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290 AIRCRAFT ENGINEERING November, 1935 Seaplane Design for Students—M. Mignet on Simplified Control for Aeroplanes Seaplan e Floa t and Hull Design . By Marcus drawings. Finally, a short section deals with Handley Page slot, because it may take live Langley. (Pitman. 7s. 6d.) flying the machine. miles an hour off the speed and because it does useful work only a t what he calls a n exaggerated At the present time some four hundred Poux This book, which is intended mainly for angle of incidence, which is not satisfactory at du Ciel have been made in France by all sorts th e use of students, deals with water pro ground level. Presumably he will no t have the of people in their own homes, an d of these more perties of floats and hulls. Two chapters are automati c slot on the ground of mechanical tha n fifty have made good flights as distinct devoted to the basic principles of flotation complication. What he actually adopts is, in from mere hops. Quite recently one fatal units, and the methods of finding the centre effect, a middle slot. He brings up a second accident was reported in France, but apart of buoyancy and metacentric heights are wing behind and a little below th e first, the idea from this, there have only been a few quite clearly shown. These chapters are followed being that the great suction over the upper minor mishaps. M. Mignet has himself made b y chapters on tank testing, float and flying- forward part of the rear wing will be very tours of 1,000 to 2,000 miles in France this year boa t hull design, and a final chapter on design effective in preventing the break-away of the an d has crossed the Channel and made demon data . air from the rear par t of th e upper surface of the strations in this country. The "Flyin g Flea" The book can be thoroughly recommended front wing. He further argues that this is undoubtedly a force to be reckoned with, not a s a sound and interesting treatment of the arrangement is naturally stable, so tha t no tail- so much, perhaps, in connection with high-speed elementary principles of float and hull design, plane in the ordinary sense is required, and that commercial or military aviation, bu t as a means and should be invaluable to students. the stability is not very sensitive to centre of of inducing the ordinary man to take to flying A note on the cover of the book states that gravity position. a s a sport; its repercussions on the general th e point of view has been taken of regarding design and, in particular, the controls of aero Wha t of aerodynamic efficiency? M. Mignet th e Hying boat as a ship with wings rather planes, may also be considerable and far- frankly has not bothered over much about this tha n an aeroplane with a bulky underslung reaching. and thinks he is fortunate in that the arrange hull. The great difficulty in flying-boat design is in balancing the conflicting requirements men t he ha s adopte d from the primary consider To M. Mignet the control of the ordinary in the air and on the water, and the ideal ations of safety and simplicity gives, in fact, a aeroplane is all wrong—or nearly all wrong. It fairly high efficiency. "I am bored with aspect treatmen t of the subject should not unduly is mostly not instinctive; it is too complicated; ratio! " he says, in deciding to adopt a small favour one requirement rather than the other. and it suffers, as regards longitudinal control a t aspect ratio. Even in a book for students, a short discussion least, from delayed action. of the air forces acting on a seaplane should There are only very scanty dat a on which to He objects to turning the rudder bar in one be included. The problem of designing a judge whether or not the "Flyin g Flea " loses direction in order to turn the aeroplane in the heavily-loaded flying-boat with good take-off in performance, owing to its special semi- other ; with the bicycle or motor car one natur qualities is almost as much aerodynamic as tande m wing arrangement . Some French wind- ally turns the handle bars or steering wheel in hydrodynamic. tunnel experiments, a description of which is th e direction one wishes to go. Further, in There are a few minor faults. The state given in Publications Scientifiques et Techniques, th e ordinary aeroplane, to turn properly one ments on page 40 about frictional and wave- Vol. 53, cover the Pou wing arrangement, but mus t not only operate the rudder, but also the making resistance, although true for ships, were made for the case of infinite aspect ratio. ailerons in a skilfully co-ordinated manner. would be very misleading if applied to floats Although they may be taken to give some indi This is too complicated. What M. Mignet or hulls. A little amplification would be cation as to what happens at top speed and want s is turning without learning. Then, too, valuable here. The book is generally very climb, they do not afford any help as regards he has another objection