808 KEPOBT — 1886. 



7. On a New High-speed Steam or Hydraulic Engine. By Arthur Rigq. 



This paper described a new construction of high-speed engine, differing fi-om all 

 of the rotary types, inasmuch as it employs cylinders and pistons of ordinary con- 

 struction. These cyHnders are all arranged to revolve in the front of a fly-wheel, 

 which is overhung on its bearings, much like the face-plate of a lathe. The 

 pistons are connected to crank-pins projecting from the face of this fly-wheel, and 

 the cylinders revolve round one centre, while the pistons revolve round a different 

 centre, which is that of the fly-wheel. These centres, being in parallel lines and 

 apart from each other, have a certain eccentricity, corresponding with half the 

 stroke of cylinders and pistons. 



The original crude idea of a revolving engine may be traced as far back as 

 1815, but little attention seems to have been given to its value, when developed 

 into a workable engine. After discussing the insuperable difficulties against the 

 attainment of very liigh speeds in ordinary engines, because of the reciprocations 

 of their moving parts, and after showing how these difficulties are more masked 

 than removed in three-cylinder engines of the triangular type, it is shown how 

 the new revolving engine evades these difficulties altogether. 



This is accomplished by a velocity being continuous in one direction, for the 

 cjlinders aud pistons partake of a continuous revolution, each round its own 

 centre : and the reciprocations are relative as between themselves, not absolute in 

 relation to the earth. 



In this construction a perfect statical balance is provided at first, and this 

 becomes an equally perfect balance from a dynamical point of view ; and, as a 

 consequence, this engine requires no more foundation than suffices to carry its own 

 weight, and it maj' be fixed upon upper floors, running even at very high speeds, 

 when so required, without shock or perceptible vibration. 



But economy in the production of power is a matter of prime necessity, and it was 

 shovsTi how easily this engine may be controlled by an automatic variable expan- 

 sion governor, and how it may be driven by very high-pressure steam expanding in 

 one or more cylinders successively. 



But it is when arranged as a hydraulic engine that this type of construction 

 possesses advantages even more conspicuous than those already described ; for, be- 

 sides being able to run much faster than has hitherto been considered possible, it is 

 the only engine hitherto invented which can be governed at a regular speed, 

 using only that amount of water which is required to produce the power given 

 out. Hydraulic engines, it is well known, consume just as much water per 

 revolution whether running empty or doing their full work, and it has long been 

 a desideratum to discover a water motor that can run smoothly, and be governed 

 in an economical manner. 



Governing an inelastic fluid engine can only be accomplished by determining 

 the total travel of its piston per minute, and this can be done by varying the rate 

 of revolution with a stroke constant, or by varying the stroke with a rate of 

 revolution constant. 



It was shown by a model, and by diagrams, that the length of stroke is always 

 twice the eccentricity, or the distance between those two centres around which the 

 cylinders and pistons respectively revolve ; and it is easy to alter this distance 

 while the engine is running, so that the stroke of all the cylinders is under perfect 

 control ; and it may be changed either by hand or governors, the latter action being 

 automatic. It is thus that a hydraulic engine of this type is under perfect control, 

 and runs at a regular speed, however greatly the demand for power may vary. 



Engines of this revolving type have been constructed and worked both by steam 

 and water power ; they run quietly and well, and seem to realise all the expecta- 

 tions foreshadowed by their designers. 



