The Aeroplane Speaks [3]
the less such drift, and the better the Aeroplane's proportion of lift to drift; and, being slow, we shall require a LARGE SURFACE in order to secure a large lift relative to the weight to be carried. We shall also require a LARGE ANGLE OF INCIDENCE relative to the horizontal, in order to secure a proper inclination of the Surface to the direction of motion, for you must remember that, while we shall fly upon an even keel and with the propeller thrust horizontal (which is its most efficient attitude), our flight path, which is our direction of motion, will be sloping upwards, and it will therefore be necessary to fix the Surface to the Aeroplane at a very considerable angle relative to the horizontal Propeller Thrust in order to secure a proper angle to the upwards direction of motion. Apart from that, we shall require a larger Angle of Incidence than in the case of a machine designed purely for speed, and that means a correspondingly LARGE CAMBER.
``On the other 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
``On the other 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