PneuCar MKII



The purpose of this project is to make a lego car running on air pressure.

I know i am not the first one to make an engine like this, but i have not yet seen a valve like i use. Hope you find it interesting.

I use the newer types of pneumatics which lets you put pressure on both 
under and over the piston.

The main obstacle was of course to make the engine itself. Actually I have
made several models of the engine and two PneuCars. The initial PneuCar MkI
had only one pneumatic cylinder, and it worked despite I had to push it to 
get it started. This was due to the fact that if the pressure was put on while
the engine was in a "dead spot" the engine did not start and had to have a 
little "push". After the push the car runs OK, but not very smooth. The other
problem was the valve (air switch) that is timing the air flow to the cylinder, 
which was not precise. But hey, it worked.

After making the MK1 model worked I started to create the MKII with two purposes:

1. A "V" engine without any "dead spots" and smooth running.
2. Better valves for better timing.

1. The V engine should leave out the dead spots because there is always at least
one piston which has pressure on it, and drives the other piston past the 
"dead spot". It was not difficult to make this part.

2. The valves (air switches) was a bit more tricky, but I found out that the best
 way was to flick the switches with "mechanical fingers". In the MK1 model 
engines I used an arm like the ones you can se on old steam locomotives, but 
it didn't work as well as this one.

After coming up with the solutions I have uses a lot of time making the design 
as compact as possible and timing the valves properly for smoothest running. 
The initial MK2 engine was huge with a completely separate valve house.

The sound of the engine is nice, floppety,floppety,floppety,floppety.

Of course the air tank delivered from Lego is not big enough, and I had to cheat
a bit. It is made of 0,5 l. box of bear (yes, I am old enough - too old). It has 
also an air valve from an old tire so it  can be filled from my electrical 
pump. Besides that it is 100% lego.

I like building Lego. It’s a pity I have not taken pictures of my other 
previously projects.



tonnyrh@hotmail.com
(Norway)