MONOPLANE “SOUTHERN CROSS.”

Hokitika Guardian, 6 September 1928, Page 4

MONOPLANE “SOUTHERN CROSS.”

PROPELLERS. Tho propellers on tho “Southern Cross” itro made of “Micarta” by tho Wcstinghoii.se Electric and Manufacturing Company, East Pittsburgh, Pennn, U.S.A., whoso New Zealand distributors are Messrs 'Turnbull and Jones, Ltd. Tho basic material of Micarta is an especially woven cotton fabric impregnated with phenolic resin, which solidifies into a tough substance of great strength under the combined application of beat and heavy pressure.

In tbe manufacture of propellers tbe impregnated cotton fabric is cut in templates which when built up, layer upon layer, assume tbe exact shape and size of the finished propeller. These laminations of fabric arc then accurately measured and adjustments made, by removing or adding layers. About 22fi laminations make up ono propeller. Tho pile of fabric is next placed in a highly polished bronze mould and heated by steam, a bead pressure of several hundred tons being simultaneously applied. Tbe beat and pressure are kept in tbe mould for several hours until the laminated fabric lias become a solidified substance of uniform structure. After cooling, the propeller is taken from tbe mould and small burrs and “fins” incidental to moulding are stripped off. No other finishing is necessary, ns the propeller in moulding lias taken on the high smooth finish that had been given to the surface of tbe mould in polishing it. . , . The propeller is then sawed through the middle of the hub, making two separate blades; tbe bub end of each is then rough machined to fit a steel balancing arbor and a preliminary check on balance is made. Alter this check, the hub of the blade is finished to 'fit the steel hub and a final balance is taken. Each blacle is balanced separately against a standard, thereby making Khem interchangeable. At the time of balancing each blade is checked for angles, track, width, thickness and surface defections, the blade is now a finished product. AVcstinghou.se Micarta propellers have figured in several of the recent trans-oceaiiic flights, among which are the successful “hops” of Lieutenants Maitland and Hegenberger in their large tri-motored Army Fokker plane, and Martin Jensen, pilot of the Breese monoplane “Aloha” which finished second in the Dole race from Oakland, California to Honolulu. The Bureau of Aeronautics, of the United States Navy, uses Micarta propellers extensively a.nd several of tlie more important airplane builders have selected thorn as standard equipment. AVater and moisture have no effect on Micarta propellers and stone bruises will not splinter them. Due to the resiliency of Micarta, there is no tendency of the propeller to crystallize. Another advantage is that Micarta is considerably lighter in weight than metal, weighing about one half as much ns aluminium and change of temperature, which is a handicap to wood propellers, has no effect upon it.

Micarta. is also used for such accessories as control-wiro pulleys and fair loads, and aileron, elevator and rudder hinges. Tho pulleys, fair loads and hinges all have graphitized self-lubri-cating bearing surfaces which reduce friction and wear to a minimum,

Micarta control-wire pulleys are now used by every prominent aircraft manufacturer in the United States and were part of the equipment of such famous planes as iho “Spirit of St. Louis.” “America,” and the "Columbia” which were used in the trans-Atlantic flights of 1 Colonel Lindbergh, Commander Byrd and Chamberlain respectively.

The propellers of the “Southern Cross” on its arrival here are not the original propellers used for the transpacific and trans-Australian flights, but are new ones, duplicates of those used for the original great flights, and were presented to 'Squadron-Leader Kingsford Smith by the AA’estingliouseCompany. Two of tho original propellers are being returned to East Pittsburgh and will be kept as souvenirs, tho third of the. original propellers is being retained by SquadronLeader Kingsford Smith and FlightLieutenant Charles Ulm, one blade each.