Rc airplane materials list

Building and maintaining RC (radio-controlled) airplanes is a hobby that combines engineering, craftsmanship, and passion for flight. Whether you are a beginner or an experienced builder, understanding the materials you will need is crucial for creating a high-performing and durable aircraft. This guide will explore 8 essential materials, focusing primarily on balsa wood construction but also covering other popular materials like foam, carbon fiber, and various adhesives. By the end of this article, you will have a solid foundation to start your RC airplane project or maintain your existing fleet.

1. Balsa Wood

Balsa wood is the cornerstone material for building RC airplanes, known for its lightweight and easy-to-work-with properties. Balsa is widely favored because of its high strength-to-weight ratio, making it ideal for constructing the framework, wings, and fuselage of the airplane.

Why Balsa?

The unique characteristics of balsa wood make it the go-to material for most RC airplane builders. It is extremely light, which helps keep the airplane’s weight down, allowing for better lift and maneuverability. The wood is soft enough to be easily cut, sanded, and shaped, but still strong enough to provide the necessary rigidity for structural components. Balsa wood is typically available in sheets, sticks, and blocks, making it versatile for different parts of the airplane. For example, thin sheets of balsa are often used for wing skins, while thicker blocks might be used for crafting the nose or fuselage.

Best Practices for Using Balsa

When working with balsa, it’s essential to select the appropriate grade. The wood is classified into light, medium, and hard grades. Light-grade balsa is best for non-structural parts like wingtips or decorations, whereas medium and hard grades are used for load-bearing structures like spars and ribs. Some popular balsa brands include SIG and Midwest Products, known for their high-quality, consistent balsa wood supplies.

To cut balsa, a sharp hobby knife like the X-Acto #1 knife with a fine blade is recommended. Always cut along the grain to prevent splintering, and use a metal ruler for straight cuts. For curved cuts, a scroll saw might be more appropriate. When gluing balsa, use a thin layer of CA (cyanoacrylate) glue, as too much adhesive can seep into the wood and add unnecessary weight.

2. Carbon Fiber

While balsa is the primary material for many RC airplanes, carbon fiber is increasingly popular, especially in high-performance models. Carbon fiber is known for its exceptional strength and stiffness while being significantly lighter than metals like aluminum.

Where Carbon Fiber Shines

Carbon fiber is commonly used in areas where strength and rigidity are critical without adding weight, such as in spars, wing reinforcements, and control rods. Because it doesn’t warp or bend easily, carbon fiber ensures that your airplane remains stable at high speeds and under stress, which is especially important for aerobatic or racing models. Brands like DragonPlate offer carbon fiber sheets, rods, and tubes that are specifically designed for RC applications.

Handling and Working with Carbon Fiber

Working with carbon fiber requires specific tools and safety precautions. Unlike wood, carbon fiber can release fine, harmful particles when cut, so wearing a mask and using proper ventilation is crucial. A Dremel tool with a diamond cutting wheel or a fine-toothed hacksaw is recommended for cutting carbon fiber rods or sheets.

When bonding carbon fiber to other materials, such as balsa or plywood, epoxy resin is the adhesive of choice. West System Epoxy is a well-known brand for this purpose. Ensure that the surfaces are clean and free of dust before applying the epoxy. Clamp the pieces together and allow sufficient curing time to ensure a strong bond.

3. Foam (Depron and EPP)

Foam materials like Depron and Expanded Polypropylene (EPP) have become increasingly popular in the RC airplane community, particularly for electric-powered models and park flyers. Foam is lightweight, inexpensive, and easy to shape, making it ideal for constructing entire airframes or reinforcing specific components.

Depron vs. EPP

Depron foam is a rigid, lightweight material that is excellent for constructing flat wings and fuselage components. It has a smooth surface, which makes it easy to paint and finish. On the other hand, EPP foam is more flexible and durable, which makes it ideal for planes that might take a lot of impacts, such as those flown in tight spaces or by beginners.

Foam is often used in combination with carbon fiber rods to reinforce wings and fuselages. The foam provides the shape and volume, while the carbon fiber adds the necessary rigidity. BlueCor and Model Plane Foam are popular choices among hobbyists due to their consistency and quality.

Cutting and Shaping Foam

Foam can be easily cut with a hot wire cutter or a sharp knife. For more precise work, especially when creating airfoils or complex shapes, a CNC foam cutter can be used. When gluing foam, be sure to use a foam-safe CA glue or specialized foam glue like UHU POR, as regular CA glue can melt the foam.

Painting foam can be tricky since some paints can also cause it to melt. Acrylic-based paints are generally safe and provide a good finish. For a more durable and professional look, consider covering the foam with a lightweight fiberglass cloth and epoxy resin before painting.

4. Plywood

Plywood is another crucial material in RC airplane construction, particularly for reinforcing balsa structures and creating motor mounts. It offers more strength and durability than balsa, making it ideal for parts of the airplane that need to withstand higher stresses.

Application in RC Airplanes

Plywood is often used in the firewall (the section of the fuselage where the engine or motor is mounted), landing gear mounts, and wing joiners. The extra strength provided by plywood helps distribute the forces from the motor, landing gear, and wing loads across a broader area, preventing damage to the more delicate balsa structures.

Lite Ply, a popular choice among modelers, is a type of plywood that is lighter than standard plywood but still offers excellent strength. It is commonly available in 1/16 to 1/8 inch thicknesses, depending on the application.

