# Presentation: 474590

## The Wright Brothers,Wind Tunnels andNASAA Centennial of Flight Story1903 - 2003

**Notes:**
As part of NASA’s celebration of the first hundred years of flight, I’d like to share with you a centennial of flight story called The Wright Brothers, Wind Tunnels and NASA.

Now, neither the Wright Brothers nor NASA were the first to use wind tunnels. The Wright Brothers did NOT invent the wind tunnel, however refined them in such a way that their wind tunnel research was quite accurate. How do we know about its accuracy? We know because NACA repeated those same airfoil tests in their wind tunnels and achieved nearly the same results.

As you’ll get a glimpse of today, there is a link between the Wright Brothers and NASA and that link is through a tunnel of wind.

## The Wright Brothers

- Orville and Wilbur
- Dayton, Ohio
- Wright Cycle Company
- Brain synchronicity
- Systematic in their experimental approach

**Notes:**
The brothers were both mechanical in more than a “fix it” kind of way. They enjoyed putting something together and making it work. They were also very methodical in how they approached solving problems. They were strong readers and good researchers.
Many biographers believe that one reason the Wright Brothers were the first to achieve powered, controlled flight in a heavier-than-air aircraft was because they were brothers and had a close relationship of their minds. They would bounce ideas off each other and spend countless hours thoroughly discussing a problem. They put forth countless possible solutions, and would take turns arguing each side. They performed experiments systematically, maintained close observations and kept very precise and careful records.Each experiment would lead to the next experiment. There was no trial and error. It was accomplished through carefully observed experimentation. Historians believe that the major differences between the brothers and other flight experimenters of their time were their similar ways of processing and their methodical approach. Which leads to the conclusion that “two heads are indeed better than one!”

## The Wright Brothers

- Read the research
- Talked with colleagues
- Determined problems to be solved
- Delineated a process for solving problems safely

**Notes:**
Before even attempting to build and fly a machine, they did a lot of reading and research. By the time the brothers started working on the problems surrounding controlled, powered flight, much work had already been accomplished, recorded and published. Early flight experimenters like Chanute, Langley, Cayley  and Lilienthal. One of the many problems the brothers faced was that some of the accepted scientific ideas of the time were not completely true or had not been properly researched. Since the science of flight was relatively new, and the technology of the time could not disprove some of the theories, much was accepted as it was first put forth. Regardless of the state of some of the accepted flight theories of the time period, the brothers persevered by following these steps (see slide above).

## The Wright Brothers

- Problems to be solved
- Balance during flight: a way to safely control the airplane’s motion
- An engine to move it through the air
- Wings needed to lift an airplane into the air

**Notes:**
The basic flight problems to be solved were these 3:
Balance during flight: a way to safely control the airplane’s motion
 Lilienthal had died flying because he used his body to balance his gliders whenever they were hit by turbulence. There had to be a better way. The motions around the 3 axes had to under complete control regardless of the wind.Yaw, pitch and roll had to be controlled with the aircraft’s body, not the pilot’s.
Wings needed to lift an airplane into the air
There had to be an optimal wing shape and camber. It was here that the brothers encountered airfoil experiment tables that were incorrect. They then had to solve a problem that they thought had already been solved.
An engine to move it through the air
The technology of the time did not have a small, lightweight, yet powerful engine. The brothers would have to develop one for their aircraft.

## The Wright Brothers

- Problem
- Balance during flight:  						a way to safely control the airplane’s motion

**Notes:**
To balance the wing lift, they decided to put in front of the wings a smaller, flat horizontal surface, which could be raised or lowered. They called it a “horizontal rudder.” It served the same purpose as our modern day rudders in that it would control the pressure of air moving along the wings, maintaining equilibrium from the front to the back of the aircraft. This feature kept the Wright Brothers’ aircraft from nosediving or spinning out of control.
To solve the problem of side-to-side equilibrium,they developed a process called “wingwarping” which initially mimicked the wing motion used by birds trying to control  their flight position when hit by a gust of wind. Birds will slightly twist the tip of their wings up or down to maintain their side-to-side balance. They attached a system of wires crisscrossing from the leading edge of one wing to the trailing edge of the other wing (so they would work in tandem). The pilot could control and balance the airplane during a wind gust by pulling on these interconnected wires.  

