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Most common agricultural motors used in finland

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Most common agricultural motors used in finland

2026-05-08T12:07:32Z

Toro Andersen: Created page with " = Most Common Agricultural Motors Used in Finland = ''By Eng. J. Kantola'' Previously, up until the outbreak of the world war, Finland used mainly motors imported from Sweden, England, and America, along with locomobiles as power sources for agriculture. Our own motor industry was still in its infancy; mass production was out of the question. Sweden, which has a number of good specialized factories for motor manufacturing, supplied considerable quantities of agricultu..."

= Most Common Agricultural Motors Used in Finland =
''By Eng. J. Kantola''

Previously, up until the outbreak of the world war, Finland used mainly motors imported from Sweden, England, and America, along with locomobiles as power sources for agriculture. Our own motor industry was still in its infancy; mass production was out of the question.

Sweden, which has a number of good specialized factories for motor manufacturing, supplied considerable quantities of agricultural motors to Finland. These were mostly vertical, two-stroke engines equipped with hot-tube ignition, running on crude oil or petroleum.

The Swedish also manufacture horizontal motors suitable for agricultural purposes, but as their price is somewhat higher, they were imported to our country in relatively small quantities.

From England, medium-sized and larger power machines were generally imported, mainly gas engines that were initially fueled by coal, later by sawdust and wood waste or peat. In their manufacture, England surpassed all other countries. Gas engines were extremely economical as power sources for mills, electrical plants, and combined mill and saw facilities where mill operation was the primary function. Steam engines are better suited as power sources for proper sawmills. Furthermore, relatively large quantities of small crude oil and petroleum motors were imported from England, mostly of vertical construction and equipped with magneto ignition.

American agricultural motors have a different construction from those mentioned above. Almost without exception, they use horizontal four-stroke engines with magneto ignition, and cooling is accomplished through an open water jacket surrounding the cylinder. Gasoline or petroleum is used as fuel. Operating reliability is usually good, but fuel consumption is relatively high.

Before the war, motors were imported from America in considerable quantities. However, during the war period, there was a fundamental change in the agricultural motor trade, as in many other things. As Finland's currency value declined, foreign motors became so expensive that hardly anyone could afford to buy them. At the same time, the price of domestic locomobiles rose proportionally much more than other machines, depending on the increase in boiler plate prices. This gave an impetus to domestic motor industry, and "motor factories" sprang up like mushrooms after rain.

Since the initial difficulties can now be considered overcome and weak and poorly managed motor workshops have disappeared, we can state that domestic motor manufacturing is on a reasonably satisfactory footing. We have several motor workshops whose products are of good quality and uniform, despite still relatively small production volumes. However, the manufacture of small motors must be mass production rather than individual production if it is to succeed properly. We are still far from achieving this. So few agricultural motors are used in Finland that they would not be sufficient for a single large motor factory, let alone several. We therefore have no choice but to export motors to other countries if we wish to maintain a proper motor industry. And export does not seem at all impossible.

In the following, we provide some brief information about the agricultural motors most commonly used in Finland. We first mention the most common domestic products.

== 1. B. M. W. Motors ==
The largest and most significant of our domestic motor factories is Björneborgs Mek. Verkstads Ab. in Pori. The B. M. W. motors it manufactures have achieved the greatest distribution in Finland, and they have been exported to other countries, for example Estonia. They are constructed according to the Swedish general type, being two-stroke engines equipped with hot-tube ignition, running on crude oil or petroleum, of vertical design.

[Figure 1. 8 HP B. M. W. motor]

For actual agricultural purposes, B. M. W. motors are now manufactured in 5, 8, 10, and 15 horsepower, mounted on wooden bases so they can be easily moved from place to place. Thus, the range is as complete as is needed in agriculture.

Previously, these motors were troubled by a slight tendency to vibrate. Last summer, the factory changed the arrangement of various parts of the machine, positioning the motor in the middle of the base between the fuel and water tanks, and strengthened the base. This eliminated the mentioned defect without making the machine significantly more difficult to access and maintain. During the past summer, the previous 7 horsepower motor was converted to 8 horsepower by increasing the cylinder diameter from 130 mm to 140 mm, so this size can now easily drive threshing machines equipped with rollers 600 to 700 mm long.

The B. M. W. motor speeds are quite high, being 750 rpm for the 5 hp engine, 600 for the 8 hp, 500 for the 10 hp, and 450 for the 15 hp. The piston mean speeds are thus 3.4, 3.5, and 3.6 meters per second. The motors' compression ratio is high (semi-diesel system). This has achieved relatively low fuel consumption, being approximately 275 grams per hour per brake horsepower when the motor is fully loaded.

