John Henry Macalpine

John Henry Macalpine (1859-1927) was an engineer who made valuable contributions to marine engineering, particular with regard to vibration problems.

1871 Thomas D McAlpine 47, drysalter of the High Church, lived in Paisley with Rachel McAlpine 51, Archibold McAlpine 24, George M McAlpine 21, William McAlpine 15, Charles McAlpine 13, John Henry McAlpine 11

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1927 Obituary

THE LATE MR. J. H. MACALPINE.

We regret to record the death of Mr. John Henry Macalpine, which occurred at Mount Vernon, N.Y., on May 31 last, at the age of 68. Mr. Macalpine, after a very active life, had been in bad health for the past four years, and in February, 1926, suffered a stroke from which he never completely recovered.

Though a great deal of his work was carried out in the United States, Mr. Macalpine was of Scotch extraction and was born in Paisley in 1859. After studying under Kelvin at Glasgow University, where he had a successful scholastic career as regards the winning of prizes, but left without taking a degree, he joined the firm of Messrs. R. Napier and Sons, though he does not seem to have been regularly bound in apprenticeship to them. He gave twelve years’ service to this company, enjoying throughout the confidence of its general manager, Dr. A. C. Kirk, and during part of the time he was its representative in Russia. In 1892, he went to the United States for the first time, as superintendent of the Detroit Dry Dock Engine Works, Detroit, while subsequently he served for some four years at the Bureau of Steam Engineering, Washington, on the staff of Rear-Admiral George W. Melville, the Engineer-in-Chief of the United States Navy. These six years in America were followed by a return to his native land, where for some months he acted as the engineering partner of Messrs. Blackwood and Gordon, Port Glasgow. At this period, however, he was paying increasing attention to the investigation of the vibration of steamships, a subject on which he, in collaboration with Mr. H. C. Flood, published an article in Engineering of July 13, 1894, and two subsequent issues.

This contribution was intended to supplement the then recent work of Yarrow and Schlick, by showing that while a simple-harmonic motion, such as would occur on a reciprocating engine piston, if the crank were infinitely long, could be represented by a curve of sines, in actual practice the curve produced would have pointed crests and hollows of still smaller curvature, and that these differences would become more pronounced the shorter the connecting rod in proportion to the stroke, a fact which, it was claimed, had been previously overlooked. As a result of experiments on the Anchor Line steamship Circassia, he also found that the vibrations of the ship, set up by the engine, were three in number, one with a period the same as the period of revolution of the engine, one with half that period and one with a fourth of that period, the second period vibration being much the most prominent as the engines were run, the intensity being the greatest when the speed was 57 r.p.m. A very slight increase in this intensity would therefore have caused considerable annoyance. Macalpine further discovered that, at a very slightly lower speed, the fourth period reached its maximum. At such times the vibration in the after end of the saloon was most unpleasant, though it only persisted for a minute or two at a time. There were two points of minimum vibration for the second period vibration, the positions of which were discovered by experiment. The view taken was that to place the engine at the nodal position was no remedy, even if that position could be determined with sufficient accuracy, because it was by no means certain beforehand, whether the forces or couples would play the more important part in causing the vibrations. Since, however, the forces vanished when the couple was a maximum, they could not produce effects which would even approximately counteract one another, however the machinery was placed in relation to any part of the ship.

This communication seems to have attracted little attention, and it was not until nearly three years later (February 19, 1897) that Mr. Macalpine returned to the subject in our columns. His second article marked a step forward in that it suggested that the proper way of preventing vibration in steamships was to provide an engine which was practically balanced in running and thus to remove all causes of disturbance. The chief reason advanced for this procedure was that to attack the problem through the ship was to introduce too many factors, some of which, such as the speed of the engine and the disposition of the cargo, were not fixed quantities. A second article in the same year (October 22, 1897) was devoted to an analysis of the inertia forces of the moving parts of an engine, one of its objects being to explain the occurrence in steamships of vibrations of shorter period than that of the revolution of the engine. The author’s methods showed a considerable grasp of mathematical analysis, combined with a clear recognition of the practical importance of the subject.

