CHAPTER II
A DESCRIPTION OF THE CURTISS BIPLANE
No type of aeroplane is more familiar in America than the Curtiss biplane. By long experimentation, this machine has been developed for practical use; and is now used for military purposes in Russia, Japan, Italy, Germany, France, and the United States. The machine is of the general type known as "biplane," in which there are two sets of wings, or surfaces, one being directly above the other. This type of machine seems to be the most favoured by Americans, for it not only allows of a greater spread of lifting surface for a given width of plane than in the monoplane, or single-wing type, but also it is much stronger than other machines of the same weight, as its design permits of a system of bridge-trussing known as the "Pratt Truss." In the Curtiss machine this feature is especially pronounced, because of the greater safety which rigid planes have when compared with the flexible wings.
The woodwork of these aeroplanes is entirely of selected spruce and ash, all the posts, beams, and ribs being laminated. The propeller is a
## particularly difficult piece of laminated work, being built up of from
twelve to eighteen layers of thinly cut wood, while the upright posts of the central section are made up of ash and spruce, the heavier and more flexible wood forming the core. A feature of strength is to be found in the double trussing which is placed in all of the vital parts of the aeroplane, where the greatest strength is required. All this trussing is made with a cable of galvanised steel wire tested to withstand a pulling strain of nearly half a ton.
Transportation and military use have been especially considered in the construction of the planes. The upper and lower planes are made up of interchangeable panels, which are so joined together that the machine is easily assembled and taken apart and may be transported compactly in two flat boxes which scarcely make one full wagon load, as indicated in an illustration in this book.
The wing-panels are made up with a light and strong wooden framework covered with cloth especially made and treated with a rubber coating for the purpose. The curved ribs are laminated also and the panels held together by a system of trussing which gives them great strength. These panels are covered both top and bottom.
Light and strong bamboo rods extend to the front of the main planes, supporting the elevator or forward horizontal surface, which acts as a rudder to steer upward and downward. Similar bamboo rods at the rear support the vertical rudder and rear elevators and stabilising plane. Front and rear elevators work in conjunction with each other so that as the front of the machine is directed up, the rear of the machine is depressed by the two rear elevators, called "flippers" from their resemblance to these appendages of a seal or a turtle, each of which is controlled by an individual set of cables, so that if one should break or get out of order the other may be used independently. The front or rear elevators are sufficient to maintain the fore and aft balance of the machine in flight, so if anything happens to one the other will enable a safe landing to be made. Some aviators take off the front elevating plane entirely, relying solely upon the two rear ones for horizontal control.
The elevators and the vertical rudder are manipulated by a single steering post at the top of which is the steering wheel. Turning the wheel to the right or left steers the aeroplane to the left or to the right as a boat or an automobile is steered, while pushing the wheel forward directs the machine downward and pulling the wheel causes it to rise, a system of control in accord with the natural impulse of the operator.
To maintain the lateral balance of the aeroplane, there are small movable planes, or "ailerons," attached at the ends of the main framework, midway between the upper and lower planes, at the rear. These ailerons are so arranged that the front edge remains in the same position; while one swings upward, the other swings downward, at the back, thus giving an upward pressure of air on the under side of the one, while the other is depressed by the air which strikes it on top. This movement is controlled by a movable back to the aviator's seat or a frame or yoke which fits around the shoulders of the aviator in such a way that he moves the ailerons to the proper position when he leans to the high side of the aeroplane as it tilts and is thus able automatically to correct its balance.
The motors with which the military and cross-country models are equipped are of the eight-cylinder "V-shaped" type, developing sixty and eighty horse-power. The propeller is attached directly to the motor shaft, thus doing away with any necessity of gearing, which consumes power, increases the risk of breakage, and decreases reliability. The speed of the motor is controlled by a throttle opened and closed by a movement of the left foot.
The seat for the aviator is placed well forward of the main planes, giving him a clear view not only ahead, but also straight downward. On the military model, a passenger-seat is provided immediately beside that of the aviator, and a dual system of control makes it possible for either passenger to operate the machine independently of the other.
[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.
30, Full Set Rear Bamboos, Wired Complete; 31, Full Tail Equipment, consisting of Rear Bamboos, Posts, Tail, Rudder and Flippers.
POSTS
32, Wing Panel, 3/8" x 2 3/4" x 54 1/2"; 33, Wing Panel, 3/8" x 2 3/4" x 60"; 34, Engine Section, 1 1/2" x 2 3/4" x 54 1/2"; 35, Engine Section, 1 1/2" x 2 3/4" x 60”.
DIAGONAL ASH BRACES, FROM FRONT WHEEL TO ENGINE BED
36-37, Diagonal Ash Brace, Tinned, Right & Left; 38-39, Diagonal Ash Brace, Left & Right; 40-41, Diagonal Ash Brace, Tinned & Ironed, Left & Right.
DIAGONAL SPRUCE BRACE, FROM FRONT WHEEL TO WING PANEL
42-43, Diagonal Spruce Brace, Left & Right; 44-45, Diagonal Spruce Brace, Ironed, Left and Right; 46, Skid; 47-48, Engine Bed, not Tinned, Right & Left; 49-50, Engine Bed, Tinned, Right & Left.