to the double lateral clear, but the explanation of Froude's law on behaviour a t the stall. Such indication as these control system; it involves the use of the feet page 41 could be considerably improved. On experiments give is that both top speed and which, he says, are "th e bucolic things from page 60 the statement is made that water climb may be little, if any, different from which one must not demand any skilful or rudders are usually fitted on medium and large- normal. The results vary with the relative accurate movement." Either the rudder or sized twin float seaplanes and that springs angle between the planes. They show, how th e ailerons must go then ; which is it to be? are usually fitted in the rudder control systems. ever, that it is possible, with a wing arrange Both have drawbacks, bu t he considers those of I n fact, in this country water rudders are men t very similar to tha t of M. Mignet, to obtain th e rudder to be the less dangerous. The fitted to all twin float seaplanes and springs a favourable interference effect between the ailerons, therefore, go, bu t the rudder has to are never fitted to the control systems. two planes, resulting in a higher maximum lift- be operated by hand. drag ratio than in the normal biplane. This H. M. G. The objection as regards delayed action is maximum is, however, more sensitive t o forward concerned with the longitudinal control. The speed than the normal arrangement. Th e Flying Flea (Le Pou du Ciel). By incidence of th e wings, and with it the lift, can Henri Mignet. (Sampson Low. 7s. 6d.) On the question of lateral control M. Mignet only be altered indirectly by altering the (An English Translation from the French, by admit s that the absence of the aileron control elevator angle, which alters the tail lift, which th e Air League of the British Empire.) leads to a slight delay in the response of the rotate s the whole aeroplane. A bird can alter machine which is rather akin to the delay in th e lift of its wings directly by rotating and This is an exciting book. M. Mignet is th e fore and aft control of an aeroplane. This altering the relative disposition of parts of its nothing if not enthusiastic, and his enthusiasm delay arises because the lift is the effective wings. M. Mignet accordingly decides to alter is infectious, even when one is not altogether force producing a turn, which can hardly begin th e lift directly by rotation of the wing, which convinced of the force of his argument. It is therefore until the machine has banked by he connects through a cable with the control th e book of a man "wh o loves aviation as he virtue of th e application of th e rudder producing stick. Objecting to an y form of control which loves his children, as he loves his wife, with all a sideslip which raises the forward wing-tip. involves pushing, he pivots the wing so that his heart and soul." An aeroplane pilot flying the "Flea " for the th e hinge is always ahead of the centre of M. Mignet describes first the difficulties he first time will be rather disconcerted by this pressure. What he has in mind is a control me t with as a man-in-the-street in flying a con delay for a little, but will soon become accus which will exert a pull roughly proportional to ventional aeroplane on the few occasions when tomed to it. th e lift. But in his first experiments he used h e made the attempt , and how it set him think a wing section with considerable centre of pres I t is claimed tha t anyone who can nail u p a ing as to how the control of an aeroplane could sure travel and found that after easing off the packing case can make a "Flyin g Flea." Even b e simplified. He then sets forth in great detail stick to gather speed the control column pulled so the amateur must almost inevitably come th e reasoning underlying the design of the harder and harder against him, owing to the u p against difficulties. He is promised willing "Flyin g Flea." This is a fascinating section rushing back of the centre of pressure on reduc help in this direction, however, by the Air of th e book to anyon e interested in th e dynamics tion of the incidence. This disconcerting League of the British Empire, whose Secretary- an d aerodynamics of the aeroplane. A little behaviour is cured by reflexing the trailing General, Air Commodore Chamier, contributes too much eloquence, perhaps: but then that edge of the wing to give nearly constant centre a Preface and an "Envoi " to the book, and is M. Mignet. The section takes up nearly half of pressure. invites all who are really interested in the th e book and is followed by almost another half "Flyin g Flea " to get in touch with the League. in which minute instructions for making the The next danger to be guarded against is tha t Flying Flea are given, together with detail of the stall. M. Mignet discards the fixed H . B. I.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Nov 1, 1935
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