MOST UP-TO-DATE

Hauraki Plains Gazette, Volume 52, Issue 3245, 29 March 1943, Page 6

MOST UP-TO-DATE

LATEST TANK ARSENALS AUSTRALIAN PRODUCTION RECENT DISPLAY IN SYDNEY The recent display in the streets of Sydney of Australian cruiser tanks on their way from the New South Wales production line for delivery to the Army for final inspection and test under service conditions, throws a spotlight on the greatest manufacturing spectacle that Australia has seen since the war began—the production by our own engineers of the main armaments for our armoured divisions (states Edward Axford, in the Sydney Morning Herald).

The factories in which the tanks are built are the most up-to-date, Ibest equipped tank arsenals in the world—because they are the latest. Before building them, two Australian engineers were sent to the United B'ates to study American mass production methods.” They saw how the American automobile and locomotive industries are achieving production miracles which will shortly astound the world, and.' they came back with advanced, ideas about factory techn;que. The result is the rise of two great Australian lines for the production and assembly of tanks, the marshalling of local industrial resources and the manufacture of guns, machinery and armour steel on a scale hitherto believed impossible in this country.

To-day we are making what is probably the 'best cruiser tank ever built, a tank of original design, strongly protected and heavily gunned.

A visit to an Australian tank assembly plant is an awe-inspiring experience. Under the lighted vault of a huge saw-tooth roof, 500 ft. long and 14<'ft. wide, runs a double railway track. It begins at the door you have ?n ered, travels the full length of the factory until it is almost out of sight her doubles back and emerges at the door opposite.

This is the assembly line. Stretched along it, from one end to the other, is a long column of steel-grey monsters, score after score of squat metal robots sbH with caterpillar tracks. Contours are rounded, smooth and streamhue d to deflect enemy shells, the silhouette is low to reduce visibility and each circular turret projects the muzzle of a gun. This is Australia’s own cruiser tank, Australian in everything except the engines which power it. It is the land battleship our armoured divisions have been waiting for.

It was designed by a group of young Australian engineers and draughtsmen to fit in with the manufacturing facilities found in Australia and. at the same time fulfil the specifications demanded by the Army. To advise the designers on the fight-

ing characteristics of the latest tanks a British tank expert, Colonel W. D. Watson, was sent out from England at the request of the Federal Government.

The new tank is remarkable for a

large number of original Australian features. Apart from details concerning armament, armour protection, and performance, . some interesting facts may be disclosed. It is the fastest tank of its weight in the world. It is the first tank in the world to have a complete armoured steel hull cast as a solid unit. The tank is armed with Australianmade guns of both large and small calibre. The main gun is mounted in a revolving turret with a 360 degrees traverse, enabling the gunner to swing the muzzle completely round the compass and engage targets in front, to the sides, and to the rear. There is a crew of five, commander, gunner, loader, driver and forward gunner. Helpful Factors

In building tanks of this type we were helped by a number of very important factors. For one thing, we had a considerable field of precision engineering to draw upon. We were producing our own armour, thanks to the enterprise and ingenuity of the Australian steel industry. We were making tank weapons of more than one calibre and they were just as good as 'he guns made in Britain and' America. Finally, we were manufacturing a great deal of the ancillary equipment that goes into a tank, including the radio gear, and optical glass for the periscopes.

The things we were not making were he engines and transmission gear. These involved tremendous problems. American tanks were equipped with aero engines, but the United States tank programme was already experiencing difficulties because all the aero engines were needed for building bombers. The Germans used Diesel engines, not the ideal engines for

tanks because they compel the army to duplicate its oil supplies. Began To Experiment

Australian experts began to experiment. In the United States they had seen multiple petrol engines used in armoured cars. They decided to adapt the idea to the Australian tank. It meant a complete revision of the design for the transmission, creating new gear ratios which had to be dealt with in an original way. There were pessimists, .'both here and in America, who said it could not be done. The Australian designers insisted, however, that it was the only way; that unless we improvised on the engine problem we would never get anywhere. They staked their reputations on this view and won. What began as a makeshift power unit is now 'being copied in the tank factories of America.

