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  • heritage toronto slide

  • Plaque Celebrating Aviation History in Mount Dennis

    Saturday, July 15 - 10:45 am

    Hearst Circle and "The Wishbone" (Opposite Harding Park in Mount Dennis)

    Reception to follow at The Atrium, 12 Division Police Station, 200 Trethewey Drive, North York

    This event is a joint function of Heritage Toronto, CAHS (Toronto Chapter & National) and 400 Squadron Historical Society.  The plaque is honouring the airfield that hosted 1st flight over Toronto in 1910, the startup location of DeHavilland Aircraft in Canada in 1928 at this airfield and in 1932 the first operational base of the RCAF 400 "City of Toronto" Squadron as 10 Sqn and later 110 Sqn.

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    FINAL Invite Trethewey july15 545

    Background on the William G. Trethewey Property

    By Dr. Robert Galway

    This property was purchased by William Trethewey following his sale of two Silver mining properties that he discovered in Cobalt, Ontario on 1904. He and his brother Joseph O. Trethewey made millions in this transaction. William Trethewey came to Toronto and purchased 600 acres in Weston, near present day Jane St. & Lawrence Ave. in 1907 The Royal Automobile Club of Canada and the OML of which Trethewey was a member, asked for permission to use a portion of the property for an exhibition Air Meet. This took place July 9-16th, 1910 following closely on the heels of the initial Air Meet held in Pointe Claire, PQ.

    During the Toronto meet, French Aviator Jacques de Lesseps completed the first flight over the city of Toronto as he had done two weeks previously in Montreal. The Toronto flight occurred on July 13, 1910. This is the basis for recognizing Jacques de Lesseps on the Heritage Toronto Plaque that will be unveiled this summer on July 15, 2017.

    However, this is not the sole reason for recognizing the contribution that this plot of farmland made to Canadian aviation history.

    Following the Air Meet of 1910, the property became the center of early aviation activity in Toronto. Indeed, it became known as de Lesseps Field. In 1928 de Havilland UK decided establish a manufacturing center in Canada. They were persuaded to do so because of the success they had met in selling the DH60 Moth to the Ontario Provincial Air Service. In their search for a suitable property, they were put in touch with Frank Trethewey who had inherited the property on his father’s demise in 1926. Trethewey leased a parcel of the land to de Havilland and with the incorporation of de Havilland
    Canada was appointed to the DHC Board.

    Consequently, the Trethewey property became the first manufacturing site of de Havilland. In fact the first building used to assemble the DH60 series was the Trethewey Canning Shed made famous by the sketch completed by famous aviation artist, Robert Bradford.

    Frank Trethewey was given the opportunity to purchase DH aircraft at a significant “favored” price. He and his brother were RNAS veteran pilots. In the 1930's he was Chairman of de Havilland Canada.

    The establishment of de Havilland Aircraft on this property in 1928 is the second reason to grant historic recognition to this property.

    Frank Trethewey not only over time purchased three aircraft from DHC but went one step further and joined the RCAF. This led to the establishment of the RCAF Squadron 10/ 110 on Trethewey Field. Frank Trethewey was one of the first four flying officers appointed to the Squadron. In 1940 he was appointed commanding officer of Base Trenton.

    The squadron was formed in October 1932 as 10 (Army Cooperation) Squadron and began flying in 1934 at the Trethewey Farm airfield (aka de Lesseps Field) in Toronto. In April, 1935, the City of Toronto adopted the squadron which then became officially known as “10 (City of Toronto) Squadron”. In 1937, the squadron was re-designated “110 (City of
    Toronto) Squadron”.

    The squadron flew five basic types of aircraft, all biplanes, from Trethewey until late 1939 when it deployed to Rockcliffe. During the Trethewey era, the squadron was involved in recruitment and flight training. At Rockcliffe, the squadron underwent conversion to the Canadian-built Westland Lysander until mid-February 1940. The squadron then deployed to the UK as the first RCAF squadron to enter the Second World War.

    In the UK, the squadron was initially equipped with the Lysander III and was involved in the Army Co-op and photo reconnaissance role. The squadron was active in the Dunkirk evacuation (27 May - 3 June 1940) but not directly involved in the Battle of Britain (10 July - 31 Oct. 1940). In mid-1941, the squadron was re-designated “400 Squadron”.

