How to build Moonbeam, a 100 MPG microcar

Why three wheels?

one gallon challenge 2011
Summer 2009: The One Gallon Challenge
The Microcar Concept
Why three wheels?
Why Not Electric?
Street Legality
Test Drives
How to Build Moonbeam
photos 1 and 2
Photos 3 and 4
Photos 5 and 6
Photos 7, 8, and 9
Some more Pictures
Improvements you might make
How you may use this information
Links and Videos to Check Out
Maine to Santa Monica at slow speed
Report from Santa Monica's Altcarexpo
Progress Report Jan 8, 2009
Moving On! August, 2011
The Sequel to Moonbeam: Sunbeam
      As I began planning a microcar in September 2005, I started to think about a three-wheeler.  If you look at microcar history on you'll see that many microcars are three-wheelers.   But coming fresh to the subject, you might wonder why one wouldn't build a four-wheeler.   It's a more stable configuration,  which keeps its width naturally for passenger and cargo carrying, and is well known and tested. 
     We pioneers and prototype makers are, to some degree, trapped with three wheels.   We want to go beyond two wheels for reasons of stability, enclosure, year-round use, and user friendliness.  Yet we are blocked from four wheels by the large amount of safety regulations of such cars.   And yet, for a prototype to be tested, seen, and thereby enter vehicle evolution, it needs to roll on the roads, and therefore be licensed, insured, and inspected.  A four wheel car will need dual brake systems, safety glass windows, air bags, impact bumpers, etc.
     These requirements are based on safety, which is good.  It's not that we are sleazes who want to build death-traps!   Rather, we need a little slack to try something new, something which in eventual production will have more safety refinements.  Building three wheelers,  which are classified as motorcycles, we have that breathing space.
     And once we accept, grudgingly perhaps,  that the bureaucrats have the last word, we get excited about three wheels.  Here's why.
     Three-wheelers come in two styles: "tadpole" style with two wheels in front, and "trike" style with two wheels in back.  During strong braking, almost all of a vehicle's weight shifts forward.  During braking the tadpole style acts  like a four wheeler, with two wheels still able to brake and steer.   The trike style, however,  acts more like a motorcycle, and is prone to tip sideways.  So, if we are going to three wheels with year-round, user friendly,  safe driving in mind--we end up with tadpole style.
     We soon encounter other advantages:  with only one driving wheel in the back, you don't need a differential, and you can use an unmodified motorcycle or motorscooter drive system.  When I'm putzing in Moonbeam 50 miles from home, I'm so glad my drivetrain was designed by hot-shots in Tokyo, instead of a shade-tree mechanic named Jory Squibb!
    Finally  with this configuation, you have cut down on a propulsion wheel, but not on a steering wheel, which makes for safety.
    Are you warming up to three-wheelers?  They're quite common in China,  where a good dozen passenger-carrying small cars are manufactured.  One looks like the picture below. They cost between $1200 and $1800 FOB China, and some run on CNG, natural gas!
         But I am pretty sure the car below is  unsafe, being trike style, and that--if true--is significant.  The car's evolutionary history comes from the tricycle rickshaw, through the motorized tricycle truck, and then naturally on to this first-generation passenger car.  All are trike style.
   When I was at the altcarexpo in Santa Monica in December 2006, I got a good chance to inspect a "Zap"  a USA-installed electric conversion of a Chinese three wheeler.  I feel quite cautious about the quality of the car.  Price is not everything,  but surely before long, small chinese cars will be here in numbers.