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Aviation History
1920
1920 - 0422.PDF
APRIL 15, 1920 *' translated inscriptions. The dash itself consists of twoseparate aluminium sheets as shown, with discs crudely in- scribed. The actual cocks had been removed. The evidenceof the inscriptions is obvious. Radiator •• It is evident from the photographs, and from varioustraces that still remain on the machine, that two separate half-radiators were fitted, one on each side of the engine,at the front of the fuselage. (See view of complete machine.) The positivfe shutter control can still be traced from thepilot's seat to each half-radiator. . _••.-... -; PaintingThe body is painted a chocolate-brown colour, except underneath, where a white pigment has been applied. Thewings are painted a pale green, with irregular patches of light mauve on top, and white underneath. The tail planesand elevator are white above and below. • Close examination revealed the fact that under the layerof chocolate paint on the body was a layer of pale green colour, and a similar colour could be seen on the tail planes-wherever the white had peeled off. The chocolate and white were all flat, unvaried colour. Careful scrutiny of the fuselageside revealed the fact that on the top of the green colour, on the starboard side, the inscription "JUNK.D.I." hadbeen painted—the slightly-raised edges of the letters could just be traced. This had been obliterated by the chocolatepaint, but is important as evidence that a German single- seater fighter may be put in the " D " class, whether mono-plane or biplane. On the other hand is the case of the Fokker monoplane, also a single-seater fighter, known by theold-style classification E. (for eindecker, i.e., monoplane). Armament The photographs show two Spandau guns, fixed on channelduralumin bearers, immediately in front of the pilot. They are fired in the usual manner through interrupter gearscontrolled from the joystick. Nothing unusual was noticed with regard to the aluminium chutes and ammunition.magazines. CORRESPONDENCE [The Editor does not hold himself responsible for opinions expressed by correspondents. The names and addresses of the writers,not necessarily for publication, must in all cases accompany letters intended for insertion in these columns,.] AIRBRAKES AND THE SIDESLIP LANDING.[2011] I have read with great interest, Lieut. Courtney's article on " Airbrakes and the Sideslip Landing," and alsoyour preface to same, and as I am one of those to whom you extended an invitation to express opinions, I should like totrespass on your time for a few moments. The first point is with regard to your reference to highlanding speeds. Let us consider what is " Landing Speed." Landing speed is the speed at which a machine ceases to fly.In landing, it is customary to glide in and hold off a few inches from the ground until the machine ceases to fly, anddrops these few inches to the ground. Due warning is usually given by the controls becoming " sloppy " that this drop isabout to take place, and whilst there is still sufficient control, the tail is helped to drop in time to make a three-point landing.Assuming that the machine is allowed to land as above, and is not forced onto the ground, the distance run in pulling upon any machine will be quite short, so that, provided the pilot arranges to make his landing reasonably close to thenear boundary of the aerodrome, there should be little difficulty in pulling up. It is coming in at too high a speed and beingobliged to hold off whilst half the aerodrome is crossed waiting for the speed to drop to landing speed that constitutes whatis usually termed a fast landing. I have not flown any post-War machines, but have flownmost Service types, and I do not remember any machine that would run far once it was on the ground. Say we take up a type of machine we have never flownbefore. Let us go up a few hundred feet and find out its landing speed. Shut off the engine and hold her level untilshe drops her nose, and note the speed at which she does so : say it is 45 m.p.h. Now add 10 m.p.h. to this, and try flyingthe machine on the glide at 55 m.p.h. to see if the controls are quite effective and whether there is a suspicion of stalling.If everything is O.K., we may cut things a little finer and glide about at 50 m.p.h., and we will probably find that whiletwo of the controls are quite tight, the third is " sloppy." We decide, therefore, to bring the machine down to land at55 m.p.h. We find we come in well under control, we hold off only for a few yards and the machine " settles " (as thefarmers put it), and we are surprised at the ease with which the machine lands, especially as someone has probably toldus it is " dangerous and must be brought in at least at 75." Should the day be very rough, we give the machine another5 m.p.h. on the glide, and, of course, hold off a correspondingly greater distance. I recollect seeing a pilot bring in a Bristol monoplane toland at a speed I should put at about 80 m.p.h. He was obliged to hold off almost the full length of the aerodrome,and only just pulled up within its boundary. I noticed, how- ever, that the distance actually run on the ground was quiteshort. I had never flown this breed before, and when I first took it up I applied the above methods of finding its landingspeed. I found that it would glide almost as slowly as an Avro under perfect control, but to keep it at it required abouta 14-lb. backward pull on the stick. (This machine was very nose-heavy with the engine off.) I brought it in to land witha 10 m.p.h. margin, and found I had to hold off about five lengths before it " settled." I had been thinking of theprevious time I had seen it flown, and came in very close over the near, hedge to have ample margin. When I looked back, having come to rest, the hedge was only 50 yardsbehind me. After this first effort, I always brought this machine in as above and had no trouble at all, and had enoughconfidence to put it into any field in which an Avro could pull up. The point I have endeavoured to bring out is that thereare so many pilots who glide at 30 or 40 m.p.h. in excess of the landing speed and then complain that the machine " landsfast." I noticed the " most-talked-of pilot of last summer " while flying at Hendon would come gliding in to land at a verycomfortable speed for a quiet landing, and when about 150 ft. up would do a little dive for about 100 ft., and, in consequence,float half-way across the aerodrome before the machine touched. Why he did it has always been a mystery to me. Now, to deal with airbrakes. Why glide at a speed so muchin excess of the landing speed that an airbrake is necessary ? Lieut. Courtney's remarks on side-slipping as an aid tojudging distance are very sound, but his application of his airbrake when gliding strikes me as being misleading. Brakingis taking off speed. Should he have that excess of speed to take Off ? I do not think the term " airbrake " should be usedwhen speaking of gliding in to land. By all means, swing your tail when practically on the ground, and so use your airbraketo take off at once that 10 m.p.h. you have to lose by holding off, and stop. This is the only time your keel surface is usedas a true " brake." It is obvious that, in side-slipping in to land, you must not lose forward speed, otherwise the machinestalls. Correct side-slipping needs practice on all machines, and to be useful in landing one must be able %o hold the noseat such an angle that on coming out into the normal gliding angle of the machine, no excess of speed has been gathered.I think that many readers will agree with me that the noses of some scouts have to be held amazingly high in a sideslipto obviate this. There is a point which I think Lieut. Courtney forgot tomention, and I feel sure that he will agree with me, and that he does it himself. I refer to maintenance of direction insideslip. When gliding in to land, one selects a spot on the aerodrome for one's landing, and glides towards it at normalgliding speed with, as Lieut. Courtney says, plenty of height. A sideslip becomes necessary and the machine is put into one,but in such a way that, whilst slipping, direction is maintained towards the spot selected. To do this, the nose of themachine must be swung well out to the left or right, other- wise one is liable to sideslip off one's course. It is entirely a matter of opinion, of course, but rather thancome down in the steps depicted on your page 368, I should prefer to arrive at the point A looking along the side of themachine at the spot selected, and then swing the nose gently round, say, to the left, and put the right wing down and side-slip gently at the spot all the way, increasing or decreasing the slip as necessary. This is a very comfortable method, andgives one a good view of the spot all the time, and there is no control wagging or work attached to it. Why the Air Ministry objects to sideslip landings is quitea mystery. I can picture the pilot (rare specimen) who always did what he was told, forced landing a machine full of pas-sengers in a small field arriving over the hedge too high and overshooting in compliance with Regulations for want ofa little sideslip. Lancaster Gate, April 4. E. J. D. 422
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