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http://www.thingiverse.com/thing:2163032
Tape Measure Car by V21Steve is licensed under the Creative Commons - Attribution - Non-Commercial license.
http://creativecommons.org/licenses/by-nc/3.0/

# Summary

Hi, This is a variation on a Tape Measure Car racer I saw on Youtube and made to give students doing a BTEC Project unit some ideas on how they could design a similar car.
The initial vehicle seen used CD's or DVD's as wheels, my original design had only 3 wheels as I wanted to show progression and design development through modifications.

The first modification I made was to design new wheels for the rear which I printed and then fitted them with a printed tyre from Ninjaflex. When we again tried to run the vehicle it did provide better traction but we had problems with the steering, the vehicle tended to steer to one side and then tip over, although it did travel faster than with the final design.

The second modification was to change the front wheel, the same feature was used to hold the steering wheel but modified to hold 2 wheels, this gave a lot better stability and steering control which also resulted in less crashes.

Parts Printer using a Makerbot Replicator 2X at Bradford College - UK and the front wheels made from Aluminium or could be printed from the students own design. The rear Axle was turned from Nylon and we stepped this so that it increased the speed as the racer ran the tape out. The rear axle ran in 2 needle bearings approx. 7/16" (12mm) OD and 1/4" (6mm) ID these can be glued to the body when the rear axle is completed.

TheTape measure length needs to be agreed by students if you are to race these so that no unfair advantage is gained from using different tapes i.e 5Metre, 7.5M or 10M lengths.

Pull out the tape coil and clamp it so that the coil does not rewind, then cut the coil as required, drill a small hole in the tape and attach your string, line, wire as you see fit. Slowly allow the tape measure to pull in the string, once fully re-wound attach the string to the rear axle. 
**** Note - if you tie a solid knot to the rear axle the racer will stop suddenly and then reverse as the string is wound back into the tape. (do you tell student this or let them find out themselves). Look on the photo's for hints to stop this.

Once completed you can race these, challenge students - to make the fastest, the longest travel, lightest, etc. 

The Bradford College racer managed nearly 7MPH which we video'd and then used software to calculate the speed over a 3 Meter distance, use 2 video camera's synchronised (started) at the same time so frame rates are constant. Have 1st camera aimed at the start tape and the 2nd camera aimed at the second tape 3 metres away.

We also managed a distance of the full length of the workshop Atrium at college, how far will yours go ?.

See the attached photo's of the race and calculations.

Additional activities then include speed calculations, conversion of speed in metres to MPH. Measuring distance travelled or weight of items.


# Print Settings

Printer Brand: MakerBot
Printer: MakerBot Replicator 2X
Rafts: Yes
Supports: Yes
Resolution: 0.2mm
Infill: 12-15%

Notes: 
The only problem I had was the Chassis and wheels lifting off the build plate on a couple of builds

# How I Designed This

## Designed using Autodesk Inventor R2017

If you want or would like files for this let me know.