## The Wright Brothers

- Balance Solutions
- Horizontal rudder
- Wingwarping
- Hip cradle

**Notes:**
To balance the wing lift, they decided to put in front of the wings a smaller, flat horizontal surface, which could be raised or lowered. They called it a “horizontal rudder.” It served the same purpose as our modern day rudders in that it would control the pressure of air moving along the wings, maintaining equilibrium from the front to the back of the aircraft. This feature kept the Wright Brothers’ aircraft from nosediving or spinning out of control.

To solve the problem of side-to-side equilibrium,they developed a process called “wingwarping” which initially mimicked the wing motion used by birds trying to control  their flight position when hit by a gust of wind. Birds will slightly twist the tip of their wings up or down to maintain their side-to-side balance. They attached a system of wires crisscrossing from the leading edge of one wing to the trailing edge of the other wing (so they would work in tandem). The pilot could control and balance the airplane during a wind gust by pulling on these interconnected wires.  

## The Wright Brothers

- Problem
- An engine to move it through the air
- Lightweight
- Minimal vibration
- Powerful enough to turn the propellers

**Notes:**
Because there was no small, lightweight, yet powerful engine to provide the thrust needed for their aircraft,they hired a mechanic to build an engine to their specifications, Charlie Taylor. He built an engine while the brothers concentrated on reworking their aircraft to accommodate the engine’s placement.Balance had to be maintained.The engine and its propellers’ added weight would need to be considered in the aircraft’s final design.
Very little data was available during these early experimental years. The Wright Brothers had to gather and analyze their own data. A scientific formula was needed to compile data to design an effective propeller for thrust. They were breaking new ground with these mathematical calculations. They would not waste time with trial and error, they would solve the problem mathematically.

## The Wright Brothers

- Engine Solutions
- Small, powerful, gas engine
- Powered 2 propellers

**Notes:**
The propellers which would be turned by the engine were there to provide the thrust needed for the aircraft’s forward movement. The only research on propellers that existed was about boat propellers. The brothers had to come up with their own mathematical calculations to determine the optimum size and shape of the propellers. They decided on 2 rear mounted pusher-propellers and had one rotate clockwise and the other rotate counter-clockwise to maintain the aircraft’s stability.
Engine: 180 lbs., 4 cylinder, 12 horsepower, water-cooled engine, started by spark from dry battery, fed gas from small tank, placed opposite side of aircraft from pilot for balance.
Propellers: airfoil shape, 8.5 feet-wide, spruce, rear mounted, connected to engine by strong, bicycle-type chains through steel shafts, oppositional rotation for stability. (Note: If they rotated in the same way they would tend to turn the airplane in the direction they were rotating.

## The Wright Brothers

- Problem
- Wings needed to lift airplane into the air
- Determine the length-to-width ratio
- Proper amount of camber
- Most efficient angle of attack
- The center of pressure

**Notes:**
Their first wing testing machine was made from a bicycle wheel placed horizontally across another bicycle. Airfoil shapes were placed on the horizontal wheel. The bike was pedaled which rotated the wheel. This created a constant wind on the shapes being tested. This method gave inaccurate results, so they had to come up with another testing method. 

## The Wright Brothers

- Wing Solutions
- Throw out previous tables and theories
- Devise a better method of testing wings
- Use new test results to design a better wing

**Notes:**
They designed a tunnel apparatus that used a small engine to consistently turn a fan that blew air through the tunnel.They tested about 150 airfoil shapes made from steel sheets that were mounted on a scale that measured lift. A small glass window set within the top panel allowed them to view the wing models during the experiment.