By using the two-stroke system and high engine speed, the motor weight has been kept relatively small, which has some significance in agricultural motors. A 5 hp motor in full condition with base and cooling equipment weighs only 300 kg, the 8 hp weighs 460 kg, the 10 hp already weighs 800 kg, and the 15 hp weighs 1430 kg.

The two-stroke system, which eliminates the inlet and exhaust valves and the mechanism driving them, which are necessary in four-stroke engines, along with hot-tube ignition, makes B. M. W. motors structurally simple and easily understandable. Later we will make more comparisons between two- and four-stroke motors, as well as between hot-tube and electrical ignition.

Since many Finnish and most Swedish agricultural motors are of the two-stroke system, and their structure is essentially similar, we describe below briefly the operation and structure of B. M. W. motors.

In Figure 2, 9 is the piston, which moves up and down in the cylinder. The crankcase 11 is completely sealed and functions as an air tank or more properly as a motor air pump.

The motor operates as follows:

When the piston moves upward, a vacuum is created in the crankcase, which causes the air valve 30 to open and admit air into the crankcase. When the piston comes down again, this air is compressed in the crankcase. As the piston approaches its lowest point, the air port B opens, allowing air from the crankcase to enter the cylinder, pushing out the remaining combustion gases through port C and filling the cylinder. When the piston moves up again, the air in the cylinder is compressed, and just before the piston reaches its highest position, the fuel pump injects the necessary amount of fuel through the vaporizer 4 against the hot interior wall of the ignition ball 2, causing the fuel to ignite, creating strong pressure in the cylinder and forcing the piston downward. Just before the air port B opens, the piston opens the exhaust port C, through which combustion gases escape to the muffler 19 and from there through the pipe 51 to the outside. Thus, the excess pressure in the cylinder dissipates before fresh air enters through port B.

This repeats with each revolution. The governor 46 regulates the motor speed by reducing the length of the fuel pump stroke as the motor load decreases or speed increases, and increasing it as the load increases or speed decreases.

The motor can be adjusted to run in either direction.

When starting the motor, the ignition ball 2 must be heated with lamp 18. Afterward, the lamp can be extinguished, as the ball remains hot from the heat generated by explosions, unless the motor is loaded extremely lightly.

The cleanliness of the cylinder and the motor's performance can be improved, fuel consumption reduced, and ignition timing and ball temperature controlled by introducing a small amount of water into the cylinder. This is done either through the drip tap 8 or pump 75. In the latter case, water flows through the ignition ball's pipe, which connects to the fuel vaporizer support.

The cooling of the cylinder and its cover is done with water, which in the smaller 5 and 8 hp motors circulates on its own without mechanical aids in such a way that heated water tends to rise and cold water flows from the water tank in its place (so-called thermosiphon system), and in larger motors by means of a pump. The main bearings are ball bearings.

Björneborgs Mek. Verkstad manufactures, in addition to the aforementioned, primarily agricultural purpose motors, also 7–50 hp fixed single-cylinder, 3–100 hp fixed twin-cylinder, and 8–200 hp 1–4 cylinder boat motors.

As already mentioned, many of the motors manufactured in Finland, such as Borgå Båtvarvin Alfa, Ahjon Simson, Grönlund's GG motor (production discontinued), etc., are of essentially the same construction pattern, so we pass over them here relatively briefly.

The same can be said of many Danish and most Swedish agricultural motors, Columbia, Bruzaholm, Phenix, Avance, Lysekil, Bergsund, and many others, which were once imported to Finland in considerable quantities.

[Figure 2. Cross-section of B. M. W. motor]

== 2. Alfa Motors ==
Alfa motors are used in Finland in relatively considerable quantities, and generally, with few exceptions, have functioned satisfactorily. They are two-stroke engines equipped with hot-tube ignition, running on petroleum or crude oil, of vertical design. In structure, they generally resemble B. M. W. motors. Fuel consumption should be considered relatively high. Motors for agricultural purposes are manufactured in 6–7, 10–12, and 20–24 hp.

[Figure 3. Alfa 6–7 HP]

== 3. P. S. M. Motor ==
The motor is a two-stroke engine equipped with hot-tube ignition, running on petroleum, of vertical design. In construction, it differs from the aforementioned mainly in that, instead of water cooling, air cooling is used; that is, the cylinder is equipped with wide fins into which a fan blows cold air. Thus, the risk of the cylinder and pump overheating has been eliminated and the machine has been made simpler. On the other hand, the cooling cannot be as effective and steady, especially in hot weather and in larger engines.

