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Aviation History
1942
1942 - 2072.PDF
374 FLIGHT OCTOBER IST, 1942 Correspondence The Editor does not hold himself responsible for the views expressed by correspondents. The names and addresses 9f the writers, not necessarily for publication, must in all cases accompany letters. FLEET FIGHTER PERFORMANCE Fiats' Advantage Over Fulmar I S his letter in Flight ol September 17th, Mr. G. S. Henderson attacks my suggestion that manoeuvrability is worth extra armament, but does he offer any alternative explanation in the particular case mentioned ? If the reason for Fiats shoot ing down Fulmars is not superior manoeuvrability then perhaps someone would suggest a different one. Mr. Henderson appears to miss the whole point by his repeated references to armament and structural qualities. He does not appreciate the fact that a pilot may have a lot of guns and not get a chance ol using them. A burst on the target is worth any amount in the air Also, the answer to the question does not lie in the Battle of Britain. There was no one aircraft during that period which had definitely better manoeuvrability than any other. Strip ping an aircraft of a few guns does not give it an advantage such as the Fiat has over the Fulmar. How great that advantage is Mr J Henderson could under stand if he had ever seen Gloster Gladiators "shooting the works." J. H. GYROSCOPIC CONTROL Meredith and Cooke's Automatic Pilot I PRESUME that Mr. J. Vivian Holman, in his letter to Flight of August 27th relating to "Gyroscopic Control," infers that Messrs. Meredith and Cooke are somewhat indebted to gyroscopes and, in particular, to the pioneer work of the Sperry Company in 1909 on gyroscopic, stabilisation of aircraft. The possibility that they may have acquired a gyroscope through the medium of a toy-shop or Christinas tree must not be ruled out! However, I do appreciate Mr. Holman's verifying Messrs. Meredith and Cooke's definite contribution to scientific pro gress relating to aircraft control, and accept his assurances that their invention in no way resembles the principle em ployed in the Sperry Automatic Pilot. It is also gratifying that Messrs. Meredith and Cooke's invention has received public, as well as Mr. Holman's, recognition. I would also add to the interesting information given by Mr. Holman that Messrs. Meredith and Cooke's Automatic Pilot was tested and proved successful in 1925, whereas the use of the Sperry Automatic Pilot, fitted to the Winnie Mae was first made public at the conclusion of the late Mr. Wiley Post's historic flight in 1933. A. J. PAYNE. ASTRO-NAVIGATION Siderograph and G.M.T. Watch COL. A. L MIEVILLE'S letter in your issue of Sep tember 17th prompts me to ask if he has ever used the Longinea "Siderograph." This is a very beautifully made instrument, produced, I think, in the U.S.A., though why it was ever given this name 1 do not know, for it produces no graph at all. What it does do, however, is to show one, by means of hands on a dial, the exact value at any instant of G.H.A. Aries. I have used it, but for reasons which I will give later I do not like it. ll is, of course, rated to siderial time; it can be stopped and started at any time; it is heated to a constant temperature, and by means of a press button one can record the average G.H.A. Aries during the taking of a sight. No reference to an almanac is needed in the case of stars, but the practical navigator, having taken his sight, worked it out, and finally plotted it, must still refer to the much-despised G.M.T. rated watch. For it is no good plotting any position line of any sort unless the time in G.M.T. is put against it. So one might just as well start off in the first place by using the G.M.T. watch. Grandpapa may not have used an Astrograph, but he could choose from more than two (or three) stars, and he did at least know what an Hour Angle was. A. C. LORAINE. FUEL CONSERVATION American Regenerative Scheme YOUR correspondent, A. N. I., has drawn the attention of readers Flight, September 10th) to the advantages of electric regeneration over the conventional power-dissipating schemes of testing engines, such as calibrated propellers, water- brakes, electric brakes and similar devices. A satisfactory scheme of regenerative testing should satisfy the following con ditions:— (1) It should accommodate a large range of engine sizes. (2) It should be capable of driving the engine as well as absorbing power from it and must be capable of operating in either direction of rotation. (3) It should be capable of transforming the rapidly fluc tuating power of the engine into readily utilisable electric power. The electric power generated is most conveniently pumped into the supply mains; this means pumping electric power from a varying-speed source into a constant frequency system. A simple method oi accomplishing this has been developed in the United States, as follows: The scheme consists of a conventional synchronous machine, connected directly to the mains and ccupled to the engine through a hydraulic clutch. With the clutch disengaged, the synchronous machine is brought up to speed and synchronised in the usual manner The clutch is now engaged, whereupon the synchronous machine, acting as a motor, starts the engine up. The engine is then brought up to a speed higher than the synchronous speed of the machine which, then acting as a generator, is loaded back on the power system—the machine running at synchronous speed owing to the slipping of the hydraulic coupling. In order to load the engine below synchronous speed, the rotor of the "synchronous machine may be locked by means of a brake; the engine power will now be dissipated in the hydraulic coupling. M. C. PHILIP. CONTROL OF THE RUDDER Why Not Rotate the Stick ? • IS there any further justification for the continued existence of the rudder-bar on modern aircraft? It has always seemed to me to be somewhat Heath-Robinsonish and a sur vival of the days when not only did it take a considerable effort on the part of the pilot to work the rudder, but the problem of combining three separate movements in one control column proved too much for the technicians of those early days. It should, however, be quite practicable to overcome these difficulties now, especially with the various aerodynamical aids to rudder movement with which most aircraft are now adays fitted. The idea of turning the control column itself to actuate the rudder, in addition to its normal fore-and-aft and lateral move ments, would seem to be particularly adaptable to the light cabin aircraft that is fitted with a wheel, or two segments of a wheel, for the aileron control. The "people's airplane" of the future, should it ever materialise, and should it not take the form of some kind of helicopter or autogiro, will, I think, almost certainly be fitted with this type of control. The ordinary or " moving stick " type of control column could be branched at the top, thus forming a " Y " shape, or it could be triangular, or fitted with a cross member to form a " T." And while we are about it we may as well arrange matters so that the rudder control functions in what I might call a "natural" manner. That is to say, if, for example, with the new type of control I advocate, we wish to turn to the right, we will turn our wheel to the right and at the same time draw the right-hand side of the wheel towards us. It seems to me that such a movement would become " instinctive " to a learner in much less time than the present orthodox rudder-jjedal method. Also, it would make for simplicity, the cockpit in the case of civil aeroplanes would look a lot neater, and in the case of service machines there would be a useful saving of space. I am not a pilot, and it would be edifying to hear the opinions of experts on the subject. A. VV. FELTON.
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