the company will shift its engine developmental resources towards an axial flow jet engine. Fairey got the message and abandoned its tandem system altogether. Now, the company’s main military project will be fitted with a side-by-side engine system housed behind the main gearbox. Rolls accepted the idea and a new engine system was born, call sign AP-25.

The changes on the engine system caused the alteration of the original overall plane layout. The aircraft that emerged after the redesign program was a much cleaner unit. It had a completely clean trailing edge without hinge brackets, which was a mainstay of Fairey’s recent designs. The wing structure was laminated to allow an even air flow. The main armament, the torpedo, was still housed on the airframe’s centerline but now bombs, depth charges, rockets or any supplemental weapon system would be carried under the wing outboard of the main undercarriage between and below the heavy cannon. The two side-by-side engine configuration drove its own propeller through an independent mechanism train carried by a central gearbox. The two jet pipes exhausted through the bottom of the fuselage just behind the wing area. Internal fuel capacity, with a torpedo profile, was now 545gal. Top operational ceiling was estimated at 49,000′. There were plans to convert the Program A and B into a single entity with a two-seated arrangement.

A complete aircraft layout was submitted to NE Rowe, the MAP’s new Deputy of Development and Production on November 13th. Rowe accepted Fairey’s statement that Rolls would have the new AP-25 engine ready for operational testing by December 1946. On the morning of November 21st, Rowe advised Fairey of a MAP amendment to the original specification profile. The new order called for a true dedicated dive bombing platform, instead of the strike fighter boxed role first envisioned. On January 2nd 1946, the Admiralty issued a new set of pre-production order for the aircraft with a target date of January 1948. Immediately Fairey ran into pre-developmental problems. First, the now dive bomber proved to be too heavy for naval operations forcing the engineering team to shed almost 1,000lb of weight, most of them from the reinforced steel main fuselage. More importantly to Fairey than the weight issue was the development delays confronting Rolls Royce.

On October 17th, Royce executives advised their Fairey’s counterparts on the delays facing the engine, now known as Coupled Tweed, but still expected the power plant to be ready by the following January. By early 1947, the Admiralty was increasingly skeptic of the whole dive bomber/strike fighter concept. Their top leaders could not cover the high amount of monetary resources the Fairey platform was ‘eating’ yearly. For them, the time of the dive bomber has log passed and on March 12th, it made it official with the cancelation of the entire program.

For Royce, the termination of the project marked a shift in the company’s priorities and investments. As for Fairey, the company enjoyed a few success stories afterward. In the months following the cancelation, the engineers that worked on the strike program, as well as all the data collected on it, was used on the Gannet Program.

Fairey Aircraft Since 1915, HA Taylor, Putnam 1974
RAF Bomber Command and its Aircraft 1936-1940, James Goulding and Philip Moyes, Ian Allan 1975
Planemakers II, David Monday, Janes 1982

Story By: Raul Colon e-mail:rcolonfrias@yahoo.com