Backgrounder

BCATP Hangar No. 1 National Historic Site of Canada, Brandon, Manitoba

One of Canada's most important contributions to the Allied effort during the Second World War was the British Commonwealth Air Training Plan (BCATP). Under the plan, Canada trained more than 130,000 Commonwealth airmen at Canadian air bases.

At the outbreak of war, the Royal Canadian Air Force (RCAF) had only five airports and 4,000 personnel under its wing. It had to expand — and fast.

The Brandon Airport was one of the 75 new aircrew training sites built in this expansion. It became a service flying training school. Like many of the training airports, the Brandon Airport featured several hard-surfaced runways laid out in a triangular form. Five hangars lined one side. About 25 other buildings behind them provided accommodations to servicemen, teachers and ground crew.

Hangar No. 1, a "double landplane hangar," was constructed in 1940-41 and measures 34 by 49 metres (112 by 160 feet). Its most notable architectural feature is the roof structure of 112 feet clear span, employing the Warren truss system. Developed in 1848, the Warren truss system consists of parallel upper and lower chords with inclined connecting members forming a series of equilateral triangles. The trusses are built of Douglas fir, as are the rigidly braced wood columns on which they rest. Hangar No. 1 also uses bolted joints and split ring connectors, making the joints stronger than in traditional Warren truss systems.

The flat roof was originally sealed with two layers of tarred felt, covered in fibre board, then tarred and gravelled. The roof's covering was specially designed to withstand the suction lift of high-velocity winds passing over the hangar. It also was made to resist ruptures by preventing any ballooning effect typical of hangars. (Ballooning is caused by interior air pressure generated by high winds blowing through open doors and penetrating through gaps in the roof sheeting.)

Of the 701 BCATP hangars constructed, only 41 are known to have survived. The Brandon Airport's Hangar No. 1 is among the few that remain relatively unaltered, in good condition and in their original location. It is located in an operating airport and, by housing the Commonwealth Air Training Plan (CATP) Museum, it is directly associated with the historical interpretation of the program responsible for its design and construction.