Orville and Wilbur Wright - Master Engineers

June 30, 2011

I've been meaning to write this for a while and finally got around to it.

For some reason I was researching the Wright flyer, the first successful airplane in the United States and perhaps the world.

For most people that is enough, but I was curious about the brothers and started digging. I didn't get that much more information about them, though some of it was tragic, what I did find was an astounding number of inventions and innovations that were necessary for the Wright Flyer to actually fly. Almost all of them are directly traced back to the Wright brothers.

Some of the technology I found came before the Wright brothers, but it wasn't well documented or claimed for patent. Other technological breakthroughs were modifications to existing information, while others still were wholly new creations based on the Wright's research.

Case in point. The airfoil was not a Wright invention, but no one had actually documented the shapes and specifics either. The Wrights, using thorough research, found the best shapes and documented them.

A number of things may not be that well known about the Wright brothers. For example, neither graduated high-school.

Orville dropped out of high-school to start a printing business. Wilbur attended for all four years, but the family moved just before he was to receive his diploma.

Wilbur planned to attend Yale university in 1885~1886, but lost heart (and almost all ambition) after losing his front teeth in a hockey accident in Dayton Ohio. Orville was deeply involved in a printing press he'd created.

In 1889 Orville started a printing business centered around a printing press he designed and he his brother built. The press was special in that it was designed to print large format papers and runs of up to one thousand sheets at a time. They even printed Paul Lawrence Dunbar's paper the Tattler.

Orville continued to build printing presses and be actively involved in printing eighteen years after Wilbur's death.

In 1892 the brothers began building and selling the "safety bicycle" under the Wright Cycle Exchange banner. They later changed the name of the company to the Wright Cycle Company. Contrary to popular belief the brothers did not resell someone elses bicycle, they engineered and manufactured their own.

So by the time they became interested in human flight, they'd already had two successful business behind them. One in printing and the other in bicycles.

Introduction to Flight
In 1896 three momentous events in flight took place; events the Wrights were certain to have known about.

• May, Smithsonian Institution Secretary Samuel Langley successfully flew an unmanned steam-powered model aircraft
• Summer, Chicago engineer and aviation authority Octave Chanute began successfully testing various types of gliders along Lake Michigan
• August, Otto Lilienthal, a German glider designer, was killed in the plunge of 56 feet on his glider. Up to then Lilienthal is reputed to have made up to two thousand glider flights with his designs.

Up to this time no one had developed a powered aircraft capable of carrying a human being under directed flight. In fact, up to this time, no one had figured out the ideal shape of a wing for sustained, controllable, powered flight.

Successful flight depended on three variables. Engines, wings and control.

The Wrights were convinced that the first two issues had been resolved (later finding that none of the three had actually been worked out) and began concentrating on controlling aircraft. Gliders were the natural choice for this research.

Unlike others attempting to master powered flight the Wrights felt that controlling the wing surfaces was key to steering and altitude. Up to this time other aviation pioneers relied on shifting body weight to control their gliders. The common thought of the day was that no pilot would be able to overcome shifting winds and manage total control of an airplane, so the commonly sought after characteristic was stable straight line flight, not the ability to turn. The Wrights, on the other hand, felt that pilot survival depended on his or her ability to control the flight.

The Wrights, felt that no amount of stability could be built in to the airplane and that the best chance of survival was to provide the pilot with total control of the aircraft. To that end the Wrights set out to give the pilot the ability to turn, gain and lose altitude, take-off, and land.

Having observed birds, the Wrights decided that controlling wing shape was key to directional flight. Thus was born the idea of wing-warping which emulated a bird's ability to change direction by lifting or dropping its wingtips.

They also designed their wing so it "drooped" at the far ends. Though this made the wing less stable in straight level flight, it was done to help minimize the effect of cross-winds on the wing.

In 1901, being cautious, the Wrights built an unmanned glider to test both the airfoil and wing shape they'd settled on. Though they flew the glider at least fifty times (some think it was as much as one hundred) the Wrights were disappointed with the lift characteristics of the wing. They noted that the wing only had 1/3 the projected lift suggested by Lilienthal's formula.

This caused the Wrights to deeply question another formula, called the Smeaton Coefficient, which had been used for almost one hundred years up to that time. They later proved it to be the correct computation of lift.

They returned to Dayton and with a wind test rig mounted on a bicycle, began testing various wing shapes. The rig was a third wheel mounted forward of the handlebars of a bicycle. The wheel was mounted horizontally and could spin freely in the wind. Wing designs were tested balanced against a brick shaped structure opposite.

