WELL AHEAD

Evening Post, Volume CXXIII, Issue 102, 1 May 1937, Page 10

WELL AHEAD

RONGOTAI HANGAR

SPECIAL COVERING MATERIAL

IMPORTED DOORS v. •'.-'•■■.

The building of the new hangar at Rongotai is now well ahead, and there does not seem to be much doubt that it will be ready for the accommodation of the Wellington-Auckland service planes when this fast airline commences operation about the, middle of the year. The steel: frarrfe is practically complete, and the specially-protected roofing and walling-sheets are being bolted down. These corrugated sheets, of heavy-gauge steel, are coated with a ...protective seal of asbestos and bituminous compound, which covers edges las well, as both surfaces, so that corrosion is as fully guarded against as possible. . The sheets are supplied to the , -exact dimensions required, and so go into position with the seal unbroken. The lower part of the walls of the hangar will be mainly glazed, and this work has not yet been commenced. - The question of the type of door panels to close the 130 ft opening'was ■t discussed very fully before the decision was made to import the panels •» ready for hanging. The economies which, on paper, might have been 'effected by local manufacture appeared 'attractive, for imported doors run fairly high, but there are plenty of catches in building door panels 12ft wide and /.30ft high and guaranteeing that when they are in position they will keep out weather and sand and still run easily enough for hand operation when a'heavy wind is jamming them on the .-.rollers. . •■ "'"The specifications for the Rongotai . hangar doors had to be drawn tightly, -for the wind and sand drift complica- , tions there are at times bad enough, and driving sand and salt spray make . ;for early corrosion troubles. An order was therefore placed with a Canadian firm which specialises in this one branch of hangar construction. KEEPING THE HEIGHT DOWN. As each additional foot of height of the hangar would mean a reduction of about ; .ten feet in the •effective, length of the already-limited runways in the line of the building the overall height chad to be kept down as far as was "I practicable, and consequently the usual -method of hanging the doors from upper ■"rollers (which system requires a deep -truss) could not be followed, and the panels of the Rongotai hangar doors will run on bottom rails, one for each :: panel. This arrangement has, however, • certain advantages, one of which is . that one panel maybe run back independently of the others. BUILT FOR ANY WIND. The hangar-has been designed with an ample margin of strength against heavy winds, and though the strongest gales so far recorded at Rongotai have not exceeded about 80 miles an hour in their worst gusts, doors, roof, and walls have been designed to stand up -, to" 100 miles an hour blows, with, ol course, the usual engineering safety :: margin over the worst anticipated. The ■roof trusses have been designed to take the heaviest lifts anticipated as necessary when machines are being ■J overhauled. The sweep of the roof back from the truss abpve the doorway is very like the sweep of an aero- : plane wing, not out of any desire to fall in with the streamline craze because everybody's doing it, but because the calculations of the engineers showed that that was the most economical form for a great expanse of roofing exposed to the lifting effect of heavy 'southerly winds, for that lift is a double- lift; the direct push upwards from wind trapped by roof and walls, and the low-pressure lift above and to the rear of the hangar. So if the Rongotai hangar has that up-to-the-moment aeroplane sweep it is because it pays, not because it's the fashion. WHEN MORE MACHINES COME. The old hangar is enclosed in the new hangar, the roof trusses of which are well above the old roof peak,; and as soon as the new structure is sufficiently ahead to give protection to •club and visiting machines the shed will be demolished and the work of laying the floor pavement will be commenced.

If there is a point of doubt about the new hangar it is whether it will be large enough to accommodate both the commercial and the club and other light planes which may be-operating to and from Rongotai in a few years, during the Exhibition period for instance. The' hangar construction is such that it may be lengthened as the need arises, but before that could be done : the ■ other buildings, one of which, the clubhouse, has already been once moved, would have to be spaced further apart.

That, however, is a problem that will not have to be met for some time. In the meantime a much more troublesome problem has to be solved: how is Wellington to go about enlarging the aerodrome to give the margin of safety essential for the operation of larger transport planes. It will just be ridiculous if Wellington cannot receive Exhibition visitors by air from north and south because the aerodrome, next door to the Exhibition, and the aerodrome, not of a country centre, but of the capital city, is too small for the large machines that could be filled by Exhibition trippers.