FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1944
1944 - 0566.PDF
2)2 FLIGHT MAKCH I6TH, 1044 MAKING ONE RUNWAY DO at angles to it. Thus, even'taking a fairly modest dimension, such as 2,000 yards, an air port must, to give at least this length of run way, be a square measuring 2,000 yards a side. This gives an area of four million square yards or, in more familiar figures, 825 acres. The value of this, if near a town, will be considerable. To allow for swings and other deviations in unfavourable weather conditions, it is gener ally agreed that runways should be some 300 yards wide. That would represent something like tin' equivalent of 7 miles of runways in an airport of 2,000 yards a side. This is not quite a fair figure to take because the whole airport area would not be runways. But even if we take, within our hypothetical air port of 2,000 yards side, only four runways, the total is still impressive. If we think of our airport as lying with two of its sides facia south and two facing east-west, the south-west-north-east and south-east-north-west diagonals would measure 2,830 yards each. The north-south and east-west runs would be 2,000 yards. These four runways would total a distance of about 5J miles. If aircraft characteristics were such that the four run ways could be placed end to end, we should thus have a runway 5J miles long! Even the largest and most heavily loaded aircraft envisaged should not require more than that. This distance compares with the 2,830-yard diagonal of the square airport. The advantages are too obvious to need stressing. From the technical point of view it has been proved pretty thoroughly that it is possible so to equip aircraft that they can land safely and take off safely with the wind at right-angles to the runway. The idea is far froai new, but it deserves the most careful study by our Direc torate of Civil Aviation, aircraft operators and municipal authorities The scheme was fast proposed in 1938, when Mr. The Maclaren drift undercarriage on a Mustang. The wheel-setting mechanism is behind the shock-absorber leg. north- O. F. Maclaren devised what he called his drift under carriage. It was tried with a fair measure of success on the little Arpin pusher monoplane. The idea was so to arrange the undercarriage (in the Arpin this was a tri cycle) that the wheels could be set at the angle of drift so that although the aircraft was were parallel with the flight path s "crabbing" the wheek |fe The outbreak of war put a stop, for a time, to further progress, but later Airwork, Ltd., of Heston, Middlesex, took up the idea and developed it. Several types of air craft, single-engined and twin-engined, were fitted with the Maclaren pre-set undercarriage, and in all cases it was found that, from a technical point of view, it did all that was claimed for it. It now remains for interested people to decide whether the additional one per cent, of the loaded weight which this undercarriage represents compared with the orthodox type is not well worth while. The system is applicable 10 tricycles but equally to the tailwheel type. The additional weight of a tricycle is approximately 3 per cent, of the loaded weight. Boundary Layer Control READERS who perused the article which appeared under the above title in last week's issue of Flight will undoubtedly have noticed the discrepancy which existed between the illustration in Fig. 5, page 261, and the text which purported to relate to it. We regret to state that the illustration which appeared was inserted in error, and to rectify the matter we publish herewith the correct illustration of the Bristol exhaust- actuated boundary layer control proposal, together with a reprint of the relative text. A project sponsored by the Bristol Aeroplane Co., Ltd., A. H. R. Fedden and F. M. Owner, in 1936, is shown dia- grammatically in Fig. 5. This is of interest as it employs the energy of the exhaust gases from a normal engine, which would otherwise be lost, to suck in the air from the boundary layer over part of the upper surface of an aero foil. No demand is made on the power output of the engine and no auxiliary source of power is required. A radial engine driving an airscrew is mounted forward of the leading edge of the whig of what is apparently a very large aircraft. The exhaust gases are collected in a ring A, located at the leading edge of the engine cowling, and delivered by a tail pipe B to a mixing chamber C. The upper surface of the wing, along a band D lying at about the middle of the chord and running lengthwise of the wing, is formed with a series of perforations. These are preferably small, closely pitched holes, say, one sixty- fourth of an inch diameter and spaced one-quarter of an inch apart. An inlet conduit E leads from the perforated strip to the chamber C, lrom which a conduit F leads to an outlet orifice in the lower surface of the wing near the trailing edge. From the tail pipe the exhaust gases discharge through a Melot-type multiple ejector-nozzle, or " thrust-aug- mentor" G. Together, nozzle G and chamber C constitute a fluid ejector which draws air through the perforated strip D, along the conduit E to the chamber and expeis it rear- wardly, together with the exhaust gases, through conduit Fr^ The path from the perforations to the outlet is designed to give a smooth flow and diverges gradually to the cham ber and then converges to the outlet. In this manner the kinetic energy of the air in the conduit E is converted to pressure energy. In chamber C the air is entrained by the exhaust gases and in flowing to the outlet the pressure energy is reconverted to kinetic energy and a forward thrust is obtained to assist the propulsion of the aircraft. Fig. 5 Bristol exhaust-actuated boundary layer control.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
