scholarly journals X. The aerodynamics of a spinning shell

1921 ◽  
Vol 221 (582-593) ◽  
pp. 295-387 ◽  
Keyword(s):  
National Physical Laboratory ◽  
The Other ◽  
Scientific Interest ◽  
Physical Laboratory ◽  
Heavy Work ◽  
General Scientific ◽  
Made In

This paper contains the results, theoretical and experimental, of work undertaken, at the request of the Ordnance Committee, by the authors as Technical Officers of the Munitions Inventions Department. Permission to publish such parts as appear to be of general scientific interest has now been granted by the Ordnance Committee and the Director of Artillery. The publication of this paper has received their sanction. The experiments in question were carried out at the firing ground of H. M. S. “Excellent,” Portsmouth; the Experimental Department, H. M. S. “Excellent,” also provided the 3-inch guns used and the material for the construction of the range. The authors’ best thanks are due to the officers of this department, especially Lieut.-Commander R. F. P. Maton, O. B. E., R. N., without whose cordial co-operation these experiments could never have been carried out; also to the other officers of the Munitions Inventions Department who assisted in the heavy work of making and analysing the observations. The aeronautical measurements at low velocities, required for comparison, were made in the wind channels of the National Physical Laboratory, by arrangement with the Director and the Superintendent of the Aero­nautical Department, to whom also we wish to express our thanks.

scholarly journals The pressure distribution on the head of a shell moving at high velocities

1920 ◽  
Vol 97 (684) ◽  
pp. 202-218 ◽  
Keyword(s):  
Relative Motion ◽  
Static Pressure ◽  
Dynamic Pressure ◽  
National Physical Laboratory ◽  
The Body ◽  
Physical Laboratory ◽  
University College London ◽  
General Scientific ◽  
Axis Of Symmetry ◽  
Made In

The pressure at any point of a body moving through a fluid may be considered to consist of two components — the static pressure , which would be the pressure at that point, if there were no relative motion between the body and the fluid—and the dynamic pressure due to the relative motion. The sum may be called the total pressure at the point, and is, of course, always positive; the dynamic pressure alone may be negative. Experiments, of an introductory kind, were undertaken by the authors, at the request of the Ordnance Committee, to attempt to determine, as a function of the velocity of the shell, the dynamic pressure at various points on the head of a shell, whose axis of symmetry and direction of motion coincide or nearly coincide. The results appear to be not without general scientific interest, and are therefore presented in this paper by permission of the Ordnance Committee. The authors’ best thanks are due to the officers of the Experimental Department, H. M. S. “Excellent,” on whose range the firing trial was carried out; to the other officers of the Munitions Inventions Department, who shared the work of observation and computation; to the Director of the National Physical Laboratory, where the comparative observations at low velocities were made in a wind channel; and, above all, to Mr. W. J. Goudie, of University College, London, on whose determinations of the rates of burning of powder-train time-fuzes at high rotational speeds the whole experiment was based.

“ Ten Years' Testing of Model Seaplanes ”

1923 ◽  
Vol 27 (149) ◽  
pp. 224-243
Author(s):  
G. S. Baker
Keyword(s):  
Experimental Work ◽  
Royal Society ◽  
General Meeting ◽  
National Physical Laboratory ◽  
The Other ◽  
Experimental Tank ◽  
Know How ◽  
Other Hand ◽  
Physical Laboratory ◽  
Hull Design

An Ordinary General Meeting- of the Society was held at the Royal Society of Arts, on Thursday, February ist, 1923, Professor L. Bairstow in the chair.The Chairman, in opening- the proceedings, said that Mr. G. S. Baker, O.B.E., of the National Physical Laboratory, would deal with flying boats and seaplanes. He would deal with the hull and its design, that part of the seaplane which differentiates it from the aeroplane. That subject had been touched on very lightly by Major Rennie at the previous meeting of the Society, in view of the present paper by Mr. Baker.Mr. Baker had begun work in 1912 on the problems of hull design, at a time when nothing of a definite nature was known; a few individual experiments had been carried out, but there was no systematised knowledge at all at that time. From that state of ignorance a great deal of experimental work had now rescued us. He did not know how far Mr. Baker would stress the point, but it was quite clear, from the investigation of certain accidents to seacraft, that there were fundamental differences in the behaviour of seaplane hulls on the water, differences which had a great deal of effect on the risk of flying-. For instance, if one type of hull was such that when the plane rose in the air it stalled, then all the aerodynamical consequences of stalling- followed, and there was difficulty. On the other hand, it appeared that we had a type of flying- boat which did not make the plane stall on getting into the air, and consequently if it came back to the water it was still controlled. For this type of development, which he believed really dated back to the C.E.i, we were mainly indebted to Mr. Baker and his associates at the National Physical Laboratory, and to the generosity of Sir Alfred Yarrow in placing such a magnificent piece of apparatus as the experimental tank at the disposal of the nation.Mr. Baker then read his paper on “ Ten Years’ Testing of Model Seaplanes.”

