A Little More oomph
 

  BACK    Home    History Wing    Adventure Wing    Exhibits & Programs    Company Store    Information Desk    NEXT 



Entrance 

History Wing 

The Wright Story 

Inventing the    
Airplane 

  Up       

 
(You are here.)      

Eyes on the Skies 

An Inkling    
of an Idea
 

 A Warped    
Experiment 

Kitty Hawk 

Off on an    
Adventure 

Not within a    
Thousand years 

Kitty Hawk    
In A Box 

Wagging Its Tail 

Propellers-R-Us 

The French    
Connection 

The Darkest Hour 

December 17 1903 

Jonahed 

  A Little    
More Oomph
 
(You are here.)       

A Practical    
Flying Machine 

Wright Timeline 

Down       

The Wright    
Catapult 

My Flying    
Machine Story 

            

Need to    

find your    

 bearings?    

Try these    
navigation aids:    

 Site Map 

Museum Index 

Search    
the Museum
 

 If this is your first      
visit, please stop by:    

About    
the Museum
 

Something to share?     
 Please:     

Contact Us 

            

  Available in Française, Español, Português, Deutsch, Россию, 中文, 日本, and others.
 

hat was needed, of course, was speed. Specifically, airspeed.

Wilbur explained the problem to Octave Chanute in a letter sent 8 August 1904:

"We have found great difficulty in getting sufficient initial velocity to get real starts. While the new machine lifts at a speed of about 23 miles (37 kph), it is only after the speed reaches 27 or 28 miles (43 or 45 kph) that the resistance falls below the thrust.* We have found it practically impossible to reach a higher speed than about 24 miles (38 kph) on a track of available length, as the winds are mostly very light and full of lulls in which the speed falls to almost nothing."

At the moment of take-off, the wings of the aircraft had to be moving through the air fast enough to generate the necessary lift to support the Flyer and its pilot. At the same time, the elevator, rudder, and warping portions of the wings ― the control surfaces ―  had to be moving through the air fast enough to develop the aerodynamic pressures necessary to give the pilot positive control of the airplane. The airspeed at which the Flyer had sufficient lift and control was the minimum flying speed. Wilbur thought this to be "27 or 28 miles."

The Wright brothers were launching the Flyer II pretty much the same way they had launched the Flyer I. They laid a wooden monorail parallel to the wind direction, whatever that happened to be. They placed a small wheeled carriage or "truck" on the rail, then placed the Flyer on the truck. The Flyer faced into the wind and was tied it to a stake to restrain it. The brothers started the engine and when the propellers were whirling as fast as they possibly could, the pilot released the restraining rope. The thrust from the propellers accelerated the aircraft down the rail and into the wind. The speed of the aircraft moving along the rail was its groundspeed. The groundspeed plus the wind speed was the airspeed ― the speed of the air flowing over the wings.

In Kitty Hawk, there had been strong winds to help achieve flying speed. Sitting on its launch rail on 17 December 1903, the wind was already blowing at speeds in excess of 20 mph (32 kph) over the wings of the Flyer I. The aircraft had only to accelerate few miles per hour before it reached a sufficient airspeed to fly. But the winds that blew through Huffman Prairie averaged only 7 to 9 mph (11 to 14 kph) throughout the summer. One most days, the Flyer II had to gain a great deal more speed than its predecessor before it could lift off successfully. The Wright brothers reasoned that a longer rail would give the aircraft more time to accelerate, and sometimes laid a monorail over 250 feet  (76 meters) long. Still, they couldn't reliably get the Flyer II up to flying speed.

This didn't mean that the airplane wasn't flying at all. As Wilbur explained to Chanute, the brothers could get the Flyer II off the ground ― briefly ― at air speeds around 23 mph (37 kph). The Flyer would lift off the the rail and wallow along in what later came to be known as "ground effect." During this phenomena, the air is compressed between the ground and the wings, supporting the aircraft just a few feet off the ground at airspeeds that would ordinarily be too slow to fly at higher altitudes. The Wrights tried mightily to take off in ground effect and continue to accelerate until they reached flying speed (where "the resistance falls below the thrust*"), at which point they would be able to climb to an altitude where they could safely navigate the airplane and avoid nearby cattle, fences, and trees.

But flying in ground effect was tricky in an unstable aircraft, particularly one that was so temperamental in pitch. The aircraft continued "bobbing up and down" as they flew, requiring Orville and Wilbur to constantly use the elevator to maintain level flight. If the nose remained up, the Flyer would lose airspeed, stall, and drop like a stone. If it remained nose down, it would crash into the ground.  Because the ground was only a few feet away, the pilot had just a fraction of a second to correct the pitch and bring the aircraft back to level. Add to these difficulties the fact that the Flyer was flying very slowly and the air was not yet flowing over the elevator surfaces at a speed that would give the pilot effective control. So the aircraft was slow to respond to its controls and more often than not the brothers could not level the aircraft in time to avoid a catastrophe. Dave Beard's wife (their neighbor at Huffman Prairie) often sent one of her children running across the field with a bottle of liniment to sooth Orville and Wilbur's bumps and bruises.