The brothers were said to have mounted wing shapes to this rig and then bicycle furiously along the streets to Dayton observing the effects of wind across various wing shapes.

Change in Airfoil
They eventually discovered that the wing cross section everyone else was using was too thick; that the highest point on the airfoil was too high and actually interfered with lift. They settled on a wing design that was thinner with a shallower camber. The camber is the fattest part of a wing seen edge on.

They also discovered that the wing design in common use was too deep and that wings performed better if they were longer and narrower. All of this research also lead to the discovery that their competitors were assuming the wing had more lift than it actually possessed. Eventually the formula they settled on gave an actual lift figure that was one third the amount of lift that everyone else assumed was being generated. Their figures proved to be accurate.

No small wonder there were so many crashes.

Wind Tunnel
Realizing that peddling around Dayton on a modified bike was just not providing enough wind, they built a wind tunnel in their shop. They also determined that building full size wing models would bankrupt them. For this reason the wind-tunnel with model wings was a logical next step in their research.

The wind tunnel was not a Wright Brothers invention. It had been developed by Francis Herbert Wenham in England to directly address the issues of unreliable results from spinning an object through the air. Wenham developed the first wind tunnel in 1871. However, the Wright wind tunnel was only the second built in the United States at that time.

The Wright's wind tunnel was all of six feet long with a fan contained in the zinc reinforced housing at one end. The tunnel also included an observation window so the Wrights could directly observe the effect of wind on each wing design.

The also built lift balances, basically an apparatus to test the effect of lift on each wing. These balances were built of sharpened bicycle spoke wire and hack-saw blades. Despite the kludgey sounding nature of the materials the balances were quite sensitive and accurate.

Using this wind tunnel the Wrights conducted tests on wing designs for three months. There is no information on just how may different wing configurations the brothers tried, but some sources claim that up to two hundred different wing shapes were tested. They were trying to improve lift while reducing drag. They eventually came up with thirty-eight designs that balanced lift against drag to their satisfaction.

The "winning" wing design was eventually discovered to be a longer narrower wing with a slimmer cross-section.

"Having set out with absolute faith in the existing scientific data, we were driven to doubt one thing after another, till finally, after two years of experiment, we cast it all aside, and decided to rely entirely upon our own investigations. Truth and error were everywhere so intimately mixed as to be undistinguishable (sic). Nevertheless, the time expended in preliminary study of books was not misspent, for they gave us a good general understanding of the subject, and enabled us at the outset to avoid effort in many directions in which results would have been hopeless." - Orville Wright

The control problem was eventually solved with a front canard, rear rudder, and wing warping.

Warping the wings provided directional control, the front canard enabled the flyer to gain or lose altitude, and the rudder prevented the effect of wing-warping from causing a loss of lift when executing turns.

Interestingly these control problems were solved almost simultaneously with the lift problem.

The Airfoil
The Wrights did not invent the airfoil. What they did do was determine the thirty-eight best shapes for an airfoil. On the "ramp-up" to human flight other experimenters were taking a "scatter-gun" approach to wing design. Only Otto Lillienthal had settled on a particular wing shape cross-section, but had not done much to explain why he had. He concentrated instead on documenting his experiences and the overall design of his gliders.

Lillienthal also determined to control his gliders by shifting his body weight around its center of gravity; no attempt was made to control flight through the wing surfaces.

Lillienthal was eventually killed in a glider accident which broke his spine. After what some claim was up to two thousand successful flights, he fell 56 feet when he lost control after his glider stalled. He died the day after his accident.

Warping the Wings
The brothers determined to slightly change the "rise" or "dip" of the tip of the wings by bending the wing during flight. By causing the right wing-tip to dip and the left wing-tip to rise they could effect a right hand turn. By causing the left wing-tip to dip and the right wing-tip to rise they could perform a left hand turn.Unfortunately the wing tip with more bite also produced more drag. This in turn caused the entire structure to spin slightly in the wrong direction.

This effect caused the possibility of the wing tip hitting the ground. The brothers called this effect "well digging." They solved this problem by adding a controllable rudder at the back of the glider.

The Rudder
Up to then rudders were a common addition, but all rudders were fixed. The Wrights made their rudder steerable and directional. This corrected the "well digging" problem and gave the potential pilot much more control during turns.

In effect the rudder did not directly aid the turn, the warped wing did that, what the rudder did do was correct the problem of the difference in lift between one end of the wing and the other. This effectively solved the control problem during turns.

The Canard
The Wrights also incorporated a control surface forward of the wings called a canard. The canard provided control over the pitch or up and down attitude of the airplane. Later Wright flyers moved the pitch control behind the rudder; by then it was called an "elevator."

