In the Beginning

By Staff
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Fig. 1: Original style Otto-Langen engine as shown at the Paris Exposition of 1867, utilizing vertical cross head rods and depicting the original patent.
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Fig. 2: Overriding roller clutch cut away showing internal arrangement and relationship to the piston rack.
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Fig. 3: Cut away view of original Otto-Langen atmospheric engines (1866-1867).
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Fig. 4: Second generation Otto-Langen showing simpler construction, governor and redesigned slide valve assembly.
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Fig. 6: HP Otto-Langen at Rough and Tumble Engineers Historical Association of Kinzers, PA. One of the earliest of its kind worldwide.
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Fig. 7: 3 HP Crossley Otto-Langen, showing improved design, incorporating double flywheels, simplified construction. Author standing alongside to demonstrate the massive-ness of this machine.
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Fig. 5: HP Crossley-built Otto-Langen at museum in Birmingham, England showing similar arrangement to German counterpart. Photo: John Rex.

34 Redway Street, Grand Island, New York 14072.

Probably the most historically significant engine ever in
production was the Otto-Langen atmosphere engine, designed and
produced by Nicolaus Otto and Eugene Langen between 1864 and 1878.
It was an important stepping stone for the introduction of the 4
stroke cycle engine later developed by Otto in 1876 (see fig. #1).
Several unique mechanisms appeared in this engine. Most famous was
the overriding, or roller-wedge clutch that engaged only the
downward movement of the piston and rack assembly, which resulted
with the spinning of the main shaft and flywheel (see photo #2).
Secondly, the free piston concept: where the piston movement was
independent of the main shaft. As the engine fired, the piston was
allowed to travel as far as the explosion carried it. The rack,
connected to the piston in conjunction with a gear, housing the
directional clutch, made this mechanical movement possible-similar
to a rack and pinion gearing system engaging in only one direction.
Use of a crankshaft was unnecessary with this system. Another
mechanism was the noncontinuous rotating cam. Even though the
camshaft itself spun continuously with the main shaft, the cam and
follower only cycled at one revolution intervals, at such time the
piston returned to its lowest point. As this happened, a spring
loaded pawl engaged a ratchet, thus spinning the shaft. Nearing one
complete revolution, a tail on the pawl caught a lever, disengaging
it and ending the cycle. Slide valve operation and piston/rack
lifting (for the intake stroke) were both controlled by this
momentary operation.


Otto-Langen atmospherics use a gaseous fuel for combustion and
flame ignition in conjunction with a slide valve for ignition. The
operational cycle of this engine develops its power from
atmospheric pressure rather than from the explosion itself. Otto
and Langen’s cycle is neither 4 cycle, 2 cycle, sterling, nor
any other common form of engine operation. This German based cycle
is both noncompression as well as atmospheric. Gas and air are
introduced into the cylinder by a vertical movement of the piston
via a chamber contained within a flat sliding valve affair, under
negative pressure conditions. At this point, the slide valve
closes, capturing within it a flame (lit from an external pilot) to
the cylinder, exposing it to the air-gas mixture. Compression of
the air/gas mixture does not happen in this cycle, rather ignition
occurs immediately after the intake of air and gas (hence the term,
noncompression). Upon ignition, the piston rockets upward, with
momentum carrying it beyond the expansion point of combustion,
creating a substantial negative pressure or vacuum within the
cylinder. At the apex of the piston’s travel, atmospheric
pressure, as well as the piston/rack assembly’s weight, takes
over pushing the piston downward for the cycle’s useful power
stroke of approximately the first half of its travel. Downward
motion and energy of the piston is captured to the main shaft by
means of the directional roller clutch contained within the main
shaft gear, in which the piston’s rack gear meshes. Remainder
of the piston’s half downward movement creates a slight
positive pressure within the cylinder. This positive pressure is
released through an adjustable hand valve, located on the face of
the slide valve assembly. Adjustment of this valve regulates speed
of the engine. Restricting this outward exhaust flow retards the
engine speed by slowing down the piston velocity for the last half
of its downward stroke. As the piston approaches the cylinder
bottom, a boss near the top of the piston rack depresses a lever,
releasing the pawl that engages the cam shaft, revolving it for one
revolution. With the cam now in motion, two important things
happen. First, the piston is raised, and secondly the slide valve
is raised exposing the cylinder inlet ports thus drawing in a
mixture of air and gas. As the cam nears half of a revolution, the
flame is reintroduced to the cylinder repeating the below cycle
(fig #3).

Carburetion for this engine consists of merely an air port and a
valved gas port both leading to an area adjacent to the inlet of
the engine. As the slide valve raises, a chamber contained within
it unites the air inlet, gas inlet and he cylinder opening
together. Upward motion of the piston draws air and gas through the
chamber into the cylinder.


Earliest engines manufactured in a glorious Grecian column style
were the result of several years of research by Otto and his
counterpart Eugene Langen. Initial production of these engines
commenced in 1864 and continued until 1872 from their factory in
Cologne, Germany. Langen, the cosmetic mastermind of the project,
designed the Greek pillar cylinder. This early design incorporated
two shafts, a main shaft which the flywheel was attached to and a
cam shaft that intermittently engaged the cam followers.

