Aero-engine designer, born in Bristol, SW England, UK. He established the engine building department of the Bristol Aeroplane Co in 1920, where he was chief engineer until 1942. Initiating a famous range of piston engines, including the Pegasus and Hercules, he was also notable for his unique development of the sleeve-valve engine. He held a variety of governmental and international posts until 1960, and was president of the Royal Aeronautical Society in 1938, 1939, and 1945.
Sir Roy Fedden was an engineer who designed most of Bristol Engine Company's successful aircraft engine designs.
Fedden was born in the Bristol area to fairly wealthy and influential parents.
His apprenticeship was completed in 1906, and he immediately designed a complete car. He managed to convince the local firm of Brazil Straker to hire him, and the design was produced as the successful Shamrock. He remained at Brazil Straker over the following years, and he was particularly influential in convincing company management to take on the repair of various aircraft engines when World War I started.
In 1915, Fedden started the design of his own aero engine, along with his draughtsman Leonard Butler. The two were inseparable for the next twenty years, and most of their designs were stamped "FB" to indicate the shared credit. They designed two engines during WW1: the 14-cylinder radial Mercury, notable for the cylinders being arranged helically instead of in two rows, and the larger, more conventional, two-row Jupiter design of about 400 hp.
During this period the aviation portions of Brazil Straker were purchased by Cosmos Engineering, where work on the designs continued. Bristol then decided to try the Jupiter in their new Badger design, finding that it too completely outperformed the competing ABC Dragonfly. Production of both designs for Bristol was to start immediately, but the war ended only days later and the contract was cancelled.
With the ending of the war, Cosmos had no production designs, and their repair work was quickly dwindling. Convinced of the quality of the Cosmos designs, the Air Ministry "made it be known" that they would be rather happy if the company were purchased by Bristol, which eventually took place in 1920. Sir George White later noted that they acquired Mercury design and seven engines, all the assets of Cosmos, along with Fedden and his design team, all for just £15,000.
Bristol soon found a role for the larger design, which entered production at Bristol's new engine plant in Filton as the Bristol Jupiter.
By the late 1920s, the Jupiter design was no longer competitive, and Fedden and Butler started work on a pair of new designs. Re-using their earlier name, this design emerged as the Bristol Mercury, while a more powerful design at the same size as the original Jupiter became the Bristol Pegasus. Fedden and Butler immediately turned to such a design, adapting the Mercury to become the Bristol Aquila, and the Pegasus as the Bristol Perseus. However, both of these engines quickly found themselves at the "low end" of the power spectrum as ever-larger aircraft designs demanded ever-larger engines to power them.
To solve this problem, the two designs were quickly adapted to two-row configurations, resulting in the Bristol Taurus and the superb Bristol Hercules. Not one to rest on his laurels, Fedden then started adapting the Hercules into a two-row 18-cylinder design as the Bristol Centaurus. The entire Bristol sleeve-valve range would see widespread service throughout the war on a wide variety of designs.
With Hercules production in full swing in 1941, Fedden returned to the Centaurus. Newer designs intended to mount engines of this size appeared near the end of the war, notably certain versions of the Hawker Tempest, taking over from the Sabre in that design.
For his role in creating some of the most successful aircraft engines of the era, Fedden was knighted in 1942. Although Fedden had created a long line of hugely successful engines for Bristol, he had fought constantly with management over funding priorities. Without Butler's influence it seems Fedden "had enough", and shortly after being knighted, he left Bristol to take up a variety of positions within the Government.
On his return, Duncan and Fedden set up Roy Fedden Ltd. in 1945. He then turned to a new turboprop design which also found little interest. Finally they decided to design their own car, powered by a three-cylinder air-cooled radial, but they found it had serious handling problems and tended to flip over when being cornered hard.
After this, Fedden worked for a time consulting with George Dowty, but soon retired and spent his time teaching at the College of Aeronautics at Cranfield University.
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