The Aeroplane Speaks | Page 6

hand, if we are thinking merely of Speed, then a SMALL SURFACE, just enough to lift the weight off the ground, will be best, also a SMALL ANGLE to cut the Drift down and that, of course, means a relatively SMALL CAMBER.
``So you see the essentials for CLIMB or quick ascent and for SPEED are diametrically opposed. Now which is it to be?''
``Nothing but perfection for me,'' said Efficiency. ``What I want is Maximum Climb and Maximum Speed for the Power the Engine produces.''
And each Principle fully agreed with her beautiful sentiments, but work together they would not.
The Aspect Ratio wanted infinite Span, and hang the Chord.
The Angle of Incidence would have two Angles and two Cambers in one, which was manifestly absurd; the Surface insisted upon no thickness whatever, and would not hear of such things as Spars and Ribs; and the Thrust objected to anything at all likely to produce Drift, and very nearly wiped the whole thing off the Blackboard.
There was, indeed, the makings of a very pretty quarrel when the Letter arrived. It was about a mile long, and began to talk at once.
``I'm from the Inventor,'' he said, and hope rose in the heart of each heated Principle. ``It's really absurdly simple. All the Pilot has to do is to touch a button, and at his will, VARY the area of the Surface, the Angle of Incidence, and the Camber! And there you are--Maximum Climb or Maximum Speed as required! How does that suit you?''
``That suits us very well,'' said the Surface, ``but, excuse me asking, how is it done without apparatus increasing the Drift and the Weight out of all reason? You won't mind showing us your Calculations, Working Drawings, Stress Diagrams, etc., will you?''
Said the Letter with dignity, ``I come from an Inventor so brilliantly clever as to be far above the unimportant matters you mention. He is no common working man, sir! He leaves such things to Mechanics. The point is, you press a button and----''
``Look here,'' said a Strut, rather pointedly, ``where do you think you are going, anyway?''
``Well,'' from the Letter, ``as a matter of fact, I'm not addressed yet, but, of course, there's no doubt I shall reach the very highest quarters and absolutely revolutionize Flight when I get there.''
Said the Chalk, ``I'll address you, if that's all you want; now drift along quickly!'' And off went the Letter to The Technical Editor, ``Daily Mauler,'' London.
And a League was formed, and there were Directors with Fees, and several out-of-service Tin Hats, and the Man-who- takes-the-credit, and a fine fat Guinea-pig, and all the rest of them. And the Inventor paid his Tailor and had a Hair- Cut, and is now a recognized Press Expert--but he is still waiting for those Mechanics!
``I'm afraid,'' said the Slide-rule, who had been busy making those lightning-like automatic calculations for which he is so famous, ``it's quite impossible to fully satisfy all of you, and it is perfectly plain to me that we shall have to effect a Compromise and sacrifice some of the Lift for Speed.''
Thud! What was that?
Efficiency had fainted dead away! The last blow had been too much for her. And the Principles gathered mournfully round, but with the aid of the Propeller Slip[[1]] and a friendly lift from the Surface she was at length revived and regained a more normal aspect.
[[1]] Propeller Slip: As the propeller screws through the air, the latter to a certain extent gives back to the thrust of the propellor blades, just as the shingle on the beach slips back as you ascend it. Such ``give-back'' is known as ``slip,'' and anyone behind the propellor will feel the slip as a strong draught of air.
Said the Stagger with a raffish air, ``My dear young lady, I assure you that from the experiences of a varied career, I have learned that perfection is impossible, and I am sure the Designer will be quite satisfied if you become the Most Efficient Compromise.''
``Well, that sounds so common sense,'' sighed Efficiency, ``I suppose it must be true, and if the Designer is satisfied, that's all I really care about. Now do let's get on with the job.''
So the Chalk drew a nice long slim body to hold the Engine and the tanks, etc., with room for the Pilot's and Passenger's seats, and placed it exactly in the middle of the Biplane. And he was careful to make its position such that the Centre of Gravity was a little in advance of the Centre of Lift, so that when the Engine was not running and there was consequently no Thrust, the Aeroplane should be ``nose- heavy'' just to the right degree, and so take up a natural glide to Earth--and this was to help the Pilot and relieve him of work