FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1939
1939 - 2013.PDF
662 JUNE 29. 1939 An I.C.I. " Mark 3 " grass dryer in course of erection at Thorney Island aerodrome. AERODROME MAINTENANCE at a PROFIT for the OWNER How the " Grass-drying" Process Operates T^VERY mcnth sees more agricultural J—' land going out of production as farms become aerodromes, and it is generally recognised that in the national interest something should be done about the consequent loss of valuable food. Since grazing and haymaking are ruled out on busy modern aerodromes, continuous cutting is resorted to, the cut grass being dumped outside the aero- drome as so much waste. Yet this young grass is the ideal fcod for livestock. From the point of view of aerodrome authorities, however, the important point is that the young grass can be pre- served by drying, instead of being allowed to go to waste; it will then yield a product that can be sold at a profit. Grass drying is a very simple process. Instead of being cut by gang-mowers, the grass is both cut and collected by an implement called a "Cutlift." This is supplied with special trailers, in which the cut grass is brought to the drying machine, where it is dried in a current of hot air and preserved with its food value practically unimpaired. The dried grass may then be baled or ground to a meal in a mill, the product in either case keeping indefinitely. The Equipment The drying and grinding plant will, of course, be chosen to suit the acreage of the aerodrome and the probable yield, but, speaking generally, an aerodrome Of 150 acres, producing from 200-300 tons of dried grass per annum, requires a dryer with a capacity of 4 cwt. of dried grass- an hour, or 15 cwt./hr. water evaporation. This costs less than £500, installed complete with foundations. A grinding mill of similar capacity costs £25°-£30°- On larger aerodromes a very convenient and very economical drying unit can be laid down in which two dryers feed a central mill, the whole plant having a capacity of 8 cwt. of dried grass per hour or 30 cwt./hr. water evaporation and costing £1,300 in all. On some aerodromes cutting is re- stricted either to certain hours of the day or must be done exclusively at night. In most cases, however, arrange- ments are made between the grass dry- ing plant foreman and the chief aero- drome officer for cutting to be done day and night on certain areas, the "Cut- lift" carrying warning flags visible to pilots. When considering the adoption of a grass-drying system of aerodrome main- tenance, regard must be paid to the work of the whole season. For example, fertilising, rolling and harrowing must be done in the " off season," so that cut- ting and drying can proceed smoothly and satisfactorily in summer. Thus two or three "key men" will be employed throughout the year as general ground foremen, while extra labour will be taken on during the drying season to cope with increased duties. The greatest incentive at the moment to the development of commercial grass drying, it is claimed, is the ready market for the product, for grass meal com- mands prices which vary from £9 to £11 per ton, according to quality, and the excess of demand over supply favours the higher price. Costs of producing dried-grass meal naturally vary, but after making reasonable allowances for fer- tilisers, cutting, carting, fuel, repairs, labour and depreciation and other charges, the all-in cost of production should not be more than £$-£& pet, ton. This allows a handsome profit, but even if there was no such profit, the installa- tion of a grass-drying system would still have the advantage of reducing the actual cost of aerodrome maintenance, given reasonably good management. Dryers of guaranteed performance are now available at much lower prices than in the past. The new I.C.I. (Imperial Chemical Industries, London) " Mark3 " plant, for example, which is in operation on farms and aerodromes for the,first time this season, is said to be obtaining results which make it reasonably certain that before long many more aerodromes will be managed on the grass-drying system. AN "AIRCRAFT DISCONNECT" R many years the Cannon Electric Development Co., of Los Angeles, has been co-operating with the leading American aircraft manufacturers in the manufacture of special cable connectors, designed primarily for use in aircraft radio, instrument and electrical circuits. The result of this co-operation has been the development of a wide range of connectors varying from the single-pole type to one with as many as 37. The connectors are available with straight and ninety-degree receptacles. The shell of the ninety-degree receptacle is split to facilitate access to the con- tacts. In both types the shell of the pin and socket members is made of alu- minium alloy finished with transparent lacquer. The socket is drawn into the pin member by means of a quick- threaded knurled ring. The design of this type of connector is such that the pin member is mounted to the instrument panel. Its poles are re- cessed so that risk of touching them when withdrawing the socket is reduced to a minimum. In the case of connectors being used in the earthing circuit of a magneto it is obviously necessary for the safety of the ground crew that when the socket is withdrawn the magnetos should not be- come "live." To overcome this pro- blem a Cannon socket has been developed in which a small earthing switch has been so incorporated that on removal the plug leads are automatically earthed. Cannon connectors are available in this country from Aviation Corporates, Ltd., 50, Pall Mall, London, S.W.i. Two alternative types of socket are available for the Cannon connector
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
