WIRELESS WORLD

Nelson Evening Mail, Volume LXVI, 9 November 1935, Page 14

WIRELESS WORLD

RADIO NOTES PILOTLESS AIRCRAFT POSSIBILITIES OF MACHINE Details of experiments, which hjivo been going on in secret in England with pilot, aircraft, have now been announced. Hitherto extraordinary precautions were taken to prevent anything about them leaking out. The experiments show that a full-size aeroplane, without any human occupant, can now be taken off from an aerodrome, flown on a given course, manoeuvred in the air, and oven looped and spun, and landed again with certainty, and Accuracy. The military implications of this development are extensive. The power of the aeroplane as a weapon of war lias once more been increased. The existing pilotless aircraft is purely a target machine, but bombing and possibly photographic reconnaisance will eventually be possible by. the same technique. The pilotless- aircraft would have no fear and would fly through barrages which might deter or hamper the human pilot. During the war there was much talk of “aerial torpedoes.” Actually, there was no such thing as a bomb capable of flying under its own power to an objective after being previously set. The war-time “aerial torpedo” was a myth. But it is no longer an impossibility. With the existing knowledge it would be possible for British, engineers to build what would in effect fulfil the popular conception of the aerial torpedo. The pilotless aeroplane developed by tlihe Air Ministry technologists is a wooden biplane similar in general construction to the machines used by the light aeroplane clubs. It is known as

the..Queei’r Bcc, "and ’it has an air-cooled-, engine. It can be equipped either with a wheel undercarriage for use from an aerodrome, or with a float undercarriage for use from the water. It is also equipped so that it can be catapulted from the deck of a warship or any other place. Tti its present stage of development it is only capable of verv short-range flights, its radius of action being Tint more than 10 miles. Tt ran he enntrollcd hv radio from either shin or hatterv. and it is used and intended solely for target purposes. Its sneed is about 100 m.p.h., and its ceil - ipe- about 10.000 ft. ' Machines of this type have been flying successfully for some time and have, been remilnrlv used as targets for "imncr practice. Tliev c-htv nothing hevoiu 1 their radio controlling mechanism. Details of the controlling mechanism remain seeret. Reports indicat" flint Dri-many is well advanced in the teohnionn o f the pilotless aeronlane. ns well as the United States of America. Experiments ha-re been carried out in France and Ttaly. THE DAY OF THE LOUD-SPEAKERS Hitler has stated that lie conquered Germany with loudspeakers. This contention seems to have been reflected in the exhibits at the recent Germtin vnd’o show. Thanks to the demand for high-’ power amplifiers for political purposes, apparatus of this kind was more in evidence at Berlin than in London. German amplifiers up to about 20 watts are of the class “A” type, while those above employ modified “quiescent” systems. Methods of suppressing harmonic distortion appear to he more widely used. Perhaps the most progressive amplifier seen at Berlin was a Philips model, which automatically changes itself over from class “A” to class “B” when a given signal strength is exceeded. Tbps it seems that Berlin is leading in the field of amplification development.

FP.OM THE HEIGHTS The first of a series of broadcasts from high spots of the British Isles was heard in transmission 1 recently, when a speaker ascended to the top of the Royal Albert Hall, London, and gave his impressions to listeners. The. height of the Albert Hall is 120 feet. Among other high spots which may be visited are the following:—Blackpool Tower; the Church of St. Mary Redcliffe, Bristol; Canterbury Cathedral; Edinburgh Castle ; the 8.8. C. transmitter at Moorside Edge; the National Museum of Wales, Cardiff; Greenwich Observatory; Birmingham Town Hall: York Minster; the Norman Tower, Windsor Castle; Eddystone Lighthouse. MARVELS OF SHORT WAVE Modern alchemy achieved through the medium of micro-waves is the prospect opened by research now being undertaken. Hitherto it has been possible to use only low power calculated in watts for micro-wave transmissions. In future, it is hoped, through a new type of valve, to use kilowatts. Mr J. H. Owen Harries, the 29-year-old inventor of the Harries valve, is entering this field of research. “Astonishing results have already been achieved with microwaves oil small power, and is sufficient to show what may be done with high power,” Mr Harries said in an interview in London. “It is possible, for instance, to kill bacteria, preserve eggs, and so affect fermenting beer .that a totally different process occurs. When high power is used it will be hard to place a limit to the possibilities of microwave transmissions. Chiefly they appear to affect organic matter, but it seems clear that substances can be made to change their character. Indeed, the sort of transformation the alchemist dreamed of no longer appears quite so fantastic. “One thing I hope to achieve is the clearing of fog from the bows of a ship by means of a micro-wave ray. Medical science should also benefit greatly. Mr Harries has spent nearly five years experimenting in valve characteristics, and lias collaborated with the National Physical Laboratory. He made his valve, however, at his little laboratory at Frinton. • # « *

“Attention, everybody. Another war has been declared. Yes, England and Germany are once more opposed in mighty conflict.” This was the opening of an announcement from an Australian 13 station recently, and was followed by a description of a naval engagement in which it became clear that the announcer was broadcasting not facts, but an advertisement for a film. Complaints and inquiries were made by listeners and the Director of Postal Services (Mr IX p. Brown) ordered officials of the station to submit the manuscript to him. Later he issued a warning that any station which continued to broadcast such items would be in danger of having its license suspended. A HANDY CONDENSER It is often found advantageous, especially when the “B” battery has had some use, to connect a one-microfarad fixed condenser across its terminals. This has the effect of eliminating any stray noises that may be caused by the par-tially-run-down battery. A one-mfd. fixed condenser for this purpose can be made up very easily by following the directions given by “Spark Gap” in the November “Australian Journal.” Tlie materials needed are 22 sheets of tinfoil, 24 sheets of waxed paper, two pieces of cigar-box wood, well varnished, and two switch-point studs for bolts. Ordinary writing paper may he used. This should first be dried thoroughly in a slow oven and then immersed, sheet by sheet, in melted paraffin wax. The waxed paper is cut into sheets- 4£ inches by 4g inches, and the sheets of tinfoil to 4 inches by 4 inches. Four inches of the tinfoil sheets' are* laid between the waxed paper sheets, allowing half an inch to overlap for connections. Each sheet of tinfoil is arranged between two sheets of paraffined paper, one sheet of tinfoil being so arranged that it projects to the left, and the next so that it projects to the right. The whole is then clamped between t the two varnished hoards, and connections made to each of the protruding sides of tinfoil, the whole being bolted firmly together. By placing washers on top of each set of overlaps, in order to bring the thickness of these to the same height as tlie waxed sheets and tinfoil of the condenser proper, a good firm contact can he made. Another method of making contact with the tinfoil sheets is to stitch them together with fine, bared copper wire, bringing an end of tlie wive to a convenient terminal screw.