A Trip Back in Time
Building a Wright Flyer
By Emily Refermat
When 100 years has passed, it's nice to be able to stop and look back on where you've come from. The Centennial of Powered Flight on Dec. 17 of this year is a time to do just that.
The EAA, as part of this centennial celebration, contracted Ken Hyde, president and co-founder of the Wright Experience, to build a reminder of our past - an exact copy of the 1903 Wright Flyer. (Sponsored by the Ford Motor Co.)
Armed with respect and enthusiasm for the original Flyer, Hyde and the team of assembled artisans, mechanics, and engineers began a two-year process of recreating the aircraft that started it all. And, as fate would have it, that included stepping back in time to look at the world when powered flight was only a dream and two bicycle shop owners with no formal education discovered the secret of powered flight.
Following an invisible trail
The most daunting challenge for Hyde, and the team of craftsmen, was the lack of blueprints and plans that the Wright Brothers left for their inventions. The Wrights had presented drawings for a 1906 patent, but they weren't much help. It seems that in the Wrights' effort to prevent people from stealing and infringing on their ideas, they only provided the barest of information and worked in secret. Hyde and the team instead had to rely on what the brothers did leave behind - letters back to family and friends, notes in the small notebooks the brothers took to the field, the few remaining Wright artifacts, and the grainy black and white photographs taken at the time.
To rediscover the Wrights' genius, Hyde and the team looked at how the Brothers developed their theories about flight and what experiments they used to test their designs.
Wright research techniques revived
Until 1901, the Wrights, inspired to the dream of flight, had been using existing aeronautics data. But after very disappointing results in that summer, they began to question the validity of this data, deciding to test it. Probably due to their familiarity with bicycles, the Wrights' first test used a modified bicycle to measure different wing cross sections - airfoils. Hyde and the team replicated this experiment fashioning a classic looking old English-style men's three-speed with a wheel mounted horizontally across the handlebars. Two vertical rods are attached to the horizontal wheel and each holds a small metal plate. One plate is flat, but the other is slightly convex (the airfoil), acting like the wing of a glider. According to the data the Wrights had available the pressure of the wind on the flat plate should equal the pressure on the airfoil (set at a 5-degree angle to the wind) allowing the wheel to remain stationary. The data was wrong. The pressure was greater on the flat plate and the wheel turned toward it. Not only did this mean that the data was wrong, but it also meant the Wrights had to create more precise and systematic tests to develop their own theories.
The brothers built a wind tunnel and so did Hyde and his researchers. The wind tunnel is a rectangular box made of wood. It's 6 feet long, 16 inches high, and has an electric fan at one end of the box that pushes a steady stream of air at 27 miles per hour toward a delicate balance. Following in the Wrights' experiment, the "new" balance is made from hacksaw blades and bicycle spokes. The Wrights had hung different airfoils on one side of the balance while having a flat plate on the other. This flat plate was a reference and allowed the Wrights to test more than 200 airfoils until they determined the perfect shape for their plane's wing.
These experiments and the addition of various kites and gliders lead Hyde and the team in an amazing adventure reliving the discovery of flight through the Wright Brothers' methods. It became clear to Kevin Kochersberger, an assistant professor of mechanical engineer at the Rochester Institute of Technology that the Wrights were excellent problem solvers and Hyde calls theirs a very scientific approach.
Meticulous attention to detail
Reproducing the Wrights' experiments and discovering how they developed their theories of flight is one thing, but it takes more to make an exact replica of the Wright Flyer. It takes determination to examine every detail.
For example, Hyde struggled to find a manufacturer that could reproduce the muslin used on the 40-foot wingspan of the original Wright Flyer, down to the thread count per square inch. A piece of the original muslin still exists and courtesy of Marianne Miller Hudec, a great-grandniece of Wilbur and Orville, Hyde and the team got to examine it. The original muslin was adapted from muslin called Pride of the West that was used to make women's underwear. Besides providing specifics about the material itself, the muslin also provided clues to the construction of the plane's wings. Hyde says it shows where the ribs pushed against the material leaving marks of their width. It shows the seams and how it was sewn.
The new fabric's porosity was especially important because if the new material were too porous, too much room would exist between the threads allowing too much airflow. If the weave were too tight, the flyer would have too much lift.
