Evening Star Newspaper, June 9, 1929, Page 109

THE SUNDAY STAR, WASH Making the Jump Safe For Airmen Major E. L. Hof fman, Holder. of the Collier 1'ro- phy, Has Been Active i Developing the Old, Clumsy Parachute Into an Almost Flawless Life-Saving Ap- paratus BY FRANK HARMEL. HE parachute, the aviator's “ace in the hole,” which is now in general use by men in the flying profession, and which has been ‘instrumental in saving in this country thus far 122 lives, not to mention the number of lives it has saved in foreign countries, did not attain its present state of popularity without the cus- tomary struggle for recognition. Like every so- called new-fangled device, it met with indiffer- ence, opposition and even ridicule. A few pilots who served overseas during the war, and who in aerial combats had seen enemy pilots use the parachute successfully, expressed a desire for this article of flying equipment, but the average pilot, feeling secure that nothing would happen to him anyway, considered it as unnecessary impedimenta. Even after several Army pilots were saved from certain death by the parachute no widespread enthusiasm pre- vailed regarding its use. Nowadays every pilot and passenger in an Army plane wears the parachute. Several years ago orders were issued by the chief of the Army Air Corps making its use compulsory. In view, however, of the wonderful reputation for effi- ciency which the parachute enjoys today it is safe to say that pilots in the military and naval air services as well as in commercial aviation would hardly think of making & flight without it, orders or no orders. The efficiency of the present type of Army parachute can be attributed more to the whole- hearted interest and unfiagging activity exer- cised in its development by Maj. E. L. Hoflmap, Army Air Corps, than to any other factor. Maj. Hofiman was rewarded for the outstanding part he played in the development of this flaw- less life-saving apparatus when President Cool- idge in 1926 presented the Collier Trophy to him. This trophy is awarded annually for the greatest achievement in aviation in America the value of which has been thoroughly demon- strated by actual use during the preceding year. It is generally conceded that the first para- chute was built and used by & Frenchman in 1784. This parachute was a rigid structure, covered with very strong paper and fabric, and it was used in a jump from a building in Paris. In England, a year or so later, the same type of parachute was used in a jump from, a hot- alr balloon. Subsequent leaps were made from balloons with various shaped parachutes. Prac- tically all of them, however, were of rigid construction and were therefore already open. About 1880 the late Capt. Thomas Baldwin came into prominence by jumping from hot-air balloons with a parachute which was a fores runner of the present type. Capt. Baldwin was the first really successful parachute jumper, success in this case being gauged by the length of time a man lived while engaged in this pro- fession. win in rapid succession, the most prominent one being A. Leo Stevens, who constructed a great many parachutes, one type of which was used extensively by the Army in connection with balloon flights. The first practice jump from an airplane was accomplished in 1912, when a parachute in a conical type of container was used. This con~ tainer was attached to the airplane and the parachute was Jlaunched when the jumper after leaving the plane caused it to be pulled out of its centainer. g From this time until thé World War numer- ous parachute jumps were made from nlrplnne_s during exhibitions, but it remained for. the great conflict to prove the unquestioned value of the parachute as life-saving apparatus for use with airplanes as well as balloons. Other balloonists followed Capt. Bald- - Maj. . L. Hoffman, who is largely re- sponsible for the present life-saving parachute. He was presented with the Collier Trophy in 1926. ARLY in 1918 airmen of the allied armies < reported that German pilots were using parachutes to escape from their planes when- ever they were shot down out of control or set on fire. This was the beginning of insistent demands on the part of allied airplane pilots for parachute equipment. The demand was partly filled by the British adapting balloon- type parachutes to some of their airplanes. The Air Service of the American Expeditionary Forces endeavored to produce a satisfactory parachute by combining the good features of several parachutes already in existence. All of these, however, were very bulky, heavy and hard to place on the airplanes to any advan- The balloon parachute, however, was used ' to good purpose by members of the American Air Service who were assigned to the lighter- than-air branch. From the World War records it is gleaned that 117 emergency parachute jumgps were made from balloons in the zone of operations—108 by officers and 9 by enlisted men. Of these 117 jumps, 59 were made from balloons which had been attacked and set on fire by enemy airmen and 58 from balloons which were attacked but not set on fire. The out- standing figure among these balloon jumpers of the World War was Lieut. G. Phelps, who was credited with five jumps, three of them from burning ballcons. Work on the parachute was started at the Air Corps Engineering Division at Dayton, ’ Ohio, in September, 1918, and for the first nine months it was under the supervision of Floyd Smith. . Thereafter, and until the assignment of Maj. Hoffman as chief of the equipment sec- tion, of which the parachute department was a component part, Guy Beall was in charge. At the start, only a meager amount of infor- INGTON, D."C.; ‘JUNE 9, l‘mf}’ART 7. 21 DTS S A o T s S — | s e Sergt. Nichols wearing the new parachute pac... mation was available concerning the parachute. All the various types of parachutes then in use in this country and abroad were secured and carcfully rtudied. Such scant attention was paid, however, to parachute development, that the whole proposition was in danger of dying from stagnation. The almost general attitude prevailsd that the parachute would possess no value in peace time and that to conduct fur- ther experiments would be a waste of funds. Even the small amount of work that was done in ecnnection with parachute development was beset with difficulties. Funds were lacking and the psrachute department received virtually no support. This discouraging state of affairs ex- isted until Maj. Hoffman took charge. This officcr was keenly interested in the parachute and scnsed the great possibilities of the equip- ment, which thus far has played such a promi- nent pert in reducing casualties among flying personnel. Obteining the necessary funds to carry out his' experiments, Maj. Hoffman proceeded to _build up an organization. He secured suitable floor space for the parachute department, pur- chased sewing machines, tools, material and other paraphernalia, inciuding special air- planes, weights and dummies for testing pur- peses. After studying the