Long before the kitplane craze, Bernard Pietenpol designed airplanes that average consumers could build and fly themselves.
About 80 years ago a group of aviation enthusiasts concluded that the “big guys” had cornered the market on aircraft construction and sales, pricing most people out of owning airplanes. They set out to design planes that could be easily built and safely flown by novice pilots. Their success marked the beginning of the homebuilt movement. Much to the disapproval of traditional aircraft manufacturers, who lobbied for legislation to quash the nascent movement, homebuilt designs by pioneers such as Edward Heath, O.C. Corben and Bernard Pietenpol proved extremely popular.
Although Pietenpol actually constructed very few airplanes, many still consider him the father of homebuilt aviation. What’s more, the plans for two of his designs, the single-seat Sky Scout and two-place Air Camper, are still being sold today.
Pietenpol was born in 1901 and raised in the southern Minnesota community of Cherry Grove. He showed remarkable mechanical aptitude as he grew up, building and rebuilding his share of automobiles and motorcycles. He also became intrigued by airplanes, but found flying too expensive. Pietenpol decided the cheapest way to obtain his own flying machine would be to design and build it himself.
With the help of his woodworker father-in-law, W.J. Krueger, and two friends, Don Finke and Orrin Hoopman, Pietenpol began experimenting with various wing and fuselage designs, as well as the engines to power them. He was convinced that automotive engines, which were much cheaper and more readily available than aircraft power plants, could be used to propel planes. Given their goal, to develop an airplane that anyone could afford to purchase, build and fly— without the need for expensive factory-supplied parts or special construction expertise—the search for the best combination involved a series of trials and errors. Pietenpol not only wanted an airplane that was easy to construct, it also had to be reasonably easy to pilot, since many of those he envisioned flying it would be, like him, novices.
Their first attempt was a small biplane on which they bolted a Ford Model T engine—very cheap and plentiful at the time. Without much alteration, however, it could only develop about 20 hp on its best day. The prototype could not have been called a success. Pietenpol later admitted: “It would have flown if I’d have known how to fly it. Luckily I didn’t.”
His second project was a similar biplane design using a Gnome rotary engine, a step up from the Model T with a proven track record. Although the Gnome generated 50 hp, it ran with a horrible screeching sound and had a nasty tendency to catch fire. After extensive tests, Pietenpol labeled the Gnome a “growler” and abandoned it.
Next he bought plans for a Lincoln Sport Biplane from the magazine Modern Mechanics and Inventions, whose aviation writer, E. Weston “Westy” Farmer, had become influential in homebuilt aircraft circles by the late 1920s. At that point successful de – signs such as Edward Heath’s Parasol and O.C. Corben’s Baby Ace were being sold both as finished aircraft and in kit form. However, building them required welding skills and the ability to fabricate intricate control mechanisms—well beyond the average backyard builder’s scope. Those parts could be purchased separately by mail, a practice Pietenpol eventually adopted for his own designs. But the Heath and Corben models also recommended aircraft power plants that were expensive and hard to find.
Displeased with the Lincoln’s overall performance, Pietenpol traded it for a Curtiss JN-4 “Jenny” powered by a water-cooled OX-5. He later admitted that he wasn’t very fond of the Jenny’s airframe design or its temperamental and underpowered V-8.
Meanwhile Ed Heath’s Parasol was gaining popularity, as were his kits. If Heath could succeed, Pietenpol asked himself, why couldn’t he? He decided to sell the Jenny and renew his efforts to design and build his own plane. His father-in-law and Finke helped with woodworking and construction, while Hoopman created the design sketches, later to be transformed into blueprints they hoped to sell.
Pietenpol’s design, dubbed the Ace, was a 27-foot-span, high-wing monoplane similar to Heath’s Parasol. But unlike the Parasol, which relied on a welded tube airframe produced in a Chicago factory, the Ace featured all-wood construction, so an average woodworker could build it without needing to know how to weld (Pietenpol later offered a steel tube fuselage version as an option). When he and Finke first flew their plane on September 1, 1928, it was powered by an aluminum 16-valve Model T engine (coincidentally called “the Ace” conversion) developed by Horace Keane. With 30 hp, it was just barely capable of getting the two men into the air and safely back on the ground.
