BIG JUNKERS

Wairarapa Times-Age, 12 November 1938, Page 9

BIG JUNKERS

FOUR AIOTORS AND WIDE RANGE

BUILT FOR BOMBERS. TRANSFORMED INTO AIR LINERS. About two years ago the German Air Ministry placed orders with several German aircraft manufacturers for large four-engined aeroplanes (writes Wayne Thomis in the “Chicago Tribune”). It then was believed that very large aircraft offered advantages over smaller machines —advantages in speed, range, and military load which offset the increased initial cost and the larger numbers of trained men needed for the crews.

These theories followed the trend of thought in the United States, where the Army Air Corps purchased the Boeing B-17 and B-15 four-engined bombardment planes and the navy ordered four-engined patrol bomber flying boats from the Sikorsky and Consolidated companies. But conditions in Europe are very different from those in the United States. Great range was not as necessary there as it is here. Smaller, less expensive military bombers were built and flown. They demonstrated that they were perfectly fitted for operations over the European continent, cost less for each ship, and needed smaller numbers of men in their crews. For a fixed budget and a small number of trained airmen, more of the smaller ships could be put into the air than of the larger bombardment planes. Accordingly German’s Air Ministry heads changed their policies to meet this situation. Orders for the large bombers were cancelled, and the manufacturers, in order not to loSe the funds already invested in engineering data and partial construction of the planes, transformed them from bombers into commercial air liners.

FIRST TO BE FLOWN. The first of these metamorphosed monsters to be completed and flown was the new Junkers Ju 90 —named der Grosse Dessauer (the Giant of Dessau). Dessau is the town in which the Junkers works is situated. This ship is the German equivalent of the new Douglas DC-4, and the Boeing fourengined air liners which will be flying in this country soon. The Junkers company pioneered the all-metal low-wing type of aeroplane, building the world’s first purely commercial machine to this formula in 1919. It has held to the same principle in all its subsequent craft, retaining it in this, its largest aeroplane built to date.

Many of the earlier Junkers machines had a corrugated outer skin, crinkled to add strength, but in the Ju 90 the corrugations have been put inside, with a perfectly smooth outer skin, as in the latest American machines. The Ju 90 is similar to American aeroplanes also in that its tail is of the popular double fin and rudder type, with these surfaces at the outer edges of the tailplane. In its present form the Ju 90 is capable of carrying 40 passengers at a cruising speed of 225 miles an hour. It is said to land at less than 60 miles an hour —due to the Junkers double wing flap and to a split trailing edge flap fitted under the fuselage. Incidentally, this is the first use of the split flap by the Junkers company. EQUAL TO AMERICANS. This performance, which has been proved by test flights, is equal if not better than the best similar American aeroplanes. The new Boeing is supposed to have a cruising speed nearly equal to that of the Junkers, but the Douglas is expected to be definitely slower. The three ships are, however, not exactly comparable, for they differ in size, weight and power. The Douglas is a 60,0001 b machine, the Boeing a 43,0001 b craft, and the Junkers weighs 50,7001 b fully loaded. Both the Boeing and Douglas planes have 3,000-mile cruising ranges, while the Junkers has a 1,200-mile range with full passenger load or an ,1,800-mile range with reduced pay load and more fuel. Dimensions of the Junkers are as follows:—Span, 114.8 ft; length, 103.5 ft; the main passenger cabin is 34.5 ft long and 9.Bft' wide. The seats are arranged in pairs on each side of a central aisle. Four seats form a compartment. There are large baggage holds behind the main cabin and under the flooring.

Lavatories also are at the rear. COCKPIT IN THE NOSE. In the nose is the pilot’s cockpit, with dual controls, complete flying, navigating, and engine instruments, and a special seat for a radio operatornavigator. The amount of room inside the plane is best seen before the sound proofing is in place. Factory memoranda assert that the sound proofing has been unusually well done, virtually cutting off all motor roar.

The factory description of the plane states that its construction is robust, entailing minimum expenditure on maintenance and repairs. All-import-ant components have been designed for easy accessibility and replacement. Any engines of 800 to 1,200 horsepower can be fitted. In the first machine Junkers Jumbo 211 engines, Vl2 inverted, liquid cooled, and delivering 1,100 h.p. for take-aff, are standard. They turn controllable-pitch propellers. The two main landing wheels retract in flight into the engine nacelles behind the inboard engines on each side. These engines are not Diesel types, but standard four-cycle, electric ignition motors.

The Ju has a top speed of 255 miles an hour at 2,000 ft with the engines delivering a full 960 horse-power at that altitude. This extreme speed is part of its heritage as a bomber.