"I think, then," said Efficiency, "I should prefer to have that wash-out,[7] and my friend the Designer is so clever at producing strength of construction for light weight, I'm pretty sure he won't mind paying the price in Lift. And now let me see if I can sketch the completed Aeroplane."
"Well, I hope that's all as it should be," she concluded, "for to-morrow the Great Test in the air is due."
[Footnote 4: Morane parasol: A type of Morane monoplane in which the lifting surfaces are raised above the pilot in order to afford him a good view of the earth.]
[Footnote 5: Skin friction is that part of the drift due to the friction of the air with roughness upon the surface of the aeroplane.]
[Footnote 6: Banking: When an aeroplane is turned to the left or the right the centrifugal force of its momentum causes it to skid sideways and outwards away from the centre of the turn. To minimize such action the pilot banks, _i.e._, tilts, the aeroplane sideways in order to oppose the underside of the planes to the air. The aeroplane will not then skid outwards beyond the slight skid necessary to secure a sufficient pressure of air to balance the centrifugal force.]
[Footnote 7: An explanation of the way in which the wash-out is combined with a wash-in to offset propeller torque will be found on p. 82.]
It is five o'clock of a fine calm morning, when the Aeroplane is wheeled out of its shed on to the greensward of the Military Aerodrome. There is every promise of a good flying day, and, although the sun has not yet risen, it is light enough to discern the motionless layer of fleecy clouds some five thousand feet high, and far, far above that a few filmy mottled streaks of vapour. Just the kind of morning beloved of pilots.
A brand new, rakish, up-to-date machine it is, of highly polished, beautifully finished wood, fabric as tight as a drum, polished metal, and every part so perfectly "stream-lined" to minimize drift, which is the resistance of the air to the passage of the machine, that to the veriest tyro the remark of the Pilot is obviously justified.
"Clean looking 'bus, looks almost alive and impatient to be off. Ought to have a turn for speed with those lines."
"Yes," replies the Flight-Commander, "it's the latest of its type and looks a beauty. Give it a good test. A special report is required on this machine."