The Horizontal Wind Tunnel at East London College

1914 ◽  
Vol 18 (71) ◽  
pp. 302-307
Author(s):  
A. P. Thurston ◽  
N. Tonnstein
Keyword(s):  
Wind Tunnel ◽  
National Physical Laboratory ◽  
The Other ◽  
Horizontal Wind ◽  
Bell Mouth ◽  
Physical Laboratory

The horizontal wind tunnel at East London College consists of a wooden tube, .2 feet square in section by lift. 6in. long, through which air may be drawn at velocities up to 50 m.p.h. by means of a 6½ h.p. motor. It was designed and constructed by Messrs. Cedric Lee and G. Tilghman Richards from sketches supplied by one of the authors and was modified later by the addition of a wind disperser as the result of information kindly supplied by Dr. Stanton, of the National Physical Laboratory. This disperser was added principally with the object of reducing the draught in the room and of preventing pulsations of the air current. The tunnel is provided with a bell mouth to ease the air into it, and at the other end it is connected to the disperser by a metal duct, 3ft. 6in. long, expanding from 2ft. square to 3ft. 6in. diameter. The propeller is mounted in the enlarged end, which is cylindrical for some 7 inches, so as to draw the air through the tunnel.

scholarly journals An account of the pendulum observations connecting kew and greenwich observatories made in 1903

1906 ◽  
Vol 78 (524) ◽  
pp. 241-247
Keyword(s):  
National Physical Laboratory ◽  
Base Station ◽  
Central Bureau ◽  
Geodetic Institute ◽  
Secretary Of State ◽  
Physical Laboratory ◽  
The Government ◽  
Made In

1. The observations, of which a brief account is here given, had their origin in the decision of the Government of India to resume the pendulum work which was brought to a close in 1870. Professor F. R. Helmert, Director of the Central Bureau of the International Geodetic Association, to whose advice the India Office is much indebted, recommended the use of a half-seconds pendulum equipment as designed by Colonel von Sterneck. This equipment was ordered through the Geodetic Institute at Potsdam, and the constants for the necessary pressure and temperature corrections were determined there by Professor L. Haasemann, under Professor Helmert’s direction. A redetermination of these constants was made at Kew, at Professor Helmert’s suggestion, and results were obtained in very close accordance with those found at Potsdam. The apparatus gives only relative determinations of gravity; it was thus necessary to select a base station. As Kew Observatory had been the base station of the older Indian pendulum observations it was again selected, Dr. Glazebrook, Director of the National Physical Laboratory, having given permission and promised all necessary assistance. Meantime, a suggestion was made by the Astronomer Royal, and accepted by the Secretary of State for India, that the opportunity should be taken of swinging the pendulums also at Greenwich, thus allowing of a fresh intercomparison of g at Greenwich and Kew.

scholarly journals Leonard Bairstow, 1880-1963

1965 ◽  
Vol 11 ◽  
pp. 22-40
Keyword(s):  
Wind Tunnel ◽  
National Physical Laboratory ◽  
Practical Applications ◽  
Aerodynamic Derivatives ◽  
Physical Laboratory ◽  
Engineering Department ◽  
Tunnel Design ◽  
Wide Experience ◽  
Wind Tunnel Design ◽  
Made In

Leonard Bairstow was born at Halifax in Yorkshire on 25 June 1880 and began his education in the elementary and secondary schools of Halifax. In 1898 he obtained a scholarship at the Royal College of Science, London, where he was a fellow student of H . E. Wimperis, who declared in later years: ‘I remember that, for several decades there, the most brilliant student that had been produced by the College was Professor Bairstow. He had an uncanny faculty of making himself acquainted with and making completely original suggestions on subjects which we did not think he knew anything about.' He became a Whitworth Scholar in 1902 and took prizes in mechanics and astrophysics. In 1904 he entered the Engineering Department of the National Physical Laboratory. There he worked under Dr T. E. (later Sir Thomas) Stanton on problem s of fatigue and of aerodynamics. In 1909 he was appointed to the staff of the new section of Aerodynamics (later called the Aerodynamics Division), of which he became the Assistant (or Principal) in charge. During this period he carried out some pioneer investigations into wind-tunnel design, and made important developments and practical applications of the theory of aircraft stability due to G. H. Bryan. This theory he illustrated by the use of small mica models of aircraft, and the necessary measurements of aerodynamic derivatives were made in the wind tunnel. In 1917 he was elected a Fellow of the Royal Society and made a G.B.E. Glazebrook had offered him the post of Superintendent of the Aerodynamics Department at the N.P.L. but Bairstow resigned and was appointed to the Air Board to work for Sir David Henderson on the design of aircraft and on aerodynamics research. There Bairstow worked at the Hotel Cecil as deputy to Alec Ogilvie and, with his wide experience, was able to co-ordinate the departmental work on structural strength, aerodynamics, performance and air screws.

scholarly journals I. Experiments made to determine surface-conductivity for heat in absolute measure

1872 ◽  
Vol 20 (130-138) ◽  
pp. 90-93 ◽  
Keyword(s):  
Atmospheric Temperature ◽  
Limited Range ◽  
The Other ◽  
Thermo Electric ◽  
Metallic Contact ◽  
Physical Laboratory ◽  
Absolute Measure ◽  
William Thomson ◽  
The University ◽  
Made In

