Normally this cargo rack mounts behind a standard bike to extent the back wheel 1.5 feet back and makes room for its own large panniers, it has a a wood deck on top and plenty of tie down points for heavy duty hauling.
This project is about minimizing the bike and having a compact "sport hauler" where the rider and passengers all sit on the rack. The rack is the only seat, but(t) it's big enough for a couple of people.
The other two bikes can be seen on my hobby website woodenbikes.com
Step 1: Start by Looking at What You've Got
I wanted to make a compact sport hauler where I could sit on the rack and pedal semi-recumbent.
Step 2: General Layout and Cogitating Stage
I used the cargo rack from the big blue bike and the black rear suspension triangle from the Mongoose bike and the front triangle from a different 16" girls bike.
Step 3: Conceptualizing With the CAD System
CAD (Cardboard Aided Design) employs a full scale cardboard cutout of my: arm length to wrist, torso, thigh, lower leg and foot, crank and area swept bu my foot as I pedal. It has brad pivots at the shoulder joint. hip joint. knee joint and pedal axle as well as at the crank/bottom bracket axle. The movable joints let me reposition it to look at different torso angles (recumbent position or upright or crouched racer position etc. different leg extensions, knee clearance toe heel clearance etc.
A stick represents the ground line and I arrange a few bikes and parts on the ground with the CAD system to get a picture and a feel for the design possibilities, problems, and solutions.
I got the idea for the CAD system from this well thought out design method by Bikesmithdesign.com
12 steps to design a recumbent
Step 4: Front and Back Triangles Bolted Together
Step 5: Move Cargo Rack From Big Bike to Sport Bike
Step 6: Connect Long Shifter Cable and Long Brake Cable
Step 7: 2 Chains Are Joined to Make a Long Chain
Step 8: Get the Handle Bar Grips Somewhere Within Reach
In this simple stem I used a hacksaw straight cut and square cross section thin wall steel tubing the make the stem. I welded both pieces of the stem to opposite ends of the steel tube to make a tall stem.
A non-welded method is to just use very tall bars (like Ape hanger bars, or half moon beach bars turned up) and the regular short stem. You can also buy a stem extension that fits between the stem and the steerer tube.
Step 9: All Ready for Prototype Test Ride.
Notice how compact the new front end is compared to the prior big mountain bike.
Step 10: Shakedown Cruise
I noticed the bottom bracket was a bit low causing the pedals to scrape in the turns. So raised it by making some adjustments.
Step 11: Snugging Up the Joint Between the Two Half Bike Frames
Step 12: Take It to Maker Faire
Some of the students riding it on Education Day would get up speed, then stand on the deck and hold the bars while doing bike ballet and bike surfing.