This careful testing led them to design wings for their aircraft which were slimmer and longer than before (32’ x 5’). The wings had a smaller curve (hump) over the top. The high point of that curve was then set nearly one-third of the way back from the leading edge. The forward elevator also was changed based upon their wind tunnel research. It was smaller than before and was shaped like a small wing.

## Wind Tunnels

- Whirling Arm Machines
- Used in earlier 							airfoil research
- Generated its own 					turbulence, thus 						inaccurate data
- Could not accurately measure					 the small forces exerted on a model at high speeds

**Notes:**
Before there were tunnels and fans blowing air, there were “whirling arms.”  With this device, the test object was attached to the end of an arm.  The arm was rotated in place kind of like an aeronautical centrifuge.
Benjamin Robbins (1707 - 1751), an English mathematician, was the first to construct a whirling arm and use it for research.  His first machine had an arm four feet long.  It was spun by a falling weight acting on a pulley and spindle arrangement.  The arm tip reached speeds of only a few feet per second.  He then mounted various shapes onto the arm and spun them in different orientations.  His work established that different shapes, even though they present the same area to an airstream, do not always have the same amount of air resistance (drag).
Later, George Cayley (1773 - 1857) used a whirling arm machine to measure the lift and drag of various airfoils.  His work contributed to the design idea that an engine is used to create forward motion that moves the wing through the air.  The wing (without flapping) generates lift.  This simple idea of separating propulsion from lift was a revolutionary change in the way people of that time thought about aircraft.  This meant that aircraft did not have to be built with flapping wings!
The flaw in this machine was that the moving arm’s eggbeater action set all the air in the vicinity into a rotary motion.  This adversely affected the test results.  Aircraft models in effect flew into their own wakes.  It was difficult to determine the true relative velocity between the model and the air.  It was also difficult to mount instruments and measure the small forces exerted on the model when it was spinning at high speeds.  Something better was needed.

## Wind Tunnels

- A simple device
- Enclosed passage through which air is driven

**Notes:**
That something better was a wind tunnel.  This rather simple device consisted of an enclosed passage through which air is driven by a fan or other drive system.
Wind tunnels were first used for research in Great Britain by Frank Wenham in 1871.

## Wind Tunnels

- Basic operation
- Drive system = a fan and motor
- Controlled airstream
- Test section = enclosed passage
- Test instrumentation for data collection

**Notes:**
The heart of a wind tunnel is the test section.  Usually a scale model is mounted on a strut.  A carefully controlled airstream produced by the drive system (a fan and motor) is moved through the test section which produces a flow of air about the model.  The aerodynamic characteristics of the model and its flow are directly measured by specially placed balances and test instrumentation.

## Wind Tunnels

- “Tunnel” Vision
- Overall better design than whirling arm because it is a self-contained system
- Allowed for controlled, systematic testing
- Made data gathering easy 	and reliable
- Became the standard method for airflow tests

**Notes:**
Frank Wenham (1824 - 1908) of Great Britain received funding from the Aeronautical Society of Great Britain to build a wind tunnel.  It was 12 feet long with a fan-blower driven by a steam engine and located upstream of the model.  The fan would propel air down the tube to the model in its test section.  Wenham’s experiments with the wind tunnel resulted in the accumulation of vast amounts of data on lift and drag forces.
Wenham’s research found that the lift-to-drag ratios were much higher than originally theorized.  This meant that wings could support a much more substantial load than originally thought.  It also revealed the effects of aspect ratio (area of a wing in relation to its length and how much lift the wing gets) on lift.  Wenham’s wind tunnel tests showed that long, narrow wings (like those used on gliders) provide more lift than short, stubby wings with the same area.
The wind tunnel really helped researchers understand the factors that controlled lift and drag.

