Find out the results of our 2020 Helicopter & Engine Manufacturers Survey; learn about Airbus’s non-pilot emergency landing training course; heli-safaris at Kenya’s Tropic Air; TracPlus & the MD 500’s origins.
The small community of Homewood, Manitoba, may not be the first place that comes to mind when people think of Canadian aviation landmarks, but it was the location of one of the most notable achievements in the country’s aviation history — the flight of the first Canadian-made rotary-wing aircraft. The story behind that flight, which took place in the winter of 1938/1939, is the story of three brothers: Douglas (Doug), Nicholas, and Theodore Froebe.
The Froebes were born in Chatsworth, Illinois, during the 1910s, where they regularly saw early aircraft flying over their farm. “I guess that’s where I became interested in flying machines to start with,” Doug Froebe later recalled in an interview with the Western Canada Aviation Museum. “There were Curtiss JN-4 ‘Jennys’ and de Havilland DH.60 Gipsy Moths, and all kinds flying over.”
In 1921, the Froebe family immigrated to Canada after their father purchased a farm in Manitoba. As they matured, the mechanically gifted Froebe boys experimented in building sleds and snow machines on the farm, while continuing to read up on developments in aviation. They saw an ad in Mechanics Illustrated magazine about the Heath Parasol kit, and placed an order for the “build-your-own” airplane.
Powered by a 27-horsepower motorcycle engine, the Heath Parasol was a high-wing, single-seat airplane with a 26-foot wingspan. Over 20,000 were built and 24 were registered in Canada. The aircraft was found to be very stable, and it handled quite easily. The kit cost about $1,000 — a lot of money in the late 1920s.
The Froebes’ aircraft gradually came together, and it was ready to fly in 1927. But the brothers’ attempts to get the aircraft into the air, having had no flying instruction, were not successful.
Doug Froebe knew he had to get some flying lessons. He contacted Connie Johannsson, of Johansson Flying Service, in Winnipeg and was soon taking his first flying instruction in a de Havilland DH.60 Gipsy Moth. According to Doug, at one point during the flying lessons, Johansson turned to him and said, “Take the control stick between your two fingers; you are not handling a plow now.” Doug soon caught on and made some competent landings.
He returned home and started flying the Heath Parasol. After his first successful flight, he moved the tail wheel back on the fuselage to correct a tail-heavy issue. The brothers also had to warp the wings so as to counteract the engine torque. But on his next flight, Doug quickly became lost. After making a complete turn and straightening the airplane out at about 100 feet elevation, he was able to land in a soft field without hurting the Parasol. On his fourth flight, Doug was not so lucky. After getting airborne, he got uncomfortably close to some high tension powerlines. He pushed down on the stick, and the underpowered Heath Parasol ended up landing partly on a gravel road, sliding into ditch, then ending up in a fence. The fuselage and landing gear were damaged, but Doug was fortunately not hurt.
Undeterred, the brothers purchased a damaged Barling NB-3 aircraft for $250. Designed by Walter Barling in 1927, the NB-3 was a tandem-seat low-wing aircraft with an open cockpit. It was powered by a 60-horsepower Anzani engine, which was later upgraded.
The three Froebe boys restored it back to flying condition as money became available. Nicholas, Theodore, and Doug travelled to Portage la Prairie to take proper flying lessons on the Barling NB-3, and all became proficient flyers as time went by. Then, in 1933, a friend had an accident with the aircraft near the Froebe farm. This ended the brothers’ fixed-wing flying for a while.
Switching to rotary-wing
It was about this time that the Froebes turned their attention to rotary-wing aircraft. Aware of the limitations of contemporary projects to develop helicopters, the Froebes knew they needed to solve problems with torque and design a successful rotor system if they were to successfully build their own.
