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Benz Model One

September 1, 2021

After completing the model of the Trillium I went looking for a model engineering project.
When I came across pictures of the first car built by Karl Benz I decided this was it.  The
car is a tricycle configuration with a single cylinder four cycle engine.  It has two speeds:
forward and stop.

To get information on the car I went to the Mercedes Benz archive web site and to the German
patent office.  There was a lot of information available.  Benz created a number of cars based
on this one and the pictures and other information I found did not always identify the model
depicted so some creative license was required.

November 26, 2021

After two months of machining I have the majority of the model created.

To start I needed a scale drawing of the car.  An image was loaded into Turbocad and using the features
of that program I created the plan shown here.


Tires have yet to be installed on these rear wheels.

The wheels of models like this always cause me some anxiety so they are the first things I make.  The rims are
turned from a piece of aluminum plate.  The spokes are 1MM stainless steel rods.  The tires are O-rings as seen
here on the front wheel.  The front wheel has 32 spokes, the real wheels each have 60 spokes.


The frame of the model is made of tubing as was done in the original car.  The arm extending out from the front
 is for the fork of the front wheel.  The piece hanging down is a step used to get up on the seat.


Here we see the steering mechanism.  The driver would turn the shaft with the white gear which will cause the
rack to move back and forth.


This is a profile view of the engine.  The gearing on the right converts the vertical motion of the crank shaft to
horizontal and reduces the speed of rotation by half as required to operate the valves.  The square block on the
left is the intake valve.  The arm below it drives the exhaust valve.  The large wheel below the engine is a fly
wheel which keeps the rotation of the engine smooth and even.  The arms below the engine slide over the frame
tubes.  The flat pulley at the top of this image drives the belt to the axles.


Here we see the radiator used to cool the engine.


This is the carburetor.


This mechanism is what gives the car the ability to move forward or to stop.  The flat pulley on the right is fixed
to the axle while the pulley on the left is free turning on the axle.  To have the car move the long arm is moved
forward causing the drive belt to move to the right pulley thus driving the axles.  When the arm is pulled back
the drive belt is moved to the free turning pulley thereby removing any driving force from the axle.  Pulling the
arm back further will cause the brake to be applied.


February 15, 2022

The car is now finished complete with the tires and sprockets I was waiting for.

Profile of the completed car.  The rear wheels turn independently on the axle.  On the full size car, the shaft holding the forward sprockets is split inside of the two flat belt pulleys and connected by a differential between the pulleys allowing the rear wheels to revolve at different speeds when the car is turning.  On the model there is not enough room for a differential so the shaft driving the forward sprockets is one piece.

Benz build five cars, each with some modifications from the original design, which made building the model difficult in some cases because pictures of the different cars were not clearly defined as to which model was being shown.  In order to have the model accurate to the original design it was built based on the patent Benz registered.


View of the rear quarter.


The front of the car is seen here.


Another profile view.


Here we see the cam shafts along with the intake and exhaust valves.  Also, the piston rod and crank shaft are seen above the fly wheel.