Martin China Clipper
Самолет Model 130 China Clipper, предназначенный для длительных трансокеанских перелетов, представлял собой четырехмоторный моноплан, спроектированный по схеме летающей лодки с двухреданным корпусом совершенно новой конструкции.
критериям Model 130 превосходил DC-3, и три лодки закупила в 1935 году авиакомпания "Pan Am". Экипаж каждого гидроплана состоял из четырех человек, лодка в дневной полет могла брать на борт до 48 пассажиров. Силовая установка включала четыре мотора Pratt & Whitney R-1830 Twin Wasp мощностью по 600 л. с., установленных на передней части крыла.
Flight, January 1935
AMERICA'S LATEST "CLIPPER"
The New Martin Trans-oceanic Flying Boat: Accommodation for Fifty Passengers: Mail Range of 4,000 miles
A MAXIMUM range of about 4,000 miles is calculated for the new “Clipper” flying boat launched recently by the Glenn Martin Company for Pan American Airways. This figure is for mail-carrying purposes. When the craft is used as a carrier of both mails and passengers the range is estimated at 3,000 miles. The estimated maximum speed is about 180 m.p.h. and the cruising speed 160 m.p.h. At 75 per cent, of the available power the duration should be slightly over 20 hours, and at that power the calculated speed is 145 m.p h.
The general arrangement drawings, for which we are indebted to our American contemporary, Aero Digest, show the shape of hull and wings, and it will be seen that a slight "gull's wing" shape has been given to the centre-section.
For ordinary ranges the machine can be equipped with passenger accommodation for fifty, but at present the cabin layout is being arranged for eighteen, with settees so designed that they can be converted into berths. This arrangement has been chosen with the trans-Pacific service in view. By carrying the engine exhaust pipes back over the top of the wing, and by suitably lagging the walls of the cabins, the noise level has been reduced to 72 decibels, which is approximately equivalent to the noise in a Pullman carriage on a straight and fairly good track.
The First Test
On the first test flight, carried out by Mr. W. K. Ebel, the Martin company's test pilot and assistant chief engineer, the machine left the water in twelve seconds.
Interesting features of the Martin "Clipper" are the use of sponsons for maintaining lateral stability on the water, and the stowage of the fuel (4,000 American gallons) in the hull. In this country it has for many years been the practice to put the fuel tanks in the wings, well away from the hull, so as to reduce fire risk. In the Martin the lower portion of the hull itself forms the petrol tanks, and it is probable that a considerable amount of weight has thereby been saved. It will be remembered that in the giant Dornier "Do. X" twelve-engined flying boat the tanks were also housed in the lower part of the hull. During the discussion on Dr. Dornier's lecture at the Royal Aeronautical Society several speakers expressed doubts as to the wisdom of this placing of large quantities of petrol. Presumably the Martin engineers have decided that the fire risk is smaller in practice than might be expected, there is certainly something to be said for the arrangement from the aircraft designer's point of view, for not only does he save most of the weight of the fuel tanks, but he lowers the centre of gravity of the boat a great deal when the tanks are full. This is of importance when sponsons are used for lateral stability.
If the figures published are to be believed, the Martin engineer must have saved a very great deal of structure weight, not only in this manner, but in many others, as the empty weight of the machine is given as 23,100 lb., while the gross weight is 51,000 lb. This would give a ratio of gross weight to tare weight of 2.205. In other words, the machine carries as disposable load approximately one and one-fifth times its own weight. If the figures are correct they show very great skill on the part of the designers. An average value is 65 per cent.
Power is supplied by four fourteen-cylinder Pratt and Whitney "Twin Wasp" engines of 800 h.p. each. The engines are located slightly forward of the leading edge of the wing, carried in streamline nacelles, and enclosed in long N.A.C.A. cowls. As already mentioned, most of the fuel is carried in the lower part of the hull, but a certain amount is carried in the sponsons. Engine-driven pumps transfer the petrol to service tanks in the wing. Three-bladed Hamilton Standard controllable-pitch airscrews are fitted.
The span of the monoplane wing is 130 ft., and the total wing area is 2,315 sq. ft., of which the sponsons account for 145 sq. ft. The overall length is 90 ft. At full gross weight the wing loading is just over 22 lb. per sq. ft., and the power loading 16 lb. per h.p. The machine has been designed to fly at 6,000 ft. with full load on any three of its four engines.
В ночных полетах Model 130 China Clipper компании "Pan Am" перевозил только 78 пассажиров, для которых в салоне оборудовались спальные места.
22 ноября 1935г.: компания "Pan American Airways" открыла первую регулярную почтовую авиалинию через Тихий океан полетом самолета Martin М.130 China Clipper из Сан-Франциско в Манилу, Филиппины, через Гонолулу, острова Мидуэй, Уэйк и Гуам.
AMERICA'S LATEST: Recently reported as having made the 2,100 mile flight between Alameda, California, and Honolulu in 17 hr. 9 min., this Glenn Martin "Flying Clipper," which forms part of the new Pan American equipment, has cut the previous time for the journey by 50 min. The engines are Pratt and Whitney Twin "Wasps" driving constant-speed Hamilton Standard airscrews. Passenger accommodation is for about 46.
CHINA CLIPPER: This, the first of the big Martin boats to be delivered to Pan American Airways, has now been put on the experimental trans-Pacific service between Alameda (California) and the Philippines. In its "daytime" layout, the China Clipper carries forty-three passengers and cruises at 157 m.p.h. for 3,000 miles.
Pan American's "China Clipper" was one of the three Martin M-130 flying boats.
An impressive flying picture of the first of the three Martin boats designed for long-distance transoceanic work - the China Clipper.
Styles from the States: The Martin 130 (four 800 h.p. Pratt and Whitney Twin Wasps). The gross weight is 51,000 lb. and maximum speed is over 170 m.p.h.
FOR THE PACIFIC? The big Martin flying boat, several of which are on order for Pan American Airways, on test near Baltimore.
On its first test flight the "Clipper" left the water in twelve seconds, flying "light."
FAR EASTERN TERMINUS: The Manila-Hongkong section of Pan-American Airways' Pacific service was covered for the first time at the end of October with Mr. Juan Trippe and nineteen passengers. In due course, Imperial Airways' Penang - Hongkong and Atlantic services will be used to carry passengers as well as mail and the Anglo-American girdle will be complete. Here is the Martin Philippine Clipper arriving at Hongkong.
FOR THE PACIFIC SERVICE: The Martin China Clipper at Baltimore before its first passenger flight as a unit in the Pan American fleet
"Seawings" is the name given to the stabilising members of the Martin. Aerodynamically they give 50 per cent of the lift of that of an aerofoil of corresponding area.
TRANS-PACIFIC. - The "Philippine Clipper" of Pan American Airways arriving at Hong Kong, where the trans-Pacific service connects with Imperial Airways.
AMERICA'S NEWEST: The Martin flying boat ordered for a proposed Trans-Pacific service of Pan American Airways. Note the sponsons for lateral stability on the water, and the cowling and placing of the 800 h.p. two-row radial engines.
TRANS-PACIFIC: This sectioned drawing of the Martin China Clipper, which is reproduced by permission of our American contemporary, Aero Digest, clearly shows its layout as a passenger carrier. The position of the main fuel tanks is interesting.