In (2013) my 3 kids and I built our first soap box cars.
We didn't have a specific plan for these cars, and made the basics from a website that we found. (see the example page for details)
My eldest daughter wanted hers to look like a model T.
My second daughter wanted hers to look like a piece of pie.
My son wanted his to look like a race car.
Please keep in mind that in NO WAY am I a carpenter. Just a dad who wanted to spend time with his kids and give them a great time!
We got a 3/4" sheet of plywood to use as the base for each of the cars. We cut the plywood in half lengthwise and screwed the pieces together. This made the plywood base 1 1/2" thick. We cut down the base according to the design that the kids wanted, and based on how much room the kids would need to have inside the car.
We used 2x4's for the steering and rear axles. We attached these using long 1/2" diameter bolts and nuts with several washers between the axles and the base of the car.
We had 2 different sizes and styles of wheels. The larger wheels were pneumatic, and the smaller wheels were a urethane tire. We used lag bolts to attach the wheels to the axles.
We made the framework for the upper bodies of the cars using 2x4's and 2x2's. Then we attached 1/4" plywood over the framework to make the body shape. This proved to be the most time consuming part of the build, as most of the shapes were not normal!
We made the braking system using hinges, 2x4's, and bungie cords, with a bicycle tire attached on the underside to contact the road. After some trial runs, we figured out that we needed to cut the 2x4 on an angle to make the brake surface area bigger for better stopping power.
The brakes were controlled by a foot pedal mounted inside the car on a hinge on the base. These were attached to airline cables that ran to the brake lever arm. A Quick tip on braking, for lots of braking power, make the foot pedal wide enough for the driver to use BOTH feet!
Steering was controlled by way of strings attached to the back of the front axle, lead through an eyelit into the driver area of the car.
When we were all finished, each of the cars weighed between 95 and 115 pounds.
We didn't have a specific plan for these cars, and made the basics from a website that we found. (see the example page for details)
My eldest daughter wanted hers to look like a model T.
My second daughter wanted hers to look like a piece of pie.
My son wanted his to look like a race car.
Please keep in mind that in NO WAY am I a carpenter. Just a dad who wanted to spend time with his kids and give them a great time!
We got a 3/4" sheet of plywood to use as the base for each of the cars. We cut the plywood in half lengthwise and screwed the pieces together. This made the plywood base 1 1/2" thick. We cut down the base according to the design that the kids wanted, and based on how much room the kids would need to have inside the car.
We used 2x4's for the steering and rear axles. We attached these using long 1/2" diameter bolts and nuts with several washers between the axles and the base of the car.
We had 2 different sizes and styles of wheels. The larger wheels were pneumatic, and the smaller wheels were a urethane tire. We used lag bolts to attach the wheels to the axles.
We made the framework for the upper bodies of the cars using 2x4's and 2x2's. Then we attached 1/4" plywood over the framework to make the body shape. This proved to be the most time consuming part of the build, as most of the shapes were not normal!
We made the braking system using hinges, 2x4's, and bungie cords, with a bicycle tire attached on the underside to contact the road. After some trial runs, we figured out that we needed to cut the 2x4 on an angle to make the brake surface area bigger for better stopping power.
The brakes were controlled by a foot pedal mounted inside the car on a hinge on the base. These were attached to airline cables that ran to the brake lever arm. A Quick tip on braking, for lots of braking power, make the foot pedal wide enough for the driver to use BOTH feet!
Steering was controlled by way of strings attached to the back of the front axle, lead through an eyelit into the driver area of the car.
When we were all finished, each of the cars weighed between 95 and 115 pounds.
The picture above shows the cars shortly before the paint was applied.
During and after the first ever race day we found out a few things that caused issues.
1: Steering allowance. For the first year I set a steering restriction on the cars of 15 degrees. This allowed the drivers to steer WAY more than necessary, and resulted in crashes. This has been fixed by reducing the steering allowance to 5 degrees.
2: Steering with strings. These strings were found to be too hard to control and sometimes the steering would jam up in a direction. This has been fixed by requiring steering to be done by mechanical means (steering wheel or lever). Having turnbuckles and airline cables for the steering will make the steering tight and easier to operate.
3:Wooden axles and lag bolts. This turned out to be an issue whenever an accident happened. The lag bolts tended to tear out of the wooden axles and would make the car unable to compete in more races. I have changed the rules to state that steel axles will be required this year. It wasn't a safety concern, but everyone wants to race as many times as they can! I will update everyone once I find someone who will make these for a cheap price.
4:Bearing type. The smaller wheels with urethane tires were horribly slow. They had flanged bearings in them and the grease within was too thick and would not allow for good acceleration. We will either be changing the wheels or will be changing the bearings this year to a precision sealed bearing in order to fix that issue. (This comment has nothing to do with safety, but is handy to know)
See the pictures of some of the failures on the photos/ video page!!!!
During and after the first ever race day we found out a few things that caused issues.
1: Steering allowance. For the first year I set a steering restriction on the cars of 15 degrees. This allowed the drivers to steer WAY more than necessary, and resulted in crashes. This has been fixed by reducing the steering allowance to 5 degrees.
2: Steering with strings. These strings were found to be too hard to control and sometimes the steering would jam up in a direction. This has been fixed by requiring steering to be done by mechanical means (steering wheel or lever). Having turnbuckles and airline cables for the steering will make the steering tight and easier to operate.
3:Wooden axles and lag bolts. This turned out to be an issue whenever an accident happened. The lag bolts tended to tear out of the wooden axles and would make the car unable to compete in more races. I have changed the rules to state that steel axles will be required this year. It wasn't a safety concern, but everyone wants to race as many times as they can! I will update everyone once I find someone who will make these for a cheap price.
4:Bearing type. The smaller wheels with urethane tires were horribly slow. They had flanged bearings in them and the grease within was too thick and would not allow for good acceleration. We will either be changing the wheels or will be changing the bearings this year to a precision sealed bearing in order to fix that issue. (This comment has nothing to do with safety, but is handy to know)
See the pictures of some of the failures on the photos/ video page!!!!