Article: The Fairchild Super 71 Leaves an Enduring Mark in Aircraft History

  • Image of Fairchild Super 71, CF-AUJ on floats with wheels fixed

    Altitude, Winter, 2009

    The restoration of the Fairchild Super 71, registration CF-AUJ, is a major achievement for the Western Canada Aviation Museum because it preserves for posterity a unique and important aircraft in Canadian aviation history.

    The Fairchild Super 71 is an important aircraft because it was the first aircraft designed in Canada for bush operations and the first to be built by a Canadian company. The Super 71 also incorporated new and leading-edge concepts in its design.

    CF-AUJ is unique for another reason – it was the only civil model ever built and therefore the only Super 71 to fly in commercial service.

    The completion of the restoration this year is a tribute to all the members of the restoration shop who persevered at the project for more than 12 years.

    History: The Short Version

    CF-AUJ was built in 1934 at the Longueuil, Quebec, plant of Fairchild Aircraft Ltd., the Canadian subsidiary of Fairchild Aviation Corp. CF-AUJ was purchased by Canadian Airways Ltd., which first assigned the plane to Oskelaneo, Quebec, before re-assigning CF-AUJ to Sioux Lookout in northwest Ontario in 1939. CF-AUJ provided service there until October 3, 1940, when it smashed into a submerged object on takeoff from Lost Bay on Confederation Lake near Red Lake, Ontario. The damaged aircraft was salvaged within months to recover a 75-pound cargo of gold, and the leased engine. The wreckage languished on shore for the next three decades until two salvagers moved the surviving pieces to Red Lake. The museum acquired the wreckage in 1974 and final title to CF-AUJ in 1978. The remnants of AUJ were moved first to Lac du Bonnet, Manitoba, and then to St. Andrews in 1974. In 1997, the restoration process began in earnest.

    The Fairchild Aviation Corporation was founded by Sherman Fairchild in 1929, and based in Farmingdale, New York. Fairchild Aircraft Ltd. of Longueuil, Quebec, was a subsidiary of the American firm and it operated in the province from 1920 until 1950. Fairchild continues today as M7 Aerospace in San Antonio, Texas.

    Super 71’s Pioneering Features

    In a promotional write-up for the Super 71 published in the August 1935 edition of Aero Digest, Fairchild made the statement: “since 75 per cent of Canadian aircraft are operated on floats during the summer season and on skis during the winter, the Fairchild ‘Super 71’ was primarily designed as a seaplane, and its float equipment was given primary consideration by its designers.”

    The promo article goes on to say that the aircraft “is convertible into a transport with accommodations for eight passengers, or a cargo plane which can carry 2,000 pounds of payload for 600 miles at a cruising speed of 121 mph.”

    According to an article by William Paul Ferguson, published in 1977, the design program for the Super 71 was noteworthy “because it was based upon a survey of the needs of bush airline operators, and thus was the first aircraft to be designed and built in Canada to meet specific Canadian northern aviation requirements… Because the Super 71 was designed upon the advice of experienced operators, rather than nebulous guesswork, the radical product embodied many hoped-for capabilities. In toto, the design incorporated a large and accessible cargo area, high-wing monoplane configuration, control surfaces which retained effectiveness throughout all attitudes and – most importantly – the capability for year-round operations.”

    The article also observed “the new Fairchild product was a sophisticated composite construction air freighter which utilized not only proven concepts but also radical innovative features.”

    The high-wing monoplane configuration made dockside loading and unloading relatively easy. The cabin, which provided a clear floor space 13ft 6in long by 5ft wide and 4ft high, could accommodate most of the largest mining equipment then in use. Cargo handling was aided by a main access door of 32in that could easily be doubled to a maximum size of 65in to accommodate oversize items. The cabin walls were insulated against heat and cold, and a heating system for cockpit and cabin was incorporated into the fuselage structure.

    It was the Super 71’s role as a cargo plane that determined the location of the cockpit behind the wing structure. This unusual cockpit location afforded optimum balance whether empty or fully loaded, thus relieving the pilot of having to calculate weight distribution and centre of gravity. This feature, however, compromised the pilot’s forward vision to such an extent that pilots and operators were wary of the design; it is believed that potential purchasers may have held back on their orders because of the unusual cockpit position. (In fact, when the Royal Canadian Air Force ordered a version of the Super 71 it specified that the cockpit be re-positioned behind the engine.)

