I set out to design and build a human powered buggy for a competition in the area. The front and the back are powered independently from one another through special hubs. I love these types of projects so I though it would be feasible. I was lucky enough to have a shop with a lot of material and access to fabrication machines. I know that this is not the best, most efficient design but all of the material used was from the shop so yeah, some of it is overkill but this thing is rock solid. If you like my build PLEASE vote for my project above.
The rules were that the buggy must be driven by 2 humans with no power besides by human, it has to fold up into a 3ftX3ftX3ft cube, and has to be able to be carried by 2 humans 20 ft. Then it is to be raced around a track where it is timed and the fastest time wins. We ended up getting 6th but that was pretty darn good, and never broke any parts. Below are some videos of the buggy:
Steering and A-Arm assembly:
First Drive (indoors):
Step 1: Building the main frame
The inspiration behind this was an antenna tower style frame that uses 3 tubes in a triangular pattern for strength. The wall thickness on the tube was a bit much but I used it because it was what I had. Triangles were cut out of aluminum sheet metal with 3 holes in them in which the tubes protrude through. These plates were then welded into place. Note that almost everything was welded on the project because I did not want any hardware coming loose or forget to bolt something down. So I only used hardware where I thought necessary. The frame was made into 2 halves because it needed to fold in the center. So 2 identical frames were made and a hand machined hinge connected the two halves. Also you can see the latching mechanism that was hand machined. It's kind of like a padlock latch on a shed door but this one you pull up and twist the lock then it fits through the latch then you can fold the buggy in half.
After the two halves were finished there needed to be a flat surface to mount the four wheels to. This is why there is square tubing welded on the ends to create a mounting surface. Then tabs were machined and welded on. These will be where the A-arms will attach, and bushings were pressed into these tabs. I then weighed it and it was only about 42 lbs.