## Wind Tunnels

- The Wright Brothers’ Model
- Wooden box
- Window
- Fan
- Test section

**Notes:**
The Brothers wanted to test different types of wing surfaces and develop accurate air-pressure tables. They built a 6 ft. long wooden box with a glass viewing window on top and a fan at one end. It was NOT the first wind tunnel, but it was the first time a wind tunnel had been used to to test materials and aircraft parts to obtain data that was used in the design and construction of an airplane.
The work was painstaking and tedious: testing measuring and calculating. These tests added greatly to the world’s understanding of how an airfoil works.Upon completion of their test, the Brothers were confident that they could more accurately than ever before calculate in advance the performance of an aircraft’s wings.

## Wind Tunnels

- The Wright Brothers’ Results
- A set of highly accurate tables that predicted in advance the performance of an aircraft’s wings
- Changes in their aircraft design
- Biggest glider yet
- Longer wings
- Narrower wings
- Tail section

**Notes:**
Armed with their new knowledge from their own wind tunnel tests, the Brothers designed their biggest glider yet! Its wings were longer with a tip to tip measurement of 32 feet. The wings were narrower than before, too with a width of 5 feet. For the first time, the glider design had a tail with two 6 foot high vertical fins, designed to help stabilize the machine during turns. The entire glider weighed just under 120 pounds. 

Note on the tail section: After some more flight testing, the Brothers discovered that a redesign of the tail was needed. They removed the 2 vertical fins and replaced them with a movable single-vaned tail 5 feet high. The tail was connected to the wingwarping wires. This allowed its movement to be coordinated with the warping of the wings. The pilot in the hip cradle could twist the wings and turn the tail at the same time.The movable tail rudder proved to be a great success and gave the pilot excellent control of the airplane’s movement.

## Wind Tunnels

- American Wind Tunnel Pioneer
- After the Wright Brothers
- Hugo Mattullath  $$
- Albert Zahm, researcher
- Catholic University, 			Washington, D.C.
- Closed 1908

**Notes:**
The Wright Brothers used their wind tunnel only during their own research. After their initial success, there was a lack of interest by business and government ventures in the commercial use of aircraft.
Wealthy industrialist Hugo Mattullah saw a future far beyond the wood and fabric aircraft currently being designed and funded a wind tunnel laboratory at the catholic University in Washington, D.C. The laboratory had a test section of 6 x 6 feet and was operated by Albert Zahm. This facility was remarkable, not only because of its size, but also by virtue of its unique methods of instrumentation, calibration, and application to aeronautical research. It had a test section 40 feet long and 6 feet square. It used a set of flow straighteners of honeycomb and cheesecloth to assure an even distribution and flow of air. Zahm developed ingenious pressure gauges with a sensitivity of a millionth of an atmosphere. With this impressive research facility, Zahm invetsigated the drag losses due to the friction of air flowing over aircraft surfaces. Zahm demonstrated successfully that skin friction was indeed a major element of drag during subsonic flight.

When Mattullah died, Zahm lost his funding and U.S. leadership in aeronautical research dramatically slowed when the laboratory was closed completely in 1908.

## Wind Tunnels

- European Researchers
- Riabouchinsky
- Eiffel
- Prandtl
- National Physical Laboratory (England)

**Notes:**
Riabouchinsky
Russian, operated Russia’s first important wind tunnel. 1.2 meter test section which gave reliable test data. 1904 - 1920
Eiffel (The “Tower” guy)
French,1909 wind tunnel had 1.5 meter test section using an open-jet flow. Open-jet had air jetting from a special nozzle that directed into the test section at speeds up to 20 meters per second. The returning air was not channeled by a separate return passage.
Prandtl (Boundary Layer Theorist)
Gottingen, Germany, the world’s first continuous, return-flow tunnel was put in operation 1908. Highly efficient design used vanes at the corners to turn the airflow and used strategically placed screens and honeycombs to smooth and quiet the airflow. He tested a variety of airfoils, streamlined bodies and aircraft components. He also was the first one to measure pressure distributions over rotating propeller blades. Prandlt’s later wind tunnel work contributed greatly to overall wind tunnel design: a stilling chamber upstream from the test section where airflow disturbances can die out and a contraction cone at the entrance to the test section to better regulate airspeed. These have become standard tunnel features.
National Physical Laboratory (NPL, England)
Government supported wind tunnels.Operated by Thomas Stanton, it began with a small tunnel in1903 and larger ones built after 1912. It incorporated into its design elaborate flow straighteners and baffles that gave steady aerodynamic flow. It later built a duplex tunnel that measured forces on full size models. It used a sophisticated means of supporting the model which enabled it to measure forces and turning moments about all 3 axes.

