Wright Brothers First Fatal Airplane Crash

Wright Brothers First Fatal Airplane Crash It had only been five years since Orville and Wilbur Wright made their famous flight at Kitty Hawk. By 1908, the Wright brothers were traveling across the United States and Europe in order to demonstrate their flying machine. Everything went well until that fateful day, September 17, 1908, which began with a cheering crowd of 2,000 and ended with pilot Orville Wright severely injured and passenger Lieutenant Thomas Selfridge dead. A Flight Exhibition Orville Wright had done this before. He had taken his first official passenger, Lt. Frank P. Lahm, into the air on September 10, 1908, at Fort Myer, Virginia. Two days later, Orville took another passenger, Major George O. Squier, up in the Flyer for nine minutes. These flights were part of an exhibition for the United States Army. The U.S. Army was considering purchasing the Wrights aircraft for a new military airplane. To get this contract, Orville had to prove that the airplane could successfully carry passengers. Though the first two trials had been successful, the third was to prove a catastrophe. Lift Off! Twenty-six-year-old Lieutenant Thomas E. Selfridge volunteered to be a passenger. A member of the Aerial Experiment Association (an organization headed by Alexander Graham Bell and in direct competition with the Wrights), Lt. Selfridge was also on the Army board that was assessing the Wrights Flyer at Fort Myers, Virginia. It was just after 5 p.m. on September 17, 1908, when Orville and Lt. Selfridge got into the airplane. Lt. Selfridge was the Wrights heaviest passenger thus far, weighing 175 pounds. Once the propellers were turned, Lt. Selfridge waved to the crowd. For this demonstration, approximately 2,000 people were present. The weights were dropped and the airplane was off. Out of Control The Flyer was up in the air. Orville was keeping it very simple and had successfully flown three laps over the parade ground at an altitude of approximately 150 feet. Then Orville heard light tapping. He turned and quickly looked behind him, but he didnt see anything wrong. Just to be safe, Orville thought he should turn off the engine and glide to the ground. But before Orville could shut off the engine, he heard two big thumps, which gave the machine a terrible shaking. The machine would not respond to the steering and lateral balancing levers, which produced a most peculiar feeling of helplessness. Something flew off the airplane. (It was later discovered to be a propeller.) Then the airplane suddenly veered right. Orville couldnt get the machine to respond. He shut off the engine. He kept trying to regain control of the airplane. . . . I continued to push the levers, when the machine suddenly turned to the left. I reversed the levers to stop the turning and to bring the wings on a level. Quick as a flash, the machine turned down in front and started straight for the ground. Throughout the flight, Lt. Selfridge had remained silent. A few times Lt. Selfridge had glanced at Orville to see Orvilles reaction to the situation. The airplane was about 75 feet in the air when it started a nose-dive to the ground. Lt. Selfridge let out a nearly inaudible Oh! Oh! The Crash Heading straight for the ground, Orville was not able to regain control. The Flyer hit the ground hard. The crowd was at first in silent shock. Then everyone ran over to the wreckage. The crash created a cloud of dust. Orville and Lt. Selfridge were both pinned in the wreckage. They were able to disentangle Orville first. He was bloody but conscious. It was harder to get Selfridge out. He too was bloody and had an injury to his head. Lt. Selfridge was unconscious. The two men were taken by stretcher to the nearby post hospital. Doctors operated on Lt. Selfridge, but at 8:10 p.m., Lt. Selfridge died from a fractured skull, without ever regaining consciousness. Orville suffered a broken left leg, several broken ribs, cuts on his head, and many bruises. Lt. Thomas Selfridge was buried with military honors at Arlington National Cemetery. He was the first man to die in an airplane. Orville Wright was released from the Army hospital on October 31. Though he would walk and fly again, Orville continued to suffer from fractures in his hip that had gone unnoticed at the time. Orville later determined that the crash was caused by a stress crack in the propeller. The Wrights soon redesigned the Flyer to eliminate the flaws that led to this accident. Sources Howard, Fred. Wilbur and Orville: A Biography of the Wright Brothers.  Alfred A. Knopf, 1987, New York.Prendergast, Curtis. The First Aviators. Time-Life Books, 1980, Alexandria, VA.Whitehouse, Arch. The Early Birds: The Wonders and Heroics of the First Decades of Flight. Doubleday Company, 1965, Garden City, NY.

