Lego reversible steam engine; a vacuum cleaner powered engine 2

December 9, 2007. This month, I finally finished a working demonstrator of a steam engine with with double acting cyliners and reverse bars! For a better understanding of this machine, a brief history of my trials and errors is given.

  Oktober 2005
Lego pneumatic engine , reversible LPE
February 2006
Vacuum cleaner powered 2 cylinder engine
May 2007
LEGO train steam engine with reverse bar

The history of this development started in 2005 with a pneumatic engine for a car or a train. In 2006 I started to explore the possibilities of using a household vacuum cleaner. The engine worked, but did not produce any output power. This year, I finally figured out, how real reverse bars work and how they could be realized in LEGO. The new engine worked but did not produce much output power. Then, I realized that bigger cylinders and pistons and more airflow, by using bigger air tubes, could be an improvent. The result is a marine steam engine with reverse bars.


The phase shift between the pistons and the valves can be controlled by the operator with the big wheel. The next picture shows a detail.

It appeard to be not possible for me to make a realistic central ax with excentric parts for the connecting bars to the pistons and the valves , I have solved this problem by using a central axis that is hidden under the "excentric axes."


The following pictures show how thevalves move along the steam inlets and outlets of one of the cylinders


This machine has slightly more output power than the preceeding versions. The speed is about 60 rotations per minute and it produces a nice sound (if you are able to filter out the noise of the vacuum cleaner :-).

The next machine might be a machine that looks like a triple expansion steam engine with bigger cylinders.

Very nice looking models of vaccum cleaner powered working LEGO steam engines can also been found on Andrea's LEGO website on . Othe rlinks are given on my pages of the preceeding versions.

The next creation is a "triple expansion " engine based on these concepts.