March 1, 1941— February 2, 2014
Joe Martin Foundation "Metalworking Craftsman of the Year" award winner for 2001
George Luhrs spent his working life as a professional machinist running his own business before retirement. He did aerospace and R&D work that required great precision. Now he finds challenge in building the world's smallest running internal combustion engines.
Among George's credits are wins in the 2000 and 2001 Sherline Machinist's Challenge contests at the NAMES show in Michigan. He was also awarded the Joe Martin Foundation award for "Metalworking Craftsman of the Year" for 2001. The following biographical information was provided by George Luhrs and his wife, Barbara.
We regret to announce that George passed away February 2, 2014. This page will continue to honor his life and his work as the master of the world's smallest ignition internal combustion engines.
Luhrs has been building engines of all
sizes for most of his life. As a kid, he
worked on all kinds of models, including
free flight and "U-control"
airplanes, model boats and model cars.
He fixed and rebuilt small engines and,
as a teen, worked on cars. In order to
do these things, he learned how to use
many tools, including the machine shop
equipment needed to make and repair
worked his way through school in a
machine shop. His education consisted of
a degree in mechanical technology, which
prepared him to be a metallurgist, a
tool and die designer, draftsman,
machine tool operator and mechanical
engineer, all of which he has used both
in his business and with his hobbies.
after he graduated, George decided to
set up shop in his own basement. For
over 35 years until he retired 2 years
ago, he was self-employed in the machine
shop industry. At first he manufactured
parts for aerospace corporations, and
then did design and research and
development work for several private
firms. He has also designed and built
unique machinery for a few local
companies. He considers himself
fortunate to have been able to earn his
livelihood doing what he enjoys most.
the years, when his shop machines were
not tied up with customer work, George
would build models of engines and also
many pieces of miniature apparatus, such
as a drag saw, washing machine, cement
mixer, water pump, grinder and others,
to show how the engines were used. His
hobby equipment consists of the same
full-size industrial machinery that was
used for the machine shop business. He
designed and built all his own
specialized tooling used to make the
parts for his model engines. This
includes gear cutting, miniature bolt
making and special cutters.
has had several specific goals in mind
over the years. One is to build running
gas engines smaller and smaller. Both
their size and getting them to run
reliably is a challenge, and that
challenge is what keeps his interest.
Each time he has achieved a goal in one
size, he tries to make the next one even
smallest engine he has designed and
scratch built so far is a 1/8" bore,
stroke, single cylinder, four
cycle, overhead valve, sparkplug
ignition engine. It runs, but he is
still trying to get this one to run as
well as all the others. The four
cylinder, four cycle ignition engine
which won first place in the Sherline
Machinist’s Challenge at the N.A.M.E.S.
show in 2000 was designed and built from
scratch. It took over 600 hours to complete.
For the 2001 contest, George switched
to a radial design and created a
5-cylinder aircraft engine with
1/4" bore and stroke which took
first place for the second year in a
For the 2001 contest, George switched to a radial design and created a 5-cylinder aircraft engine with 1/4" bore and stroke which took first place for the second year in a row.
the 2000 contest, all the engines George had
designed and built were single cylinder,
four cycle engines. For that contest his
challenge was to build a small
multi-cylinder four-cycle engine and
have it run reliably. Next year's
5-cylinder radial expanded his range
even further. All his engines
are overhead valve sparkplug ignition
engines. They all run using homemade
coils for make-and-break ignition and
miniature model airplane type coils to
fire the sparkplugs. These are mounted
in battery boxes or in the base of each
engine so as not to distract from the
engine itself. The sparkplugs he makes
for these engines range in size from ¼-32
thread for the large engines, 6-40
thread for the mid-size ones and 2-64 or
0-80 threads for the smallest engines.
George accepts his plaque and check from Joe Martin Foundation representative Craig Libuse for being selected as the "Metalworking Craftsman of the Year" for 2001.
other goal is to show that there are
still people who make things from
scratch; that is, no kits and no
castings. Most importantly, he wishes to
promote model building as a hobby to the
younger generation by passing along as
much knowledge as he can to anyone who
is interested in learning. Toward this
last objective, he has done a fair
amount of work as a guest speaker to
encourage interest in the hobby at his
local grade school, the Boy Scouts,
model airplane clubs and many live steam
club meets. He also participates in
numerous antique car shows each year and
always displays his engines along with
either a 1930 Pontiac or a 1960 Maserati.
Many times the small engines generate
more interest than the antique cars.
has recently spent time tutoring a
talented newcomer to model engine
building named Jared Schoenly. When they
first met, Jared was just ten years old,
but he already had an incredible amount
of knowledge of small engines. Over the
past nine years he has spent time
visiting my George and his wife to learn
more about engines and get some hands-on
experience in George’s shop. He has
eagerly absorbed all George can teach
him, and now at age 19 he is an honors
mechanical engineering student at the
University of Pittsburgh. He will soon
be entering his own scratch-built
engines in shows and contests and
hopefully taking what George has been
able to teach him to a new level. His
parents also work to encourage the hobby
and have put on the Cabin Fever
Exposition in the Pennsylvania area for
the past six years. The show is rapidly
increasing in attendance, which is
helping meet George’s goal of seeing
new people enjoy the challenge of
George is seen as his show display booth with some of his engines and awards.
(Click photo for larger image.)
|This single cylinder spark plug gas engine has a bore of 1/8" and a stroke of 5/32" and displaces only .0019 cubic inches. It was designed and built from scratch in 1996. Part of a penny can be seen at the bottom of the photo for size reference. (Thomas Oversluizen photo)|
|A close-up view of the single cylinder and carburetor. The external pushrods that operate the valves can also be seen. No one has yet challenged George's claim that this is the smallest running spark plug fired gas engine. By the way, it buzzes kind of like a bee when it is running. (Thomas Oversluizen photo)|
|This four-cylinder inline aircraft engine won the 2000 Sherline Machinist's Challenge contest in Michigan. It is displayed on a laminated wood base with a matching laminated wood propeller. The display base is mounted to a glass covered case that displays all the components of a second engine.|
|This view shows the engine and display base without the display of individual components. The spark plug fired engine features a bore of 1/4" and a stroke of 5/16" for a displacement of .061 cubic inches. A quarter is used for size reference. (Thomas Oversluizen photo)|
|A side view of the engine gives a better idea of the fine worksmanship in each piece. Again, a quarter is shown for size reference. (Thomas Oversluizen photo)|
|The display base is shown here with the engine and laminated stand. Laid out in an orderly display are all the components needed to make up the engine. (Thomas Oversluizen photo)|
|Here is a second version of the engine George built to demonstrate its ability to actually run. A small fuel tank can be seen at the rear, and tiny throttle controls extend to the rear.|
|George's winning entry in Sherline's 2001 contest displayed two 5-cylinder radial aircraft engines plus a third engine in parts in the glass covered frame behind. The running spark plug fired engines have a 1/4" bore and 1/4" stroke. A penny is used for size reference in the foreground.|
|A detail of one of the radial cylinders and head shows the external rods driving the rocker arms to operate the valves.|
|Another close-up of the engine shows the fine work in the laminated three-bladed wood propeller.|
|Yellow spark plug leads add a bright touch. Tiny throttle controls can be seen to the rear and below the bullet shaped fuel tank to which the engine is mounted.|
|Inside the glass covered display case are all the parts to make up a third engine. This close-up shows the level of perfection of each tiny part needed to make an engine this small actually run.|
|This small Stover hit-n-miss engine is another example of George's work. (Thomas Oversluizen photo)|
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