The Science of Magnetic Field Lines

The Science of Magnetic Field Lines A magnetic field surrounds any electric charge in motion. The magnetic field is continuous and invisible, but its strength and orientation may be represented by magnetic field lines. Ideally, magnetic field lines or magnetic flux lines show the strength and orientation of a magnetic field. The representation is useful because it gives people a way to view an invisible force and because mathematical laws of physics easily accommodate the number or density of field lines. Magnetic field lines are a visual representation of the invisible lines of force in a magnetic field.By convention, the lines trace the force from the north to south pole of a magnet.The distance between the lines indicates relative strength of the magnetic field. The closer the lines are, the stronger the magnetic field is.Iron filings and a compass may be used to trace the shape, strength, and direction of magnetic field lines. A magnetic field is a vector, which means it has magnitude and direction. If electric current flows in a straight line, the right hand rule shows the direction invisible magnetic field lines flow around a wire. If you imagine gripping the wire with your right hand with your thumb pointing in the direction of the current, the magnetic field travels in the direction of the fingers around the wire. But, what if you dont know the direction of current or simply want to visualize a magnetic field? How to See a Magnetic Field Like air, a magnetic field is invisible. You can view wind indirectly by throwing small bits of paper into the air. Similarly, placing bits of magnetic material in a magnetic field lets you trace its path. Easy methods include: Use a Compass A group of compasses can show the directions of magnetic field lines. Maciej Frolow / Getty Images Waving a single compass around a magnetic field shows the direction of the field lines. To actually map the magnetic field, placing many compasses indicates the direction of the magnetic field at any point. To draw magnetic field lines, connect the compass dots. The advantage of this method is that it shows the direction of magnetic field lines. The disadvantage is that it doesnt indicate magnetic field strength. Use Iron Filings or Magnetite Sand Iron is ferromagnetic. This means it aligns itself along magnetic field lines, forming tiny magnets with north and south poles. Tiny bits of iron, such as iron filings, align to form a detailed map of field lines because the north pole of one piece orients to repel the north pole of another piece and attract its south pole. But, you cant just sprinkle the filings onto a magnet because they are attracted to it and will stick to it rather than trace the magnetic field. To solve this problem, iron filings are sprinkled onto paper or plastic over a magnetic field. One technique used to disperse the filings is to sprinkle them onto the surface from a height of a few inches. More filings can be added to make the field lines more clear, but only up to a point. Alternatives to iron filings include steel BB pellets, tin-plated iron filings (which wont rust), small paper clips, staples, or magnetite sand. The advantage to using particles of iron, steel, or magnetite is that the particles form a detailed map of magnetic field lines. The map also gives a rough indication of magnetic field strength. Closely-spaced, dense lines occur where the field is strongest, while widely-separated, sparse lines show where it is weaker. The disadvantage of using iron filings is that theres no indication of magnetic field orientation. The easiest way to overcome this is to use a compass together with iron filings to map both orientation and direction. Try Magnetic Viewing Film Magnetic viewing film is a flexible plastic containing bubbles of fluid laced with tiny magnetic rods. The films appears darker or lighter depending on the orientation of the rods in a magnetic field. Magnetic viewing film works best mapping complex magnetic geometry, such as that produced by a flat refrigerator magnet. Natural Magnetic Field Lines The lines in the aurora follow Earths magnetic field lines. Oscar Bjarnason / Getty Images Magnetic field lines also appear in nature. During a total solar eclipse, the lines in the corona trace the Suns magnetic field. Back on Earth, the lines in an aurora indicate the path of the planets magnetic field. In both cases, the visible lines are glowing streams of charged particles. Magnetic Field Line Rules Using magnetic field lines to construct a map, some rules become apparent: Magnetic field lines never cross.Magnetic field lines are continuous. They form closed loops that continue all the way through a magnetic material.Magnetic field lines bunch together where the magnetic field is strongest. In other words, the density of field lines indicates magnetic field strength. If the field lines around a magnet are mapped, its strongest magnetic field is at either pole.Unless the magnetic field is mapped using a compass, the direction of the magnetic field may be unknown. By convention, direction is indicated by drawing arrowheads along magnetic field lines. In any magnetic field, the lines always flow from the north pole to the south pole. The names north and south are historical and may have no bearing on the geographical orientation of the magnetic field Source Newton, Henry Black and Harvey N. Davis (1913) Practical Physics, The MacMillan Co., USA.