Remote Controlled Car Modelling (Physical Modelling With Cardboard)

My plan was to design and model, out of modelling materials (cardboard, masking tape, glue, etc.), the wheels and body of a remote controlled car given a defined chasis and system. This model had to be be dynamic (i.e. able to move) and be of a high quality finish.

The chasis and system which I used was that of the YIHANYU Rock Crawler remote controlled car.

In this Instructable, I will show, step by step, how I modelled the mentioned parts of the car.

Supplies:

YIHANYU Rock Crawler RC Car

Several sheets of 3mm corrugated card

All purpose glue

Tools:

Laser cutter - (caution, follow all instructions of the laser cutter)

Cutting mat

Masking tape

Craft knife/scalpel - (caution, cut on cutting mat only and ensure fingers not in the way)

Metre ruler with a 90 degree edge

30cm steel ruler

30cm safety edge

Pencil

Remove the body and wheels from the chasis of the remote controlled car. They will not be needed for this model.

Using a laser cutter, cut out 8 discs of radius 55mm with a regular hexagon of side length 3.75mm cut out in the middle. You can use the PDF and DXF files attached. The use of a laser cutter is essential as it is almost impossible to do this neatly and accurately without the use of a laser cutter.

The Fusion360 files on which this was originally designed can be found here.

Ensure that you have a clean edge on a sheet of cardboard at least 350mm long with a depth along the whole length of at least 16mm. Face the rougher side (the side on which corrugations can be seen) of the cardboard up and use masking tape to fix the cardboard to your cutting mat (but do not tape into the 350mmx16mm free space).

3mm away from the edge, cut a line parallel to the edge through the top layer only of the cardboard.

The easiest way to do this is to use a metre ruler with a 'T' at the top which is 90 degrees to the ruler. Rest the edge which is 90 degrees to the ruler against the top of the cardboard and move the ruler sideways so that the distance between the long edge of the ruler and the edge of the cardboard is 3mm (use a 30cm steel ruler or the edge of a piece of 3mm corrugated card to check the distance). Then cut (through the top layer only) along the metre ruler while holding the ruler in place.

Peel off the top layer and corrugations in the cardboard and remove excess.

13mm away from the edge, cut another line parallel to the edge, again through the top layer only of the cardboard. The easiest way is to use the method outlined in step 4.

16mm away from the edge, cut another line parallel to the edge, this time all the way through the top and bottom layers.

Again, the easiest way is to use the method outlined in step 4.

Peel off the strip of cardboard created in step 5 in the same manner as in step 4, removing excess. You should have a strip of cardboard at least 350mm long 16mm wide filleted on both long edges 3mm deep with a central 'hump' of 10mm width (pictured). Reduce the length of the strip to 350mm if necessary.

On one end of the strip, cut and peel off 5mm of the top layers so that you have a rectangle 5x16mm of only the bottom layer on one end. Then cut parallel lines about 3mm apart across the strip through the central 10mm hump, again only through the top layer (but do not peel any pieces off). It should now be possible to bend and curve the strip.

Apply glue to one of the long tabs along the whole length and the small rectangular tab. Then curve the strip using the tab with glue on it around the wheel disc and stick the rectangular tab over the other end of the strip. Ensure the rougher side of the cardboard of the wheel disc is facing inward (i.e. towards the side where the strip is). Then, with some pressure run your finger along the edge of the disc to try and make the fit as tight as possible and remove any space.

Apply glue to the second long tab which is now curved and facing inwards. Then fit another wheel disc - ensuring the hexagons on this disc and the opposite disc align - into the round space so that it is glued in to form the wheel, again facing the rougher side inwards so it is hidden.

Repeat steps 3-10 once so that two wheels of width 16mm and diameter 110mm are created. Then repeat steps 3-10 twice, substituting any mention of 16mm for 12 mm, 13mm for 9mm, and 10mm for 6mm so that two wheels of width 12mm and diameter 110mm are created. You should have four wheels in total, all with a diameter of 110mm; two with a width of 12mm and two with a width of 16mm.

Using a laser cutter, cut out this net using the PDF or DXF files attached out of 3mm corrugated card.

The original Fusion360 file on which this was designed can be found here.

Make sure the smooth side of the cardboard of the net is facing up. Then cut through the top layer of card only along the lines indicated on the figure shown.

Flip over the net so that the rough side of the cardboard is facing up, and cut through the top layer of the card only along the lines indicated in this figure. Peel off the thin strips of card on the sides of the central body to create tabs for gluing.

Apply glue to the tabs and fold the net along the lines in step 13 and long lines in step 14 such that the smooth side of the cardboard is always facing outward. Glue the tabs to corresponding edges so that a three dimensional model is created.

Cut out a 107mmx45mm rectangle out of 3mm corrugated card, either by hand or using a laser cutter. Apply glue to one of the long edges and both short edges. Insert this piece between the two sides of the body (where the body is wider and about 5mm away from the edge) with the smooth side of the cardboard facing outward. Squeeze the two sides onto the edges of the rectangle for a few minutes until the glue dries somewhat.

Stick strips of white/blue tack on the edges of each of the four arches on the sides of the body, pressing them in so that they follow the shape of the arch and are not too thick. Place the body on top of the chasis, the wider end towards the front, and use slight pressure to stick it down using the white/blue tack, ensuring that the plate created in step 16 is behind the bumper. Now push each of the four wheels onto the hexagonal axles, with the wider wheels at the back and the thinner wheels at the front. Make sure that they fit well to the axles. If they do not, wrap making tape around the axles to thicken them to allow the wheels to fit better.

The model is finished now. Test it out and see what it can do!