A century of flight

With Orville Wright at the controls on the morning of Dec. 17, 1903, the Wright Flyer I made its historic first flight at Kill Devil Hills, near Kitty Hawk, N.C. By the third try at the end of the morning, Orville and Wilbur Wright had made a flight of 852 feet and remained in the air for 59 seconds. Nine months later, Wilbur Wright made the first closedcircuit flight lasting more than five minutes with the Wright Flyer II. In 1905 the Wright Flyer III made a flight of 24 miles, lasting more than 38 minutes.

What had the Wright Brothers accompli shed? Often we look to Orville and Wilbur as the pioneers of aviation. But as w ith any scientific endeavor, advancement is evolutionary. The Wri ght Brothers built on the accompli shments of earlier visionaries - from Leonardo da Vinci's sketches of "ornithopter" fl ying mac hines to the glider builders of the late J 800s.

Da Vinci's ornithopters were never tested, nor did they have a chance of success, but they certainl y stoked the imaginati on of those who fo llowed. In 1804, S ir George Cayley in England fl ew a model glider, which had all the attributes of the modern airplane . But perhaps the greatest influence on the Wri ght Brothers came fro m a succession of developments by glider enthusiasts during the prev ious decade . The German Otto Lilienthal made more than 2,5 00 successful g lider flig hts up to 1896, and the W ri ght Brothers close ly fo ll owed these events. Lilienthal' s gliders were contro lled by shifting the pil ot's weight, much as in today 's recreational hang gliders. A Scotsman, Percy Pilcher, received glidin g instructi on [i'om Lili enth al in 1895 and began developing a powered mac hine . He built an engine and tested it in 1899. U nfortun ately he was kill ed shortl y thereafter in a glidin g accident due to structural fa ilure. (Lilienthal also was killed in a gliding accident.) In Ame ri ca, Octave Chanute, also greatly influenced by Lilienthal, began to build hand g liders in 1896. He introduced a success fu l biplane glider whi ch looked

very much like the yet to be developed Wright Fl yer, but was still contro lled by weight shift of the pil ot.

The stage was now set fo r powered fli ght. Samue l Pi erpont Langley made a success ful f li ght w ith a gasoline eng ine-powered mode l aircraft in August J 903. He subseque ntl y made unsuccessful manned attempts at powered fli ght, but the fac t that Langley was on the ri ght track was confirmed in 19 14 when G lenn C urti ss, after a number of modifi ca ti ons to the salvaged Langley craft , made a successful fli ght e ight years after Langley 's death.

It was thi s pe ri od of technology growth into whi ch the Wri ght Brothers stepped, with exceptional mechani ca l skill s and an understanding of w hat it wo uld take to be successfu l. The Wri ghts ap proached the design of their airpl ane with a true scienti fic method . T hey built and operated their own w ind tunnel to acquire necessary aerodynamic data and put their di scoveri es to the ultim ate test with a se ri es of three gliders. Tn mod ificati ons of their third glider they impl emented a rudder behind the wings . Coordi nated w ith the w in g warping, the rudder prov ided compl ete lateral cont.ro l and made banked turns poss ibl e. T he control philosophy was now virtu all y identical to that used today.

The Wri ght B rothers' accompli shment was a quantum leap fro m the shoulders of their predecessors. By making use of the know ledge and ex perience of the time, and by adding their ow n signiti cant scienti fic and engineering contributi ons, they built and fl ew the first manned, powered airpl ane capable of full y contro ll ed, sustained fli ght. A seri es of Wri ght F lyers and the 1908 Wri ght Type A demonstrated in E urope set in mo ti on the chain of events which led to av iati on as we know it today.

B y the I 920s, the airplane had developed to the point that commercial applicati ons became a dri ver of progress . For success, a passenger or cargo o peration mu st o perate on a pred ictable sched ul e. In the earl y da ys airplane o perati ons were constrained by weather conditi ons and the requirement that the pi lot must have visual re ference to the hori zon fo r sa fe fli ght. Earl y airmail operati ons were fraught with danger, and many aircraft and pil ots were lost in attempts to carryo n in poor weather conditi ons.

During World War 1 the basic in struments compass, air speed indi cator, anel altimeter - were augmented by the t11rn and bank in di cator, invented by Elmer A. Sperry S r. Thi s instrument wo uld te ll the pilot if he was turn ing, informati on perhaps surpri singly not reli abl y ava il abl e from a magne ti c