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Aeroplane Endurance


Every second added to the length of a flight represented progress in the early days


THE FIRST OFFICIAL FLIGHT OF MORE THAN ONE HOUR was made by Wilbur Wright in 1908

THE FIRST OFFICIAL FLIGHT OF MORE THAN ONE HOUR was made by the American Wilbur Wright at Le Mans, France, on September 21, 1908. This photograph shows his machine in flight during the making of the record. He remained in the air for 1 hour 31 minutes 25 seconds. Previously, his brother Orville had made flights of more than an hour; but they had not been officially timed.



THE establishment of an endurance record is a significant feat. Yet there is today no official recognition of such flights, although some of the earliest endurance records received official recognition, as described in this chapter. Endurance, or duration of flight, has no place in the records of the Federation Aeronautique Internationale (International Aeronautic Federation), often referred to by its initials as the F.A.I. Endurance records dealt with in this chapter are those established without refuelling in the air.


The F.A.I. admits only four records: altitude, speed at low level, distance in a straight line and distance in a closed circuit. It is by misinterpretation of the last two of these that an unofficial “fifth record” has been created. As it takes time to cover long distances, the time factor has grown with the years to an impressive figure.


It would be possible — though such an eventuality is highly improbable — for an aeroplane to take off, meet a wind of 100 miles an hour, fly against it at a speed of 100 miles an hour for ten hours, and land again without having travelled a mile over the ground. The fact that the aeroplane had remained in the air for ten hours would mean nothing, officially; yet had the pilot turned the machine about, he would have flown 2,000 miles. Despite the non-existence of an official endurance record, feats of endurance have acquired significance. In practice, endurance may well be of equal importance to aircraft designers as speed or altitude, for endurance proves reliability far more thoroughly than the work of the test bench.


On December 17, 1903, Wilbur Wright set up an endurance record of fifty-nine seconds (see page 395). Nearly a year later, the Wright brothers succeeded in keeping their biplane aloft for ten minutes. When Santos-Dumont first flew in Europe in 1906, he remained in the air for only twenty-one seconds. Meanwhile, the Wright brothers had raised the endurance record to over half an hour. In 1908, although other aviators had made flights of much longer duration, Louis Bleriot was satisfied because he had stayed in the air for eight and a half minutes.


On October 3, 1907, Henri Farman made a flight in France which lasted for nearly three-quarters of an hour. On September 9, 1908, the hour record was passed when Orville Wright remained in the air over Fort Meyer, in America, for 1 hour 2 minutes 30 seconds. The following day he improved on this figure by about three and a half minutes; on the next two days he beat his own records, and eventually stayed in the air for 1 hour 14 minutes 20 seconds. These flights were not timed officially and it was left to Orville’s brother, Wilbur, to establish the first officially timed flight of more than one hour. This he did at Le Mans, France, on September 21, by raising the official endurance record to 1 hour 31 minutes 25 seconds.


It is not hard to appreciate the value of the endurance factor to the pioneers They had everything, including inefficient engines, against them. They experienced trouble with petrol feeds, sparking plugs, carburettors, magnetos and overheating. Even a severe gust of wind often meant disaster. Every little adjustment made the difference of valuable seconds in the air, and therefore the desire to remain aloft as long as possible encouraged the making of improvements in every detail of the machine.


When Bleriot flew the Channel in 1909, one of his greatest fears was that his engine might overheat. Latham’s failure to cross before him was largely due to engine overheating. With such a narrow margin between success and failure, even a shower of rain at the critical moment was a godsend.


After almost unlimited patience and ingenuity, engines were improved and altered month by month, and the duration record was continually being raised. The Wright brothers were ahead of their European rivals. On December 31, 1908, Wilbur Wright, flying at Le Mans, raised the record to 2 hours 20 minutes 23 seconds.


During 1909, when numbers of recruits joined the ranks of the pioneers, and when aircraft factories developed from small sheds, endurance meant everything. When men bought machines, they expected performance. Technical authorities were employed to study problems and aeroplanes became more reliable. The achievement of staying in the air longer than anyone else now meant prize money; and prize money, won by a particular type of aircraft, meant orders for the factory producing it. The great Rheims meeting attracted hundreds of potential aviators and many new records were established.


On August 27, 1909, the three-hours’ figure was passed by Henri Farman, flying at Rheims. The flight ended in darkness; it was officially timed at 3 hours 4 minutes 56 seconds. On November

3 Henri Farman raised the record, by an officially timed flight, to 4 hours 17 minutes 53 seconds.


Aeroplanes were passing through a difficult period. Lessons had been learned and the results of experience were being incorporated into designs. Manufacturers tried to maintain given standards; engines were improved and lightened. They became more trustworthy.


Aviators continued to raise the endurance record. In 1910 Olieslaegers established the record

at 5 hours 3 minutes 3 seconds, flying a Bleriot with a Gnome engine. In 1911 Fourny flew for 11 hours 1 minute 29 seconds. The honours were with France.


Werner Landmann, flying an Albatross, captured the record for Germany in 1914. He remained in the air for 21 hours 48 minutes 45 seconds. The war of 1914-18 interrupted the breaking of endurance records of the type under review.


International Rivalry


The competitive spirit was revived in 1920, and it was soon expressed in a new set of records. Flying a twin-engined Farman, two Frenchmen, L. Bossoutrot and J. Drouhin, raised to 24 hours 19 minutes 7 seconds the endurance figure set up by Germany.