By that time Henry Ford’s Model A, powered by a bigger 4-cylinder engine with an estimated 40 hp, had been on the market for several years, so Model A engines were readily available in junkyards. Team Pietenpol went to work adapting the engine to its new monoplane. When Pietenpol first flew his Air Camper in May 1929 with the new power plant, he seemed to have finally found the perfect match of airframe to engine. Converting the Model A engine required a bit more work than had the Model T power plant, but Pietenpol compensated by including extensive instructions in his building manual. He also offered to sell parts—aftermarket magnetos, carburetor heat piping, exhaust stacks, etc.—to builders who lacked the skill or equipment to make conversions. Or a buyer could purchase a ready-to-fly Model A–powered Air Camper for $750.
Pietenpol’s big break came in 1930, when he flew his Air Camper to Minneapolis to confront aviation writer Westy Farmer. Farmer had declared he wasn’t a fan of automotive engines in aircraft, and claimed the Model A was downright unusable. Face to face with him, Pietenpol told a Minneapolis fly-in crowd, “I believe that this is the safest plane for the beginner that has ever been built.” During subsequent demonstrations, Pietenpol’s plane so impressed the crowd and Farmer that Modern Mechanics and Inventions serialized the publication of Air Camper plans in four issues during 1931. The Air Camper prototype in fact became the first registered airplane in Minnesota.
The inventor had the abandoned Lutheran church where he had been headquartered dismantled, using the reclaimed lumber to construct two hangars for his operation just west of Cherry Grove. Unlike some of his fellow homebuilt pioneers, however, Pietenpol built very few planes himself, concentrating more on providing plans for his designs. During the 1930s he sold thousands of blueprint sets to eager builders all over the country and overseas.
Pietenpol was always available if a builder had questions, giving tips such as: “There is no point in using a lot of nails. The strength lies in the gusset plate and gluing.” He also offered fatherly advice: “If you realize that you are not capable of building a good ship, then do not try. Either buy a ship or have someone build it for you that can.” And he had strong views on safety, declaring: “I do not believe in stunting, it is the cause of nearly all accidents. I believe in safe and sane flying only. My advice is, do not stunt much or take unnecessary chances.”
With homebuilts gaining traction, state and federal aviation officials—pressured by industry lobbyists—began creating strong licensing and inspection requirements for homebuilt aircraft and their pilots. The homebuilt enthusiasts responded with their own lobbying efforts. Pietenpol assured customers: “Aircraft used solely for pleasure or noncommercial purposes need not be licensed….All aircraft must display the assigned identification mark. When you have your [ID] numbers on you can fly your ship anywhere in the U.S. as long as you do no commercial work in your own state, such as passenger carrying, etc. That is federal law and about all needs to be said on that subject.”
Since many aviation laws were left up to individual states, the federal government strongly encouraged state aviation authorities to crack down on homebuilt, or experimental, airplanes during the De – pression. At first they went after anyone flying an unlicensed aircraft from a licensed airfield, but soon most states passed laws prohibiting all unlicensed aircraft. Law enforcement began chasing down and ar – resting pilots of unlicensed planes, even if they were flying from their own home fields. State aeronautics statutes declared that violations were “gross misdemeanors,” levying hefty fines on pilots.
Only Oregon refused to crack down on experimental aviation. By World War II, it was the sole state that allowed experimental building and flying—one of the reasons why so many plans for Air Campers went to Oregon residents, as well as to Canadians.
While the legal wrangling over homebuilts played out, Pietenpol was working on a single-seat version of his design. In 1933 he introduced the Sky Scout. At 600 pounds it was lighter than the Air Camper, so it could use the Model T engine he had installed in his original design. Hoopman, who drew up the Sky Scout blueprints, was given the first plane built in gratitude for all his effort.
