| Show navigating the air lawn inventors tors have been at work on this problem since tho year 1500 stanley stanlcy spencers Sper cers machine the mot successful yet produced flights of two d risible airships at coney island new yot york k recently call attention anew to the slow but ap parent ly steady progress s which man Is making in the difficult art of flying the earliest historical record of an attempt to design a flying machine on really scientific principles is found in the notebooks of leonardo da vinci the famous artist and s engineer never worl wort ed the idea out I 1 ut it Is I 1 cnown DO D that tie ile principle involved was as the flap flapping of wings he ile proposed to ue 1110 u e man power for that purpose sev eral inventors during the last halt of the nineteenth century devised toys that would keep afloat tor for a moment by moving wings A typical device of that kind was A as jobert s it dates back to 1872 twisted rubber supplied the power for its operation among the first to recognize the sustaining power of an outstretched 0 it flat surface entirely apart from the question of propulsion was a german engineer herr otto lilienthal A series of experiments and observe t tens ans covering t twenty enty five years were disc assed in a book which appeared in 1899 subsequently lilienthal made short flights through the at air r by jump ing from a roo or cliff and gliding gilding forward and downward at the same time at first he be uee only one pair of stationary wings or tero vero planes to hold himself up but later he made a double decler er ills apparatus was supplied with ith a double rudder for steering sideways and up and down gravitation was his motive power ai though toward the end of his career he meditated using a small engine pilcher pitcher a young and oc oe tave chanute an american engineer have done a great deal of good work along this line the two most prominent in tors of the possibility of combining the aeroplane for sustaining the ship in air with powerful propelling mech aniam of the screw type have been sir hiram maxim and prof S P langley maxims machine m was as a colossal affair for experimental pur poses in order to ascertain how fast it would go ahead it was mounted on a railway it had three decks or sets of aeroplanes aero planes and with three men on board and plenty of naphtha for fuel weighed 8 pounds there lilienthal a aglid ng machine were two enormous screws astern the engines were rn mc avels of light ness they developed horsepower with a weight of about six pounds per horsepower while he was expert in 1895 maxims maxim a airship pulled loose from the track rose a little and then came down abruptly enough to be considerably injured since that time sir hiram has given little attention to this subject still he showed that it was possible to attain a speed of something like awen ty five or thirty miles an hour prof langley who has probably gone deeper in to the philosophy of aerial navigation tan any other living man improved on maxim in two or three ways he made a model too small to carry a passenger but big enough to test the merits of 0 the design its length was 16 feet and the distance from up tip to up tip of wing about 12 feet his steam engine weighed only twenty six ounces and developed one or one and cne half horsepower finally he launched the ship from the root roof of a houseboat on the water so that when it descended the craft boull not be injured the trial flight lasted a minute and a half and devel aped a speed of tv ta enty five or thirty miles an hour the type of airship to which that jobert s flying machine 1872 of santos dumont a belongs employs a balloon for sustaining purposes this is shaped like a cigar or sweet potato in order to minimize the re si stance of the air in moving horizon tally commandant Commac dant renard of the french army was one of the first to utilize this system he drove his propelling screws with an electric mo too tor and carried along a storage bat tery the latter nas so heay tha no one else of any consequence has adopted that form of motive power the frenchman managed to spurt at the rate of twelve or fourteen miles an ho r for a few minutes though this feat was performed somewhere between 1891 and 1885 an attempt to improve on santos dumont in another TV way ay Is being mad madi by two englishmen stanley spencer and dr barton the former sprang a surprise on the public last month by making an unannounced ascent at the crystal palace london and keep ing aloft long enough to travel thirty miles lie ile thus broke all records for 6 distance the details of his d design sigr are not yet known nonan on this side of 0 the atlantic leo stevens adopts the renard p an and a that he has improved on santos dumont lie ile has one gas bag inside of another he ile has adjust able water ballast the receptacle co cot which can be slid to and fro on a rod his ills chief novelty though in his own oven estimation is a pair ot parachutes which aie folded up blk leonardo da vinci 3 model A D 1500 wings ordinarily but are intended to open out automatically la in emerged cles cies |