P. M. S. motors, manufactured by Oulun Rautateollisuus Oy., have naturally spread mainly in Northern Finland depending on the manufacturing location and climatic conditions. Motors are manufactured in two sizes, 6 and 9 hp, both portable. As in most other Finnish motors, this one also had some small errors and irregularities in manufacture initially, but most of these have likely been corrected.

[Figure 4. P. S. M. 19]

== 4. English Petter Motors ==
Before the war, English Petter motors were sold in large quantities also in Finland, and it must be admitted that few motors have been made with such extreme precision and of such selected materials. Excellent operating reliability and long life have always been reliable characteristics of these motors. But this is not surprising. Although Petter factory production has decreased since the war, annual production is nonetheless 50,000 motors. Such mass production makes the use of all conceivable technical equipment possible.

Previously, Petters Limited manufactured both four- and two-stroke motors, but from 1915 it completely discontinued four-stroke motor manufacturing and now manufactures exclusively two-stroke system motors of two models, brands S. and M.

The Petter motor, model S, is a hot-tube ignition-operated crude oil or petroleum motor, sturdily constructed and essentially similar to the B. M. W. The bearings are extremely generous in size. Ball bearings are not used, as is generally the case in English machines. The main bearings are equipped with ring oiling, the crankpin and connecting rod pin and piston with splash lubrication. Excess oil runs into the crankcase, from which air pressure forces it through a screen into the oil tank. Thus, no oil is wasted. The lubricator is fully automatic, operated by the pressurized air in the crankcase, so it requires no adjustment when starting or stopping the motor. In newer engines, three-way cocks can be used to check the operation of each oil feeder. The governor regulates fuel consumption according to load. The motor speed can be easily changed during operation. Air is drawn into the motor crankcase through the base, so it can be obtained cleaner than directly from the motor side.

A special feature of Petter motors is cold starting. In hot-tube ignition motors, engine starting is relatively difficult. The ball must be heated 15–20 minutes with a lamp before starting. Petter's cold starting device, which received the highest award from the English Agricultural Society last year, makes it possible to start the engine in half a minute. This is done as follows:

The pipe in the motor's ball is unscrewed, a charge of special substance is inserted, ignited with a match, and the pipe is screwed back into the ball. After this, the motor is started in the usual way. The entire procedure takes about half a minute. The required substance is inexpensive. Starting is further aided by a valve that can reduce compression.

Petter motors run without any adjustment, either loaded or unloaded.

[Figure 5. 5 HP Petter Motor]

[Figure 6. Cross-section of Petter Motor]

Four-stroke motors are also manufactured in our country in considerable quantities. Of these, at least in this writer's opinion, the most notable in quality, if not yet in production volume, is:

== 5. Olympia Motor ==
Olympia is manufactured by Ab. Finska Motorfabriken in Vaasa. Practical men generally give Olympia such a review that hardly any complaints ever come from it, and that it should therefore be considered one of the most reliable Finnish motors in use.

Olympia runs on petroleum and is equipped with electrical ignition, of vertical design. The cylinder is L-shaped. The crankcase and cylinder are cast as separate pieces, and the crankcase is closed for lubrication purposes, as the main and crankpin bearings receive oil through splash lubrication. The main bearings are white metal bearings.

The motor has dual electrical ignition, which thus increases its operating reliability. It has, namely, first the usual battery ignition and, in addition, a Bosch high-voltage magneto; both have their own spark plugs. The carburetor is of Schebler design and the intake air can be taken as needed either cold or heated through the exhaust pipe.

The governor is located in the flywheel, as is common in American agricultural motors. The governor acts through lever arms on a butterfly valve in the gas intake pipe, which increases or decreases the amount of gas the cylinder receives.

[Figure 7. Olympia Motor]

The four-stroke motor operates as follows.

The piston moves from its highest position downward, creating a vacuum in the cylinder that draws the gas mixture into the cylinder (first stroke). When the piston turns to move upward again, the gas mixture is compressed (compressed), with both intake and exhaust valves closed (second stroke). When the piston has reached near its highest position, the gas mixture is ignited. The force of the explosion forces the piston to descend (third stroke, power stroke). When the piston has passed its lowest position, the exhaust valve opens and the burned gas escapes as the piston moves upward, after which the same process repeats.

