Saunders-Roe, Southampton and Isle of White
After Tecwyn’s release from the RAF in 1944 he resumed work with Saunders Roe at their Southampton works, being transferred from there to the Isle of Wight in 1946.
When in Southampton he attended the University there, studying for the Higher National Certificate in Aeronautical Engineering, which he successfully obtained in 1948. For this achievement Tecwyn was awarded the Institute of Mechanical Engineers Special Award.
During the post-war period, the Saunders Roe factory at Isle of White was involved with the ‘Princess Air Boat’.
Whilst working for Saunders Roe on the Isle of White, Tecwyn met Doris Sprake, they later married.
In 1945, Saunders-Roe was asked by the British Ministry of Supply to bid for a long range civil flying boat for British Overseas Airways Corporation, who planned to use them on transatlantic passenger services. Saunders-Roe's bid was successful, and it received an order for three aircraft in May 1946.
The Princess was powered by ten Bristol Proteus turboprop engines, powering six propellers. The four inner propellers were double, contra-rotating propellers driven by a twin version of the Proteus, the Bristol Coupled Proteus; each engine drove one of the propellers. The two outer propellers were single and powered by single engines. The rounded, bulbous, 'double-bubble' pressurized fuselage contained two passenger decks, with room for 105 passengers great comfort.
The ailerons and rudder were split into multiple sections such that if a part of the servo-powered control system failed the faulty section could be "trailed" so that it did not act against the working sections. The planing bottom of the hull had only a slight step in the keel to minimise drag in the air.