[Illustration: DIAGRAM OF CURTISS AEROPLANE, SIDE VIEW] 1. Motor; 2. Radiator; 3. Fuel Tank; 4. Upper Main Plane; 5. Lower Main Plane; 6. Aileron; 7. Vertical Rudder; 8. Tail Surface; 9. Horizontal Rudder, or Rear Elevator; 10. Front Elevator; 11. Vertical Fin; 12. Steering Wheel; 13. Propeller; 14. Foot Throttle Lever; 15. Hand Throttle Lever; 16. Foot Brake. [Illustration: DIAGRAM OF CURTISS MOTOR, SIDE AND FRONT VIEWS] 1. Cylinder; 2. Engine Bed; 3. Fuel Tank: 4. Oil Pan; 5. Radiator; 6. Propeller; 7. Crank Case; 8. Carbureter; 9. Gasoline Pipe; 10. Air Intake; 11. Auxiliary Air-pipe; 12. Drain Cock; 13. Water Cooling System; 14. Gas Intake Pipe; 15. Rocker Arm; 16. Spring on Intake Valve; 17. Spring on Exhaust Valve; 18. Exhaust Port; 19. Rocker Arm Post; 20. Push Rod. The aeroplane is mounted upon a three-wheeled chassis with one skid extending from front to rear, the whole landing gear being built strong and rigid to withstand the shock of landing, the most dangerous part of flying. Elaborate tests are made of the different parts of the machine; the panels forming the surfaces are tested by loading them with gravel until they break and weighing the amount of gravel heaped upon them before they give way. These tests have shown a factor of safety in excess of any strain that could be put on the machine in the air. The strain on the various wires and cables is also measured, with a special instrument made for that purpose, as seen in an illustration. Every conceivable test has been tried which could give information that would lead to any improvement in strength to withstand strains, in addition to the complete knowledge that has come from actual tests under all conditions in the air, and on the ground itself, by expert flyers who have done almost everything that it is possible to do with the machine as far as trying to find its weak point is concerned. Dives almost straight down with abrupt turns at the end of the drop put many times the ordinary strain on every part. Rough landings also show up any lack of strength or fault in the design of the running gear or frame of the machine, especially since this machine is not provided with any springs or other device for taking up the shock of a bad landing. CURTISS AEROPLANE PARTS–A COMPLETE LIST[11] 1, Engine Section Panel; 2, Wing Panel; 3, Wing Panel, Sparred Beam; 4-5, Aileron, Right & Left; 6, Tail; 7-8, Flipper, Right and Left; 9, Rudder; 10, Front Control, Elevator only; 11, Hydro Front Control, Elevator only; 12-13, Fin, Top & Bottom; 14-15, Non Skid Surface, Headless & Large. BAMBOOS 16-17, Front, Upper, Right & Left; 18-19, Front, Lower, Right & Left; 20, Front Cross Tie, Headless; 21-22, Front Bamboo Brace, Right & Left; 23-24, Rear, Upper, Right & Left; 25-26, Rear, Lower, Right & Left; 27, Push Rod Bamboo, 45"; 28-29, Bamboo Post, Short & Long.