Olympia agricultural motors are manufactured in two different sizes, 9–10 hp and 4–5 hp. Engine speeds are quite high at 550 and 750 revolutions per minute. Fuel consumption is normal. Starting is quick and maintenance is easy.

Olympia motors have gained a foothold in many foreign countries as well. As an interesting note, they have even been exported to the Congo.

== 6. Vickström Motor ==
This motor, manufactured by Bröderne Vickströms Motorfabrik in Vaasa, resembles Olympia in construction quite greatly, of which it is actually the "older brother." The motor's speed is high and the piston mean speed is also very high.

[Figure 8. Vickström Motor]

== 7. Tikka Motors ==
Tikka motors manufactured by Tikkakosken Rauta- ja Puuteollisuus Oy are four-stroke, petroleum-burning, vertical motors equipped with both electrical and hot-tube ignition. They have been manufactured in two sizes, 9 and 11 hp.

[Figure 9. 11 HP Tikka Motor]

In these motors, the cylinder is L-shaped, and its cover is removable. The main bearings are ball bearings. Lubrication is by splash. The carburetor is of the factory's own manufacture, extremely simple. The ignition is combined hot-tube and electrical ignition. The latter is used until the ignition ball heats sufficiently, after which only this can be used. The capsule governor is connected to the camshaft.

Fuel consumption in these machines is high.

== 8. Sirkka Motor ==
Tykö Bruks Ab. has for several years manufactured a small 4–5 hp, petroleum-burning, magneto-ignition-equipped vertical motor called Sirkka. More recently, the factory has also manufactured a larger 8–10 hp Sirkka motor.

In structure, Sirkka differs from the aforementioned first in that the cylinder and crankcase are one piece, and rest on a wooden base on cast iron flanges on the side of the crankcase. The cylinder cover is removable and water-cooled. The motor uses splash lubrication system.

The intake air is heated by exhaust gases. The main bearings are bronze bearings. The crankpin bearing is a bronze-white metal bearing. The governor is in the flywheel. Moving parts are encapsulated.

Fuel consumption is quite high. Engine speed is relatively high, 670 times per minute in 4–5 hp machines. The piston mean speed is, however, moderate. Especially the newer model Sirkka motors can be considered fully good agricultural motors.

The same manufacturer previously manufactured an 8 hp two-stroke crude oil motor called Talous, which is generally of the same construction as other aforementioned vertical two-stroke motors.

[Figure 10. Sirkka Motor, 4–5 HP]

== 9. Alligator Motors ==
As an example of American-style agricultural motors, we can mention the motor manufactured by Alex. Sjöholm's machine shop, to which some dealer has given the name Alligator. These are manufactured in 6–7, 10–12, and 13–14 hp.

It is a horizontal, four-stroke, electrical ignition-operated petroleum-gasoline motor. The carburetor is American-made Schebler. The magneto is Mars. Bearings are lubricated with vaseline. Maintenance is easy, as in a horizontal engine all parts are well visible. Petroleum consumption is low. The motors run slowly and reliably. The cylinder is surrounded from above by an open water jacket, into which more water is added as it evaporates. The motor is therefore better suited for outdoor use than for use in a closed room.

If the machine were to be used extensively in a closed room, it would need to be equipped with additional devices to prevent water vapor formation.

[Figure 11. 6–7 HP Alligator Motor]

== 10. Waterloo Motor ==
is essentially of the same construction as the Alligator. In addition to the aforementioned, many different types and brands of agricultural motors have been built in small machine shops in Finland, mostly as experiments.

= Comparison of Two- and Four-Stroke Systems =
Which is more advantageous, the four- or two-stroke system in ordinary agricultural motors, is a question to which it may not be good to give a direct answer. Both have their advantages and disadvantages.

Two-stroke motors, in which combustion occurs with each piston stroke, are much smaller in size and therefore cheaper than equally powerful four-stroke motors, in which combustion occurs only on every other stroke. Similarly, in two-stroke motors, valves and their control mechanisms are eliminated, so the machine becomes not only cheaper but also simpler. In most of the two-stroke motors in practical use here, crude oil can be used as fuel, which at least before the war came considerably cheaper than petroleum, and fuel consumption is also lower. The hot-tube ignition used in them is very understandable for the ordinary layman, and any faults are more easily corrected than when electrical ignition is used.

