FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1939
1939 - 0037.PDF
JANUARY 5, 1939 FLIGHT. 19 Commercial Aviation THE 1939 AIR ALMANAC AFTER an experimental period of practice use the Air Almanac has appeared in an improved layout and format, incorporating some very useful additional information. It will be remembered that it first appeared for the. last quarter of 1937 and continued throughout 1938 in two sections; one was a permanent part containing constant interpolation and auxiliary tables, and the other was composed of loose sheets giving the ephemeral data for every two days in Greenwich Hour Angle notation. Criticism of this layout was asked for, and the suggestions received and incorporated must have shown the keen interest taken in this publication by air and marine navigators of all countries in every part of the world. The result of the criticisms and suggestions is that the new Air Almanac, which will in future be published quarterly, is a masterpiece of ingenuity in arrangement. With the object of further facilitating the quick extraction of the essential data, saving interpolation, and removing the possibility of errors by a physically tired air navigator who may have been flying at a high altitude for a long period, the G.H.A. data is given for one day only on each sheet instead, as previously, for two days on each leaf. The daily sheets are no longer loose, but are perforated parts of the Almanac itself, and are torn off after use. The necessary constant interpolation and auxiliary tables are partly printed on the inside of the covers and partly on a double-hinged folding flap, which is placed behind the page actually being used. By this ingenious arrangement all the data required for the Sun and Stars is available at one opening, and that for the Moon at another. It is only when sights of planets are being worked out that a further second opening is necessary. Only three of the four navigational planets, Venus, Jupiter, Saturn and Mars are given each day, the one faintest, or nearest the Sun, being omitted. Every day a little foot note on the daily sheet thoughtfully helps the navigator; for example, on January 1 he reads "Venus is observable in the east shortly before sunrise. Jupiter and Saturn are well placed for observation in the west after sunset, Saturn being higher than Jupiter." Another indication of the care taken to help the user is the symbol given for the Moon at the head of each page, which represents the division of the illuminated and shadowed portions of the moon. A further new departure from the previous edition is that each day tables of civil twilight (when the Sun is 6° below the horizon), sunrise, sunset, moonrise, moonset, are given for latitudes ranging from 6o° N. to 6o° S. This addition will be especially appreciated by all who, in the past, have struggled with the working of moonrise and moonset in southern lati tudes, using the tables given in the Abridged Nautical Almanac, which were the only ones available. It is, however, a pity that the few extra sheets contained in the latter publi cation, which give Standard Times for countries, have not been included. In view of the long distances rapidly covered by aircraft, and their extensive area of operation, it may seem somewhat illogical not to be able to find, with the help of the Air Almanac, the Standard Time of a country over which one is operating. A particularly interesting statement in the Air Almanac is the mention of the new Astronomical Navigation Tables, or direct-reading tables for obtaining the computed altitude, which are also being prepared by H.M. Nautical Almanac Office. Though they have not yet appeared they have already been allotted a number—Air Publication 1618. When available they will be used in conjunction with the Air Almanac, and from the information given in the introduction to the latter and from the layout of the index of the 50 stars covered, it appears that direct-reading tabulations for 22 out of the 50 stars are being provided, and that 13 of the remainder can be reduced from the Sun and Moon sections of the Astronomical Navigation Tables. No special provision is being made for the remaining 15. Further tables in the Air Almanac cover the case of the Pole star, convert Arc into Time, allow for dip when using a marine sextant, and correct for refraction sights taken at heights up to 40,000 feet above sea level when the Astronomical Naviga tion Tables are not being employed. Refraction has been included in the latter. An interesting table, not yet published, is also allowed for in the layout of the Almanac which will correct for refraction in any observations taken under a trans parent dome in an aircraft. The Air Almanac is, of course, published by His Majesty's Stationery Office (A.P. 1602) and is sold for 5s. New Straight Interests SINCE taking over Western Airways the Straight Corpora tion has naturally had a special interest in the South Wales aerodromes—in Cardiff aerodrome, as well as in the landing ground at Swansea and the projected aerodrome at Newport. At the moment the Cardiff Corporation are con sidering an offer by the Corporation to take over their aero drome—including, of course, the flying club—and Mr. Straight is also, according to reports, negotiating with the Newport Corporation with reference to the proposed aerodrome there. Western Airways are already making use of Jersey Marine aerodrome at Swansea in the extension of their Weston- Cardiff ferry service. The Air France Party HELD as it was on the eve of Christmas Eve, this year's Air France dinner was more in the nature of a Christmas party and was, in fact, so described in the invitation. In the absence of M. Allegre, the managing director of the com pany, M. Lesieur, the passenger traffic manager, was in the chair. In his reply to Mr. Huskisson, who, during the last fort night, has been appointed managing director of Thos. Cook & Son, M. Lesieur explained that the company was hoping to start a passenger service to Cairo this month and another to South America during the summer. In addition, the Air France summer holiday services would also be extended. FORCEFUL ASSISTANCE : The new Dornier Do. 26 leaving (above) the D.L.H. Atlantic supply ship Friesenland. At the moment the machine was loaded up to an all-up weight of 19,000 k.g. (42,0001b.). On the left the Do.26 is being taken aboard.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
