Turbine Powered Lego Car

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August 17, 2004

First, a little background.  Like a lot of kids, I grew up with the original technic lego sets, but unfortunately I sold mine to help pay for college.  Now that I have the net and E-Bay, though, I've managed to re-buy most of the technic components that I had in my old collection.  Once I decided I had enough to build something decent, I sat down and built the one thing that I was never able to make as a kid:  a motorized 4 wheel drive vehicle, with steering, that was actually tough enough to do some serious climbing.  In fact, the chassis and drivetrain was so tough that it could actually spin all four of its tires if it hit a wall - the big tires from the original car chassis - with no gear breakage.  The problem was, it was terribly slow.  I simply needed more power than a lego motor has to offer.

So, after having that model around for a while, I finally took it apart to build something else, but the problem of low power stuck in my mind.  I pored over air powered Lego piston engine designs on the net looking for an idea I could use, to no avail. Then, one day at work, it struck me like a lightning bolt: Turbines, not pistons, provide the best power when you have a constant supply of pressure!  (I can't believe it took me so long to think of it, as I work with high pressure boilers and turbines...duh!)  So I searched the web for Lego turbines, but found only one.  A tiny little thing that, though functional, didn't look very hardy.  I knew I could do better.

I have since made my own prototype, which is also reversible, and boy does it go!  In fact, I'm afraid to use technic gears with it past the first gear reduction, which is an 8 tooth gear driving a 40 tooth.  After that I'm using the old type of gears - hard to find.  I hope they don't break.  If you should decide to make something similar with normal technic gears, take my advice: double or triple the gears you use per shaft.  This thing has some serious power. 

Here it is in action:

Lego Turbine Car, Medium Quality.  1.4 MB, wmv format.

Lego Turbine Car, High Quality.  5.4 MB, wmv format.

I would love to post the pictures I have of how it is put together, but for some reason I'm having trouble with my image uploading software.  If I can't figure it out soon I'll just make a "disassembly video" and put it here.  Basically it works just like my air tools - I just shoot a stream of air around a couple of the old style red gears.  To reverse it, I just pivot the nozzle to the other side of the gear and it rotates the other way.  It sounds just like an air tool too - scares my 2 year old to death.  I should also point out that the air travels in a full semicircle around the gears.  This helps in 2 ways:  First, the air has more time to interact with the gears, and second, it blows the waste air out the back of the car - every little bit of push helps! 

Plans for the future include a four wheel drive test car, and two dedicated air nozzles for the turbine: one for forward, one for reverse.  That way I can control the direction at the controller instead of at the switch on the car.  Also, I need longer hoses....lots longer!  Another thing I've thought of making is a tank.  I've got lots of the old style treads, now all I need are two reversible turbine drives, one for each tread. I thought I might also use my electric motor to turn the turret.  Ah, but I'm getting ahead of myself........


August 23, 2004

I couldn't get my camcorder to puke out its pictures, so I broke down and bought a card reader.  So without further ado, here are the pictures of the turbine car's guts:

Turbine Car Rear View - Just an overall view of the setup.

Turbine Inlet Closeup - Shows how the air hose connects to the car.  Note that the connectors, both grey and black, are hollow.

Turbine Nozzle - Shows how the nozzle aligns with the impeller wheels.  Note that the nozzle can pivot up and down to allow forward and reverse rotation.

Turbine Impellers - A partial cutaway showing a little more detail inside the air chamber.

Turbine Cutaway View - A nice cutaway view showing the complete air path.  Note that the air has to go halfway around the impellers to exit out the back,

Nozzle Assembly End View - Here I have removed the nozzle assembly to demonstrate that the connectors are hollow.  No modifications here yet, but I may try to bore out a few connectors in the future for more air flow.

Nozzle Assembly Exploded View - Shows the internal parts of the nozzle.

Turbine Drive Removed - Shows how big the turbine is.  It's about the size of the old Lego train motors.

Rounded Axle - Last but not least, a warning to those of you tempted to build this.  This is what happened to the main drive axle when I ran it unloaded for a few minutes without oil!


I have recently acquired a bunch of new tubing, maybe 50 feet or so, and I salvaged two air switches from some junked equipment at work.  Next project: a reversible turbine that is controlled at the user end instead of at the motor!

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