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Aviation History
1919
1919 - 0857.PDF
"hunting." I propose to show a record taken on an aero plane which hunted. Stable Aeroplane The lecturer then showed a speed record reproduced from an automatic apparatus attached to an aeroplane. A special clutch was provided by means of which the control column could be locked ; the record begins with the aero plane flying at 62 m.p.h. and the lock just put into operation. As the steady speed was then 73 m.p.h., the aeroplane, being stable, commenced to dive and gain speed. Overshooting the mark it passes to 83 m.p.h. before again turning upwards ; there is a very obvious dying down of the oscillation, and in a few minutes the motion would have become steady. The record shows that after a big bump the aeroplane controlled itself for more than two miles without any sign of danger. Unstable Aeroplaiie The next record shown was very different and not so easily obtained, since no pilot cares to let an unstable aeroplane attend to itself. No lock was provided, but by gently nursing the motion it was found possible to get to a steady flying speed with the control column against a stop. Once there the pilot held it as long as he cared to, and the clock said that this was less than a minute. After a few seconds the nose of the aeroplane began to go up, loss of speed resulted and stalling occurred. Dropping its nose rapidly the aeroplane began to gather speed and get into a vertical dive, but at 80 m.p.h. the pilot again took control and resumed ordinary flight. The aeroplane in this condition is top-heavy. Further Records As an aeroplane may be flown at different speeds, it is necessary to examine the effect of speed on stability, and the next record shows good stability for a modern aeroplane at speeds of 83 to m m.p.h. and for conditions more onerous than those of a locked control column. The records were taken by the equivalent of a pinhole camera carried by the aeroplane and directed towards the sun. The pilot started the record by putting the nose of the aeroplane down and then abandoning the control column. Big oscillations were produced, which died down with considerable rapidity. All records show marked damping, and without measurement it is difficult to detect any effect of speed. In the next record, which is uncommonly interesting, the effect of speed is 0 a The Aeroplane Linen Deal WHAT is believed to be the largest one-man deal since the Armistice was announced on June 19, when it was stated that the Aircraft Disposal Department had sold to Mr. L. J. Martin 40,000,000 yards of finest quality linen made for aeroplane coverings; the price stated to be about^4,000,000. The linen ranges over sixteen varieties in widths varying from 25 to 72 inches. Mr. Martin has stated that he will sell as much of the linen as possible to the British public, and that the remainder will be sold to the Allies and in neutral markets. We refer to this matter further on page 830. Jacques Schneider Maritime Cup As announced in FLIGHT recently, the next race for the Jacques Schneider Maritime Cup will be held in England early in September next, the exact date and place to be announced later. In 1914, the winner was C. H. Pixton on a Sopwith seaplane, the nominee of the Royal Aero Club, representing the British Empire. The race will be over a distance of 200 nautical miles, exclusively at sea, in a closed circuit having a minimum course of five nautical miles, and situated outside any port or en closed harbour. At least two alightings must be made on the water at points fixed by the officials. The Committee of the Royal Aero Club will select the three competitors to represent the British Empire, and reserves to itself the right to hold eliminating trials. Entries are to be made at the Royal Aero Club, 3, Clifford Street, London, W. 1, not later than July 31, 1919- Each entry must be accompanied by the entry fee of £20. R.A.F. Relinquishing Leysdown Aerodrome THE Air Ministry announces that Leysdown Aerodrome will shortly be vacated by the R.A.F. An Amballa to Simla Flight P| THE further details which are now to hand regarding the flight of Maj. H. A. Tweedie, Aus. F.C., from Amballa to Simla provide a remarkable tribute to the stability of the British aeroplane against heavy dust and thunder-storms. When Maj. Tweedie, flying a Sopwith Camel, left Amballa for Simla, visibility was so poor that at a height of only 6,000 ft. it was obvious. The upper diagram shows that at a speed ol 100 m.p.h. and a height of 10,000 ft. the aeroplane is satis factorily stable. During the period " a " the pilot did his best to fly level, whilst for " f " the aeroplane was left to its own devices and proved to be a good competitor to the pilot. At the end of "(" the pilot resumed control, put the nose down and abandoned the column to get the oscilla tion diagram which gives a measure of the stability. At a speed of 90 m.p.h. at 1,000 ft. the oscillation died down a little for the first few periods and then became steady. The stability in this condition was very small indeed, and a reduction of speed to 70 m.p.h. was sufficient to produce hunting. Two records are shown, the more rapidly in creasing oscillation being associated with climbing. The oscillations so observed are calculable, and the effect of gusts in a natural wind are readily deduced from the oscillations observed in still air. It is to be hoped that the stability of the aeroplane will now receive the attention which has in the past been devoted to performance, and has led to a British literature unjjaralleled in any other country of the world. It is easy to make an unstable aeroplane ; it is not difficult to make a very stable aeroplane. On the other hand, it needs considerable care to give an aeroplane a desired degree of stability. It is to be hoped that we have for ever ceased to regard stability with indifference, or as an undesirable quality which tends to diminish the skill required of a pilot. Once it is conceded in the necessary official quarters that the study of stability is important, there will be no difficulty in beginning the progressive collection of data ; but if this work is to proceed satisfactorily it is necessary that an appreciable part of the time of the staff of the National Physical Laboratory and the Royal Aircraft Establishment shall be continuously devoted to it. Incomparably more laborious than that relating to performance, it is work which can only be broken into at frequent intervals at a cost of serious loss of time and accuracy, and in the days to come, when the number of aeronautical engineers with mathe matical knowledge is sufficient for the needs of the industry, this data will be the fundamental stock-in-trade. The immediate needs of the industry have much support, but a policy of looking two or three years ahead has fewer advocates. in spite of the fact that such provision is necessary if Britain is to keep her lead in the air. m a impossible to see a spot five miles distant; more extraordinary still, no hills were visible. Flying by compass, Maj. Tweedie bore north-east into the clouds at 7,500 ft., and again climbing failed to get above the clouds. He then made up his mind that it was practically useless to carry on, but looking around he found nothing could be seen ; a dense fog and ominous indications of a severe dust-storm were creeping up behind. Climbing still higher, Maj. Tweedie observed that the storm was getting nearer and nearer. He says he could not make up his mind which would reach Simla first. Hoping against hope that he could race the storm he climbed his machine to 10,000 ft., and was relieved to see the Simla hill in front of him. In order to approach the aerodrome, it was necessary to come down into a cup of the hills. The moment he throttled down, however, the machine became unmanageable owing to the bumps due to the thunder-storm overhead. Eventually, compelled to approach the ground " down wind " owing to the storm, he was lucky enough to make the dangerous approach of about 300 ft. deep and only accessible from one end. Jumping a wall between trees 15 ft. higher the pilot made the landing just as the storm broke. So severe was it that within a quarter of an hour there were over 20 holes in the fabric of the planes caused by hail-stones' larger than pigeons' eggs. The arrival of the machine at Simla created a great im pression, particularly amongst the natives, who saw an aeroplane for the first time. Transatlantic Flight Items A TRIAL lasting 1 hour 20 minutes was carried out with the Handley Page machine at St. John's on June 10, while another flight of an hour's duration was made on June 19. In each case it was reported that everything worked satisfactorily. A message from St. John's on June 18 stated that Maj. ffiske of Messrs. Boulton and Paul had received word that the two Boulton and Paul entries had been withdrawn from the Transatlantic flight. This will not affect the plans of the Martinsyde and Handley Page crews who are preparing to start at the first favourable opportunity. The American flying boat NC 4 is being sent back to the U.S. on the " Aroostook."
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