RC Plane Materials: Balsa, Foam, Composites and Covering
RC planes are built from four groups of materials: wood (balsa for light structure, plywood for strong points), foams (EPO for ready-made models, EPP for crash-proof planes, Depron and foamboard for scratch builds), composites (carbon and glass fibre for spars and moulded high-performance airframes) and 3D-printing filaments such as lightweight PLA. Wooden frames are covered with iron-on film or fabric. Below: what each material is good for, its weight and its weak spots.
By Kyle HilsonUpdated: October 20264 min read
Materials at a glance
| Material | Used for | Strength | Weakness |
|---|---|---|---|
| Balsa | Ribs, spars, sheeting, fuselage frames | Very high strength for its weight | Breaks in crashes; needs covering |
| Plywood (birch, lite-ply) | Firewalls, formers, gear plates, wing joiners | Strong, holds screws | Heavy if overused |
| Spruce/basswood | Spars, longerons | Stiff, tough | Heavier than balsa |
| EPO foam | Moulded ready-made planes | Tough, repairable | Needs moulds |
| EPP foam | 3D and combat planes | Bends back, near-indestructible | Flexible, hard to paint |
| Depron/XPS, foamboard | Scratch builds | Light, easy to cut | Dents; heat and solvent sensitive |
| Carbon fibre | Spars, rods, moulded fuselages and wings | Stiffest per weight | Blocks radio signals; costly |
| Glass fibre | Fuselages, cowls, wing skins | Tough, radio-transparent | Heavier than carbon |
| LW-PLA / PLA / PETG (3D print) | Printed airframes | Complex shapes | Brittle (PLA), heat-sensitive |
Wood: balsa and plywood
Balsa comes in densities from very light (contest grade) to hard; builders pick light sheets for sheeting and harder sticks for spars. Plywood goes where loads concentrate: the firewall, landing gear mount, wing bolts. Built-up wooden planes are light and fly beautifully, and damage is repairable with new wood and glue. How a full balsa build works: balsa RC airplane guide.
Foams
Foams dominate ready-to-fly planes because they’re cheap to mould and survive bumps. EPO is the standard for moulded models; EPP is softer and tougher; Depron, XPS and paper-faced foamboard are sheet materials for home builders. The full comparison with glue and paint tips is in best foam for RC planes; specifics on sheet building in Depron RC planes and foamboard planes.
Composites
- Carbon rods and strips stiffen foam wings and fuselages cheaply.
- Moulded carbon and glass airframes are used for gliders, jets and high-performance planes; very strong and smooth.
- Carbon blocks 2.4 GHz signals: route receiver antennas outside carbon fuselages or use glass-fibre sections.
- Safety: wear a mask when cutting or sanding carbon and glass fibre.
3D printing
Lightweight PLA (foaming LW-PLA) prints thin, light skins for complete airframes; standard PLA is used for small parts, PETG for parts that get warm. Printed planes look great and are easy to replace part by part, but they are heavier than foam and can crack in crashes. Building one: 3D-printed RC planes.
Covering materials
| Covering | Weight | Notes |
|---|---|---|
| Iron-on polyester film (e.g. Oracover, MonoKote) | Light to medium | Standard for balsa planes; shrinks tight with heat |
| Lightweight films for indoor/park flyers | Very light | Less tear-resistant |
| Fabric (e.g. polyester fabric with dope or paint) | Medium | Scale look for vintage planes, very durable |
| Tissue and dope | Very light | Traditional free-flight and small models |
| Laminating film | Medium | Toughens foam planes |
How to apply films and fabric: RC airplane covering.
FAQ
What is the best material for an RC plane?
Foam (EPO/EPP) for durability and low cost, balsa for light classic builds, composites for high performance.
What is the lightest covering material?
Tissue and lightweight films; for park flyers, light iron-on films are the practical choice.
Is EPO or balsa better?
EPO survives bumps and is cheaper; balsa is lighter for its strength and lets you build any design.
Can I build an RC plane from cardboard?
Small, light models yes, but cardboard soaks up moisture and is heavier than foamboard.
More on this topic: the complete RC Airplanes guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
