FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1920
1920 - 1256.PDF
DECEMBER g, 1920 bubble itself is formed under a concaved glass roof which may be illuminated at night by a lamp of variable luminosity. The image of the bubble is reflected by means of a prism on to the object glass, which simply consists of a plain sheet of glass which acts as a semi-reflector. The image of the celestial object is seen reflected on this same glass surface, andis brought into coincidence with the bubble by revolving the spiral cam, the angle of inclination of the glass being registered on the scale. This type of sextant obviously does away with the necessity of a natural horizon, whether land, sea or cloud. In common with all artificial horizons when used in aircraft, however, the level is subject to error due to the acceleration of the machine acting on the bubble. Semi-diameter calculations are also eliminated by the use of this sextant. One difficulty with this instrument is to obtain an index error. This, however, can be obtained by suspending a mirror vertically and taking the reading of the image of the observer's eye in the mirror. On the Cairo to Cape flight the errors in the position lines, from observations with this type of sextant, were from 4 to 12 miles. During a recent extended flight the maximum error in position was as much as 34 miles obtained from the mean of six observations, and the minimum error was five miles from the mean of four observations. The variation was due to the difference in atmospheric conditions on different days, the bad results being obtained on extremely bumpy days. These tests were carried out in an aeroplane, and better results may be expected in an airship owing to the slower movement. Many other designs of sextants involving the use of bubble horizons and reflected back and front horizons have been used, but their low degree of accuracy and disadvantages in design have led to their elimination. Instruments for the rapid solution of the spherical triangle by means of plotted curves and graphical representation of formulae have been tried, amongst which may be mentioned the Baker Navigating Machine, the Veater Diagram and the d'Ocagne Nonogram. These, however, have not given the high degree of accuracy desired under all circumstances, but were admirable as a stop gap. The Bygrave Slide Rule has given remarkably good results and is rapid in solution. It consists of two cylindrical con- centric scales—one a cosine scale and the other a tangent scale—and by dividing the spherical triangle into two right- angled triangles the zenith distance and azimuth can be computed. Directional Wireless. The use of directional wireless will no doubt play an inpor- tant part in the navigation of airships in the future, and even at the present time forms a means of checking a D.R. position or a fix, but owing to the atmospheric errors that cannot be calculated or allowed for, and the difficulty of always obtaining a good fix, it should only be looked upon as an important aid and not a substitute for other forms of navigation. A good pilot should use every method available to check his position, however accurate any one of them may appear to be. Conclusion. I have endeavoured to put before you the difficulties encountered in airship piloting, and the methods employed to overcome these difficulties. I have tried to show you that an airship is not a fine weather craft, and that with adequate ground organisation there is no reason why it should not fly anywhere in the world under 'any conditions. I have tried to indicate from the pilot's point of view the main point to be considered in the design of ships of increased size, namely, the increase of speed, both to enable good regular flights to be made under all weather conditions and to reduce the difficulties from superheating. I have dealt entirely with the ship in the air, and leave it to sorrfeone else to discuss the ground organisation, one of the chief features of which is airship mooring. This mooring is now an accomplished fact and only wants developing to make it of practical value, and I hope I have shown that, as soon as mooring of airships has been developed, the airship for long-distance regular schedule flights is a sound practical proposition. A New Coupe Deutsch AT the banquet of the Aero Club of France on Decem- ber 2, a letter was read from Mme. Henry Deutsch de la Meurthe to M. Michelin, President of the Club, offering, on behalf of the Deutsch family, a new Coupe Deutsch, for an International Speed Competition, together with a sum of 200,000 francs in prizes. The Michelin Prize IT is not altogether surprising that so far no entries have been made for the prize of 500,000 francs offered by M. Michelin just before the last Paris Salon. It may be recalled that the entrant must fly at a speed of more than 200 kiloms. for the first hour, then during the next hour cover not more than 10 kiloms., and finally land in a maximum radius of 5 metres. The prize, however, will remain open until October 1, 1930, and only French aviators are eligible. Air Malls for Morocco THE Postmaster-General announces that the air-mail service between Toulouse and Casablanca (Morocco) is now being carried on three times a week in each direction. Packets should be posted in time for despatch from London on Saturdays, Mondays and Thursdays, in the mail for Paris, for which the latest time of posting at the G.P.O., London, is 3 p.m. for letters and postcards and 2.30 p.m. for printed papers, commercial papers, and samples. The Airco Service to Paris THE appointment of a receiver for the Aircraft Manu- facturing Co., Ltd., appears to have been responsible for a report that the Airco London-Paris service was to be dis- continued. We understand, however, from Mr. Frank Searle, managing director of Aircraft Transport and Travel, Ltd., that there is no intention at present of stopping the service. A Record Trip to Paris WITH the aid of the gale, one of the Airco 4 limousines, on the Handley Page services to Paris, made a record flight on December 4. Piloted by Lieut. Vaughan Fowler, and carrying two passengers, the machine left Cricklewood Aerodrome at 1.17 p.m., passed over the aerodrome at Lympne in 33 mins., and reached Paris in 1 hr. 48 mins. The Liore- Olivier Amphibian TESTS with the three-motored flying-boat exhibited by MM. Liore and Olivier at the last Paris Show not having proved satisfactory, the makers set to work to transform it into an amphibian, as suggested by the Technical Section of the Aviation Department. A special chassis has been . fitted and, piloted by the naval pilot Martin, the machine has made several flights at Villacoublay, the best including a climb to 2,500 metres in 32 minutes. Theoretically, the ceiling of the machine should be about 3,500 metres. The land chassis is of the retractable type, which when the machine rises in the air can be drawn up under the lower wing. A Caproni Liner SOME details are to hand from Turin of a machine being built at the Caproni works which is really of the " giant " - order. It is a hydro-triplane, fitted with eight 400 h.p. Liberty motors. The three planes are 40 metres span, and fitted with ailerons. The eight motors are arranged in tandem, four at the front and four at the rear of the planes, and mounted in nacelles which are joined by false fuselages. The machine is fitted with an automatic stability device, and is controlled by a wheel, the working parts being fitted with ball bearings, so as to reduce the strain on the pilot to the minimum. An electrical signalling system is installed for communicating with the engineers. There is accommodation on board for ninety passengers. Progress in Argentina MUCH enthusiasm in the Argentine has been shown in aviation since the demonstration school at El Palomar was established by Handley Page, Ltd., in December last. Many pilots' have been trained there for Government service, as well as private owners who have purchased aeroplanes for the establishment of local services. A popular feature of the school has been the periodical demonstrations which have taken place there, and also the many excursion flights. To Our Readers As we continually receive complaints from our readers that they experience difficulty in obtaining their copy of FLIGHT promptly each week, we would point out that under such circumstances the publishers will be glad to receive subscriptions. If the appropriate remittance is sent to the publishing offices, 36, Great Queen Street, W.C., it will ensure FLIGHT being received regularly each week upon the day of publication. 1258
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