    The Super 71 was the first aircraft built in Canada with a monocoque fuselage, a construction concept that uses no internal bracing and that derives strength from its skin. The Super 71 fuselage is made up of consecutive duraluminum forming rings interconnected by intercostal, or longeron, Z-bars and covered in a duraluminum skin.

    Also, the float undercarriage for the Super 71 was designed on the basis of hydrodynamic principles and experimental data gained from laboratory water tank tests. The Super 71 floats introduced “float steps” to help break the surface tension between float and water to aid lift-off. The concept of “steps” has been a feature of seaplane floats ever since.

    The wing design of the Super 71 was one unremarkable feature in an otherwise radical design concept. The wings on the Super 71 are similar to the Fairchild 71, differing mainly in the internal bracing and a non-folding requirement. Traditional spruce construction with a cotton fabric cover was chosen for the Super 71 because Fairchild was not confident that maintenance shops in the 1930s had the skills required to repair aluminum wing damage.

    One anomaly in the Super 71 wing structure is the centre section, where an arched parasol arrangement bridges the gap over the fuselage between the right and left wing sections. This short bridging section features a negative dihedral to provide additional separation between it and the fuselage to give the pilot some, though limited, forward vision.

    Tail control surfaces were a combination of duraluminum and fabric components. The high position of the tail structure was dictated by input from bush flyers who wanted the tail as far as possible above the water to keep it out of the flying spray during takeoff.

    The Super 71 was designed to accept several of the most widely used engines of the 1930s, but only the Pratt & Whitney T1D1 Wasp, a nine-cylinder radial engine of 520 hp, was fitted. An important, and vital, consideration affecting the Super 71 power plant was the ability to adjust the airflow over the engine in hot summer and extremely cold winter conditions. The Super 71 cowling had two independent sets of louvers, controlled from the cockpit, providing regulation of both crankcase and cylinder head temperatures. In addition, an engine oil cooler provided further temperature control. According to the Fairchild’s promotional article in Aero Digest, “further protection of the engine and assurance of operating under the extreme operating range experienced in Canada, is provided by overhead carburetor air intakes and complete preheating equipment.” In actual use, the engine cowling was removed, and at some point altered, because the original design did not provide enough cooling during summer operations.

    Into the Air: First Flights

    The Super 71 lifted off the water at Longueuil for the first time on October 31, 1934, with Fairchild P8 floats installed. The evaluation of this and other test flights showed that the aircraft generally exceeded predicted performance parameters. Fairchild was also required to submit the Super 71 design to the National Research Council for evaluation. According to Ferguson’s article, the research council’s report provided a ringing endorsement. A letter from NRC director, J.H. Parkin, was unusually effusive for a government review agency; he wrote: “all aspects of the design were tested in a wind tunnel and the aerodynamic characteristics are very good and leave little room for improvement.”

    The commercial certificate of airworthiness was awarded to the Super 71 in May 1935, and the registration letters CF-AUJ were applied. The aircraft was then acquired by Canadian Airways Ltd. initially on a lease/purchase agreement. Canadian Airways purchased CF-AUJ outright in 1935 after a number of modifications by Fairchild. This was the only Super 71 ever built, although there is some evidence that Fairchild started, but did not complete, a second aircraft.

    Variation of the Model

    The effusive endorsement by the National Research Council led to a call from the Department of National Defence asking Fairchild to design an aircraft for reconnaissance and photographic missions using the Super 71 airframe as its base. The requisition also specified that the cockpit be re-located ahead of the wing.

    The Super 71P was the result and two 71P aircraft were ordered and delivered to the Royal Canadian Air Force at Trenton, Ontario, in 1936. The cockpit was relocated ahead of the wing in accordance with the specification and the centre wing section was faired into the fuselage behind the cockpit.

    Performance of the Super 71P was disappointing. This may have been an unexpected result of the relocation of the cockpit forward of the wing, which then upset the airflow over the tail surfaces when in a nose-high attitude.

