Early, in 1938. while waiting for his model to undergo wind tunnel testing at Hawkers, the young Russian born Canadian engineer, Michael Gregor hoped he got his design right. The NACA data that he was able to access helped determine his choice of a semi elliptical wing shape. His design borrowed from the Grumman F3F biplane that the Canadian Car & Foundry had a licence to build. Next was an engine. The U.S. seemed the obvious source because of proximity.
As he waited, Michael went over his design choices. A radial engine, for simplicity. Flush riveting and stressed aluminum skin to reduce drag. A bubble/tear drop canopy for good visibility and the retractable landing gear of the F3F for rough field operation, he thought were good choices. More controversial was the inclusion of folding wings. The harsh conditions and limited hanger space that he felt the aircraft would operate in, it seemed a logical choice. His last choice of eight gun,Browning's, four/wing was to it common with what the British were doing.
Michael, the Hawker engineer said, your model did very well in the wind tunnel test, what are you planning to power it with? I was thinking an American radial would be best replied Michael. Bristol has very good radial engines, why not check them out while you are here. They might even offer a licence to build them in Canada.
The letter of introduction from Hawkers provided Michael the opportunity to tour Bristol's engine facility. The small size, compact and quiet Taurus he found particularly impressive. The 1,050 hp rating on 87 octane fuel would be ideal for his aircraft. A licence agreement, in principal, was made followed up over several months to a formal agreement.
Flight testing of the prototype began in December, 1938 and a number of issues came up. The canopy had vibration problems at speed and the Taurus radial, supplied by Bristol, had some reliability problems. GM Canada, which was contracted to build the Taurus, under licence, looked at fixing the engine issue. The canopy required a redesign to correct the vibration problems.
While fight testing continued, GM brought in several engineers including some from their diesel division to try to fix the teething issues with the Taurus engines. What was eventually found was quality control issues with the pistons. One of the fixes that the diesel engineers tried was to fuel inject the engine. The engine, with improved pistons and fuel injection, gained a modest increase of power of 8%, which raised the output to 1130 hp on 87 octane fuel. The slight increase in unit cost was felt worth the increase in performance and was accepted by the CC&F.
The Dominion Day celebration, in Ottawa, July 1, 1939, was highlighted by the flights of various aircraft, including DeHavilland Moths, Avro Prefects and Hawker Harts. The last aircraft to appear, were 3 FDB-1s, which overtook the other flights at over 300 mph.
Over the next few weeks orders began to come in. The Canadian Government had previously ordered 25 but had increased this to 50. Finland ordered 25, France ordered 25 and the Duchy of Grande Fenwick 3. The FAA also showed some interest but were limited by Treasury as to what they could purchase.