N966CD, A Stearman Story

by Noel Allard
Published in Midwest Flyer – June/July 2018 issue

The Chuck Doyle (Sr) story is long in the telling, but for this narrative, let us focus on one airplane; one airplane from a collection of dozens owned from 1933 until Doyle’s death in 2008.

The airplane we’ve come to know as “the Doyle Stearman” has a record going back to its manufacture in 1942. Stearman PT-17D rolled out of the factory with a shipping label to Corpus Christi, Texas, one of America’s training bases. It was used by the U.S. Army Air Force for training pilot candidates in basic training in cross-country and aerobatic maneuvers.

In 1948, Chuck Doyle purchased five PT-17’s from Angelo “Shorty” De Ponti, who held a War Assets Administration license to sell surplus military aircraft. At the same time, Doyle purchased five surplus BT-13 aircraft. His plan was to swap the Pratt & Whitney R985, 450 hp engines from the BT’s into the Stearmans. This he proceeded to do, selling the engine-less BT’s for scrap, and taking three of the Stearmans to Grand Forks, North Dakota where he leased them to airport manager and agricultural pilot, Les Jolly.

Doyle was a captain with Northwest Airlines at this point and took the time between airline flights to commute in a Staggerwing from Minneapolis to Grand Forks for a second job as a spray pilot.

In the meantime, Doyle had plans for the two other Stearmans as well. The two remaining were licensed NC5445N and N966CD. The pair were built up in a tuck-under garage at his mother’s home at 50th and Morgan Avenue in South Minneapolis. Floyd Homstad, a highly skilled welder, built up the engine mounts for all five Stearmans and Doyle fitted all of them, including the ones he attached to the Stearmans in his mother’s garage. 

When NC5445N was in the construction stage, Doyle fitted a smoke oil system to it and a banner tow hitch. Doyle had learned these skills from his contemporary, Red McManus.

With this biplane he set out to earn extra money towing banners and “smoke-writing,” as he called it. The second Stearman in his possession, N966CD, was also rebuilt under a standard aerobatic license, so he could use it to perform aerobatics in airshows. This aircraft lacked the smoke and banner hooks. Doyle incorporated a company called “Sky Signs” for the part-time business.

The smoke-oil system incorporated a 50-gallon Corvus oil tank that fed the paraffin-type oil through a tube into the hot exhaust pipe of the big 450 hp Stearman engine. (Corvus oil is not as flammable as other oil. Instead, it vaporizes and produces voluminous white smoke, ideal for trailing big letters across a blue sky).

Doyle decided later on that he preferred N966CD for the sky signs business and had the smoke system and banner hookup refitted to it. Doyle also did extensive modifications to the Stearman, including removing the upper-wing cutout for front seat passengers. The Corvus oil tank replaced the passenger seats. Doyle added wheel pants, a headrest, cowling, prop spinner, dorsal fin fairing and a nifty cut down BT canopy to keep him warm at 10,000 feet where he did his sky-writing, and in fall weather closer to the ground where he towed banners over University of Minnesota football games.

In 1951, Doyle made a deal to sell NC5445N to a budding aerobatic pilot who promised to pay the $3,000 asking price following an airshow performance with a wingwalker at the Minnesota State Fair in St. Paul.

Unfortunately, the pilot misjudged a loop and pancaked into the ground in front of the grandstands, throwing the female wingwalker to her death and losing his own life when the crashed airplane caught fire. That incident caused the fair officials to cancel all airshows in the future, and Doyle also decided to have no further involvement in airshows.

Doyle continued using N966CD until the 1980s. The turquoise and cream starburst-striped plane and its pilot became fixtures in the Minneapolis-St. Paul area, where on almost any given day, a tiny spec in the sky might be writing advertising slogans or greetings, or even wedding proposals! Or over some events, as many as five to eight banners might be towed, such as during the course of a university football game or a baseball game at the old Met Stadium in Bloomington, Minnesota – the growl of the big Pratt & Whitney engine bringing everyone’s attention skyward. But the impact of Doyle’s skywriting was felt further than the football field.

Dave Weiman of Midwest Flyer Magazine attributes his early interest in aviation to watching Doyle perform skywriting near his parents’ home while growing up in Minneapolis near the University of Minnesota campus. Weiman met Doyle on several occasions in more recent years and shared his story with him, and he was pleased.

From the air, Doyle could not see the letters directly from his perspective looking out over the smoke. Before each flight, he blocked out his message in crayon on cardboard scraps as it might look from on top of the letters, just the reverse of the view 10,000 ft. below. Smoke letters were generally three miles long and two miles wide. In his prime, Doyle was one of only five skywriters doing this craft in the U.S.

Banners were towed using a 400 ft. rope attached to a weighted pole from which the banners trailed. Individual 7 ft. or sometimes 10 ft. high letters could be clipped onto the banner lines to form the message. When alone, Doyle would lay out the banner on the ground with the 400 ft. rope lying across the letters. He would commence his takeoff over the sign, pulling the rope into the air first, then the banner as he gained airspeed. If he was fortunate to have an assistant, the assistant could hold the banner pole in the air and Doyle would pull it out of his hands. Chuck Doyle Jr. held his first banner pole at the age of 9.

Upon Chuck Doyle Sr.’s death in 2008, his son, Chuck Doyle Jr., acquired N966CD. Doyle rebuilt the biplane, and then had it rebuilt again by Rare Aircraft of Faribault, Minnesota.

Chuck Doyle Jr. had his first solo flight in the Stearman at age 16. After a day of making up banners and running for them as they were dropped, Chuck Doyle Sr. felt it was time for his son to take the Stearman “around the patch” for the first time. So, Jr. took off, and did a couple more things to his father’s displeasure.

Now retired from the airlines, himself, Chuck Doyle Jr. has continued the tradition started by his father in collecting and restoring vintage aircraft at his shop at Sky Harbor Residential Airpark in Webster, Minnesota, and the beautiful biplane is flying better than ever. But he has not continued his father’s smoke-writing or banner-towing business. Instead, Doyle rebuilt the Stearman with four ailerons, an inverted fuel and oil system, installed a real front seat under the fairing cover, and licensed the aircraft in the experimental category.