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Aviation History
1921
1921 - 0325.PDF
MAY 12, 1921 the ignition control handles for advance and retard, therebeing push and pull rods to all motors. The cabin itself is of the convertible type, having attach-ments for twenty-six seats, berths and mail compartments. When used as a day machine all twenty-six seats are installed,and when used as a sleeper there are six seats and berths. These latter are of the disappearing type, and can be extendedwithin a few minutes. The machine carries a complete lighting system for dashboard, cabin lights, wing and taillights, and a large search light and a heating system. At the rear end of the cabin, and on the right side of the machineis located the main entrance door. Directly across from this door on the right side of the machine is a complete bathroom,the first ever installed upon any aeroplane. There is a shower bath, washstand and towels, mirror, drinking water andlavatory. A large overhead water tank of both hot and cold water is used for the shower, while the tank containingice water is used for drinking purposes. The whole com- partment is white enamelled, with white rubber draw-curtainson the windows and entrance, while the floor is tiled. Behind the bathroom is a mail chute and baggage room.This is reached through a door which also allows entrance for inspection of the rear end of the body. An inspection walkruns from this door to the stern. Constructionally the body is composed of spruce longeronsthe entire length. These are pin jointed at the front allowing a complete removal of the whole front engine with its controland attachments, radiators, etc. The longerons are again Square spruce struts carry the compression. The enginesection panels have internal wires in both directions, while all other panels are of -j\-in. cable doubled for drift loadsand single for trueing. The lift cables are double and the landing cables single. Large balanced ailerons are used topand bottom, and are connected by streamline tubing instead of wires, thereby eliminating continual care and attention.Celluloid inspection doors are placed at all aileron control cable pulleys on the lower wings. Spruce struts of streamlinesection are used externally. All cable strut fittings are of the internal type, concentrating all loads on the neutralaxis of the spar. As in the body and other parts, these fittings are chrome vanadium steel, heat-treated and zinc-plated,giving an enormous strength for their weight. On each end of the wings and under the outer struts are ash wingskids which are sprung by rubber shock-absorber cord covered by an all-metal streamline case. To the skid is hung a tubewhich telescopes into another tube mounted on a ball-and- socket joint to the rear spar. The front end of the skid ishinged to a fitting on the spar, while a diagonal tubing rakes the side action. The wings are linen covered and coated withclear varnish. The factor of safety is six throughout. Empenage.—This is of biplane type, having balancedelevators and three rudders, the outer two of which are also balanced. In front of the rudders are vertical fins. Theconstruction is similar to the wings. To relieve the weight of the elevators upon the pilot controls these are equalised byrubber absorbers attached to a lever upon the rocker shaft SLEEPER DAY PASSENGER THE LAWSON MIDNIGHT AIRLINER, L-4 : Diagrams showing the cabin lay-out for passenger or mall work. jointed immediately behind the rear end of the cabin, thusallowing the whole tail to be removed and a new one installed, thus facilitating little wastage of time in making repairs.The complete cabin section is composed of laminated spruce bulk heads with the grain of the wood running accordingto the direction of the loads, thus allowing greatest strength for least weight. The cabin is completely covered withveneer with light stiffening pieces. The windows are of safety glass while those in the pilot cabin are of celluloiddue to the convex curves of this section. The rear end of the fuselage is standard construction, having spruce struts andcable bracing, and is linen covered. At the extreme rear end and around the tail plane and tailskid section the body is againcovered with veneer to stiffen this portion and prevent twisting.The interior of the cabin is finished in mahogany and cream, and is covered with a heavy green brussels carpet,while the outside is enamelled green throughout. When used as a mail machine, mail compartments areinstalled in place of all but six of the usual passenger seats, thus allowing passenger carrying as well as mail and cargo.This is the only change found necessary for this conversion. Wing Structure.—There are five sections in the upper andfour on the lower, each hanging to the other and to the body. They are of the usual construction,consisting of two spars ofI-section spruce, and laminated in two pieces with hardwood strips top and bottom. The ribs are of the girder type, andare of spruce material throughout. All ribs are of standard section, there being no special ribs in the whole structure. in the rear end of the body. The elevators are also connectedtogether by tubes like in the aileron systerrr. The vertical fins are provided with adjustable screws on the top of thefront ends, thus allowing the top tail plane to be set to any required angle.A trimming plane is installed just ahead of the tail plane, which can be adjusted in flight from the pilot cabin by awheel before mentioned. This is worked by a screw and trunnion, so the setting is at all time positively locked inposition. All vertical surfaces are enamelled green, while the horizontal surfaces are finished similar to the wings.Landing Gear.—Four large Palmer wheels of 1,250 mm. by 250 mm., or 49 by 10, and streamline cased, compose the mainlanding gear. These are placed upon short axles of high grade steel tubing, which in turn are slid over cast steel elbowson the inner ends. This elbow is fixed to heavy compression tubes running up to the body, and are pinned there. TheVee is of triangular shape made of laminated spruce with the grain of the wood arranged as in the body bulkheads. Oneach side of the apex of the Vee are the rubber absorbers placed in line with the Vee. The nose and tail of the shock-absorber brackets are cased with streamline fairings. The tail skid is rubber absorber sprung, and is universally mountedto the body by four steel tubes. In case of failure of any part of this member the machine will fall upon a streamlinebumper secured permanently to the sternpost. Nacelles.—On each side of the body and between the topand bottom wings are placed the nacelles. These are of spruce longerons, laminated bulkheads and struts, braced by 325
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