Canadian Warplanes 4: Stinson Model 10A and Model 108 Voyager

Stinson Model 10A and Model 108 Voyager

(Library and Archives Canada Photo, MIKAN No. 3582864)

Stinson Model 105, RCAF (Serial No. 3465), 20 March 1942.

Between July and September 1940, the RCAF acquired 26 Model 105s and 10s. Purchased as commercial aircraft, each was assigned a Canadian civilian registration number and flown to Canada. Once on Canadian soil, the aircraft were transferred to the RCAF and assigned a military serial number. In this manner a Voyager aircraft with American registration NC21172 became a Canadian civil aircraft registered as CF-BSK before being taken on strength by the RCAF on 41 July 1940 with serial number 3465. And, according to American law, it was all strictly legal.

Within the RCAF, the Stinson Model 105s and 10s were used for short-range communication and courier duties and wireless training. In the communication role, it was used at various stations to ferry senior officers around for official visits and as the “Station Hack” wherein aircrew in non-flying positions could take it up from time to time to stay proficient. As a training aircraft, it was employed by both No. 1 Wireless Training School, in Montreal, Quebec, and No. 3 Wireless Training School, in Winnipeg, Manitoba.

The Stinson was a cheap, effective training aircraft. However, its one drawback was that it could only carry one instructor and one student at a time. As more and more wireless students made their way through the BCATP, the Stinsons were replaced with larger, more capable aircraft. Still, they continued to be used by the RCAF until the end of the war, with the last of them being “struck off strength” in January 1946. (Major Bill Marsh)

(DND Photo, PL-2140)

Stinson Model 105s in Montreal, Quebec, 19 August 1940.

Stinson only used the "Voyager" name to market the 90-hp Franklin-powered Model 10A and some of the post-war Model 108 series of aircraft. The 1939-1940 Stinson HW-75 (marketed as the Model 105) did not carry the "Voyager" moniker, nor did the 1940 Model 10, six of which were procured and evaluated by the United States Army Air Forces (USAAF) as the YO-54. The military field tests of the YO-54's took place between September 1940 and January 1941 at Fort Knox and Fort Benning. The Army Air Corps was not renamed the Army Air Forces until June 20, 1941. The successful tests led to an order for the slightly larger and heavier O-62, later designated the L-5 Sentinel. A number of Model 105s and Model 10As were impressed into USAAF service as the L-9B. After the Second World War, the type was developed as the Model 108, the prototypes being converted Model 10As.

The YO-54 was a stock 80-hp Model 10 fitted with a military radio and wind-driven generator to keep the battery charged. The military service tests ended in dismal failure and the type was not recommended for purchase as a liaison aircraft. It was deemed too lightly constructed with poor off-field capability and woefully inadequate takeoff and climb performance. Parachutes (required by regulation) also couldn't be worn because the cabin had insufficient headroom, and the doors were too small to allow a successful bail-out. The side-by-side seating was also a major complaint because the observer didn't have an unobstructed all-around view. (James Gray)

YO-54's had nothing to do with the eventual development and adoption of the L-5.  However, as an expedient, the Air Corps acquired 12 low-time Model 10s for domestic courier use. Stinson had bought them back from their owners, made sure they were mechanically sound, and re-sold them to the military. These were the so-called "impressed" airplanes - a description that is a misnomer because it implies they were confiscated by the government.  

The Stinson Model 10 was designed to compete in both light-commercial and private-ownership markets. Advertised as a three-seat aircraft, the third, a jump-seat, was located in the rear of the aircraft and was more suited to a small child than an adult. A welded steel-tube airframe was fabric-covered and the wings were primarily made of wood.

Other than flight instruction, there was no "light commercial" market to compete with in the 1939-1942 time frame. The target market was private owners who were recreational (sport) pilots or businessmen who bought them for personal transportation. Because Stinson wanted to avoid direct competition with the dominant light aircraft manufacturers such as Piper and Taylor, their chosen market niche was a price point midway between the slow, bare-bones 2-seat Piper Cub and the plush and fast 4-seat Fairchild 24.