    One of the two Super 71Ps, RCAF number 666, crashed and burned in August 1937, near Grand Rapids, Manitoba, taking the lives of the three crew on board. In the summer of 1977, museum members located and salvaged the meager remains of this aircraft. It was initially thought that some of the recovered parts and artifacts could be incorporated into the restoration of CF-AUJ, but this did not happen because of the design differences between the two models. The other Super 71P, RCAF number 665, remained in RCAF service well into the 1940s.

    Into the Air: CF-AUJ in Service

    CF-AUJ was assigned to Canadian Airway’s base at Oskelaneo, Quebec, for scheduled service from that location. It operated from that base until 1939 when it was re-assigned, after an overhaul in Winnipeg, to Sioux Lookout, Ontario.

    Ferguson in his article on the Super 71 observed that “the aircraft was pronounced satisfactory in all respects by both J.H. Lymburner and airline management. Airline executives did request on numerous occasions that Fairchild construct additional Super 71 units, but (according to some accounts) Fairchild resisted building more units because it believed that maintenance of the monocoque fuselages was beyond the expertise of airline field personnel. The article also argued that Fairchild did not build additional Super 71s because it was shifting its priorities to government rearmament programs.

    Nevertheless, with its eight-passenger or one-ton cargo capacity, it was a large plane by pre-WWII standards and so was very useful to customers in the remote mining areas of Quebec and Ontario. During its six-year flying history, CF-AUJ was equipped either with floats or skis; there is no record of it ever being outfitted with wheels.

    (NOTE: Lymburner was the pilot that Canadian Airways assigned to CF-AUJ and who flew it for most of its service history. Lymburner was also a member of the Lincoln-Ellsworth Antarctic expedition in 1936.)

    Image of Fairchild Super 71, CF-AUJ on floats with wheels fixed

    The Last Flight

    CF-AUJ crashed on takeoff on October 3, 1940, near the Uchi gold mine at Lost Bay on Confederation Lake, about 50 miles east of Red lake. It was reported that CF-AUJ hit a submerged object that ripped both floats from the fuselage. The aircraft sank and the pilot, Donald S. MacLaren, and two passengers clung to the loose pontoons until they were rescued. Shaken and slightly injured, they were airlifted to Sioux Lookout, 75 miles distant. The condition of one of the floats, recovered decades later, supports the idea that the CF-AUJ hit an object in the water because the leading three feet were bent upward to almost 90 degrees.

    Canadian Airways let a salvage contract to recover the valuable items – the leased engine, which was valued at just over $31,000 at the time, and the 75 pounds of gold from the nearby mine. The gold would be worth $1.2 million at the 2009 gold price of $1,000 an ounce.

    The first salvage contract went to Starratt Airways and Transportation, which held a contract to move heavy freight into the mining area by winter road. Its divers found the wreck 80 feet underwater and raised it for removal to shore. The gold was recovered from the cargo cabin and the engine and cockpit instruments stripped from the aircraft. The airframe was declared to be beyond economical repair.

    At some point in this process the wings were also removed from the fuselage. All of the wreckage was abandoned at the edge of the lake, where it stayed for the next 28 years. While the aluminum fuselage survived the elements quite well, the wings did not – the wooden spars and fabric succumbed to the action of 30 years of sun, rain, wind and snow.

    Specifications

    A Fairchild factory drawing of the Super 71 highlighted the following features: sliding transparent pilot’s hood; cabin door incorporating inward opening mail chute; easily removable panel (for extra large freight); emergency exit; anchor and tool storage in stub wings; exhaust bypass for cabin heater; oversize oil cooler; large dump valve for draining oil tank; easily removable head fairing for inspection of controls; double concentric nose shutter for independent cylinder head and base temperature control; instrument panel and compass shelf (anti-vibration mounting); gas contents gauge (large and easily read by pilot); water rudder protector and skid; heavy keel plate 5 inch wide under keel strip; heavy hardwood rubbing strip along chines; generous nose bumper with drainage space between backboard and float; and non-freezing vent well above water level.

    • Wingspan: 58 ft
    • Length: 35 ft, 6 in
    • Height: 10 ft, 6 in
    • Gross weight: 7,000 lb
    • Maximum speed: 141 mph
    • Range: 760 miles
    • Power Plant: P&W T1k1, Wasp, 525 hp

    Image of Fairchild Super 71, CF-AUJ outside museum

    This article originally appeared in the Winter, 2009 edition of Altitude.

Leave a Reply

* Name, Email, and Comment are Required