Mr. Macalpine dealt with the same subject a third time in 1901, in which year he presented a paper before the Institution of Naval Architects with the title “A Solution of the Vibration Problem.” An account of this paper, which attracted a good deal of comment both written and spoken, appeared in our issue of July 5, 1901, and in subsequent issues in the same volume. The comment was, however, by no means entirely unanimous. Mr. F. C. Billetop and Mr. (afterwards Sir) Philip Watts referred with approval to the design of the engine, with which a large part of the paper was concerned, while Mr. A. E. Seaton wrote in the contrary sense. The author took up the definite attitude that the short period forces must be balanced before any completely satisfactory solution of the vibration problem could be obtained and that this could not be done with the ordinary type of direct-connected marine engine.

In 1902, Macalpine returned to the United States, where he undertook the completion and the conduct of the trials of the U.S. destroyers Hopkins and Hull for Messrs. Harlan and Hollingsworth, of Wilmington, Delaware. In 1904, he entered into partnership with his former chief, Admiral Melville, under the style of Melville and Macalpine, consulting engineers and naval architects. This partnership lasted five years. While, however, he was devoting so great a part of his energies to the improvement of the reciprocating engine for marine work, its dominance was slowly but surely passing from that type of prime mover to the steam turbine. Macalpine seems to have recognised this as soon, or sooner, than most, for it was about this period that he invented, in nominal conjunction with Admiral Melville, his floating-frame reduction gear, which was intended to make the use of mechanical gearing practical for much higher powers than was then possible. An experimental spur-wheel reduction gear embodying this device was described in Engineering for September 17, 1909, in which article details were given of a Westinghouse equipment, which was capable of transmitting 6,000 h.p. at a pinion speed of 1,500 r.p.m., and a reduction ratio of 5 to 1. In the following year, Macalpine himself went to Pittsburgh, where, for the rest of his active life, he was engaged in co-operation with Mr. George Westinghouse in consulting work and in writing.

The object of the floating-frame device was to secure alignment wholly by the interaction of the teeth in contact and to render the operation independent of the skill of the workman in laying out and fitting the bearings. It was claimed that the results obtained exceeded those possible with the more ordinary rigid designs. As was pointed out at the time, however, there was a natural reluctance among marine engineers to adopt spur gearing for the main drive of ships and Mr. Macalpine’s ideas received little acceptance, though his design was employed on the U.S. naval collier Neptune, a description of which appeared in our issue of November 17, 1911. In a very long article, which appeared in Engineering for May 5, 1916, and no fewer than six subsequent issues, he discussed the various problems of reduction-gear design, in their relation to marine work, most exhaustively, his attitude being that the difficulties which were then being experienced could most easily be overcome by the use of his floating frame, owing to the certainty with which the evenness of the tooth pressure could be maintained and limited to 450 lb. per square inch. He insisted that his invention was not designed to counteract the effects of bad gear cutting, but to overcome the need for delicacy in alignment. He also argued in favour of the geared, as opposed to the direct-connected, turbine, an attitude of which the events of the last few years have confirmed the justice. His arguments were reiterated in a paper which he read before the Institution of Naval Architects in 1917, on which occasion they were, on the whole, favourably received. It would, however, be unwise to dogmatise on the claims made by Macalpine for his arrangement, as time alone can show whether its advantages will give it a preponderance over more ordinary methods. So far its practical application has been small.

It is curious, however, to note, as an instance of the working of the human intellect, that while in his early investigations on balancing he contended that the right course was to go to the root of the matter, in his later activities he was an equally strong supporter of a device that mitigated an evil but did not attempt to remove it.

Mr. Macalpine was, in all his work and recreations, intensely sympathetic. He enjoyed co-operating with those who were in any way connected with the subject on which he was then engaged. His concentration on any problem was great and, as might perhaps be expected, he had the natural defect of this quality, an impatience — not infrequently fiery — with those who did not understand his point of view or who were attacking the same problem from another angle. Nevertheless, it would not be too much to say that his great characteristics were his rigid probity and directness of action. On one occasion he complained to Admiral Melville that he might be suspected of not doing the right thing. Melville replied that such a fear was groundless, as his probity was universally recognised.

Mr. Macalpine was a member of the Institution of Naval Architects, of the Institution of Engineers and Shipbuilders in Scotland, and of the Society of Naval Architects and Marine Engineers, New York. He was also connected with the American Society of Naval Engineers and with the Edinburgh Mathematical Society. During his residence in Pittsburg, he took an active part in the religious and social activities of the town. He married Miss Mary J. Coats, of Paisley, in 1892, who survives him. He also leaves a daughter and two sons.

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