Among the other accessories specified in the cockpit for the above machines are a Pyrene fire extinguisher; a 2-gallon water breaker; a speaking tube for communication between the pilot and observer (1" to 1 1/8"); a flashlight signal for speaking tube; and a tool kit. The weight of the tool kit shall not exceed 11 lbs.
Fig. 16. Cock-pit of a "London and Provincial" Biplane. Control Lever in Foreground and Instrument Board Under Cowl. Courtesy of "Flight."
General Proportions of the Fuselage. The total length of the fuselage depends upon the type of power plant, upon the span or chord of the wings, and upon the arrangement of the tail surfaces. The rear end of the fuselage should be far enough away from the wings to insure that the rear surfaces are not unduly affected by the "down-wash" or the "wake-stream" of the wings. A very short fuselage gives a short lever arm to the control surfaces, hence these surfaces must be very large with a short body. With the stabilizer surface close to the wings, the "damping" effect is slight, that is, the surface does not effectively kill or "damp down" oscillations. Large tail surfaces are heavy, difficult to brace, and cause a very considerable amount of head resistance. The extra weight of a long fuselage is generally offset by the increased weight caused by the large tail area of the short body type.
When machines are crated and shipped at frequent intervals, a very long fuselage is objectionable unless it is built in two sections. It also requires much storage space and a very long hangar. Machines for private use must often be sacrificed from the efficiency standpoint in order to keep the dimensions within reasonable limits. An aeroplane requiring an enormous hangar has certainly no attraction for the average man. Every effort must be made to condense the overall dimensions or to arrange the extremities so that they can be easily dismounted. Exhibition flyers require specially portable machines since they ship them nearly every day, and the expense of handling a long awkward fuselage may alone determine the choice of a plane. It is usually best to divide the body at a point just to the rear of the pilot's seat, although many flyers look upon a two-part body with disfavor unless they can be shown that the joint connections are as strong as the rest of the fuselage.
Fig. 19. Fuselage Dimension Chart for Two Place Aeroplane Fuselage. Upper Diagram Is the Water Cooled Type and the Lower Figure Applies to a Machine with a Rotating Air Cooled Motor. See Table of Dimensions on Page 248.
As a guide in the choice of fuselage proportions, a set of diagrams and a table are attached which gives the general overall dimensions of several prominent makes of machines. The letters in the diagram refer to the letters heading the columns in the tables so that the general dimensions of any part can be readily determined. I do not claim that these dimensions should be followed religiously in every case, but they show what has been done in the past and will at least suggest the limits within which a new machine can be built.
Fig. 20. Fuselage Dimension Diagrams Giving the Principal Dimensions of Speed Scout Machines. Upper Figure Shows Typical Scout with Water Cooled Motor (Curtiss), While Lower Diagram Shows an Arrangement Common with Rotary Air Cooled Motors (Nieuport)
Fig. 19 gives the outline and dimension letters for two-place machines of what is known as the "Reconnaissance Type." Both water-cooled and air-cooled motor equipments are shown, the top machine being of the water-cooled type while the lower figure shows a typical two-place machine with a rotary air-cooled motor. Underneath this side elevation is a front view of the fuselage, and a section taken through the point of greatest depth. As shown, the fuselage is of square cross-section, but the dimension B applies equally to the diameter of a circular cross-section. Dimension C gives the height of the curved upper deck, or "turtle deck" of the fuselage. Dimension D shows the extreme length extending in front of the leading edge of the lower wing, and T shows the length of the rear portion back of the leading edge of the lower wing, the leading edge being taken as a base of measurement. The location of the deepest section, measured from the extreme front of the fuselage, is given by E, the depth at this point being indicated by B. The extreme width is shown by I. In the machine shown, side radiators are used, the blunt front end dimensioned by G and K being the dimension of the front engine plate. When front radiators are used, the dimensions G and K also apply to the size of the radiator. The amount of advance, or the distance of the chassis wheel center from the leading edge is given by S, and the distance of the wheel center below the leading edge is given by R. V is the length of the engine projecting above the fuselage top. The passenger or observer is indicated by 1 and the pilot by 2. The top plane is 3 and the bottom plane 4. The engine is located by 5, and the top fuselage-rail, or "longeron," by 7. Turtle deck is 6.
* Round monocoque body, dimensions (B) and (F) measured from outer diameter or top of circle
Fig. 20 gives the diagrams of speed scout machines, both of the air-cooled and water-cooled types. These are the small, fast, single seat machines so much used in the European war for repelling air attacks and for guarding the larger and slower bombing and observation machines. The upper drawing shows a Curtiss Speed Scout equipped with a "V" type water-cooled motor and a circular front radiator. While the front of the body is circular, it gradually fades out into a square cross-section at the rear. The lower machine is a Nieuport speed scout equipped with a rotating cylinder air-cooled motor. In this scout, the diameter of the motor cowl is given by dimension K. Body is of square cross-section. It will also be noted that the chord of the lower plane is less than that of the upper plane and that the deep body almost entirely fills the gap between the two wings.