RUNWAYS AT HAREWOOD

Press, Volume LXXXII, Issue 24985, 20 September 1946, Page 6

RUNWAYS AT HAREWOOD

STABILISATION WORK EXPLAINED z

ALL-WEATHER SURFACE FOR ALL AIRCRAFT

Confidence that “stabilised” runways at the Harewood municipal airport would fully meet the requirements of air traffic to and from Christchurch for probably th*e next five years was expressed yesterday by the City Engineer (Mr E. Somers), in an interview with a reporter of “The Press.” Such runways, in the opinion of experts, would provide first-class conditlons f in all weathers, for aircraft of the internal air services and, should Harewood become an overseas terminal, for the largest" airliners, said Mr Somers.

Explaining the process of stabilisation, Mr Somers said that most persons knew the varying properties of sand and clay under the influence of moisture. A motor-oar might not be able to move at all in dry sand, but the same»sand when thoroughly wet would make an excellent travelling surface. Similarly, clay would provide perfect going when dry but would become nothing but a bog when wet. The idea of stabilisation wes to obtain combination of these properties, so that the surface became perfectly firm and safe for the landing and taking off of aircraft in all weathers. The landing field at Harewood was entirely shingle and sand, with a grassed surface. saidJWr Somers. The process of stabilisation would probably involve the addition of clay, a little fine silt, and possibly some fine screenings. Graders and rollers would work back and forth over it until it was p erfectly level and thoroughly consolidated. Finally the whole landing area would be grassed over, not only to help the consolidation, but also to keep dust and small stones from flying into the slipstreams. The process virtually gave a surface of stone held together with a sand-clay mortar. This might seem an unpromising seed-bed for grass, but experience showed that sufficient grass grew on this type of runway to achieve the objects stated. Such runways, said Mr Somers, would stand up to the amount of traffic that could be expected here in the next few years. Should it be necessary then to provide a paved surface, it was probable that bitumen rather than concrete would be favoured. The Shingle base with the stabilised surface would provide an ideal surface for bitumen paving. It would, in fact, be very similar to the foundation of bitu-men-paved ro?ds.