## Wind Tunnels

- America picks up the pace (circa WWI)
- Zahm (again), Navy
- Durand, Stanford Univ.
- Hugh Dryden, National Bureau of Standards
- National Advisory Committee for Aeronautics

**Notes:**
Zahm (again), Navy
Aerodynamical Laboratory, 1913, Washington Navy Yard, 8 x 8 foot tunnel to generate aerodynamic data for future naval aircraft. Could test at speds up to 160 mph.
Durand, Stanford Univ.
CA,1918, 5.5 foot tunnel built for propeller research
Hugh Dryden, National Bureau of Standards
Washington, 1918, 4.5 octagonal tunnel for research on air turbulence and boumdary layer phenomena.Dryden later became a director of NACA and had a NASA facility named for him.
National Advisory Committee for Aeronautics
Through the diligent encouragement of the regents of the Smithsonian Institution and members of the National Academy of Sciences, the US Congress enacted funding to establish NACA. Its duties were to supervise and direct the scientific study of the problems of flight, with a view to their practical solution.

## Wind Tunnels

- NACA
- National Advisory Committee for Aeronautics
- Committee member: Orville Wright
- First facility, Langley

**Notes:**
Congress established NACA in 1915 to “supervise and direct the scientific study of the problems of flight, with a view to their practical solutions. . . .” The act also provided for the construction of aeronautical research facilities. A lab site was established in  1917 near Hampton, Virginia. It was named Langley Field. The first Langley wind tunnel was patterned after one being used at the British National Physical Laboratory. In 1923 NACA finished building a new tunnel called the Variable Density Tunnel in which the air pressure inside could be varied. This tunnel gathered data on 78 related airfoil sections and tested all different types of aircraft being designed during that time. All this helped to establish NACA as a technically competent research organization.

## Wind Tunnels

- NACA grows
- Wind tunnel complex built at Langley
- Tunnels get larger
- Airspeeds get faster
- Testing becomes   more specialized

**Notes:**
In 1940 NACA broke ground for a new aeronautics lab in California at Moffett Field (Ames). This facility was to continue testing new aircraft designs for the military. These aircraft were designed to fly at moderate speeds (about 250 mph). It was also set to perform high-speed aerodynamic research.

## Wind Tunnels

- Basic Parts of a Modern Wind Tunnel
- Settling Chamber
- Contraction cone
- Test section
- Diffuser
- Drive section

**Notes:**
Most wind tunnel designs feature each of the five components described below. The overall design creates high-speed, low turbulence airflow through a test section and allows researchers to measure the resulting forces on the model being tested.
Settling Chamber = The purpose of the settling chamber is to straighten the airflow
Contraction Cone = This part takes a large volume of low-velocity air without creating turbulence.
Test Section = This is where the test article and sensors are placed.
Diffuser = This part slows the speed of the airflow in the wind tunnel and provides a smooth airflow
Drive Section = The drive section provides the force that causes the air to move through the tunnel.

