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Evening Post, Volume CXIX, Issue 152, 29 June 1935, Page 30

WORK IN SHIP DESIGN

PHYSICAL LABORATORY

The increasing prosperity of the country had been reflected hi the ins creased demand for industrial investiL' gations at the National Physical i. Laboratory, states a "Manchester f j Guardian" summary of the report of s I the laboratory for 1934. j :" This increase had been most marked a in the work called for by the ship--2 building industry, and the number of I ship designs submitted to model tests ' had bQen the greatest in. the life ofj 1 the laboratory, the total being sixty, t The modifications ■ suggested and . car- ■ ried out in these designs by the labora- ' tory had affected large improvements in the resistance of a number of these , vessels. - "Assuming that only one ship of each [ type is built, that each of these ships j i is steaming for only 200 days a year, | > and that the life of these ships is ; twenty years, the net saving' to the mii dustry in coal bills alone will be ; £500,000," it is added. ; An investigation on the behaviour ■ of ships in rough weather had shown , that a first-class high-speed passenger : ship for Atlantic service should be more than 700 ft in length. This length is considerably exceeded by modern vessels of this type. For cargo vessels the length should be 450 ft or more. BIG WAVES. Observations were made of the ' height of waves in the Atlantic and the distance from crest to crest. In an Atlantic storm the waves may be up to 25ft high, rising to 40ft in a hurricane. The distance from- crest to crest may be* about 275 ft. Research work previously completed j on coastal vessels had shown that the shape of hull could be modified to give an average improvement of some 10 per cent., and during 1934 it has been found that by suitable' design of the propeller a further gain of some 7 to 10 per cent, can be obtained on these vessels. Full-scale trials of two vessels showed that the improvements on the model were actually achieved on the ship itself. > / In view |of the fact that aJ flying speed ,of 440 miles an hour has been attained, a new wind tunnel has been designed, and is in operation, which can be used for studying the behaviour of miniature aerofoils a few inches in length at a wind speed of 650 miles an hour. , Virtually all the radium used in the hospitals of the country is tested at the laboratory, and. five or six containers (about £400 worth of radium) are dealt w,ith every working day. In all the value .of the radium tested at the laboratory approaches £1,000,000. COLOURED MOTOR LIGHTS. Tests had been made with the object of determining whether colouring the beam of a motor-car headlight enables the driver to pick up objects at a greater distance in foggy weather. The colours tested were red, light orange, dark orange, and blue^green. It was found that the effect of colour filters on the range was simply that due to the reduction in the intensity of the beam. In other words, the revealing power*-of a coloured headlight beam is the same as that of a white be, am of the same intensity. Tests made with the object of enabling an aeroplane to fly stalled— i.e., as slowly as possible without losing control—had led to the trial of a new biplane arrangement in which the; upper wings* are very much tapered, while the lower wings slope considerably so that their tips come close behind the narrow tips of the. upper wing. This arrangement was found to be as good as a normal biplane as regards performance and to have a much higher degree of steadiness in stalled flight. ■ Whereas the normal machine usually tends to ,become unsteady and "drop a wing" at an angle of about 20deg with the line of, flight, the new biplane remains steady up to an angle of nearly 40deg. The new arrangement should be attractive as the basis of a design for a very safe and controllable private aeroplane.