THE INDIA RUBBER WORLD 



Giant Tires for Handley-Page Airplanes. 



iiade for any pur- 

 iiidlcy-Page air- 



PROBABLY the largest pneumatic ti 

 pose arc those with which tlic fan 

 planes of the British Government are being equipped. They 

 are Palmer Cord Aero Tyres 1500 by 300 mm. (59 .x 11.8 inches), 

 or approximately five feet in diameter and one foot in cross- 

 section, and greatly exceed all regulation pneumatic-iirc sizes 

 for either airplanes or motor trucks. 



The 1918 S. A. E. specifications for United States Government 

 airplane landing wheels specify four sizes, the largest of which 

 is 800 by 150 mm. (32 by 6 inches), the others being 750 by 

 125 mm. (30 by 5 inches), 700 by 100 mm. (28 by 4 inches), 

 and 700 by 75 mm. (28 by 3 inches). It was anticipated, how- 

 ever, that larger sizes would probably be required and added to 

 the list. The specifications call for tires of tlic rlinrhcr type. 

 smooth tread, constructed 

 of two or more cord plies 

 of long-staple cotton, so 

 arranged that an equal 

 number of plies run in 

 each diagonal direction 

 across the tire, each ply 

 being separated from the 

 adjoining ply by rubber 

 compound. Even the giant 

 cord pneumatics now lie- 

 ing turned out by .\meri- 

 can manufacturers are 

 dwarfed beside these 

 Palmer airplane tires, the 

 largest pneumatic truck 

 tire regularly on the mar- 

 ket being 48 by 12 inches, 

 and other sizes beins '_' 

 by 9, 40 by 8, 38 b> f, 

 and 36 by 6. 



That . these giant tires 

 are needed becomes evi- 

 dent on considering the 

 size and weight of the 

 Handley-Page airplane. Its wing sp 

 the span is 12 feet, and the length 



Underwood & L'nderwood, N. Y. 



Tjre Equipment of 



I is 126 feet, the width of 

 f the fuselage is 65 feet. 

 Equipped with a 350-h.-p. Rolls-Royce engine and known as the 

 "Berlin Bomber," it weighs 15 tons fully loaded, over 5 tons 

 of which is useful load. 



This type of machine represents tlic maximum achievement 

 in heavier-than-air flying during the war, and now promises to 

 be used extensively in commercial aviation, as it is able to carry, 

 for example, a five-ton load of passengers, mail, or merchandise 

 in a non-stop flight equivalent to the distance between Boston 

 and St. Louis, in twelve hours. It will be recalled that one of 

 these great airplanes flew from Ipswich, England, to India, a 

 distance of 5,800 miles, last winter and covered 700 miles of 

 the distance over the Mediterranean, which was a record flight 

 for a land machine flying over water. It is also one of these 

 machines which recently arrived in Newfoundland, and witli 

 which a transatlantic flight will be attempted sometime during 

 the month of June. 



As compared with the airplane tires of former years these 

 latest and largest tires represent a startling development. In 

 the early days of aviation all sorts of makeshifts were resorted 

 to. Bicycle and motorcycle tires of fabric construction were 

 first employed on some of the pioneer machines, but they proved 

 costly and uncertain. Later, as larger and heavier machines 

 were constructed to carry more passengers and heavier loads. 



some builders even went so far as to use full-size automobile 

 tires. The latter answered so far as reducing the shock of 

 landing was concerned, but were far too heavy and offered too 

 much wind resistance. 



The development of special tires to fit the peculiar require- 

 ments of aviation began about 1910. It was soon discovered 

 that great resiliency is a very important factor and that a live, 

 springy tire not only helps to absorb the shock of landing 

 but actually aids the machine to get oflf the ground at the begin- 

 ning of a flight. The need of security against punctures and 

 blowouts was also appreciated. As the superior resiliency of 

 cord tires for motoring had become recognized and the success 

 achieved by this type of tires in automobile track races had 

 demonstraicd their dependability, experiments were made with 

 cord tires in aviation, with 

 the result that cord tires 

 t r airplanes have been 

 1 intd to a point of effi- 

 1 nc\ equal to that of 

 1 1 tires for gasoline and 

 'iLtric automobiles. 

 1 be Palmer was prob- 

 dl)l\ the first tire of cord 

 conbtruction to be 'used 

 for a\iation purposes in 

 England, and it has ever 

 since held a prominent 

 place among airplane tires. 

 Invented by an American, 

 John F. Palmer, of Chi- 

 cago, in 1893, this parallel- 

 thread fabric construction 

 was first used in racing 

 tires on bicycles and later 

 modified and first applied 

 to the manufacture of au- 

 tomobile tires in 1900. In 

 its latter form it was 

 known as the Palmer cord 

 the lighter Palmer bicycle tire. It con- 



to distinguish i1 



sisted of two layers of parallel-lying cords crossing each 

 other at such an angle that they were tangent to the rim and 

 nearly in the line of strain which falls upon all equally. Each 

 cord consisted of several threads carefully rubbered and flattened. 



More recently, as the disadvantages in using round cord were 

 recognized, a new type of ribbon of flat cord approximately 

 one-half inch wide was developed. These inextensible flat strips 

 can be placed on the tire core at a true tangent to the rim, that 

 is, at right angles to the spokes of the wheel. This position 

 gives the most efficient power transmission from the rim to the 

 tread for the reason that force is best transmitted in straight 

 lines. 



In America The B. F. Goodrich Co. in 1910 introduced as a 

 regular product an airplane tire which in construction was a 

 modification of the Palmer bicycle tire. It was smaller than a 

 bicycle tire in diameter, but of larger cross section, being 20 by 2 

 and 20 by 2;4 inches, .\bout the same time the Continental 

 Rubber Works was making airplane tires in these same sizes 

 and also 20 by 3 inches. The Pennsylvania, Goodyear, and Hart- 

 ford companies were offering airplane tires 20 by 4, 26 by Zyi, 28 

 by 2H, 28 by 3 and 28 by Syi inches and weighing 65/2 to 8J4 

 pounds each, the former company featuring leather as well as 

 rubber treads. Two of the 20 by 4 tires were said to be capable 

 of carrying a 1,000 to 1,200-pound flyer. 