The boys headed to Oakland, California, during the winter of 1936/1937 to find out all they could on rotorcraft design and their dynamics. Doug met James Nisson, a student studying aeronautical engineering at Berkeley, and explained their plan to build a rotorcraft. Nisson put him in touch with Professor Ward, an aeronautical engineer at the University of California, Berkeley Campus. Ward worked with Doug on design parameters, and was quite enthusiastic about the rotary-wing project. He suggested the Froebes talk to Walter Barling, the inventor of the Barling aircraft, who wanted them to come down to California to build their rotary-wing aircraft.
Next, they needed to find an engine for the proposed helicopter. Charles H. Babb, owner of one of the largest used aircraft dealerships in the Western U.S., sold the Froebes a de Havilland Gipsy 98-horsepower Cirrus engine for $100 in January 1938. The boys also picked up wheels and oleos for the helicopter, and hauled everything back to Canada in their house trailer.
With great enthusiasm, the Froebe boys went to work on the helicopter frame. Between them, the three had skills in design, mechanics, and welding. MacDonald Brothers Aircraft Ltd. in Winnipeg, Manitoba, supplied the aircraft-grade steel chrome molybdenum metal tubing for the frame.
The construction of the helicopter with the Gipsy Moth engine proceeded smoothly, and next came the clutch assembly and flywheel for forward thrust. The transmission designed by Doug was from available farming machinery components, while the crown gears and a pinion were from a Chevrolet truck. Designing a flange to fit the pinion, Theodore Froebe then welded it to the shaft. The gear case was constructed of chrome molybdenum steel which had to be bent and welded to shape. The drive and contact bearings were SKF bearings.
The engine was installed in the helicopter on Sept. 5, 1938, and it was bolted to the gearbox. There were a few problems starting the engine, but that concern was soon worked out. By November, the engine had been run up from 1,300 rpm to over 2,000 rpm.
To provide the aircraft’s lift, the Froebes decided on a coaxial design with two main rotors turning in opposite directions. This would solve antitorque problems. “The rotor blade design was just logical thinking — you know, a coaxial design,” Doug recalled in his interview with the Western Canada Aviation Museum.
The rotor blades were constructed of metal with a fabric covering. The main spars were 18-gauge metal for four feet out from the hub, then 20-gauge metal out to the tip. MacDonald bent the spars and welded them together to form a semicircular half, eventually welding the halves together. The curve design of the blades came from the U.S. National Committee for Aeronautics. The curve on the bottom was the same as the top of the blade. The rotor blades provided lift and directional control, and the original versions were 20 feet in diameter. The vanes (rotor blades) were not covered during run-ups in October/November of 1938.
The Gipsy Moth engine was started by pulling the lower rotor blade around, disengaging the clutch when the engine started. The speed was increased and the clutch eased in, thus turning the rotor blades once the engine was up to the required speed. “The spars [were] really strong,” Doug recalled. “You could hang right off the tip of the blade and tip the whole helicopter over from it. There was hardly any flexibility at all. Ours were rigid all the way through.”
The helicopter was 13 feet and seven inches long. The pilot sat in a single seat at the rear of the helicopter with the main rotor mast and engine in front of him. The undercarriage had a two-wheel arrangement up front with a single tail wheel at the back. The fuel tank was originally located in the front of the fuselage.
In terms of controls, the helicopter had a collective, cyclic, and throttle, with a stick for directional control. The hubs were basically a flange with a tubular spindle and SKF bearings. The control arms were mounted forward at the leading edge so that the controlling arm would correct the tracking of the blades. “We figured if we could control the cyclic pitch control on the lower blades, it would be sufficient to give lateral and longitudinal control, and of course, the directional control is by torque, by increasing the top and decreasing the bottom through foot pedals,” recalled Doug. “There was a crank-operated collective pitch control through which you could increase all the blades together.”
Taking to the skies
By the late fall of 1938, as the Froebes prepared to attempt to get their aircraft airborne, snow had already started to accumulate in the fields around Homewood. With Doug selected as the pilot, ground run ups began in November, and by mid-December, the Frobes were ready for air tests.
