This is an attempt to make a toy rubber powered airboat. This uses off the shelf hobby store items normally used to make windup rubber powered airplanes. The boat was designed on Autodesk Inventor and laser cut on an Epilog 60 watt laser at TechShop Detroit. It was tested in my home test tank, aka bath tub. I am quite pleased with the results.
I made it at Tech Shop
Step 1: Design on AutoDesk Inventor
I designed this on Autodesk inventor. The key features are it needs to accommodate a 1/8"x3/8" stick to plug the propeller onto and it needs to clear a 5.5" diameter propeller from the mounting. The longer the stick is, the more rubber band you can accommodate which means it can go further on one wind. I have included a .pdf file for this which can be used to cut all the parts out of a 24"x4" sheet of 1/8" balsa.
Step 2: Laser Cut the Parts
I cut the parts using an Epilog 60 watt laser cutter at Techshop. The settings I use for 1/8" balsa are 35 speed, 40 power, 500hz frequency. This seems to cut the balsa clean through without excessive charing.
Step 3: Assemble the Hull
Put the 2 hull formers in place and then put the hull sides onto it and glue the whole bit together using CA or your adhesive of choice. These parts are all poke yoke so can't be put together any other way.
Step 4: Assemble the Motor Pylon
The motor pylon is assembled next. I glue each reinforcement to the main pylon. The main pylon also serves as a rudder to somewhat keep the boat going straight.
Step 5: Sheet the Hull Bottom
I just used generic 1/16" x 3" sheet balsa for the hull back and bottom. This is a common size at any Hobby store and a lot of craft stores. Cut chunks of it and glue it across the hull bottom and back. Then sand off the excessive to finish it.
Step 6: Glue on the Pylon
Insert the pylon onto the hull and glue it on. It should align itself vertically pretty well because of the width of the reinforcements.
Step 7: Mount the Propeller and Try It Out.
The propeller is a Sig 5.5" propeller with nose piece. They come in 6 packs for only a few dollars at any really good hobby store. Slide it onto the front of the pylon with the wire eyepiece facing upwards. Stick a pin into the rear of the pylon to hold the back of the rubber band. I used 1/16" x 1/8" rubber band available at the local Hobby Store in 16 foot lengths. I used about 1 foot of it for this project. Put it through the propeller, tie a knot in the back of it and loop it over the pin.
This completes construction of the boat. For more longevity you may want to coat the bottom of the hull with Epoxy or some other water proofing agent. For the purpose of this instructable I did not since I first wanted to see if it would work or not.
I tested it out in the home test tank and the results were very good.
Step 8: Video
The image attached should be a video. This is .mp4 format. Trying out to see if this work.