various types of parachutes then extant he reached the conclusion that, whatever type might be adopted for military flying, the primary consideration was that in its gperation it must be entirely free and inde- ‘pentignt of the airplane, because with any type ‘of parachute attached to the airplane its suc- /s cessfiil use was entirely dependent upon favor- . able conditions, and what was desired was a parachute which could function under the most unfavorable conditions. THE “free” type of parachute, being an en- tirely new departure, necessitated develop- ment work to cover each individual item of con- struction’. The high speeds at which airplanes operate demanded a parachute far stronger than any of the existing types used with bal- It was realized that the bulk and weight ©at a minimum and that the should possess the virtues loons, would have to parachute harn of s%xength and comfort. The problem then .was 30 to design the harness that the shock Jimparted to the wearer through the opening of ithe parachute and consequent sudden checking _of the fall should be equally distributed, to the ? end that no physical injury or discomfort would - ‘,be experienced. It /was concluded further that the parachute " pack would have to be of such shape and size as to permit it to be worn in the airplane most comfortably, and that the operation of the parachute must be simple, easy and absolutely positive, With these requirements in mind, work was started ' on parachute equipment. Numerous ideas of parachute construction were submitted to the engineering division, the main feature of most of them being an alleged positive opening device. As a matter of fact, however, none of these opening devices lived up to the expectations of the inventor, and it may be of interest to relate in this connection that the positive opening device of the Army parachute was responsible for saving the life of one in- ventor. This man came to McCook Field to demon- strate his own parachute. Profiting by previous experience, when a parachute inventor lost his life by having too much confidence in his own device and not enough in the Army parachute, an order was issued prohibiting jumps to be made from an altitude of less than 1,500 feet, with the additional proviso that when a new type of parachute is to be tested, a reserve parachute of the United States Army type must also be carried. - It was well that the McCook Field officials insisted that the inventor wear the Army chute, for his own failed to work, and he left the field with a feeling of thankfulness for the efficiency of the Army chute. Looking at the parachute—merely a large piece of fabric with a lot of strings—one is not greatly impressed with it as an article of equip- ment' requiring exhaustive study and research. Nevertheless, the parachute presented one of the most difficult studies in aeronautics. There is no rigid framework, shape or form, and it * absolutely impossible to calculate strains e® stresses, resistances or shock. This information was obtained only after the cut-and-try method. One of the first big problems in parachute construction was to make it strong enough to withstand the great shock and strain impesed upen it when used from an airplane. Previously the parachuté had been used only in jumps from balloons, which did not impose any great amount of strain- on them. When Maj. Hoffman took charge of the paras chute branch; he discovered that, up to that time, parachutes had been tested from airplanes with no more than a 50-pound weight. He ime i mediately discontinued this practice, realizing that the parachute must not only be made strong enough te hold together and carry one man under any .conditions, but that it should possess reserve strength—in other words, & factor of safety. Through a process of calculation it was de< termined that the terminal velocity of a man falling freely would be at the rate of about 350 miles an hour. The problem, then, was to de= sign a parachute which ‘would function upeon being epened, when carrying 200 pounds travele ing at that velocity. In conducting the tests, the time-fuse mecha= nism taken from the nose of an artillery sheil was utilized. The parachute with weight at< tached was dropped from an airplane and; after falling for a predetermined number of seconds, the fuse operated a release mechanisng which in turn caused the parachute to - open. These tests were continued and meodifications made from time to time, until a parachute body and rigging were devised which held togcther under a load of 200 pounds when opened after a free fall of 16 seconds: 'HE utilization of the artillery shell timee fuse mechanism in all of the parachute- drop tests proved a rather cumbersome propoe sition, and caused Maj. Hoffman to seek the solution of another puzzle—adetermine what load released from an airplane flying at maxi- mum speed would produce a strain on a para- chute similar to that imposed by a 16-second fall. Drop tests followed, wherein the load on the parachute was gradually increased until i$ was found that a weight of 400 pounds, released from an observation airplane flying at a speed of 120 miles an hour, would cause as great, if not a somewhat greater strain on the parachute, than that produced by a weight of 200 pounds after falling free for 16 seconds. By a slow process of development, a fabric was developed capable of withstanding the necessary amount of strain. This fabric, an Oriental silk, ‘was chosen because of its great strength, elasticity, light weight, small bulk when compressed and long life. Unlike cotton, it is not as much affected by the ravages of mildew, and if ignited by a match, the burn- ing part in the silk.will bubble and go out, and if a blast of air is blown on the burning silk the fire will go out immediately. Its strength is about 50 pounds to the inch. An important factor in parachute design is the amount of air which can leak through the fabric. . Even though silk would be tremen- dously strong if woven tightly, the great air pressure would cause it to burst. If the ma- terial is too porous, the parachute would not open readily; hence the porosity of the silk presented a difficult. nut to crack. Parachutes measuring 30, 36 and 40 fest in diameter wers constructed for experimental purposes. These were later cut down to smaller sizes. In the course of the experimental work it was fcund that, at times, ceriain of the rig- ging lires of the parachute would break during * drop tests, Maj. Hoffman attacked this probe lem by dAevising a mechanism for measuring and recording the shock on each individual cord dul test. The suspension cords er shroud lines were at first made of braided linem cord, but by gaining the co-oeration of a promi- nent manyfacturer of fishing line, a braided silk cord wys developed which was found to be highly satis;actory. In keepi:g with its policy of : encouraging private enterprise, the Army Air Corps was in constant touth with parachute manufacturers; informing .»hem: of ‘all developments as they «nnateThree.