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Aviation History
1961
1961 - 0758.PDF
768 FLIGHT, 1 June 1961 C.1100 A Radio-controlled Scale Model By Sqn Ldr J. Crampton, DFC, AFC, RAF (Ret) THOUGH "Flight" ventures only seldom into the model-aircraft field,we think that this article wcl' merits the space accorded to it. The author, who has served in RAF Training, Bomber, Transport and FighterCommands and is now with a leading aircraft manufacturer, has based his "C.1160" on a pre-war ultra-light of a type he would like to see revived WHEN, as a schoolbov in 1937, I saw a B.A.C. Drone Iresolved that one day I would make a powered and radio-controlled model on similar lines. The Drone was alight aircraft with the engine mounted on the trailing edge of the wing centre-section and driving a pusher propeller. The engineand propeller on the model would be out of harm's way in the event of an accident, the radio could go in the cockpit and thebatteries in the nose—and neither the radio nor batteries would be defiled by the engine exhaust. But it was not until 1960 that Iactually started to build the machine and finally, early in 1961, the dream came true and the C. 1160 left the ground—to return, Iam happy to say, in good order and one piece. The only departure from the original, 1937, conception is the adoption of a tricycleundercarriage with nosewheel steering. The fuselage, built around quarter-inch-square balsa longeronsand covered with one-sixteenth-inch balsa sheet, is 5ft long and made in halves to simplify transportation problems. In the cockpkis a modified four-channel "Reptone" receiver and two actuators, one self-centering to operate the rudder and nosewheel (steering),and the other "progressive" to control the throttle of the Taplin Twin—a splendid 7 c.c. compression-ignition engine with two-in-line cylinders firing alternately. The batteries—in the nose— together with the radio and actuators are all readily accessible byremoving the one-piece nose cowling and Perspex cockpit cover. The wing has a span of 8ft and is constructed in three sections—two outer panels of 3ft and a 2ft centre-section which includes the half-inch-square spruce engine bearers. The outer wing panelsare dowelled into the centre-section and additional support is provided by a simple strut to the lower longerons. The tailplane is of symmetrical section with a 5° dihedral and3ft span. No elevators are fitted at present, ascent and descent being governed by engine power. To overcome rotation and unstick problems during take-off the nosewheel is placed on a smallthree-wheel trolley prior to the take-off run, thus inclining the nose up about 6C. When the unstick speed has been reached the nose-wheel "flies off" the trolley, which continues along the ground and is recovered later. The engine, running on castor oil, paraffin and ether in equalparts, starts easily on a compression ratio of about 18:1. After start-up it is left to warm up at about 500 r.p.m. while a detailedcheck of all services is made. The chocks are then removed and the aircraft taxies slowly forward. The nosewheel steering system.still operative on the take-off trolley (which also rotates) enables one to manoeuvre down-wind. A turn into wind is then made andthe throttle is fully opened. This ground manoeuvring thus con- stitutes a final and practical radio check. It is a most impressive sight to see the comparatively large model—weighing about 81b—gathering speed and finally leaving the ground and climbing slowly away with a plume of exhaust smokestreaming from beneath the fuselage (the exhaust is ducted straight down through the wing and fuselage). At maximum power theengine speed is 7,000 r.p.m. The propeller is of 14in diameter with an 8in pitch. The approach is made at idling r.p.m. and the flare-out isachieved by inching the throttle open. At the end of the landing run the aircraft is turned and taxied back to base.The E.D. transmitter with R.E.P. tone unit operates on 27 Mc/s, and has a safe ground-to-air range of about one mile. The remotehand-held control box is fitted with four potentiometers (to tune each channel) and a universally mounted control stick, fore-and-aft movement controlling the throttle and lateral movement the rudder and nosewheel. This is indeed a splendid way to go flying and an ambitiousdevelopment programme lies ahead, including some air-to-ground photography. Right, pre-flight preparations with the aircraft on a convenient "base" Left, how the power- plant, control re- ceiver and batteries are accommodated Right, the ground- control transmitter and its aerial
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