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Aviation History
1931
1931 - 0346.PDF
FLIGHT, APRIL 10, 1931 place by the left thumb, move the cross slide along till itsedge cuts the centre of the main plate, engraved 90 on the chord or sum scale, and rotate the divided circle lying justabove the main plate till the middle bearing is read against the same edge of the cross slide on the nearer or lower sideof the main plate. Here it is necessary to use the inner figures of the double divided circle when the bearings in-creased with time and the outer figures when they decreased with time. In order to be reminded of this, the necessarynote has been etched on the main plate of the instrument. The track can now be read off on the left of the instrumentby means of the arrow on the left end of the main diameter against the divided circle, in this case 348° using the sameinner (or outer) figures as were used in setting the circle. If the wireless bearings available were taken from thefixed station the procedure is exactly the same until the final operation of reading the track. The track in that case isread from the right hand arrow near the word SUM and with A A marked on each side of it. In using the instrument, it is of great advantage to putdown the bearings and times, etc., in a standard form similar to that shown above. The bearings and times are written down in two columns,the bearings on the left and times on the right. Next write down the intervals of both bearings and times working out- wards from the first two columns. On the left of the bearingintervals now write their sum and difference, the latter being formed by subtracting the second interval from the firs^paying attention to sign. On the right of the time intervals write their ratio formed by dividing the first interval by thesecond, using two significant figures. Finally the middle bearing is underlined and marked " inc " or " dec " accordingto whether the bearings increased or decreased with time. Skilled navigators will appreciate the advantages of Trackdetermination when flying in or over fog or clouds, as only one extra timed fix is required to find the ground speed ;any convenient one of the timed bearings used in finding the track can be combined with the extra fix to give thedistance run in the interval on the known track which imme- diately gives the ground speed ; by combining the Trackand Ground Speed with the Course and Air Speed, the velocity and direction of the wind can be immediatelyfound. To obtain full benefit from the above method, compasscourses should be steered and the necessary alterations made as required. Although the track can now always be ascer-tained, the knowledge of the compass course from a previous fix, which can be combined with the Track found after losingsight of the earth to obtain or check the wind, enables navigation to be carried out with confidence in the result. TALES OF THE INTERNATIONAL CATERPILLAR CLUB By CHARLES DIXON S ni "'HE modern parachute of accepted design is playing\^) III an important part in military and civil aviation, 111 not only by saving valuable lives, but by makingpossible practical research and experiment of the most dangerous order under flying conditions. It has longsince passed from the experimental stage as an aircraft equipment into the stage of standardisation. Every year since the Royal Air Force adopted the BritishIrvin Air Chuto about five years ago, a number of lives have been saved, and the present year promises to set up a record,for at the moment of writing ten R.A.F. pilots have been added to the list.Each airman whose life is saved with an Irvin Air Chute automatically becomes a member of the InternationalCaterpillar Club, an organisation created by the Irvin Air Chute Company exclusively for these airmen. There are nofees or rules governing the Club. Each member is presented by the Company with a gold caterpillar tie pin, and his nameincluded in the records of the Club. Collectively the experiences of these caterpillars add toour knowledge of the causes of air accidents of every nature, and of how the airmen tend to react in face of swift danger. For these reasons the publication of their stories, as thexr bear upon the technical issues rather than the human issues,may be considered by our readers not only of exceptional interest but also of great value. A Padre Caterpillar Amongst the two hundred and seventy members of theclub there is one Padre. He is Squadron Leader K. C. H. Warner, Chaplain in the R.A.F. On January 23 last yearhe was being flown from Abu Sueir to Cairo, a distance of approximately 70 miles across desert, in a D.H.9a, witha Liberty engine, piloted by Flight-Lieut. V. J. Somerset- Thomas, R.A.F. They had been flying in a very dampatmosphere for half-an-hour, which brought them to a point fifteen miles from the nearest civilisation, when the crank-shaft of the Liberty engine broke. The. pilot immediately throttled back and switched offthe engine but the vibration was still so excessive that it broke the port engine bearer, and the Liberty began to flyto pieces. Almost at once the machine commenced an uncontrollable starboard spin, which the pilot could notaffect after several seconds of effort. He therefore decided that he and the Padre had betterjump with their Irvin air chutes. He released his safety belt, stood up, indicated to the Padre exactly what wasrequired of him, and then dived over the port side by way of example. The Irvin opened promptly after he had allowedhimself to fall several feet, and pulled him upright. The Padre did not hesitate about the necessary action. He alsoreleased his belt, jumped up, lifted one leg to the top of the cockpit and flung himself out to starboard. His only fault,perhaps, was in releasing his parachute rather too quickly. From the original account the writer judges that hepulled the ring almost as he left the cockpit, which, of course, is too soon. One should count about three (if there is time).However, there was a thirty-mile per hour headwind, which helped to fling the chute clear of the tail unit, although thepilot chute feature of the Irvin comes into effective play in such conditions by dragging out the chute at a tangent to theairman's body, instead of letting it open vertically above him, Like most airman on such occasions, the Padre was surprisedat his sense of security and comfort when the chute opened and gently floated him to the desert. He saw the abandoned D.H.9a dive into the desert, and thenhis own landing became imminent. He acted correctly in not resisting the impact, which was so slight that he hardlynoticed it, although he alighted on his left shoulder, after the manner of a fall at Rugger football. Owing to the forceof the ground wind he was dragged a considerable distance until Flight-Lieut. Somerset-Thomas, who had landed safelya short distance away, ran to his assistance. Both were none the worse for their unexpected adventure. Pitched OutWhen one ranges over the records of Caterpillar members, it is remarkable to find how many of them were flung outof their cockpits through breaking safety belts or other reaBone, The luio Flying Officer Vickore O. Eyre, RAF.,had the startling experience of being shot out of his Siskin IV when flying at 2,000 ft. It was not a question of a breakingbelt in bis case. He dropped his flying map, and bent forward with hisbelt undone to recover the map from the floor. Apparently he accidentally pushed the joy-stick forward, for the Siskinsuddenly dived round on to its back, and Eyre found himself floating on air facing skywards with his feet slightly higherthan his head. He felt no sensation of falling, and the only indication of movement to him was the feeling of pressurebehind him. It was not a moment before he thought of his Irvin AirChute, but although he could move his hands easily, to fu;d the ring he could not bend his head to guide his hands, -whichmay have been due to the stiffness of his flying suit or to tne fact that he was beginning to turn the usual long somer-saults. Before he had ceased pulling on the ring the silk canopywhisked and rustled past his feet and the opening jerk whi ' pulled him vertical did not affect him. The altitude th •'was 1,500 ft., and his descent was so slow that he thoug he was stationary. There was no sign of the abandonSiskin, ani^it worried him to think of its possible danger people in its path.As he approached the earth, his rate of descent becar, •• visible, and he turned to face the direction of his descei .A large tree in the centre of a field was a threatening obstru tion until he managed to sideslip clear, to land withoshock or injury. Then a farmer allayed his concern for otne ^ by riding up to inform him that the Siskin had crashed a nn«away amidst trees without hurting anyone. (To be continued) .._. .:.' 322
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