By August, the brothers had worked out a possible solution. Wilbur informed Chanute: "It is evident that we will have to build a starting device that will render us independent of the wind, and are now designing one." Chanute, it seems, was busy designing a "starting device" of his own. William Avery, one of the young men who had helped build and test Chanute's glider designs, was scheduled to demonstrate Chanute's latest version of his biplane glider at the Louisiana Purchase Exposition (informally know as the St. Louis World's Fair) in autumn of that year. Chanute planned to launch the glider from a small cart drawn along a set of rails by an electric motor.

The Wrights did not have access to electricity as Huffman Prairie, but they had plenty of gravity. Late in the summer of 1904, the Wilbur and Orville began to build a gravity-powered "catapult" to get them up to flying speed. A 20-foot tower (probably a salvaged derrick that had once supported a windmill) suspended up to seven donut-shaped iron weights, each weighing 200 pounds (91 kilograms), on a stout rope. This rope ran through a system of pulleys and was attached to the leading edge of the Flyer's bottom wing by way of a tow bar. When the weights dropped, the rope pulled the Flyer II along the rail, giving the airplane just the oomph it needed to reach flying speed. From a standing start, the combined thrust of the propellers and the catapult could accelerate the Flyer to 29 miles per hour (47 kph).

The Wrights first tested their catapult on 7 September 1904, and from the outset it was clear that this was the ticket that would get them back in the air. After a few tests to determine how many weights they needed (all seven, it turned out), the Flyer II lifted cleanly off the carriage as it approached the end of the rail and began to fly. Wilbur reported to Chanute in a letter of 18 September 1904:

"The starting apparatus which I mentioned in a former letter was tried for the first time on Sept. 7th. Up to the present we have made eleven starts with it. It seems to operate perfectly...On Wednesday, we made our first attempt to circle the field but did not quite succeed, though on both trials a distance of half a mile was covered."

One of those half-mile flights had lasted 59-3/5 seconds, longer than any flight they had yet made. As the time that the brothers spent in the air increased, they accumulated experience more rapidly. "Since we have been making longer flights and getting more practice, the machine is becoming much more controllable and now seems much like our gliders at Kitty Hawk," Wilbur explained to Chanute.

As their flying skills grew, they began to make progress on the problem that had lured them into aviation in the first place ― aerial navigation. On 20 September, with a dark, overcast sky threatening rain, Orville flew a complete circuit of the Prairie. For the first time, an airplane returned to where it had started (well, almost) and landed safely. Amos Root, the owner of a beekeeping supply house in Medina, Ohio, had heard that men were flying at Huffman Prairie, and he had traveled 175 miles to see the miracle for himself. He was on hand to see Orville's triumphant circular flight, and later published the first eyewitness account of a sustained, controlled, powered flight in Gleanings in Bee Culture, a journal he edited for his customers:

"When it turned that circle, and came near the starting-point, I was right in front of it; and I said then, and I believe still, it was...the grandest sight of my life. Imagine a locomotive that had left its track, and is climbing up in the air right toward you ― a locomotive without any wheels...but with white wings instead...spread 20 feet each way, coming right toward you with a tremendous flap of its propellers, and you have something like what I saw...I tell you, friends, the sensation that one feels is something hard to describe."

Root offered the story to Scientific American, a magazine to which he had occasionally contributed articles, but the editors turned him down ― it just wasn't believable.

For all their progress, the Wright's flying machine and their piloting skills still had serious shortcomings. In between their long flights, there were many short hops that ended with the aircraft partially or totally out of control. Accidents were a common occurrence, some of them potentially serious. Wilbur's and Orville's diaries from the autumn of 1904  record many disappointments:

  • "Unable to stop turning & broke engine & skids & both screws."
  • "Darted to the ground and broke upper spar, & skids, & screw."
  • "Broke tail in starting"
  • "Engine probably heated."
  • "Front rudder loose...Unmanageable."

On 1 November 1904, the Flyer was on the track with the engine running. The catapult was "cocked" in preparation for a take-off ― the weights had been raised to the top of the tower. Suddenly the stake that restrained the aircraft pulled free and the aircraft began to move on its own. Orville, who was near at hand, jumped for the cockpit and rode the Flyer down the track. He managed to keep it from taking off, but he badly wrenched his shoulder and "broke forward struts on the right side."

The most persistent problem was pitch instability. Even after 105 test flights ― their total for the year ― the Flyer II still had a tendency to oscillate up and down.  Shifting the center of gravity forward by placing iron bars under the elevator had reduced this tendency, but only marginally. Clearly there were serious flaws in the design of the machine that would have to be addressed.

