This is only the first part of the article as it appeared in the June issue of Moottori. I will post the second part from the July issue when I get it done.
Just a little background - I was researching Gillis Emanuel Huss because he designed the Aveko outboard, the first totally Finnish outboard offered for sale. The Aveko will be added to Jack Craib''s Rowboat Motor Information Site when I am done.
Outboard Motors
Their structure and development
A Critical Review, by Gillis Em. Huss
Outboard motors belong to a type of boat motor that has at one time achieved a considerable expansion all over the world. The explanation for this circulation probably lies for the most part in the fact that the mentioned motor always forms a completely ready-to-use combined transport and steering system, which anyone can attach to any kind of rowing boat in a few minutes, thus turning the latter into an easy-to-maintain and somehow fast motorboat.
After being mainly a "summer motor" for city dwellers in the early days of its market appearance, and even after that for some years, the outboard motor has conquered many industries with its well-deserved reputation as a machine that runs reliably and is easy to maintain. It is often used, for example, in pilot boats, in tourist traffic on routes where relatively expensive motorboats cannot be used, in small barges belonging to the fleets of numerous countries, for ocean survey purposes, as an aid to scientific expeditions, and very widely as a means of transport on short trips.
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Among other things, the outboard motor also has the great advantage that it does not take up usable space in the boat. This fact is especially important when small boats are in question. In such boats, the usual boat engine really usurps space for itself, unpleasantly, at the expense of the enjoyment of those on the boat .
Of the nuisances caused by oil splashes and old, spilled oil and grease on the bottom of the boat in most small motorboats, there is not the slightest trace in a boat equipped with an outboard motor, of whatever design is in practice today. After all, the machine as a whole as well as the fuel tank are then completely outside the side of the boat.
The history of outboard motors goes back a long way, probably about a decade back., — The first model, which was built by a French, German and American factory, was a standard two-stroke engine in a vertical position. On the extension of the engine's crankshaft, there was a somewhat long propeller shaft moving inside the tube sleeve. A «fish iron« was attached to the socket, just in front of the propeller, as well as a protective device surrounding the propeller. The rudder arm, which supported the small fuel tank, protruded from the crankcase as an extension of the crankshaft, directly opposite the propeller shaft.
The design can be seen in picture 1.
The device was attached to the stern of the boat with a strap, on which the rest of the device was rotatably mounted. Somehow, the long propeller shaft stuck out from the stern of the boat roughly like a stern paddle, and based on this, this outboard motor was very commonly called a «motor rudder».
The model is remarkable indeed, naturally quite improved, it has retained its place in the American market. We don't use this design as the engine has no future, mainly because it takes up a lot of space at the stern of the boat and because the length of the engine limits the maneuverability of the boat.
A notable step forward in development was the «Porto» engine, built and manufactured by the Waterman Marine Co. factory located in Detroit, which is shown in figure 2.
The engine here is the same as in the previously mentioned model model, upright two-stroke engine. At one end of its crankshaft is a wedge-shaped pinion gear, which drives corresponding wheels attached to the combined drive and starting shaft. To transfer the driving force from the vertical drive shaft to the horizontal propeller shaft, a bevel gear is used, which is completely left un-encased (at least in the first engines). The cooling water pump is operated by an eccentric fitted to the extension of the propeller shaft. —
The »Porto« engine has a cylinder diameter of 70 m/m and a stroke of 76 m/m.
The credit for inventing the basic form of outboard motors, which is mainly represented by most products today, undoubtedly goes to the Norwegian-American Ole Evinrude, who has sometimes been called the father of the outboard motor, sometimes exaggerated a bit.
The design of the Evinrude, viewed against the background of the above-explained engines, contains a whole host of remarkable details, and when this engine, with its beautiful and practical construction, was put on the market, it quickly became very popular, and with good reason.
The structure of the motor can be seen in figure 3.
The most significant detail of the Evinrude engine was the fact that the engine itself was placed in a horizontal position with vertical crankshafts. The drive shaft is immediately connected to the crankshaft with a long conveyor sleeve, where the drive shaft can be pushed. As a result of these constructions, it was possible to avoid using the necessary drive shaft gear in the Waterman engine.
Starting can be conveniently done using a handle fitted to the engine's horizontal flywheel. The gear housing, which beautifully matches the shape of the propeller hub, forms a closed chamber filled with lubricant around the bevel gear, which transfers the movement from the drive shaft to the propeller shaft. The cooling water pump, which is built inside the gear housing, gets its movement from the cam formed in the gear wheel of the propeller shaft.
Among other notable details of this engine, it should be mentioned that the sleeve device surrounding the drive shaft is telescopically protruding, so the sleeve can be extended or shortened as desired. The mounting bracket is designed in such a way that the motor can easily be placed in a position corresponding to the slope of the stern.
The diameter and stroke of the cylinder are both 64 mm.
From the above brief explanation, we can see that the Evinrude engine, when it appeared on the market already fourteen years ago, came from the hand of a fairly independent and clear-minded builder. - (to be continued)
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