The wings had spruce spars, but the rest of the structure including ribs, ailerons, flaps, leading edges, wingtips and all fittings consisted of aluminum and/or steel. Area and volume-wise, wood was the lesser of the wing components.

What made the aircraft stand out from its competitors was the inclusion of slotted flaps and leading-edge slots in the wings that gave the Voyager enhanced low-speed responsiveness and improved short take-off and landing performance. The Franklin engine gave it respectable performance with a cruise speed of 105 miles per hour (169 kilometres per hour); hence its designation as “Model 105”.

The HW-75 / Model 105 was originally designed for a geared 75-hp Lycoming, but gear-box problems with that engine led Stinson to use the 75-hp direct-drive Continental A-75 instead.  In 1940 the Continental A-80 became standard for the Model 10 although the A-75 was offered as a cheaper option. The "105" name indeed came from the advertised cruising speed, which was somewhat exaggerated. Only the 1941 Model 10A was equipped with the 90-hp 4-cylinder Franklin O-199, although the now-perfected Lycoming GO-145 was offered  as an option in the more spartan Model 10B. As far as I know, only one was delivered in the USA and the rest went to South America, sold by the government to Bolivia as L-9A's.  

What also helped the 105 and subsequent models stand out from the competition (primarily Piper) besides the slotted flaps and wing slots was extreme resistance to stalling and spinning and its relatively high cruise speed, along with a comfortable interior, optional electrical system (giving night-flying capability), optional gyro-compass and horizon, hydraulic brakes, and cabin heat. At the time, it was really in a class of its own with no close competitors in the size and horsepower range..

While the 3-seat Stinsons were commercially produced, they were designed and built for private use, not for employment in commercial transportation. These aircraft do not appear to have been sold for purported commercial applications in Canada or Britain, so a more appropriate substitution would be "civil" or "civilian" (as opposed to military), which is why they received the CF registrations and were delivered with Canadian pilots who did not hold U.S. pilot certificates. Self-delivery by the purchaser was a key component of the "loophole" in the American Neutrality Act. Also, regarding legality under the neutrality laws, a foreign purchaser formally at war had to pay cash, paid in gold bullion. Presumably, these aircraft were acquired through the British Purchasing Commission (unconfirmed). (James Gray)

The service ceiling was only 10,500 feet (3,200 meters) for the 75-hp 105 and an optimistic 12,000 feet (3,658 meters) for the 80-hp 105 and Model 10, but the practical operating altitude was well below those figures.  With one 20 U.S. gallon fuel tank installed as standard, the maximum range at 5,000 feet msl optimal altitude was 415 statute miles with no reserve. The practical effective range with a 30 minute fuel reserve was no greater than 365 miles, although at recommended cruise RPM it was 350 and 330 miles respectively. (James Gray)

(BCATPM Photo)

Stinson Model 105 (Serial No. 3478), British Commonwealth Air Training Plan Museum, Brandon, Manitoba. 277 were built in 1939 and 1940. One of 26 Model 105s acquired by the RCAF in 1939, Reg. No. FDLM was flown by the RCAF as (Serial No. 3478).

The 105 Voyager name came about as a marketing scheme in order to boost orders. Sales literature emphasized the comfort, styling, and 105 mph cruise speed while hinting at unlimited freedom and adventure. It had side-by-side seating and a third “jumpseat” in back where a passenger could ride sitting crosswise. In reality three occupants was not very practical unless the rear passenger was a child, but the extra space easily accommodated more baggage than competing 2-place designs. Voyagers were owned by notables such as Howard Hughes, Roscoe Turner, Jimmy Stewart, Wilbur Shaw, and Edgar Bergen.

(NACA Photo)

Stinson Reliant, NACA, 1940.

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