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Aviation History
1957
1957 - 0956.PDF
56 FLIGHT, 12 July 1957 R.A.E. BEDFORD . . . F.D.2) last autumn and is now using it for an extensive researchprogramme at supersonic speeds up to Mach 1.8. This programme includes the quantitative assessment of the flying qualities of thetype, accurate measurement of drag over a wide range of Mach number and g, and full-scale measurements of aerodynamic heat-ing on a typical aircraft structure. It is the first British aircraft on which the temperature-rise is large enough to permit investigationof the so-called "thermal thicket" problem. Gloster Meteor 9 (assessment of minimum acceptable longi-tudinal damping). This Meteor is being used to determine the minimum amount of fore-and-aft damping which is consideredsafe and acceptable. The natural damping of the aircraft can be reduced progressively by the pilot, using a system—similar to anautopilot in the reverse sense—which works on the elevator trim- tab. This experience should help designers to decide how far theyneed to compromise the primary performance requirement. English Electric P.1A (measurement of tailplane loads). Thismachine has recently arrived at Bedford and will be used for a detailed investigation of longitudinal stability and control charac-teristics, amplified by the measurement of tailplane loads. These loads are to be determined by extensive strain-gauging of thefuselage structure near the tailplane attachments. A first step is to carry out a temperature survey of that region, since local tem-perature gradients caused by the jet-pipes can confuse the measure- ment of aerodynamic loads. Altogether 84 temperature elementshave been installed, and an additional heat-shield has been fitted. Blind-landing Experimental Unit The unit is a very recent addition to R.A.E. Bedford, havingmoved from Martlesham Heath in April this year. It is respon- sible for research and development into bad-weather approachand landing aids for both civil and military aircraft. The problem of safe and successful landing in all weather con-ditions remains an outstanding one. Current equipment permits automatic approaches along a radio beam to a height of about150ft, the pilot taking over for the landing by visual reference to the approach-lighting pattern. The main B.L.E.U. programmeaims to eliminate this final visual phase by devising new techniques and equipment for completely blind landings. The unit was formed in 1945 with the joining-together of aradio team from the Telecommunications Research Establishment, Malvern, which had been studying approach and landing guid-ance systems, and a team from the Instrument and Photographic Department of R.A.E., which was investigating the automaticcontrol of aircraft during the same phase of flight. These two groups worked together at Martlesham Heath, forming the basisof the Blind-landing Experimental Unit. There are at present three main sub-divisions, devoted to radio, automatic control andassessment. The work of the radio section has included I.L.S. development(including an improved parabolic aerial array); development of an accurate radio-altimeter (shown on the occasion of the openingday at R.A.E., Bedford, as reported last week); design of a blind- approach system for single-seat fighters, in which the azimutherror information relative to a radio beam is presented on the D.M.E. heading needle; and the production of alternative formsof azimuth guidance at very low heights for completely blind touchdowns. One simple system in this last development usesthe magnetic field produced by an electric current flowing along ground cables laid near the runway. The automatic-control group tackles the problem of coupling the aircraft to the radio-guidance information, either by the pilotinterpreting an instrument or flight-director display, or through an automatic pilot, in which case the human pilot is free tomonitor the progress of the approach or landing on his flight instruments. The principle of an automatic approach-couplingunit included in a current civil autopilot was originally developed by this section of B.L.E.U. The section now has under develop-ment a device for the automatic control of airspeed, in order to) relieve the pilot of yet another load during the vital final-approachpart of a flight. The section makes extensive use of an analogue computer into Iwhich can be fed the actual pieces of equipment being developed, so that the overall effect of new forms of control can be studied.! The task of the assessment section is to record and analyse the Isuccess of the various aids under development, and to investigate [ their applications to new projects and the effect of changes in jaircraft aerodynamic characteristics. Among recent and current projects are a comparison of different Itypes of visual aids for the final stages of an instrument approach, [ and an examination of fog structure and its relationship with slantvisibility and runway visual range. New equipment includes an approach and landing simulator(due to be installed at Bedford shortly) which will be used to explore dangerous flight situations with safety, and to reduce theamount of flight testing required. The intention is to instal on runway 27 at Bedford Airfield the most modern approach andlanding aids, both radio and visual, and to make it an example of the best in modern all-weather runways. Naval Air Department While Naval aircraft, in common with all military aircraft, havesteadily increased in weight, size and speed, there can be no com- parable increase in the size of the ships from which they operate.Hence the continuous and exacting problem of maintaining com- patibility between the carrier and its aircraft. In the transfer of theNaval Air Department from Farnborough to Bedford, the depart- ment was reorganized and Admiralty representation increased toassist in research and development of carrierborne equipment such as catapults and arresting gears. Thus flight research on Navalaircraft is accompanied by research into the equipment they will use on board carriers. Important items of research on Naval aircraft include thedevelopment of devices such as boundary-layer control to reduce take-off and landing speeds, and the development of a techniquefor assessing the view from the cockpit during the approach phase. Also centred in the Naval Air Department is the greater part ofthe R.A.E.'s flight-research work on helicopters. The major facilities of the department include a 200ft-stroke,steam-powered, slotted-tube catapult, set in a dummy deck 5ft above the ground. A second, similar catapult is being installed atground level to investigate the use of higher steam pressures to give greater energy-levels. Two sets of arresting gear (Mk 13 andMk 11) are located in a vault below the "naval runway" (06/24), with two arrester wires per set located across the runway. The third main test facility is the safety-barrier and arrester-gear proving base, where a deadweight trolley is launched by a cordite catapult into arrester wires or safety-barrier net. Special instrumentation being developed include "Skyscreen,"for measuring aircraft speed at the moment of arrest; and TRODI (touchdown rate of descent indicator). Both depend on pairs oflight-sensitive units which, located a known distance apart, trigger a millisecond timing device. In Skyscreen the light units areseparated horizontally; in TRODI, they are vertically spaced. Other instruments which have been developed to improve opera-tional efficiency include the mirror-sight deck-landing aid. This line-up (on the official opening day, June 27) includes jet-deflection Meteor, Short S.B.5, and English Electric P. I A. \
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