On the other hand, the cylinder of a two-stroke motor never becomes as clean of exhaust gases as is the case in the four-stroke motor, and therefore the former never develops twice the power of an equally sized four-stroke motor operating at the same pressure and speed. The crankcase of a two-stroke motor must be tight, otherwise the motor will not run. So if, for example, ordinary bearings wear loose, the motor may start running poorly because the necessary compression cannot be achieved in the crankcase. The disadvantage of hot-tube ignition is its fire hazard, that starting takes about 20 minutes, and that an inexperienced person easily overheats the ball, causing it to burst.

The Burmeister and Wain Two-Stroke Cycle Engine

2026-05-08T10:54:48Z

Toro Andersen:

The INSTITUTE of MARINE ENGINEERS

Founded 1889. Incorporated by Royal Charter, 1933.

The Burmeister and Wain Two-Stroke Cycle Engine

SESSION 1936 Vol. XLVIII. Part 10.

President: The Hon. '''Alexander Shaw'''
----The Burmeister and Wain Two-Stroke Cycle Engine.

READ

By Dr. H. H. BLACHE. On ''Tuesday, October 20th, 1936, at 6 p.m.''

'''Chairman''': Mr. '''R . Rainie ,''' M.C. (Vice-Chairman of Council).
----'''''Synopsis.'''''

''MARINE engine construction especially with regard to the evolution of new types of main engines, is referred to as probably being subjected to more difficult conditions than any other form of machinery construction. Tribute is paid to those shipowners whose progressive policy leads them to adopt new types of propelling machinery''.

''The details of the B. & IV. two-stroke double-acting Diesel engine are described. Present designs make fullest use of experience gained from running and building of many engines during the six years which have elapsed since the “Amerika”, which was the first vessel fitted with this type of engine, was put into sendee.''

''The various parts of the engine are described seriatim, including cylinder covers and liners, main tie bolts, pistons, piston rings, piston rod stuffing box, eccentric driving gear for exhaust piston valves, governor, gear for reversing and manoeuvring, also that for fuel pumps, scavenge blowers, cooling of liner and cover, etc. Then the singleacting, two-stroke, trunk piston engine is similarly described. The latest methods of making cast steel crank webs receive brief reference, and the thrust blocks of the B. & W. type receive special mention, as do lubrication problems generally.''

''Comparisons are made between the B. & W. four-stroke cycle engine and the B. & W. two-stroke engine. The characteristics of the engine as regards reliability receive special mention, and a few general remarks are made regarding marine Diesel engines. The paper concludes with a brief reference to the present trend of steam and Diesel machinery.''

Members of this Institute will surely agree with the author that the problem presented by the designing of new types of engines for marine work is far from easy. In addition, shipowners generally order their new tonnage for delivery in the shortest possible time. The machinery must be ready for installation immediately the vessel has taken the water, and no excuses are accepted even if, for some unforeseen reason, it is desirable to prolong the test bed trials. A short basin trial—usually disturbed by frequent stoppages due to ships passing —followed by a one-day trial trip is, as a rule, all the time which is at the disposal of the technical experts. Then, without delay, the vessel has to go on her maiden voyage, at full power, in order not to lose a charter or keep enlisted passengers waiting.

Otherwise the former might result in a heavy monetary loss to the owner, and the latter have its sequel in articles in the daily press, unfavourable both for owner and engine builder. Marine engineers employed on technical developments are the first to pay tribute to the enterprise and progressive policy which characterise those leaders of shipping companies who have not hesitated to adopt new types of engine, as these gradually were introduced during the last quarter of a century. Amongst these may be named the following:—

(1)—Twin-screw single-acting four-stroke crosshead type for m.v. “ Selandia ” (the first ship fitted with B. & W. Diesel engines).

(2)—Twin-screw four-stroke trunk-piston type for passenger vessels.

(3)—Single-screw four-cycle long-stroke crosshead types and twin-screw trunk engines for tramps.

(4)—Twin-screw four-stroke double-acting crosshead types for passenger liners aggregating from 10,000 to 20,000 b.h.p.

(5)—Single- and twin-screw double-acting two-stroke crosshead types for combined cargo and passenger liners, aggregating from 3,000 to 30,000 b.h.p.

(6)—Single- and twin-screw single-acting two-stroke trunk-piston types for passenger vessels and fruit carriers, aggregating from 1,800 to 8,000 b.h.p.

Although it is undoubtedly of great advantage to carry out exhaustive trials on the test bed should the time be available, the conditions under which a

marine plant works on board ship are of such a special nature that prolonged running experience at sea is necessary to ensure the attainment of the desired high standard.