But through all the many problems that remained to be solved, one shining fact stood out. The Wright brothers were flying. And not just skimming along in ground effect, either ― they were really and truly flying. By 9 December 1904, when they  made their last flights for the season, the Wrights were spending up to five minutes aloft at altitudes of up to 40 feet (12 meters) and covering over 3 miles (4.8 kilometers) in a single flight. Furthermore, people were beginning to take notice,  On 9 November 1904, an Interurban train car stopped on the tracks to let its passengers watch Wilbur fly almost four circles of the Prairie. "Intelligence of what we are doing is gradually spreading through the neighborhood," Wilbur wrote to Chanute. "As we have decided to keep our experiments strictly secret for the present, we are becoming uneasy about continuing them much longer in our present location."

Just how far the word had spread became apparent in mid-November when Lieutenant-Colonel John E. Capper, a senior officer with the British Army and the newly-appointed commander of the British Balloons Section, "stopped off at Dayton on his way East and spent a day with us," according to Wilbur. Capper was traveling with his wife, "an unusually bright woman," wrote Wilbur. The Englishman did not see the Wrights fly, but it is probable that the Wrights showed him some of the many photos that they had taken of their 1903 and 1904 flights. Capper's professional interest made it apparent to the Wright brothers that there were customers out there. They wondered if they should begin promoting their invention sooner rather than later. "It is a question," Wilbur told Chanute, "... what we will do with our baby now that we have it?"

*Note: Wilbur was trying the describe flying speed when he wrote, "...it is only after the speed reaches 27 or 28 miles that the resistance falls below the thrust." The idea that resistance or drag decreases as speed increases was a misconception common among many early aeronautical experimenters. It seems to have come from Samuel Langley who postulated it as a principle of aerodynamics and called it "Langley's Law." It was quickly disproven once powered flight became a reality. But there is a definite change that comes over a small aircraft when it reaches flying speed. Captain Connie Tobias, who flew our 1903 Flyer replica, described it this way: "The wings seem to fill with wind and the airplane dances on the rail."
 


The Wright launching catapult consisted of a derrick (1) and a launching rail (2). The derrick suspended a heavy weight (3) about 20 feet (6 meters) above the ground. A rope ran from a simple pulley (4) at the top of the weight through a compound pulley (5) at the top of the derrick, then down through the simple pulley and back up through the compound pulley. From there it ran down to a simple pulley (6) at the bottom of the derrick, then under the rail to another simple pulley (7) about 65-75 feet (20-23 meters) out along the rail. From the rail pulley, it ran back to a tow bar and hook at the front of the airplane (not shown). The airplane rested on a two-wheel truck (8) which rested on the rail. When the weight dropped, the rope pulled the airplane and the truck along the rail. As the airplane took off, the rope slipped off the tow bar hook and the truck ran off the rail end. For more information about the Wright catapult, including an interactive 3D illustration, click HERE.


This is the only photo of the Wright catapult taken in its first year of operation. It shows the first seconds of Flight No. 69 on 14 October 1904  The derrick is visible just to the right of the shed.


Our working replica of the Wright's catapult at Dahio Airport (I44) near Dayton, Ohio. The aircraft on the launch rail is a 1905 Wright Flyer III replica.


Wilbur made his sketch in his notebook showing the path of Orville's flight on 20 September 1904 -- the first flight in a complete circle.


Amos Root, publisher of Gleanings in Bee Culture, witnessed the 20 September flight and wrote about it in his 1 January 1905 issue. You can read the full story HERE.

Amos Root (left) in the passenger seat of a Wright Model B at the Medina Fairgrounds in 1912. Root remained friends with the brothers and advised them on how to manage their patent.

Flight No. 82 on 9 November 1904 lasted five minutes and four seconds as Wilbur made four rounds of the Prairie, covering over three miles (4.8 kilometers).

On 16 November 1904, the bothers made four flights (Nos. 84 through 87), landing each time with no damage to the machine.

Lt. Colonel John E Capper (left) became head of the Royal Aircraft Factory and oversaw the development of several important pioneer aircraft.

In Their Own Words

  • My Flying Machine Story is Amos Root's eyewitness account of the flight that Orville made on 20 September 1904, turning a complete circle in the air in a powered flying machine for the first time ever.

Nuts and Bolts

  • The Wright Catapult explains in detail how the Wright's gravity-powered catapult was used to launch the Flyer. This includes a 3D drawing of the catapult so you can inspect it from any angle, as well as zoom in to show the parts in greater detail.
     

The Wright catapult with the 1905 Wright Flyer III mounted on the rail and ready to launch.

Back to the top

  BACK    Home    History Wing    Adventure Wing    Exhibits & Programs    Company Store    Information Desk    NEXT 

"Aviation is proof that – given the will – we can do the impossible."
 Eddie Rickenbacker

 

 

The Wright Story/Inventing the Airplane/Launching the Flyer with a Catapult

Part of a biography of the Wright Brothers

 

www.wright-brothers.org
Copyright © 1999-2010