Foam Wheels

Foam Wheels

by HilldaFlyer

I have struggled for a long time trying to come up with a way of making wheels out of light materials for my park flyers. I have practiced using a hot wire cutter to cut a circle, but getting the shape ROUND and aligned on axis was always difficult. The following is my method of choice as of today. Once you have the basic parts, you can create wheels of any size and dimension - with ease. 

So let’s get crackin’...

Materials:

• Foam insulation 

• 120 grit sand paper

• Hobby knife

• Drill

• Bolt #4 2” long, nuts and washers

• Piece of Formica 

• Plastic for hub

• Optional - Rotary Cutter

Making the foam wheel/tire

There are lots of ways to make a wheel. I thought I’d share this since this is pretty easy if you have a couple of tools and material. I had some old counter top formica laying around so I made two pairs of disk templates, 5.8 cm (2.5”) and 3 cm in diameter (to get scrap, contact a local kitchen remodeler - they always have scraps they’ll give you (a builder supply store has formica samples swatches in the kitchen department). The formica disk templates are not required, but they help hold the foam on the drill while sanding.To make the large templates I glued two pieces of formica together, back to back, with epoxy. I drilled a  ⅛” hole in the center, placed a  2” long #6 bolt with washers on either side. I put the bolt in the chuck of my drill and used a cutoff blade on my rotary tool to cut the formica to a circular shape while spinning in the drill (please use safety goggles and gloves). It made really round formica disks. Alternatively, you can use a fender washer and some plastic or plywood.

Cut the foam into an octagon a tad bigger than the formica disk template. For the example here, I’ve used 1” thick pink foam insulation cut into a 2 ½ inch square. To make thinner wheels/tires, sand the sheet thinner or use a hot wire to cut it to the thickness you desire.

Sandwich the foam between two formica disks (or washers) and place the bolt into the drill’s chuck. While spinning the foam sandwich on high speed, gently sand away the foam edges using 100-120 grit sandpaper. Make the foam flat to the level of the formica disks, I use a sanding block, but you can get really good with just your hand.

Now sandwich the foam wheel between a pair of smaller formica disks and add an indent for the wheel. I have used either sandpaper or hobby knife to do this… I like using the sandpaper better (note: When doing this with the hobby knife, wear gloves and goggles. Gently layth off foam using the tip of your hobby knife with very little pressure. Too much pressure will cause the knife to “grab” the foam it will go flying... but the picture was taken with the drill off for illustration only). 

Using the sandpaper, round the edges of the tire.

When you are done with one side, flip the wheel with respect to the drill and form the other side.

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The hole through the wheel needs to be reinforced with a hub so the foam doesn’t deform on the axle. Some have used aluminum pop rivets as hubs, bottom of soda cans, but I use clear plastic cut in small circles with a ⅛” hole cut in the center. The plastic I used was a plastic packaging of some sort and used a divider caliper to “cut” out the circle with a few passes.

Glue the plastic hub reinforcement to the wheel with hot glue using bamboo skewer to center and paint the tire. Slide the wheel onto the wire hanger and fasten with hot glue or fuel tubing. Paint the tire and hub.

If you are interested in knowing how to construct the wire landing gear pictured above, search for “Removable Landing Gear” in FliteTest. Another version was originally provided by Flying Penguin RC, Posted: February 9, 2014 Swappable Landing Gear ~ Flying Penguin RC

http://flitetest.com/articles/flying-penguin-rc-removable-langing-gear

To mount this type of landing gear, cut a rectangular shape hole in the bottom of your wing, slightly in front of the wing spar just big enough for the structural plywood to fit. Use hot glue to glue the facing plywood to the wing.

Congratulations - you’re done! 

HilldaFlyer - April 2014

Article Summary

Make foam wheels with a drill and sandpaper.