The experiments described in this paper were made in the Physical Laboratory of the University of Glasgow, under the direction of Sir William Thomson, during the summer of 1871. A set of similar experiments were made in 1865 ; but being merely preliminary, carried on by different individuals, and embracing only a limited range of temperatures, it is thought unnecessary to allude further to them here. A copper ball, 2 centimetres radius, having a thermo-electric junction at its centre, was suspended in the interior of a double-walled tin-plate vessel which had the space between the double sides filled with water at the atmospheric temperature, and the interior coated with lamp-black. The other junction was in metallic contact with the outside of the vessel, and the circuit was completed through the coil of a mirror galvanometer. One junction was thus kept at a nearly constant temperature of about 14° Cent., while the other had the gradually diminishing temperature of the ball.

Wind Tunnels

1927 ◽  
Vol 31 (200) ◽  
pp. 799-806 ◽  
Author(s):  
W. Widgery
Keyword(s):  
National Physical Laboratory ◽  
Present Form ◽  
The Other ◽  
Wind Tunnels ◽  
Circular Path ◽  
Flow Past ◽  
Other Hand ◽  
Physical Laboratory ◽  
A Current

The wind channel and the whirling arm have been devised and perfected over a period of a number of years with a view to providing reliable aerodynamic data for aircraft designers. Of late years the wind channel has been used considerably more than the whirling arm.In the two pieces of apparatus distinct methods are used. In the whirling arm the model is carried through the air, which is stationary, in a circular path by a long arm. In the wind channel, on the other hand, the model is stationary and a current of air is caused to flow past it.Various types of wind channel have been evolved, but I intend to describe fully the English wind channel in its present form, as perfected by the National Physical Laboratory and the Royal Aircraft Establishment, Farnborough.

scholarly journals National Physical Laboratory Radiocarbon Measurements VII

Radiocarbon ◽  
1970 ◽  
Vol 12 (1) ◽  
pp. 181-186 ◽  
Author(s):  
W. J. Callow ◽  
Geraldine I. Hassall
Keyword(s):  
Measurement Technique ◽  
National Physical Laboratory ◽  
Term Stability ◽  
Long Term Stability ◽  
Physical Laboratory ◽  
Made In

The following list comprises measurements made since those reported in Radiocarbon, 1969, v. 11, p. 130–136. No changes have been made in measurement technique or in the method of calculating the results described in Radiocarbon, 1965, v. 7, p. 156–161. It was necessary during 1968 to replace all the geiger counters used in the anti-coincidence rings, but the long term stability of background and standard count rates implicit in the use of a 20-week rolling mean has been maintained.

scholarly journals National Physical Laboratory Radiocarbon Measurements V

Radiocarbon ◽  
1968 ◽  
Vol 10 (1) ◽  
pp. 115-118 ◽  
Author(s):  
W. J. Callow ◽  
Geraldine I. Hassall
Keyword(s):  
Measurement Technique ◽  
National Physical Laboratory ◽  
Physical Laboratory ◽  
Made In

The following list comprises measurements made since those reported in NPL IV.No changes have been made in measurement technique or in the method of calculating results

scholarly journals A centrifugal method of making small pots of electrically fused refractory materials

1925 ◽  
Vol 107 (742) ◽  
pp. 287-290
Keyword(s):  
Internal Surface ◽  
National Physical Laboratory ◽  
Research Committee ◽  
Ferrous Alloys ◽  
Iron And Steel ◽  
Glazed Surface ◽  
Physical Laboratory ◽  
Usual Manner ◽  
Time Required ◽  
Made In

The present paper describes portion of a research on the alloys of iron, which being carried out at the National Physical Laboratory, under the direction Dr. W. Rosenhain, for the Ferrous Alloys Research Committee. Papers dealing with other portions of the work have been published in the ‘Journal the Iron and Steel Institute.’ In the course of a research on the alloys of iron and oxygen, it became necessary to hold two immiscible layers of molten iron and iron oxide at a temperature of 1,540°C. It was not found possible to hold the liquid oxide at this temperature in any pot made by bonding together previously shrunk fractory material in the usual manner; such refractories as were not directly attacked became “wetted” by the oxide, which was absorbed and an out through the pores of the pot. Experimental melts of very small quantities of oxide were made in small hollows in pieces of solid fused magnesia having a glazed surface; these showed practically no absorption of the oxide by the magnesia. Attempts were therefore made to produce a pot of pure magnesia, having an inner surface completely glazed by fusion, in the heat of a electric arc. The experiments were ultimately successful, and a method as been developed for making well-shaped pots having a glazed internal surface of fused material not only in magnesia (M. P. 2,800°C.), but also in alumina (M. P. 2,050°C.), zirconia (M. P. 2,700°C.) and tungsten metal (M. P. 3,300°C.). The time required to produce a pot (having procured the material to be fused in the form of a powder) is about 15 minutes, the time actual fusion under the arc being about 2 minutes. Two views and ertical section of magnesia pots made by the method to be described are hown in fig. 1 (p. 288).

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