RADAR EQUIPMENT FOR AIR RACE

Press, Volume LXXXIX, Issue 27149, 19 September 1953, Page 8

RADAR EQUIPMENT FOR AIR RACE

Tests Made At Harewood ARRIVAL OF THREE R.A.A.F. OPERATORS .Tests of the £210,000 ground-con - trolled-approach radar equipment for the London-Christi>urch air race next month were made at Harewood yesterday morning. The team of Royal Australian Air Force operators arrived on the Skymaster from Melbourne about 8 a.m. and soon after had the set running. Tests were made with the help of the R.A.A.F. Canberra jet bomber now at the airport, and results were considered satisfactory. The Canberra then turned off to run through tests of the new distance-measuring equipment also installed by the R.A.A.F. at Harewood for the air race.

The latest of its type in the world the radar equipment is used to locate, home, and direct an aircraft into line with the runway. With its aid a pilot can be “talked down” to within half a mile of the runway threshold or, in very bad conditions, right down to the landing. “A very major advantage of the g.c.a. is that no additional equipment is needed in the aircraft.” said the officer commanding the installation. Flight Lieutenant J. M. Francis, R.A.A.F., yesterday. “Aircraft have always been hampered by the height of cloud over the airfield on a bad-weather day. This equipment has gone a long way towards providing all-weather flying services. As long as the aircraft is' able to receive and transmit radio messages it can be landed on g.c.a.” Impressive Aerial System

On top of the last trailer in the tram of two behind the huge diesel prime mover is mounted the highly impressive aerial system of the unit. A huge, shovel-shaped lattice-work contraption with something resembling a crooked finger pointing into its centre was revealed to be the locater or search aerial. This aerial rotates at 20 revolutions a minute, sending out radio pulses every .660-millionth of a second. The duration of the pulse is half a millionth of a second. As the aerial rotates a wide vertical fan of pulses sweeps the sky and the surrounding countryside. Pulses bounce back to the aerial after they hit solid objects and this message is transmitted to the cathode screens within the operating trailer. From the resultant blobs of light the skilled operators are able to find aircraft, determine their position and direction, and detect any movements they may make. Once detected on the locater screen thq homing aircraft is brought into a 20-degree sector marked on the screen, and the operator’s gaze shifts to two other large screens graduated to show the path of descent to the runway. Reading from the blob of light and the scales on this he is able to direct the pilot in to land. Distance Measuring Mounted on the Harewood water tower is the aerial for another modern aircraft aid. It is the Australian designed and built distance measuring equipment be r acon. The Canberra made tests of this equipment, part of which is mounted in the aircraft itself, yesterday. With d.m.e (distance measuring equipment), radio pulses sent out by the aircraft are received by the beacon and checked for shape and frequency. The correct type of pulse received, the ground installation transmits a pulse to the aircraft. The time taken for this operation is measured and transferred to a distance meter in the aircraft. showing the navigator his distance from the airfield.

The d.m.e. pulses are on “line-of-sight propagation,” and they are blocked by mountains and other solid objects. Yesterday morning’s exercise was to find the gaps in the mountains through which the pulses could be sent, and check their bearings at various heights. This information will be sent to the two R.A.A.F. Canberra race aircraft in London to help them to find Harewood. More tests will be carried out by the Canberra this morning, and it is expected to leave for Laverton, near Melbourne, this afternoon.