Lego big low pressure engines

December 21, 2011. This month, I got some inspiration from a Lowlug member (Anko) . Anko has demonstrated that Lego engines that are powered by vacuum cleaners work better when they are big. Most engines that have been published have 2x2 or 4x4 pistons. Check my engines from 2007

Anko built an one-cylinder engine with a 10x10 piston.  However, bigger engines also require more Lego bricks, so I started with a one-cylinder double acting engine with a 6x6 piston and a new system for the valves. I have replaced the steam shifter by a moving valve. 

Some bricks have been removed to allow for a peek into the valve system,


 This movie shows how well it works. Because it is a one-cylinder engine, it needs a fly wheel to get through the torqueless angles. The next steps are additions of a Lego governor to regulate the speed, a reverse bar, and 1 or 2 extra cylinders.

December 26. During the christmasdays/nights , I have built a new version with a governor. The inlet and outlets had to become a little bigger to lower the resistance to the airflow.

When the wheels on the governor move up and outwards due to the rotation, a valve is opened near he inlet. This reduces the airstream through the engine. It also causes a whizzling sound. It appeared to be difficult to regulate the speed with this device. The balance and the valve do not move freely enough anymore when the vacuumcleaner is running. 

December 28, 2011.  After the disappointment about the governor, I continued experimenting, and I have built a second cylinder. It appeared to be very important to select the right bricks, new an undamaged,  for the cylinder to allow for  a smoothly moving piston. The first experiment was to connect the outlet from the first one to the inlet of the second one. Thie airflow for the second one ws not big enough enymore to make it run. 

An engin with two cylinders connected parallel with a 90 degrees shift worked well. However, there was not an increasement of output torque.

And this movie shows it runs without torqueless angles.

January 4, 2012 This time,  I have tried to built a realy big one. The challenge was to find a construction for the cylinder and the piston that does not introduce frictions. The trick was to use long beams , and thechnical beams ion the edges .

For the first engine, I tried this construction for a 10x10 piston. 

The front and back of the cylinder exists of simple fitting caps that are held in place with corner tiles

This first version has  a regular steamshifter. For the explanantion, with the following two pictures, I have removed the part that connects to the hose of the vaccumcleaner. In the pictures are three spaces between the grey and the blue bricks. The middle one is connected to the part that has been removed. The spaces at the left and right side have holes to the top and bottom of the cylinder (not visible). The yellow shifter  connects the middle space with the left spaces, and right space to the open air.After a shift to right the middle space is connected to the right space and the left space to the open air. When air streams in a little puff can be heard.  


The construction works, but  is not strong enough. Many improvements are needed to make this engine run for a long time without getting damaged. For the movie demonstration, I have used a very low airflow from the vaccumcleaner.