Sky Scout plans were published in the 1933 edition of MMI’s Flying and Glider Manual, and Pietenpol drew great crowds at fly-ins. He also offered free rides on weekends in nearby communities in an effort to convince the public that homebuilt flying could be fun as well as safe. “I built the Sky Scout to prove to myself that I could build a ship powered with that motor which would be practical,” he said, “and also to prove that the Model A engine was not the only automobile motor that would fly successfully.”
Pietenpol never stopped looking for ways to improve his airplanes’ performance. He kept experimenting with power plants, beefing up the Air Camper’s wing area on one model, for example, to handle the added weight of a V-8 engine. Even at 80 hp its performance was no better than with the Model A, however, and fuel consumption proved to be twice as high. He also tried a 60-hp Franklin aircraft engine, as well as aluminum cylinder heads that became available for the Model A, which he enthusiastically recommended as an inexpensive upgrade.
Bernard’s son Donald recalled: “In the winter of 1936, my father built a two-place Scout powered with the Ford V-8 engine. I rode along in this airplane many times as a lad…the airplane could hardly climb This may have been the reason I was so often the passenger; it probably couldn’t have carried two adults.”
By 1938 the homebuilt business was languishing due to new state laws. World War II all but shut down recreational flying, as many experimental builders and pilots joined the war effort. Pietenpol himself served as an instructor in the Civilian Pilot Training Program.
Some predicted a postwar general aviation boom when the many trained fliers returned home, but it never materialized. What’s more, given the surplus military aircraft then available plus all the restrictions on homebuilts, the aviation industry continued to suffer.
Although he kept experimenting with revisions to his Air Camper, Pietenpol soon realized he would have to find other ways to make ends meet. “Television came along to rescue me from going broke,” he said. “I pretty near starved to death on airplanes and then got into tele – vision [repair] and ate good.” He reopened his original Ford garage in Cherry Grove as a TV/radio repair shop. It is still there today, complete with beams made from aircraft wing spars.
It was 1953 before committed advocates like Oregonian George Bogardus, founder of the American Airman’s Association, convinced legislators and aviation officials to relax the restrictions on experimental aircraft. The late 1950s and early 1960s saw a resurgence in the homebuilt movement. When he wasn’t repairing TVs and radios, Pietenpol experimented with air-cooled Chevrolet Corvair engines in a new version of the Air Camper, completed in 1960, then another in 1964 dubbed the “Last Original.” By that time plans for Pietenpols had been sold all over the world.
In 1958 Robert Taylor of Iowa’s Antique Airfield formed a fivemember club to purchase a partially completed Air Camper. He later bought out the other partners and, with the help of two staff members of the Antique Airplane Association, completed the project. That Air Camper is now part of the American Airpower Museum’s collection in Farmingdale, N.Y., along with a Sky Scout and welded tube Air Camper. The Buckeye Pietenpol Club today hosts a large annual fly-in at Brodhead, Wis., usually scheduled for the week before each summer’s Experimental Aircraft Association AirVenture in Oshkosh.
In 1991, seven years after his death, Bernard Pietenpol was inducted into Minnesota’s Aviation Hall of Fame and recognized as “the father of homebuilt aviation.” The two original hangars at his Cherry Grove field have been moved to other sites: one to the Filmore County His – torical Center in Fountain, Minn., and the other to the EAA’s Whittman Field at Oshkosh.
Bernard’s son Donald and grandson Andrew continue to sell Air Camper and Sky Scout blueprints and manuals, primarily through the Internet. Andrew is also building his own hangar on the site where the two original hangars once stood. He hopes to someday offer manufactured Pietenpol parts—perhaps even kits. No doubt his grandfather would be proud to see that his legacy lives on into a new century.
Retired teacher Scott Fisher writes from Allerton, Iowa. He recommends for additional reading The Pietenpol Story, by Chet Peek. Also see the Pietenpol family Web site: pressenter.com/~apietenp/.
Originally published in the July 2010 issue of Aviation History. To subscribe, click here.