Sea-going engineers, together with the technical staffs of engine works, are of great assistance to the designer of new engine types. These men, from youth, are trained to carry out engine overhauling under difficult conditions both at sea and in harbour, to enable scheduled sailings to be maintained.

Circumstances corresponding to these, it is safe to state, are not to be found in any other branch of engineering.

In touching upon the factors which have their effect upon the design of marine engines, the varying conditions in shipping and their consequent influence upon the shipbuilding industry may be mentioned. In periods when trade is brisk the demands of shipowners are probably three times the normal. These demands react upon shipbuilders and marine engineers who are bound to keep pace. The additional work thus requires increases of staff, and often also extensions to shops and equipment involving large financial obligations. In corresponding periods of slackness, shipowners bury their building programmes, although they manage to keep their ships in service, or at the most lay-up a few of them. Thus the variations in the conditions for shipping are not so great as for shipbuilding, where the industry is liable to periods of complete idleness, which may occur with suddenness and at an unpredictable point in time.

Shipyards, in turn, are better able to cope with these variations than marine engine works, as the capital invested in shipyards is comparatively small in relation to the production, large parts of a ship being purchased either ready for use or in a semifinished state. Marine engine works, on the other hand, and in particular those building Diesel engines, must by reason of the special materials used, be capable of manufacturing the complete machinery. This necessarily implies costly shops. In lean times it therefore becomes exceedingly difficult suddenly to reduce general costs. A contributory factor in this is the utmost importance of retaining the technical staff during such periods of idleness. A sound technical staff, gathered together and trained during many years, can hardly be overrated. It is at least as important a factor for meeting demands of production as are the site, buildings, machine tools, cranes and all other equipment in which the proprietors’ capital is invested.

These, in fact, are valueless without a proper technical staff. The general public, the banks, financiers and others are very liable to overlook these principles, so simple and obvious to engineers. Shipyards and marine engine works being an absolute necessity for the maintenance of shipping —and through it of many other industries and trades—ought to receive proper support during periods of critical depression, coming, as these often do, suddenly and unforeseen. In these respects shipbuilding and marine engineering" are without a parallel in other branches of industry.

The characteristic features of the Burmeister & Wain four-stroke single- and double-acting Diesel engines were described in the author’s paper read before the Institution of Engineers and Shipbuilders in Scotland in April, 1925. The later developments in the design of the four-stroke engine, including the B. & W. topping-up supercharge system, were described in the author’s paper read before the Institution of Naval Architects in July, 1931. (This paper also referred to the B. & W. two-stroke single- and double-acting Diesel engines.)

Since then no advances of any importance have been made in the design of the four-stroke Diesel engine. On the other hand, a great deal of experience has been gained during this period with the B. & W. two-stroke engine, resulting in important improvements and in the simplification of the design, all of which are incorporated in current contracts.
----

== DOUBLE-ACTING TWO-STROKE CYCLE DIESEL ENGINE. ==
[[Category:DK]]
[[Category:Burmeister & Wain]]
[[Category:Articles]]

The Burmeister and Wain Two-Stroke Cycle Engine

2026-05-08T10:33:05Z

Toro Andersen:

The INSTITUTE of MARINE ENGINEERS

Founded 1889. Incorporated by Royal Charter, 1933.

The Burmeister and Wain Two-Stroke Cycle Engine

SESSION 1936 Vol. XLVIII. Part 10.

President: The Hon. '''Alexander Shaw'''
----The Burmeister and Wain Two-Stroke Cycle Engine.

READ

By Dr. H. H. BLACHE. On ''Tuesday, October 20th, 1936, at 6 p.m.''

'''Chairman''': Mr. '''R . Rainie ,''' M.C. (Vice-Chairman of Council).
----'''''Synopsis.'''''

''MARINE engine construction especially with regard to the evolution of new types of main engines, is referred to as probably being subjected to more difficult conditions than any other form of machinery construction. Tribute is paid to those shipowners whose progressive policy leads them to adopt new types of propelling machinery''.

''The details of the B. & IV. two-stroke double-acting Diesel engine are described. Present designs make fullest use of experience gained from running and building of many engines during the six years which have elapsed since the “Amerika”, which was the first vessel fitted with this type of engine, was put into sendee.''

''The various parts of the engine are described seriatim, including cylinder covers and liners, main tie bolts, pistons, piston rings, piston rod stuffing box, eccentric driving gear for exhaust piston valves, governor, gear for reversing and manoeuvring, also that for fuel pumps, scavenge blowers, cooling of liner and cover, etc. Then the singleacting, two-stroke, trunk piston engine is similarly described. The latest methods of making cast steel crank webs receive brief reference, and the thrust blocks of the B. & W. type receive special mention, as do lubrication problems generally.''

