Rotor blades are one of the most important aspects of a RC helicopter. It's the rotor blades that determine whether your helicopter will fly well or make a crash landing. The most powerful engine will not make your RC helicopter fly if it has faulty wings. With a little patience and a little practice, custom rotor blades can be crafted that have the potential to be of higher quality than store-bought rotor blades.
Measure a piece of balsa wood long enough for your blades and wide enough to create two blades. Measure an old blade to get your dimensions. Balsa wood can be purchased at most craft or hobby shops.
Cut the balsa wood to the proper length using a sharp craft knife. Using a cutting mat will prevent any damage to your cutting surface.
Cut the balsa wood into two strips, each as wide as your blade's widest section. You can trim the blades down later, so it's better to cut your blades too large, rather than too small.
Lay an old blade on one of the strips of balsa wood and use a pencil to trace along the curved ends.
Use a sharp craft knife to cut along the traced blade ends. Cut away any excess balsa wood from the sides of the blades.
Sand the edges of the blade using a piece of fine-grain sandpaper.
Draw a center line down the length of one of the blades. The center line is the point at which the taper of a blade begins. To find the best range for your center line, divide the width of your blade by 4, then divide the width of your blade by 3. For example, if your blade is 40 mm wide, then divide 40 by 3 to get 13.3, and divide 40 by 4 to get 10. Your center line should be between 10 mm and 13.3 mm from the bottom length of the blade. The bottom of the blade is the shorter side of the blade, and the top of the blade is the longer side with the attachment nub.
Use a piece of fine-grain sandpaper to gently sand the top edge of the blade. The edge should become rounded, and the rounding should be as symmetrical as possible.
Use a piece of medium-grain sandpaper to taper the wing. When sanding, start at the center line and work down toward the bottom of the blade. Sand both sides of the blade. When you are finished, the blade should taper slightly, with the thickest part of the blade being at and above the center line. The tapering should be as consistent and symmetrical as possible. After tapering the blades, use a piece of fine-grain sandpaper to smooth any rough edges.
Draw a line from the bottom of the blade, and perpendicular, or at a right angle, to the bottom edge of the blade, starting at the point where the bottom edge of the blade begins to taper upwards. Repeat this step for both ends of the blade. The area between the two lines and the bottom and top edges of the blade should form a rectangle. The rectangle will be your main wing surface.
Cut a piece of laminate film that is as wide as the the blade between the two drawn lines. Follow the instructions that come with the laminate film to attach the laminate to the main body of the blade. Cut away excess laminate. The seam, where the two ends of the laminate overlap slightly, should be on the trailing edge of the blade, which is the thinner, or bottom, edge. The laminate will protect the blade, as well as reduce the resistance of the wing body. Laminate film can be purchased at hobby shops and craft stores.
Place an old blade on top of the new blade and mark where the mounting holes should be. Using a power drill and a drill bit the same size as the mounting holes on the old blade, drill out the mounting holes on the new blade. Drop a little glue in the mounting holes, allow it to dry, and re-drill the holes. The glue will cause the mounting screws to grip the blade better.
Coat the unlaminated tip of the blade, the section opposite the mounting holes, with a little big of glue. Allow the glue to dry. The glue adds resistance to the tip of your blade.
Repeat Steps 6-13 for each blade.
Attach your blades to the mounting bracket. Follow your owner's manual for specific mounting instructions, as it varies helicopter to helicopter.
Balance your blades by inserting a rod through the center hole of the mounting bracket. Hold each side of the rod so that the blades spins freely. The blades are balanced when both blades rest evenly on either side of the rod. Sand down the edges of the heavier blade that are not laminated until the blades are balanced.
Attach your blades to your RC helicopter as per the instructions in the owner's manual.
Things You'll Need
- Sheet of balsa wood
- Sharp craft knife
- Cutting mat
- Fine grain sandpaper
- Medium grain sandpaper
- Sanding block
- Laminate film
- Craft glue
- Power drill
If you do not have an old blade available, contact the manufacturer and ask for the blade specifications of your RC helicopter.
A sanding block can help when tapering the blade.
Paint the part of the blade tip that is unlaminated and coated with glue. Painting the blade tip allows for better blade tracking.
Use caution when handling a sharp craft knife.
Use glue and paint only in well ventilated areas.
If your blades are not balanced correctly, or the balsa wood is damaged, your blades may not work properly.
- helicopter image by JASON WINTER from Fotolia.com