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Aviation History
1933
1933 - 0904.PDF
FLIGHT, NOVEMBER 2, 1933 Strandgren (1924) and Schneider (1925), the inventor of the famous Voith- Schneider propeller. The Volth- Schneider Marine Propeller The well-known and highly successful Voith-Schneider propeller, which operates in some points in a similar manner as the Rohrbach Rotating Wing, is illustrated in a photo. The Voith-Schneider propeller rotates about a verti cal axis, the cantilever blades projecting from a revolving drum flush with the underside of the stern plating. The blades can be " feathered " to give small or large forces in any desired direction. This type of propulsion has been in use on Lake Constance for many years on many vessels including the Deutsche Reichsbahn-Gesellschaft boats "Augsburg" and Kempten " with recorded thrust efficiencies up to 80 per cent. Tests have shown that the efficiency of the Voith-Schneider propeller is considerably in excess of the screw propeller. In addition the manoeuvrability of the boat is very greatly increased and without the use of rudders or steering gear. The following extract is taken from The Marine •Engineer for November, 1931 :—" At a recent meeting of the Hamburg Tank Society held in Hamburg, the marked superiority of the Voith-Schneider blade-wheel propulsion over screw' propulsion Was discussed. The present report reviews the discussion. ' Every type of propulsion involves subsidiary losses. In the Voith- Schneider blade-wheel the frictional resistance of the drum amounts to some 3i per cent, on the model, and so:ne 2 per cent, on th? ship. With the SEE ordinary screw propeller the boss losses are more important. The lack of wake uniformity is still more important. To get a true comparison between the two types of propulsion, propellers of equal disc-area ratio should be compared on a basis of thrust coefficient. Using an interpolation of Schaff ran's data for the screw propeller against the actual test data for the Voith- Schneider propeller, after making all allowances for subsidiary losses in both types of propulsion, the superiority of the Voith-Schneider type is a full 14 per cent. ' ' This comparison has been fully endorsed by tests on actual sister vesseh having the two methods of propulsion, and for which careful trials and full scale towing tests have recently been conducted. The results of these tesU are shortly to be published in detail." Further details given in The Engineer, May 15, 1931, show the practical superiority of this system. A boat fitted with twin propellers rotating at constant speed could be started ahead or astern, stopped or turned in either direction round her own axis by operating the steering control in the desired direction, a separate lever regulating th< speed ahead or astern. A third lever with a transverse movement provides a means of setting the propeller blades so that the vessel is moved laterally—a manoeuvre which is most valuable when making or leaving piers and wharves. An increasing number of boats are now being fitted with Voith-Schneider propulsion. To be concluded). a OUT OF THE FLYING PAN »» By W. O. MANNING, F.R.Ae.S. Mr. Manning contributes the following amusing speculations on the possible effects of removing from the Air Ministry the control of civil flying. His fun, if one digs below the surface, gives cause for serious thought. I N view of the criticism of the control of civil aviation by the Air Ministry, it seems worth while to con sider what alternative there is, for it can be taken for granted that public opinion will not permit any pilot on any sort of aeroplane to career over the country as he pleases at any height he likes. It seems inevitable that some regulations would be laid down, that aircraft owners would be made responsible for seeing that they were carried out, and that the people who would be responsible for enforcing the regulations would be the police, strongly backed up by the local magistrates. Whether this sort of control would be pre ferable "to the present is a matter of opinion. It is probable that a minimum factor of safety would be laid down by authority, and that it would be the responsibility of the manufacturer to see that it was adhered to. There would be no inspection whatever, but in place of this one might see occasionally that some un fortunate manufacturer was accused of " having with malice aforethought sold or caused to be sold an aeroplane of a strength less than that laid down by the regulations in that case made and provided, contrary to the peace, etc." Then we should have the entertaining spectacle of a bench of magistrates puzzling their brains over, say, the application of the Theorem of three moments, with the complicated Irimmings to the said Theorem devised by the ingenious Mr. Berry. However amusing such a spectacle would be to the initiated, it is hardly likely to be fair to the manufac turer concerned, as the magistrates, knowing nothing what ever about the matter under dispute, would be likely to decide it in favour of established authority, salving their consciences by reminding themselves that the defendant has a right of appeal, if his banking account will allow him to exercise it. If he cannot afford to appeal, this circumstance can hardly be considered the fault of the bench. Following the precedent now established with regard to motorists where penalties are provided in cases where the owner does not keep his brakes and his tyres in good con dition, it would be expected that similar requirements re garding the upkeep of aeroplanes would be demanded by the authorities of the private owner, and enforced by means of the village constable. And, as the motorist knows to his cost, great is the belief of the Great Unpaid in the intelligence of the rural police. " I saw the defendant flying low over the village hobviously going to land on Farmer Giles' big field. While he was apassing over I saw one of his tail wires wobbling about. After he had landed I went up to the aeroplane and saw that one of the turn buckles on his tail was not locked in the approved manner as the ends of the locking wire were turned to the left instead of to the right. I then saw the defendant, showed 'im the wire, and told 'im that any think he said would be used against 'im." Magistrate: "Do you think, Constable, that the turn buckle wire being incorrectly placed would cause the wire to wobble? " Constable: "Yes, your Worship, because the air would catch hold of it in the wrong way, the direction of the twist being opposed to the pitch of the propeller. 1 should also say, your Worship, that he flew right over the Blue Lion, and if he had come down on it he might have set it on fire, and it's the only licensed house in the village." Magistrate: '' Puddlecombe is a very isolated village is it not? " • Constable: " Yes, your Worship ; it's a good five-mile walk to the next." Magistrates retire to consider their decision, and on theiT return commend the constable, abuse the defendant, an J inflict a heavy fine. S 5S U England—Australia Race IN our issue of August 3, 1933, we published a sum mary of the regulations governing the England-Australia Race next year. The handicap formula has now been announced, and is' as follows: — HANDICAP 0-2L \ ,P1 W^L FORMULA A V = 140(1 \ L = Payload in lb. W = All-up weight in lb. of machine complete with petrol, oil, personnel and freight ready for race. P = Maximum horse-power at sea level at maker's normal r.p.m. A = Wing area in sq. ft., including ailerons. V = Air speed in miles per hour on which handicaps wi>l be based. (a) Payload.—The following only will be recognised as payload: — (1) 200 lb. will be allowed for each person carrieo together with his unsealed baggage ; and (2) All sealed packages of any description, including t," following: — , Excess baggage, spare parts, ballast, printer matter, etc. For the purpose of sealing, all articles must i securely packed or wrapped. (6) Wind Allowance.—Allowance will be made for genet. wind conditions existing over the course at the time of ye:-' during which the race is being run. This allowance will he determined beforehand and all nominators will know their full handicaps before the start of the race. 1090
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