Working with Plywood

Cutting plywood can be done with a fine-toothed saw or a laser cutter for more intricate designs. A scroll saw is particularly useful for creating curved pieces or intricate parts like control horns. To ensure a smooth finish, sand the edges lightly with fine-grit sandpaper.

Plywood can be bonded to other materials using epoxy or wood glue. Titebond II or III is a popular wood glue choice due to its strong bonding properties and resistance to moisture. When using epoxy, ensure that the surfaces are clean and free from oil or dust to achieve the best bond.

5. Fiberglass

Fiberglass is a versatile material used in RC airplane building for creating lightweight, strong, and durable structures. It’s often used to reinforce balsa wood structures, create cowls and fairings, and even construct entire fuselages in some cases.

Strength and Versatility

Fiberglass cloth is available in different weights, with lighter cloths (around 0.5 oz) used for covering wings and fuselages, and heavier cloths (2 oz or more) used for reinforcing high-stress areas. The strength of fiberglass comes from the combination of the glass fibers and the resin that bonds them together.

For example, a common use of fiberglass is to cover the entire airframe of a balsa wood airplane. This provides a smooth, durable surface that can be easily painted and finished, protecting the balsa from dings and dents. Companies like SIG and K&S offer fiberglass cloth and resins that are widely used in the RC community.

Application Techniques

Applying fiberglass involves laying the cloth over the surface and then saturating it with resin. West System Epoxy is a popular resin choice for fiberglass work due to its strong bonding properties and ease of use. Once the resin cures, the surface can be sanded smooth and painted.

For complex shapes, such as cowls or wingtips, fiberglass can be molded using a plug and mold method. A plug is made of the desired shape, often from foam or balsa, and then covered with fiberglass. Once the resin cures, the plug can be removed, leaving a hollow fiberglass part.

6. Monokote

Monokote is a popular covering material used in RC airplane construction to finish and protect the airframe. It is a type of heat-shrinkable plastic film that adheres to the surface when heated, providing a durable, lightweight finish.

Appearance and Durability

Monokote comes in a wide range of colors and finishes, allowing builders to create custom designs and color schemes for their airplanes. It adds very little weight to the model and provides a smooth, glossy finish that reduces drag. Additionally, Monokote protects the underlying balsa wood from moisture and fuel residue, which can extend the life of the airplane.

Top Flite is the most well-known brand for Monokote, offering a variety of colors and patterns. The film is available in rolls, which can be cut to the size of the airplane parts being covered.

Application Process

To apply Monokote, you’ll need a heat gun or a covering iron. Start by cutting the film slightly larger than the part to be covered. Lay the film over the surface and tack down the edges with the iron. Then, use the heat gun to shrink the film, pulling it taut over the surface. The heat causes the adhesive on the back of the film to bond to the wood, creating a smooth, wrinkle-free finish.

For more complex shapes, such as curved wingtips, it may be necessary to use small relief cuts in the Monokote to allow it to conform to the shape. After the film is fully applied, trim any excess with a sharp hobby knife.

7. Cyanoacrylate (CA) Glue

CA glue, often referred to as “super glue,” is one of the most essential adhesives in RC airplane building. It’s prized for its quick bonding time and strong hold, making it perfect for assembling balsa wood structures quickly.

Speed and Strength

CA glue comes in different viscosities—thin, medium, and thick—each suited for different applications. Thin CA is ideal for quickly bonding small parts, as it can seep into tight joints and set almost instantly. Medium and thick CA are better for larger joints and for filling gaps between parts. Brands like Bob Smith Industries and Zap are popular choices among modelers for their consistent quality.

Because CA glue bonds almost instantly, it’s important to ensure that parts are properly aligned before applying the glue. This is particularly useful when assembling the framework of the airplane, such as joining the ribs to the spars or attaching the fuselage sides.

Tips for Using CA Glue

When using CA glue, keep in mind that it can be brittle once cured, so it may not be suitable for high-stress joints unless reinforced. In some cases, a small amount of baking soda can be used as an accelerator, causing the glue to set almost instantly and filling any gaps.

Additionally, always work in a well-ventilated area when using CA glue, as the fumes can be irritating. For those who are sensitive to CA fumes, odorless formulas are available, which reduce the harshness of the fumes.

8. Epoxy Resin

Epoxy resin is another indispensable adhesive for RC airplane construction, especially when working with materials like fiberglass, carbon fiber, or plywood. Unlike CA glue, epoxy offers a much stronger bond and is more flexible, making it ideal for high-stress joints.

Strength and Flexibility

Epoxy resin is particularly useful for bonding dissimilar materials, such as attaching a plywood motor mount to a balsa fuselage. It’s also the adhesive of choice for applying fiberglass cloth to airframes, creating a strong, durable surface. West System and Z-Poxy are well-regarded brands in the hobby, offering various formulations tailored to different applications.

Epoxy comes in two parts—a resin and a hardener—that must be mixed before use. The working time (or pot life) of epoxy varies depending on the formulation, ranging from a few minutes to several hours. This allows for more time to align parts correctly before the adhesive sets.

Application Techniques

When using epoxy, it’s important to mix the resin and hardener thoroughly to ensure proper curing. Epoxy can be applied with a brush or spread with a small spatula, depending on the area being covered. For large areas, such as when applying fiberglass cloth, use a roller to spread the epoxy evenly and remove any air bubbles.

Epoxy can also be thickened with fillers like microballoons or silica powder to create a paste for filling gaps or creating fillets. Once cured, epoxy is very strong but can be sanded smooth for a clean finish.