''Comparisons are made between the B. & W. four-stroke cycle engine and the B. & W. two-stroke engine. The characteristics of the engine as regards reliability receive special mention, and a few general remarks are made regarding marine Diesel engines. The paper concludes with a brief reference to the present trend of steam and Diesel machinery.''

Members of this Institute will surely agree with the author that the problem presented by the designing of new types of engines for marine work is far from easy. In addition, shipowners generally order their new tonnage for delivery in the shortest possible time. The machinery must be ready for installation immediately the vessel has taken the water, and no excuses are accepted even if, for some unforeseen reason, it is desirable to prolong the test bed trials. A short basin trial—usually disturbed by frequent stoppages due to ships passing —followed by a one-day trial trip is, as a rule, all the time which is at the disposal of the technical experts. Then, without delay, the vessel has to go on her maiden voyage, at full power, in order not to lose a charter or keep enlisted passengers waiting.

Otherwise the former might result in a heavy monetary loss to the owner, and the latter have its sequel in articles in the daily press, unfavourable both for owner and engine builder.

Marine engineers employed on technical developments are the first to pay tribute to the enterprise and progressive policy which characterise

those leaders of shipping companies who have not hesitated to adopt new types of engine, as these gradually were introduced during the last quarter of a century. Amongst these may be named the following:—

(1)—Twin-screw single-acting four-stroke crosshead type for m.v. “ Selandia ” (the first ship fitted with B. & W. Diesel engines).

(2)—Twin-screw four-stroke trunk-piston type for passenger vessels.

(3)—Single-screw four-cycle long-stroke crosshead types and twin-screw trunk engines for tramps.

(4)—Twin-screw four-stroke double-acting crosshead types for passenger liners aggregating from 10,000 to 20,000 b.h.p.

(5)—Single- and twin-screw double-acting two-stroke crosshead types for combined cargo and passenger liners, aggregating from 3,000 to 30,000 b.h.p.

(6)—Single- and twin-screw single-acting two-stroke trunk-piston types for passenger vessels and fruit carriers, aggregating from 1,800 to 8,000 b.h.p.

Although it is undoubtedly of great advantage to carry out exhaustive trials on the test bed should the time be available, the conditions under which a

marine plant works on board ship are of such a

special nature that prolonged running experience at

sea is necessary to ensure the attainment of the

desired high standard.

Sea-going engineers, together with the technical

staffs of engine works, are of great assistance

to the designer of new engine types. These men,

from youth, are trained to carry out engine overhauling

under difficult conditions both at sea and in

harbour, to enable scheduled sailings to be maintained.

Circumstances corresponding to these, it

is safe to state, are not to be found in any other

branch of engineering.

In touching upon the factors which have their

effect upon the design of marine engines, the varying

conditions in shipping and their consequent

influence upon the shipbuilding industry may be

mentioned.

In periods when trade is brisk the demands

of shipowners are probably three times the normal.

These demands react upon shipbuilders and marine

engineers who are bound to keep pace. The additional

work thus requires increases of staff, and often also extensions to shops and equipment

involving large financial obligations. In corresponding

periods of slackness, shipowners bury their

building programmes, although they manage to keep

their ships in service, or at the most lay-up a few

of them. Thus the variations in the conditions for

shipping are not so great as for shipbuilding, where

the industry is liable to periods of complete idleness,

which may occur with suddenness and at an

unpredictable point in time.

Shipyards, in turn, are better able to cope with

these variations than marine engine works, as the

capital invested in shipyards is comparatively small

in relation to the production, large parts of a ship

being purchased either ready for use or in a semifinished

state. Marine engine works, on the other

hand, and in particular those building Diesel

engines, must by reason of the special materials

used, be capable of manufacturing the complete

machinery. This necessarily implies costly shops.

In lean times it therefore becomes exceedingly difficult

suddenly to reduce general costs. A contributory

factor in this is the utmost importance of

retaining the technical staff during such periods of

idleness. A sound technical staff, gathered together

and trained during many years, can hardly be

overrated. It is at least as important a factor for

meeting demands of production as are the site,

buildings, machine tools, cranes and all other equipment

in which the proprietors’ capital is invested.

These, in fact, are valueless without a proper technical

staff. The general public, the banks, financiers

and others are very liable to overlook these principles,

so simple and obvious to engineers.