The credit for this achievement belongs to the Director of Armoured fighting Vehicles Production, Mr A. R. Code, and his staff of designers, archi-

tects and engineers. Mr Code, who has been a lifelong student of engineering problems relating to the mechanisation of the armed forces, visited America late in 1941 to clear away difficulties immediately associated with our tank-building programme.

In the great new steel foundry and machine shop where the construction of the tank begins, the hull is cast in one big hollow piece. To a thunderous symphony of giant hammers, drills, .guillotines and steel-cutting saws, muscular workers pour streams of flowing molten metal into gargantuan moulds. It is a revolutionary technique in tank construction which supersedes the old way of building them out of riveted or welded steel plates.

The new technique is quicker and cheaper. It used to take 1000 manhours to fabricate a frame-riveted tank. Only 100 man-hours are required to complete a cast-hull tank. More important still, it makes a better tank. Tanks built of riveted steel plates suffer inherent weaknesses. When a shell strikes a rivet the terrific impact may drive the rivet into the tank, where it will ricochet like a bullet. Casting prevents such penetration, making a safer, stronger and tougher tank.

The tank’s armour is never the same thickness all over. The vulnerable parts are more strongly protected than the others. This is where cast armour is superior to both riveted and welded armour.

The designer merely makes the mould thicker where he wants thickness, and the molten metal, poured into the hollows, does the rest. At one and the same time you eliminate overlapping plates and angle-pieces, reduce weight and achieve maximum engineering

' simplicity. Each hull is cast in one piece. The turret that accommodates the main armament is also cast in a single unit. Casts of this size are not new to foundry practice. - America has been building railway locomotives in this way for many years and 25 of them were ordered for the New South Wales Government Railways long before the war. But no one thought of applying the technique to tanks until Canada showed the way with a partly cast tank hull towards the end of 1941. The United States quickly followed suit with the Mark 4 tank, known as the General Sherman, in 1942. But Australia is, still the only nation to cast the complete hull. The others do not cast the complete job. Their technique still involves the welding of rolled armour plate to a cast armoar hull section.

To see the casting in operation you enter a vast factory, 300 yards long and 100 yards wide, where giant furnaces, roaring all day and night, melt 10 tons of steel at a time. Here, too, are the great gas-fuelled annealing ovens, which bake the castings for 36 hours, anneal, harden and temper them. They are the largest gas furnaces in Australia. Machines which were unobtainable from America were built in our own factories. One big lathe,, the largest in the southern hemisphere, was made in Australia at a cost of £20,000. It performs half a dozen machining operations at a time. Two-year Programme Our factories are not Chrysler arsenals, but output is scheduled to fit in with Australian needs. To have attained mass production by the end of 1942 is a creditable achievement considering that more time was occupied in planning the tank than in equipping factories for production.

The Commonwealth Government decided to build tanks in Australia just after the fall of France in June, 1940, More than a year was spent in gathering information from Great Britain, the United States and Canada before the task of designing the tank got under way. To achieve mass production in time, the Directorate of Armoured Fighting Vehicles Production had to

get to work while the design was still in a fluid state, taking a chance while the tank architects were still uncertain.

The first hull was cast in 1941, and the first pilot model was soon ready for testing. Army and munitions experts who watched the first tank on manoeuvres early this year breathed a sigh of relief as they saw a superlative performance. It was worth all the sleepless nights of planning, all the labour and brain-fag. Mass production began nine months after the

The bottle in a carton gay Worth more than thrice the price we

pay; The bottle “blown” to safely hold Relief for every form of cold., The bottle filled with ease for Croup,. When anguished children gasp and droop; The bottle with such clinic force Holds Woods’ Great Peppermint Cure,, of course. W. E. Woods Ltd., Lambton Quay, Wellington.

design had been finally agreed upon. In peace-time it would have taken three years to attain a similar result.