ENGINE BED POSTS. BRACES AND TUBING BRACES ABOVE LOWER PLANE
51-52, Engine Bed Post, Front, Right & Left; 53-54, Engine Bed Post, Rear, Right & Left; 55-56, Engine Bed Brace, Front, Lower, Right & Left; 57-58, Engine Bed Brace, Rear, Lower, Right & Left; 59-60, Engine Bed Brace, Rear, Upper, Right & Left; 61-62, Engine Bed to Surface, Rear, Upper, Right & Left; 63, A Brace to Surface, Front, Upper; 64, Cross Tie Brace under Upper Surface; 65-66, Aileron Brace, Upper, Right & Left; 67-68, Aileron Brace, Lower, Right & Left; 69-70, Seat Post, Right & Left; 71-72, Carburetor Brace, Right & Left.
CHASSIS BRACES. FORKS AND TUBING UNDER LOWER PLANE
73, Cross Tie Rod, Lower, Under Lower Surface; 74, Long Span Brace, Rear Wheel to Rear Wheel; 75-76, Skid Fork, Right & Left; 77-79, Vertical Fork, Front & Rear, Right & Left; 80-81, Leader Fork, Rear, Right & Left; 82-83, M Brace, Right & Left; 84, Y Brace; 85, V Brace, Front, Skid to Diagonal; 86, V Brace Spreader and Bolt, Front; 87, Brace, Center, Skid to Diagonal; 88, V Brace, Center, Skid to Double Seat; 89, V Brace, Rear, Skid to Diagonal; 90-91, Combination Foot Throttle & Brake, Single & Dual.
92, Brake Shoe; 93, Brake Shoe Hinge; 94, Brake Shoe Lug; 95, Brake Shoe Spring; 96, Steering Column, Single; 97, Steering Wheel, Spider, Fork and Bolt; 98, Steering Wheel, Spider, Fork & Column, Assembled & Wired; 99, Steering Column, Dual; 100, Steering Wheel, Spider, Fork & Bolt, Dual; 101, Steering Wheel, Spider, Fork, Bolt & Column, Assembled & Wired, Dual; 102, Foot Rest; 103, Push Rod, Metal, with Swivel End, Dual.
104, Seat, Single; 105, Seat with Fittings for Shoulder Yoke, Single; 106, Seat, Complete with Shoulder Yoke, Whiffle-tree Case and Whiffle-tree, Single; 107, Seat, Double; 108, Seat with Fittings for Shoulder Yoke, Double; 109, Seat, Complete with Shoulder Yoke, Whiffle-tree Cases and Whiffletree, Double; 110, Seat, Passenger; 111, Seat Supporting Brace, Passenger; 112, Rear Beam Reinforcing Plates.
113, Cable, 1/32"; 114, Cable, 1/16"; 115, Cable, 3/32"; 116, Cable Casing; 117, Short Circuiting Switch; 118, Snaps, 3"; 119, Main Plane Socket; 120, Main Plane Socket, Wired Complete; 121, Main Plane Plate; 122, Aileron End Wire Connection; 123–124, Aileron Cross Wire Clamp & Clip; 125, Aileron L; 126, Aileron Post Lug; 127, Aileron Brace Wire Connection; 128, Aileron Corner Wire Guide; 129, Aileron Corner Pulley, 3"; 129, Aileron Pulley, 3".
131, Bamboo Curved Rudder Wire Guide; 132, Skid Safety Wire Connection; 133, Copper Sleeve; 134, Tin Thimbles; 135, Diagonal Ash Brace Iron; 136, Diagonal Spruce Brace Iron; 137-138, Engine Bed Post Plate & Wire Connection; 139, Engine Bed Bolt; 140, Fin L Irons; 141, Fin Hinge; 142-143, Front Control Bracket & L Iron; 144, Hydro Front Control, Brace Lug; 145-146, Hydro Front Control Supporting Post, L & R; 147-148, Hydro Front Control, Supporting Post Lug, Left & Right; 149-150, Hydro Front Control Push Rod & Bracket; 151-152, Hydro Front Control Post & Diagonal Brace; 153, Hydro Splash Boards.
154-155, Flipper Post & Wedge; 156, Flipper Hinge; 157, Flipper Wire Guide, Straight; 158, Rudder Swivel; 159, Curved Corner Wire Guide; 160, Rudder Lever Clip; 161, Rudder Wire Connection; 162, Rudder Wire Guide, Curved; 163-164, Terminals, Short & Long; 165, Turnbuckles; 166, Wheel, 20" x 4", Complete; 167, Wheel, 20" x 4", Less Tire; 168-169, Wheel, 20" x 2 1/2", Complete & Less Tire; 170, Inner Tube, 20" x 4"; 171, Casing, 20" x 4"; 172, Tire, 20" x 2 1/2"; 173, Axle.
174, Gas Tank, to Attach to Engine Bed; 175, Bamboo Brace Clip; 176, Flexible Gasoline Pipe; 177, Radiator; 178, Radiator Brace; 179-180, Propeller, Bolt & Tinned; 181, Propeller, Complete Not Tinned; 182, Cap Screw, Nickel Steel, 5/16-24 x 1 3/4; 183, Cap Screw, Nickel Steel, 5/16-24 x 2 1/4; 184-185, Spring Washer, 1/4 x 3/16 & 5/16 x 3/8; 186, Wing Pontoon, Complete; 187, Pontoon Paddles; 188, Hydro Drain Plug; 189, Hydro Braces; 190-191, Hydro Spacing Tube & Bolt, Short & Long.
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