Shipyards and marine engine works being an

absolute necessity for the maintenance of shipping

—and through it of many other industries and

trades—ought to receive proper support during

periods of critical depression, coming, as these often

do, suddenly and unforeseen. In these respects

shipbuilding and marine engineering" are without a

parallel in other branches of industry.

The characteristic features of the Burmeister

& Wain four-stroke single- and double-acting Diesel

engines were described in the author’s paper read

before the Institution of Engineers and Shipbuilders

in Scotland in April, 1925. The later

developments in the design of the four-stroke

engine, including the B. & W. topping-up supercharge

system, were described in the author’s paper

read before the Institution of Naval Architects in

July, 1931. (This paper also referred to the B. &

W. two-stroke single- and double-acting Diesel

engines.)

Since then no advances of any importance have

been made in the design of the four-stroke Diesel

engine. On the other hand, a great deal of experience

has been gained during this period with the

B. & W. two-stroke engine, resulting in important

improvements and in the simplification of the

design, all of which are incorporated in current

contracts.
----

== DOUBLE-ACTING TWO-STROKE CYCLE DIESEL ENGINE. ==
[[Category:DK]]
[[Category:Burmeister & Wain]]
[[Category:Articles]]

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Engineering Abstracts 1946

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Toro Andersen:

[[Engineering Abstracts|Back to the index of Engineering Abstracts]]

= Engineering Abstracts from 1946 =

== German Wartime Technical Developments. ==
SCHADE, H. A., Commodore, U.S.N. Society of Naval Architects and Marine Engineers (New York), paper read at Annual Meeting, 14th November, 1946.

A general description is given of certain selected items in Germany which have been reported by the U.S. Naval Technical Mission in Europe. The author's remarks fall under the following headings :-

Submarines. The Type VllC submarine, of conventional design, was built in large numbers during the war. Of the revolutionary Type XXI, 119 were completed, but none went out on war service. This type was designed as a highly-manoeuvrable high-speed vessel, which could remain submerged for long periods and operate at greater depths than most submarines. The sukmerged speed was 18 knots, and the surface speed 16 knots with super-chargers and somewhat less without them ; back pressure in the Schnorchel (breathing-tube) prevented the engines from attaining their rated capacity, so the superchargers were removed as the Schnorchel was indispensable. Trouble with the hydraulic system, which was far more extensive than is usual in submarines, was a major defect of Type XXI. These vessels, about 250 ft. long and with all-welded hulls, were prefabricated in nine sections which were welded together.

Surface Vessels. The all-welded triple-screw battleships Bismarck and Tirpitz were 821 ft. long, had load displacements of 52,700 tons, and were propelled at 30 knots by three sets of geared-turbine machinery totalling 150,000 s.h.p. A design known as battleship "H" was developed, and construction was started, but plans were changed frequently. Originally 910 ft. long, 56,400 tons displacement, and 30 knots on three shafts, each having four Diesels of 12,500 s.h.p. per engine, the ultimate design was 1,132 ft. long, 141,500 tons displacement, and 30 knots on four shafts, two with four Diesels each totalling 60,000 s.h.p. per shaft, and two shafts each with geared turbines of 80,000 s.h.p. per shaft. The Prinz Eugen, 692 ft. long with a load displacement of 19,500 tons and a speed of 32.5 knots, was fitted with anti-rolling tanks, and was propelled by three geared-turbine sets. The S-38, a Diesel-propelled wooden-hulled 45-knot torpedo boat, had special side rudders for decreasing the required power at high speeds.

Turbines and Gears. In general, the German turbine propulsion equipment was inferior to similar American machinery. The policy of using single reduction gearing with three or four pinions meshing with the main gear resulted in low turbine speeds and high specific weights. Turbine design and manufacture were mediocre, and there was poor utilisation of energy in the heat cycle ; the steam conditions should have produced high propulsion efficiencies. Some specific plants are discussed.

Diesel Engines. The six-cylinder and twenty-four cylinder M.A.N. were well-developed and reliable. The Daimler-Benz Model MB 511 is an outstanding four-cycle supercharged lightweight Diesel for naval craft ; on a continuous rating of 1,980 b.h.p. at 1,480 r.p.m., the bare engine weight is 4.4 lb/lb.h.p.

The Hamburg Model Basin. A large variable-pressure cavitation water tunnel and a smaller tunnel were constructed, but were completed too late to be used. A new towing carriage, an extended towing basin, and a new manoeuvring basin were under construction.

An appendix lists the relevant Naval Technical Mission Reports.

Engineering Abstracts 1948

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