From compiled information, these early Otto-Langen engines
appeared to vary somewhat with almost each example. The first few
used a precarious pair of vertical rods to guide the piston/rack
assembly with the main shaft gear. Acting as a crosshead it can be
assumed that this system was very prone to misadjustment by jarring
of these rods. The most famous and important of the Otto-Langen
examples incorporated this design; it was exhibited in the Paris
Exposition of 1867 and was almost overshadowed by the Lenoir
noncompression engine. Fortunately for the German duo, engines were
judged by efficiency and performance. After several long tests, the
grand prize was awarded to them. For its day it was the most
efficient gas engine ever produced. None used less fuel per HP per
hour, a consequence of the free piston, allowing unrestricted
expansion of the gasses. Complete expansion utilizes more power
from the expansion and allows for cooler operation. As strange as
this engine appeared, not to mention its spastic running
characteristics and reportedly loud operation, the beginning of its
success started here. Some were produced with two slide valves, the
second valve controlling incoming gas to the main slide valve.
Later versions were manufactured without vertical ‘cross
head’ rods and incorporated a simple notched bar contacting the
smooth side of the rack to maintain gear contact. Some versions had
spoked gears, some had individual bearing pedestals, etc. All early
units were built without governors.

A graceful engine it was not. With a piston and rack assembly in
excess of 100 lbs. for the ? HP unit, the descending piston
hammering against the cylinder bottom raised havoc with buildings
and foundations (a major disadvantage of the free piston concept).
Taking this into consideration, as well as the weight and height,
it is not surprising production engines never exceeded 3 HP.
Technical books from the late 1800’s make mention of the need
for a good solid foundation under the engine. Second floor
installations usually were inadequate. A 2 HP engine weighed in at
a whopping 4,000 lbs. and stood an impressive 10? feet tall!
Hammering of the piston was, however, reduced by a petcock at the
engine’s exhaust. Greater restrictions of this valve slowed the
piston’s descent as well as reducing the speed.

After several years of production, a less cosmetic, more
mechanically developed version was offered (see fig #4). The
Grecian column styling was removed, as was as the cam shaft.
However, a governor and improved overrunning clutch were added. A
shorter, squattier machine was the newer concept. Governing of this
engine was accomplished by means of a cam gear driven fly ball
governor, interrupting the pawl from reengaging the cam. This
version is, in fact, the first internal combustion hit & miss
engine. Many parts, such as the cam and followers, pawl and ratchet
were relocated to the main shaft. Production of this later version
spanned a course of 6 years from 1872 to 1878.

Success of these engines was noted by many manufacturers.
Crossley of the UK was one of these that managed to get its foot in
the door. Patent rights were granted to this English company for
the building of atmospheric engines, bringing the dawn of a world
renowned engine manufacturer.

Initial examples from Crossley (their first attempt in engine
construction), incorporated the use of a governor serving dual
function. Exhaust gas restricting by a valve and interruption of
the pawl engagement were both governor controlled. Resembling very
closely the early German engines in mechanical layout and
operation, the Crossley-built units had a smooth sided column
without the added expense of casting a Greek column. Vertical cross
head rods were never used (see fig #5).

Crossley, famous for its high quality products, made several
improvements and design changes over the years resulting in many
variations of the original concept. Even greater than the
Otto-Langen deviation between existing examples, Crossley appeared
to have spent extensive research on improving the pawl, slide valve
and governing operation.

During the approximate fifteen years of atmospheric engine
production, Crossley built almost half as many engines as
Otto-Langen. Total production of these engines by all manufacturers
is estimated to be less than 5000.


Today, a good estimate would be less than six examples of the
original Grecian column Otto-Langen version survive worldwide, with
only a couple in operating condition. Rough and Tumble at Kinzers,
PA has the oldest Otto-Langen engine in North America, and perhaps
the oldest internal combustion engine in the United States. Being
an extraordinary example, it is comforting to know that each August
at their annual show it is displayed in its full running glory (see
fig. #6). This engine has been restored and is operated by John
Wilcox. Its unorthodox operation, dual slide valve arrangement, and
flame ignition attract crowds of people all day long.

It is most unusual to view engines of such importance anywhere.
The fact that less than 5000 Otto-Langen engines were manufactured
in all versions, 125 years ago, and in Europe, contribute to its

Henry Ford Museum at Dearborn, Michigan has a Crossley-built
engine of the 3 HP size. Although a static exhibit, its monstrous
size, improved design and originality make it a most worthwhile
exhibit (see fig #7). The Smithsonian Institution in Washington,
D.C. has at least two examples, one being an earlier Crossley and
the other a later Otto-Langen. Operational status of these two is
not known. Several other examples appear in museums throughout
Europe, where it is understood some are run on a regular basis.

An attempt was made here to give a brief overview of a great
stepping stone for the 4 stroke-cycle engine used almost
exclusively today.

Information on the above was gathered through a multitude of
books and sources. I would like to thank the following for their
assistance: Rough and Tumble Engine Association at Kinzers; Woody
Sins, Rochester, New York; John D. Rex, Chelmsford, Massachusetts;
William E. Worthington, Jr., Smithsonian Institution; John Bowdich,
Henry Ford Museum.

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