On Dec. 20, Doug got into the pilot’s seat, and the helicopter was started up. He made his first attempt at flight after reaching about 1,400 rpm. Working the controls, the tail rose up about three feet, and Froebe pulled the stick back, resulting in the two front wheels leaving the ground. The helicopter was in the air. Froebe was able to fly a short distance and settled the helicopter to the ground. The first “flight” had lasted about 20 minutes — and was a huge success.
Nicholas Froebe wrote in the log book: “3 wheels off. Running very true. Several jumps were accomplished with all wheels off at once. Highest being 3 feet. No failures were encountered.”
The team was extremely excited, but Doug was a bit nervous about the whole episode. “It was a harrowing kind of experience,” he recalled. Nevertheless, history had been made — the first man-controlled vertical flight in Canada.
However, there were a few problems that required attention. It was obvious that the helicopter was nose-heavy, and there was significant vibration and shaking. The gas container was moved to the back of the helicopter behind the pilot’s seat to improve the center of gravity. Later flights saw the helicopter reaching five to six feet off the ground for distances over 50 feet.
But the severe vibration continued to be a problem as additional flight tests took place. The Froebes lengthened the rotor blades to 28 feet, which resulted in some improvement. Next, they removed some of the rubber from the rotor hub mounts, and added balance weights on the leading edge of the blades. Nicholas tried to fly the helicopter during one of the flights. The helicopter shook so badly that he never tried to fly it again.
The aircraft also experienced torsional problems, which developed after it passed 1,400 rpm. Eventually, bearings in the rotor hubs failed and they were unable to solve the problem. A few months into 1939, after trying to refine the helicopter into a reasonably safe aircraft to fly, the Froebes abandoned their project. They had carried out a series of short flights for a total of four hours and five minutes of flight time by March 2, 1939.
All this was during the depths of the Great Depression of the 1930s, when money was hard to come by, and the world was on the brink of war. Disappointed, the Froebe brothers decided to go back to fixed-wing flying.
Making a mark
After the war, Doug was approached by a group of businessmen that were interested in forming a company to promote the development of helicopters. All he had to do was build a flyable helicopter, and then he could apply for $100,000. “I would supply the helicopter and would be the test pilot,” he recalled. He also had to put up a $50,000 of his own money into the new company, for which he would get one-fifth of the company. He turned the offer down.
Sadly, Theodore was killed in an accident while flying a Heath Parasol in 1943, and Nicolas died in a crop dusting accident in 1959. Doug continued to do some flying over the years and ended up moving to California. He maintained his interest in aviation.
In the mid-1970s, Doug returned to Manitoba to start a new aviation venture. “I built a 20-foot diameter aircraft that I called an ornacopter which had wings,” he recalled. “By flapping with the wings you would eliminate the torque. I had two wings flapping down and two flapping up at the same time. It weighed around 130 pounds. I brought it up to Homewood in 1976 to try it out. I was able to get about 25 to 30 revolutions per minute out of it just by peddling.” However, Doug never was able to get his ornacopter to fly. He ended up giving it to the Winnipeg museum.
The original coaxial helicopter was found in a granary on the Froebe farm in the 1970s in surprisingly good shape. Arrangements were made with the Froebe family to have it moved for display at the Western Canada Aviation Museum (now renamed the Royal Aviation Museum of Western Canada) in Winnipeg.
In later life, Doug said of the Froebe helicopter: “I don’t know if it amounts to much — maybe an interesting object of art, I suppose you might say.”
Despite this modesty, the Froebes had a lot to be proud of. They had made history in the Canadian aviation industry, achieving rotary-wing flight before Igor Sikorsky flew his VS-300 helicopter in the U.S.
This year will mark the 80th anniversary of the Froebe helicopter flight, and the town of Homewood has not forgotten its place in aviation history. It is marking the occasion with the erection of a special monument to celebrate the Froebes’ historic achievement.