Patent Filed
With all of the control and lift problems solved the Wright brothers applied for a patent for the "Flying Machine" on March 23, 1903. They still hadn't solved the power problem and had yet to build and actually fly a machine.

The Wrights were now faced with the third apex of the flight triangle. They had mastered both lift and control and now needed a power source for their flyer. Of course power is useless unless it is applied to something.

Two Problems
In reality the brothers faced two problems. The design of the propeller and the design of the engine. No clear data existed for proper propeller design despite the fact that they had been used for decades as propulsion for boats. No one, it seems, shared their specifications for propellers.

Propellers
According to historians the brothers found themselves deeply involved in discussions and arguments, sometimes heated, about how the propeller should be designed. They decided that the propeller should be a rotating wing with the same basic characteristics of their lifting wing. Eventually the brothers settled on a design that was made of laminated spruce carved into the proper shape by hand. The final shape of the propeller was determined by more wind-tunnel tests.

There were two propeller, each just over eight feet long. The propeller were to be mounted behind the wing to prevent disturbing airflow over the front of the wing. The propeller were to rotate opposite each other; one clockwise and the other counter-clockwise to neutralize the effect of torque.

Wilbur determined that the propellers they'd designed were 66% efficient at moving air. Tests in early 2000 determined that the propellers were actually 75% efficient under normal conditions and up to 82% efficient in ideal conditions. This is remarkable considering the best propeller made today is 85% efficient.

Engine
Now that the propeller design was solved they had to come up with a power plant to drive the propellers. They wrote to a number of manufacturers with weight and horsepower requirements, but no one made an engine light enough with the proper amount of horsepower to satisfy their requirements.

Charlie Taylor, one of their bicycle shop mechanics, was tasked with the development of an engine. Taylor, working closely with the Wrights, developed a power plant in six weeks.

It was notable in that the block was made of an aluminum copper allow (aluminum was still rare and expensive metal), used a magneto, was fired by Nicola Tesla's still new invention the spark-plug (patented five years before) and was water cooled. It also delivered fuel directly to the cylinders via gravity fed fuel-injection.

The Wrights needed an engine that weighed between 160~170 pounds and produced at least eight horsepower.

The engine Taylor built weight 152 pounds and produced twelve horsepower far surpassing the Wrights bare minimum specifications.

Despite all of these advances the Wrights were painfully aware that their aircraft still may not fly without enough of a headwind. They had already designed a catapult system to assist in glider trials.

In typically Wright fashion, they were not about to let the variables of wind speed, take-off altitude and ambient temperatures slow them down. They beefed up the catapult system by adding more weight and more length to the catapult rail.

On December 17, 1903 Orville, on winning (or losing) a coin toss made the first of four flights evenly divided between the brothers. The flight lasted twelve seconds and covered one hundred twenty feet. The fourth and final flight took place around noon that same day; Wilbur was at the controls.

The last flight lasted fifty-nine seconds and covered about eight hundred and fifty-two feet of distance. The flight ended in a hard landing, damaging the flyer, but the brothers were convinced that all of the errors they now faced were directly attributable to the pilot not the airplane. The first Wright flyer cost slightly more than $1,400.00 (in 1903 dollars) to build.

In 1904 the Wrights created the Wright Flyer II. On September 20, 1904, Wilbur managed to fly a complete circle, the fist time ever in a powered heavier than air aircraft. He covered over four thousand feet and flew for a minute and a half.

As the reader can see from the article the Wrights faced many problems, not the least of which was inaccurate and deadly lift formulas.

In the drive to create a flying machine the Wrights pioneered or substantially modified the following:

• Determined the ideal airfoil design based on Lilienthal's basic shape
• Reworked lift formula and figures for accuracy
• Created wing-warping for maneuverability
• Added a movable rudder (for yaw control)
• Added a movable canard or elevator (for attitude control)
• Made expert use of the wind-tunnel to determine the best wing shape; they discovered thirty-eight shapes
• Created superior propellers based on their airfoil design
• Created a light weight gasoline powered fuel injected engine
• Created an improved catapult system for launch
• Created an airplane that could carry a person and be completely controlled by that person

Perhaps best of all the Wrights, with their meticulous documentation, created a manned powered flying machine that could be reproduced and marketed to an anxious public.

The author was not compensated in any way, either monetarily, with discounts, or freebies by any of the companies mentioned.

Though the author does make a small profit for the word count of this article none of that comes directly from the manufacturers mentioned. The author also stands to make a small profit from advertising attached to this article.

The author has no control over either the advertising or the contents of those ads.