## Wind Tunnels

- Types
- Open-loop
- Closed-loop
- Subsonic
- Transonic
- Supersonic
- Hypersonic
- Refrigerated
- Full-sized
- Scale-sized

**Notes:**
Open-loop = The air comes through one end and flows out another.
Closed-loop = The air is not released, but is recirculated through the tunnel
Subsonic = speeds slower than the speed of sound
Transonic = speeds between Mach 0 .7 and 1.1 
Supersonic = speeds faster than the speed of sound Mach 1 to 4
Hypersonic = Speeds at or faster than Mach 5
Refrigerated = Colder than most, used to test for the effects of icing on aircraft performance
Full-sized = Can fit a full size aircraft model into its test section
Scale-sized = Is designed for use by scale models (much smaller in size than the real thing). Usually used to test high speed flight

## NASA

**Notes:**
On October 1, 1958, the National Advisory Committee on Aeronautics was transferred over to the new National Aeronautics and Space Administration (NASA). The official start of NASA was the beginning of a rich history of unique scientific and technological achievements in human space flight, aeronautics, space science, and space applications. 

Building on its NACA roots, NASA has continued to conduct many types of cutting-edge aeronautics research on aerodynamics, wind shear, and other important topics using flight testing, computer simulations and wind tunnel testing. 

## NASA

- Langley Research Center

**Tests conducted include airfoils, vertical takeoff, spinning/tumbling situations and the effects of wind gusts on aircraft**
**Thirty tunnel systems**
**Aerothermodynamic**
**Subsonic**
**Transonic**
**Supersonic**
**Hypersonic**

**Notes:**
At Langley Research Center located in Hampton, Virginia, models in wind tunnels are used in conjunction with computers and flight simulators to learn about the flight characteristics of new aircraft designs and modifications.  The wind tunnel testing includes airfoils, vertical takeoff, spinning and tumbling situations and the effects of wind gusts on aircraft.

Langley is working to develop technologies to enable aircraft to fly faster, farther and safer.  Research is also being conducted to enable aircraft to be more maneuverable, quieter, energy efficient and less expensive to manufacture and maintain.  Invaluable tools in this quest are Langley’s 30 wind tunnels whose capabilities are unique to NASA.  Wind tunnel systems include aerothermodynamic, subsonic, transonic, supersonic and hypersonic.

## NASA

- Ames Research Center

**Tests conducted on a wide variety of  aircraft, spacecraft and other vehicles, as well as structures**
**Three tunnel systems**
**National Full Scale Aerodynamic Facility (40x80x120)**
**12 ft. Pressure Wind Tunnel**
**Unitary Tunnels**

**Notes:**
NASA Ames offers the services of three premier wind tunnel facilities which test a wide variety of aircraft, spacecraft and other vehicles, as well as structures.
There are three tunnel systems at Ames:
1.  The 12 ft Pressure Wind Tunnel is used for testing that includes high-lift systems and high angle-of-attack aircraft.
2.  The National Full Scale Aerodynamic Facility consists of two test sections:  The 40 by 80 foot test section is the smaller part of the closed circuit, single return wind tunnel. The 80 by 120 foot test section is the larger part of the wind tunnel and tests large- or full-scale models including full-scale rotors.  This is the world’s largest low speed wind tunnel.
3.  The Unitary also consists of two test sections: The 9 by 7 foot wind tunnel  and the 11 foot Transonic Wind Tunnel.  Both are used primarily for force, moment and pressure tests of aircraft configurations or specific components.

## NASA

- Glenn Research Center

**Five tunnel systems**
**Supersonic**
**Transonic**
**Low speed tunnel**
**Icing tunnel**
**Tests conducted include nozzles, rocket applications, jet engines and aircraft icing conditions **

**Notes:**
The NASA Glenn Research Center in Cleveland, Ohio, maintains and operates five wind tunnels in accordance with its commitment to researching innovative aircraft propulsion technologies and flight safety.  The tunnel systems include two subsonic wind tunnels, a transonic tunnel, a low speed tunnel and an icing research tunnel.

Tests conducted include inlet and nozzle research, rocket applications, jet engines and aircraft icing conditions.

## NASA

*One hundred years of aviation...*

**Notes:**
The world of aviation has evolved dramatically in the last one hundred years.  From the genius, vision and persistence of two bicycle manufacturers from Ohio to the engineers and researchers of today, the future of aeronautics promises many exciting and revolutionary ideas and technologies that will benefit mankind for generations to come.