Besides the muslin, the propellers also presented a challenge. Larry Parks, an aerospace engineer and expert woodcarver, worked tirelessly to make two precise and accurate Wright propellers for the replica. Parks' expertise in circa 1900 woodworking procedures and materials was essential in the recreation. After closely examining the 1903 propellers (as well as the 1904 versions), Parks determined that the specific woodworking tools used by the Wrights included a hatchet, drawknife, spokeshave, and gouges. Every detail was copied. The propellers each began as 50 pounds of spruce and ended weighing 9 pounds. Dave Meyer, an aeronautical engineer, supervised the computer imaging and evaluation of the propellers. He assisted in the design, building tools, and templates for Parks, and was a consultant throughout the process. Meyers can't help but be impressed by the Wrights' propeller, one of the earliest, being almost perfect by today's standards. The propellers are so accurate that when tested in NASA's full-scale wind tunnel, the results were astounding. The reproductions, when tested at a nominal rotational speed of 350 rpm, measured a thrust of 64.2 pounds. The Wright Brothers' static thrust measurements were 67.1 pounds (recorded in a notebook by the Wrights on Nov. 21, 1903 as between 132 and 136 pounds for both propellers together).
The steel chains that operate the props look like heavy-duty bicycle chain (for reasons I'm sure you could guess) and the steel propeller shafts are made similar to how a bicycle is manufactured.
This attention to detail and dedication to make the most accurate replica of the Wright Brothers Flyer is what will resurrect this ghost from aviation's past and make her fly again.
Engine of myth
Charles Taylor, without whom this story would not be complete, was the original aircraft mechanic. He built the engine using his mechanical mind and scraps of paper that have long been lost. It was up to two new brothers, the Hay brothers (Steve and James), to rebuild the Wright engine and give power to powered flight. The Wright engine was rebuilt from scraps of designs and replicas with only the slightest changes. For example, the outside diameter of the piston and the inside diameter of the piston were both recorded as 4 inches on the Wright plane. Due to this impossible specification, the piston is three-thousandths of an inch smaller.
The aluminum and copper engine is water-cooled. Its horizontal inline cylinders have a liner, 4-inch bore, 4-inch stroke, and tubular connecting rods. Iron tubes screw into the aluminum crankcase. The engine does not have a fuel pump or carburetor. Instead the gas runs through a fuel line from a tank mounted on the wing strut and vaporizes as it drips onto the hot engine block. Also without an oil pump, the engine needs to be preoiled, not being meant to run for a long time. And there is no exhaust pipe or muffler; the exhaust comes out by the pilot who is only inches away. The engine weighs approximately 180 pounds.
Teach the pilot to fly
Flying the new Wright Flyer will no doubt be as challenging to the pilot of today as it was for Orville and Wilbur. No current aircraft would have prepared the four chosen pilots for what they will find themselves doing while flying the Wright Flyer. The Wrights placed the pilot lying down on the stomach on the lower wing, inches from the engine to reduce drag. A wooden lever controlled the elevator and cables moved the wings for the aircraft to turn - "wing warping" is what the Wrights called it.
Northrop-Grumman is sponsoring the training of the pilots selected to fly the Wright Flyer. The training involves both simulator training and actually flying a replica of the 1902 Wright Glider to prepare them. The pilots include Ken Hyde, Chris Johnson, Kevin Kochersberger, and Terry Queijo.
Bihrle Applied Research is putting out a simulator for the public using military simulation to bring a "realistic representation" of the Wright designed aircraft characteristics.
Microsoft, one of the sponsors of the EAA Centennial Celebration, has created a 1903 Wright Flyer simulator called "Microsoft Æ Flight Simulator: A Century of Flight" which has been touring with the replica. The pilot in this simulator will operate the airplane with a hip cradle, in a horizontal position using hand levers and a shifting of the hips to control virtual takeoffs and landings. A giant projection screen with the sand dunes of Kitty Hawk completes the effect.
A vision of the past
Now, once again, the Wright Flyer is ready to fly. With a spruce and blonde ash frame, it stands 7 feet high on two sled-like runners (the Wrights didn't add wheels to their planes until 1910). The 40-foot 4-inch wingspan (the 4 extra inches are on the right wing to balance out the weight of the engine) has precisely 120 curved ash ribs and is covered with muslin. The Flyer weighs 605 pounds without the pilot.
Two propellers that rotate in opposite directions sit behind the wings, powered by a 12-horsepower, four-cylinder engine, allowing the Flyer to travel approximately 30 mph. The elevator is mounted in the front of the aircraft and two vertical rudders bring up the rear on its tail. It stands waiting, ready to fly.
If on Dec. 17, 2003, you are at Kill Devil Hills in North Carolina, you will see something no one has seen for 100 years - the Wright Flyer, or the most accurate replica, will again take to the sky. It will be the culmination of not only 100 years of powered flight, but also the thorough research and hard work of all involved in making the Wright Flyer fly again. Hope to see you there.
Popular Science (www.popsci.com)
"Rebuilding the Genius Machine"
"Rev to Glory" vol. 180 no. 10