In 1921 two Americans, Edward Stinson and Lloyd Bertaud, flying a Junkers Larsen, added two hours to this figure. The Frenchmen recaptured the record in 1922, with a time of 34 hours 19 minutes 7 seconds. The following year three Americans, L. Oakley, J. Kelly and Lieut. MacReady, flying a Fokker T2, stayed in the air for 36 hours 4 minutes 34 seconds.


Seconds no longer counted; even minutes were now of little consequence. Each additional hour in the air meant so much more faith in aeroplane and engine — and a possibility of adding 100 miles to a regular air route. Clarence Chamberlin and Bertrand Acosta proved what a well-built engine could do in 1927, when they passed the 48 hours’ figure for the first time. Their time was 51 hours 11 minutes 25 seconds. By 1931 the duration record had been raised to 84 hours 32 minutes, by the Americans Walter Lees and Frederic Brossy, flying a Bellanca machine.


On August 27 1909 Henri Farman stayed in the air for 3 hours 4 minutes 56 seconds

MORE THAN THREE HOURS IN THE AIR. This feat was achieved for the first time at the Rheims flying meeting in 1909. On August 27 Henri Farman, shown flying his machine, stayed in the air for 3 hours 4 minutes 56 seconds. On November 3, 1909, Farman raised the record, by an officially timed flight, to 4 hours 17 minutes 53 seconds.



An excellent example of endurance was provided by the flight of the German Dornier Do 18 seaplane, from England to South America. On March 27, 1938, this aeroplane was catapulted from the base ship, Westfalen, lying in Start Bay, Devonshire, and a landing was made at Caravellas, Brazil, on March 29. The Federation Aeronautique Internationale has recorded the flight as a new long-distance record for seaplanes. Far more striking to many, however, is the fact that the machine remained in the air for nearly two days.


The Do. 18 was powered by two Junkers Jumo diesel engines, and carried a crew of four, two of whom were pilots. Captain Hans Weiner von Engel, an air-line pilot in the employ of the Deutsche Lufthansa, was transferred to the Dornier Company for the flight, and his co-pilot was Erich Gundermann, test pilot to the Dornier Company. Helmut Rosel was engineer and radio operator, and Hans Joachim Stein was a second radio operator.


The launching took place at 15.05 (3.5) p.m., Central European time, on March 27. For some time conditions were favourable; then headwinds were encountered and progress was slowed up for some hours. The machine flew on in a southerly direction, passing the Spanish coastline during the night of March 28. Here the favourable northeast trade winds were picked up, and the machine’s ground speed increased. Thus the fliers recovered much of the time lost at the beginning of the flight. The trade winds, which once meant so much to the old merchantmen, helped the Do. 18 on her way until the Equator was reached. Then the pilots had to contend with constantly changing weather conditions, and with winds which varied from hour to hour. This, apart from affecting the time of the flight, necessitated a great deal of accurate navigation. Head and side winds prevailed until Las Palmas, Canary Islands, was sighted at 3.30 (Central European Time).


32 Hours in Formation


Flying steadily on her course, the Do. 18 passed the Cape Verde Islands at 11.15, and headed out across the wide ocean towards South America. After slightly more than eleven and a half hours the island of Fernando de Noronha was reached, and at five minutes past two on the morning of March 29, the machine was over Recife (Pernambuco). Sao Salvador (Bahia) was passed at 5 a.m., and just over five hours later a landing was made at Caravellas. The duration of the flight was from 15.05 hours, March 27, to 10.05 hours, March 29. The time in the air was exactly forty-three hours. During that time 5,220 miles were covered.


Among Great Britain’s most notable achievements in this sphere was an R.A.F. formation flight to the Near East in July 1938. This flight covered 4,300 miles in 31 hours 55 minutes. It was the longest non-stop journey made by an organized military unit.


Four Vickers Wellesley bombers of the R.A.F. Long-Range Development Unit left Cranwell, Lincolnshire, at 4.15 a.m. on July 7. They flew to Ismailia, in Egypt, and then on to a point between Koweit and Bahrein Island, in the Persian Gull. Thence they returned to Ismailia, landing there at 12.10 p.m. on July 8.


Apart from the data to be gained from flights of exceptionally long duration, there is a limit to the value of duration flights after a certain stage has been reached. The longest flight that is likely to be made to regular schedule is governed by some tract of water or dangerous ground. There are few useful routes which do not offer landing places after 4,000 miles have been passed.


The weather, too, must be considered. A trip to Scotland from London might well be completed in an hour, in a fast machine, given a following wind; but the same trip might equally take two and a half hours in the same machine if the weather were unfavourable. On a short journey such as this, the difference in time would merely be inconvenient. If the mileage were trebled and the flight were over water, the position would assume a new aspect altogether.


A definite link exists between time in the air and distance flown. The record for distance in a closed circuit may well be considered the same as the unofficial duration record, although it is the distance, rather than the time, which is recognized. In recent years, because distance has a more direct bearing upon practical flying, the time factor has come to matter less and less. Reduced to terms of endurance, however, the time factor will always be the more impressive of the two.


A CATAPULTED GERMAN SEAPLANE remained in the air for nearly two days in 1938A CATAPULTED GERMAN SEAPLANE remained in the air for nearly two days when flying from Start Bay, Devonshire, to Caravellas, Brazil. The aircraft left on March 27, 1938, and by its flight created an official distance record for seaplanes of 5,220 miles. The seaplane was a Dornier Do.18 powered by two Junkers Jumo engines; it carried a crew of four.


You can read more on

“First Air Meeting at Rheims”

and

 “The Influence of Air Racing”

and

“Refuelling During Flight”

on this website.