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Aviation History
1945
1945 - 1769.PDF
FLIGHT SEPTEMBER 6TH, 1945 BOMBER'S RADAR radai systems is known by the somewhat cryptic title of H2B, and has already been described to a certain extent in previous issues oi l-'light. This is .the device which has been colloquially called the genbox, and has the great advantage that it is completely self-contained in each aircraft and has no relation to ground stations whatsoever. H2S was first used with effect on Hamburg in July, 1943. seven attacks—four K.A.F. and three U.S.A.A.F.—resulting in the place being virtually wiped-out. Krupps also had its final demolition through H2S -when 5,000 tons were un- loaded at 2.30 in the afternoon in March of this year ; 10/10 cloud covered the target and the Pathfinders marked it with smoke puffs (a day version of Wanganui) which guided the bomb aimers of the iriin force. What makes H2S so valuable is that, being in ioto an aircraft installation, it can be used anywhere in the world —furthermore it cannot very well be jammed. The air- craft carries the transmitting and receiving stations, the transmitter emitting a pulsating sheet of scanning signals downwards and outwards in conjunction with a parabolic "mirror" which rotates in phase with the sweep of the scanning signals at about 50 r.p.m. The exploring sheet of signals impinge on the earth's surface and set into oscillation everything thereon (with the exception of water), the oscillation so caused thereupon re-radiating into space a fraction of energy. This minute amount of energy is received back at the aircraft and amplified to give a pictorial representation on a cathode-tube screen. These ground returns, as they are called, appear on the screen in greenish patches, 'but any regular solid in the form of a factory, for example, will ensure a good- quality return and will appear' on the screen as a lighter green patch. As water gives no return at all, a coastline or river will appear on the screen as a sharply defined dark area, and a town will appear as a patch of lightish green of a shape approximating to the actual shape of the town, although no really accurate degree of definition is possible. On the screen a '' spoke'' light-band extending from the centre (which represents the aircraft's position) to the periphery sweeps round the screen at the same speed as the sweep of the scanning signals, that is, 50 r.p.m. The ground returns given on the screen are brought about by the passage of the spoke and fade after it has passed, but the properties of a fluoroscope are such that the image lingers and is, of course, regenerated approximately once each second so that the shape and position is fairly readily determined. This system is not very good at low altitudes. because the ground returns are then so intense as to make the perception of any one particular feature rather difficult. The range swept by the scanner can be varied, and a pip of light on the spoke band can be aligned on the image of a given town in order that the distances of the aircraft from that town can be read off against a scale. Addition- ally, there is a second spoke which does not sweep round although its radial position on the screen is determined by the aircraft's heading. In conjunction with this, a glass plate is fitted over the screen and engraved on its surface is a diametral gridline. This plate has a serrated edge and has degrees of arc marked around its perimeter, and in order to obtain the bearing of a town relative to the air- craft, the bearing spoke of the screen is brought over the image of the town and the gridline turned until it is coin- cident with the bearing spoke. The bearing of the town relative to the aircraft's head is then read off the graduate^P scale oti the gridplate. H2S is not normally operated by the navigator, but is the special concern of another crew member, called, in Service parlance, the "box-basher," whose job it is to give the navigator the information the latter requires. The box-basher's job is by no means an easy one, and it is easy to understand that, after sitting for hours peering at a dim, flickering screen, he should climb out of the aircraft and totter into the interrogation officer feeling somewhat dopey and with puffed-up, bloodshot and aching eyes. If the descriptions of the wonders of radar systems and the enormous aid they have given to the bomber crews have given the impression that the bombing raids were semi-automatic and the crews had a great deal of their work automatically done for them, let it be dispelled once and for all. Radar made the accuracy of our bombing attack possible, but it in no way alleviated the hardships and hazards undertaken by every man on every raid. The aircrews of Bomber Command have had a gruelling, tough and mortally dangerous job throughout our years of war— a job second to none in any branch of any Service—they are the power and the glory of our Air Force. R.A.F. GIFT TO DANES AT Aarhus,. in Denmark, recently, the scene of one of themost spectacular R.A.F. Mosquito "pin-point" attacks, Air Chiei Marshal Sir W. Bholto Douglas, Air Commander-in-Chiet British Air Forces of Occupation, presented to the Crown Prince of Denmark a cheque for 470,000 kroner (about £20,000).The presentation was made at the biggest store in Aarhus when Sir Sholto Douglas opened an R.A.F. exhibition there. The cheque was a contribution from the R.A.F. to aid thoseDanes unavoidably injured in the R.A.F. raid on the Gestapo Headquarters at Aarhus, Copenhagen and Odense It repre-sented the proceeds of the big R.A.F. fly-past which took place in Copenhagen last month, and at which more than half thepopulation of Copenhagen were spectators. The Crown Prince and Sir Sholto Douglas arrived at the exhibition together,and the crews of six of the Mosquitos which took part in all the three "pin-point" attacks in Denmark were also present.Typhoon squadrons of No. 83 Group flew over Aarhus at roof- top height at the same time. The exhibition was similar to those already seen by millionsin Brussels, Paris, Copenhagen, Antwerp and Nice. In addition to hundreds of photographs of all phases of theactivities of the R.A.F., there is a Link trainer which the spectators can use, a Spitfire, a cinema showing R.A.F. docu-mentary films, and working models of all types of R.A.F. apparatus. THE WANBOROUGH ACCIDENT IT was not stated, at the adjourned inquest at Godalminglast week, what was the nature of the secret device on which Mr. Henry V. Becker (34), Scientific Officer, RoyalAircraft Establishment, Farnborough, was engaged when he was killed on August 23rd at Wanborough, near Guildford, through the disintegration in the air of the Mosquito aircraftin which he was acting as observer. Walter George Bushell, Senior Engineer Officer of the Experimental Flying Depart-ment at Faniborough, told the coroner that he had no doubt whatever that the aircraft before the accident was thoroughlyserviceable. The accident, said witness, was caused through adversecharacteristics developing in the experimental equipment. This •experimental equipment was being developed to u iaircraft safer, and Mr. Becker had been engaged on these J since their beginning.Fit. Lt. Clive L. Brooke, R.A.F., Farnborough, the injured pilot of the aircraft, said that.it broke up in mid-air withoutapparent cause. " I was thrown out but had sufficient con- sciousness to pull the cord of my parachute." Medical evidence was given that Mr. Becker's-death was clueto multiple fractures and injuries, and a verdict of accidental death was recorded. AVRO VICTORY BANQUET AN Avro Victory Banquet organised by the Superintendents'and Foremen's Joint Council was held recently at Belle Vue, Manchester. The guest of honour was Sir Roy Dobson,C.B.E., director and general manager, who paid a tribute to the energy and skill of some 300 key personnel who had madepossible the organisation of the Avro bomber programme. Sir Roy outlined the achievements of the company during thewar and forecast a period of intensive research and develop- ment in the peace to come. " I would like to give you all arest," he said, " but if I did so, it would be ' goodbye ' to Avro." The dinner was followed by a programme of entertainment, and music was played during the evening by the Avro Band.
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