    Today, the Squadron is located at Camp Borden and is the main maintenance centre for maintenance of the RCAF's Tactical Helicopter Squadrons.

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Canadian Car & Foundry / Burnelli CBY-3 Loadmaster

Canadian Car & Foundry / Burnelli CBY-3 Loadmaster

Loadmaster By Mathias Joost

Perhaps the most unusual aircraft design ever built in Canada was the Burnelli CBY-3 Loadmaster, built by Canadian Car and Foundry (CC&F) in Montreal. The development of the aircraft, of a lifting body design, is a story in itself, covered in Ray Conrath's article "The Cancargo CBY-3 Loadmaster" in the Spring 2004 edition of the CAHS Journal. However, its operational usage forms another story, as it almost seemed as if it was always seeking a home.

The Loadmaster was in built in Montreal at the former Curtiss-Reid plant that CC&F bought. First flown on 17 July 1945 and registered as CF-BEL, the airplane received only a limited Domestic Certificate of Airworthiness, as it did not meet the stall requirements. CC&F formed a subsidiary, Cancargo, in February 1947 to market the aircraft, which soon resulted in an operational trial.

In March 1947, Canadian Pacific Airlines became a participant in the airlift of mining equipment to the Knob Lake area of northern Quebec, in what was to become the site of Iron Ore Company of Canada's Schefferville operations. CPA operated two DC-3s while Bristol Aircraft of the UK crewed its Bristol Freighter for demonstration. The DC-3s operated by Hollinger Ungava Transport formed the bulk of the transport effort, which would carry on until 1954. In March and April 1947, a total of 300 tons of equipment was airlifted from Mont Joli and Sept Isles, Quebec. The CBY-3 carried 28 tons of this; however, CPA decided not to buy any Loadmasters.


Thereafter, the Loadmaster made various test flights in the Montreal area before proceeding to Uplands at Ottawa on 28 August where it conducted two test flights, one for the Department of Transport and one for the Royal Canadian Air Force. In early September there was even a demonstration for the Argentinean Navy. Cancargo's marketing efforts produced another chance to demonstrate the Loadmaster, when from 24–29 May 1948, the Loadmaster flew demonstrations in the Washington, DC area and then flew further tests for the United States Air Force at Wright-Patterson Air Force Base from 16–20 June. The USAF concluded that the aircraft's cargo configuration was not suited for their cargo loads and complained of the lack of heat in the cabin when carrying passengers. More flights were made for the RCAF on 20 and 21 December 1948 and in April 1949, the Loadmaster dropped paratroops at the Canadian Joint Air Training Centre at Rivers, Manitoba.

In February 1951, CC&F gave up trying to have the Loadmaster certified in Canada and exported it to the United States. There it was registered as N17N to the Central Aircraft Corp. of New York (the successor to Burnelli Aircraft) on February 9. More marketing followed, with a potential chance at glory being announced on 29 December 1954. The Loadmaster had been selected to land an Arctic expedition at the North Pole in March 1955; however, after the Loadmaster had been reconfigured to carry 20 passengers and 41 sled dogs, the expedition was cancelled.


In 1956, it appeared that the Loadmaster would get a break when the Venezuelan national airline Rutas Aereas Nacionales leased the aircraft, where it was registered as YV-C-ERC or possibly YC-X-ERC). Despite the fact that the Loadmaster served well, no orders were forthcoming. When the decision was made to upgrade the engines, which could not be done in country, the Loadmaster was flown back to the United States on 8 December 1959. And there it was allowed to languish before finding a final resting place in 1964 at the New England Air Museum in Windsor Locks, Connecticut, north of Hartford.


The Loadmaster was an aircraft whose benefits from its lifting body design could apparently not overcome its most unusual design. It also could not compete with surplus Second World War Dakotas going for $5,000, which Canadair was refurbishing for Trans-Canada Air Lines, Canadian Pacific Airlines and other customers. In addition, newer designs offering greater speed and comfort. The Loadmaster was simply not the right aircraft at the right time.

BurnelliCCF CBY-3 600

Editor's Note: The CBY-3, retired to the New England Air Museum, has shown noticeable deterioration from its extended time in outdoor display. In 2011, the museum announced that the one-of-a-kind Burnelli CBY will be moved into the restoration facility for its restoration, anticipated to begin in mid-2012, and take several years.