Materials
PETG (Polyethylene Terephthalate Glycol-Modified)
For vacuum-forming clear canopies for radio-controlled aircraft, PETG has become one of the most popular materials. Combining excellent clarity, good impact resistance and ease of forming, it offers an ideal balance of performance and practicality for both sport and scale modellers. For most R/C aircraft canopies, 1 mm clear PETG sheet provides an excellent combination of strength, rigidity and optical quality.
Vacuum Forming Performance
One of PETG's biggest advantages is its forgiving forming characteristics. Unlike some plastics that require precise temperature control, PETG has a relatively wide forming window.
Benefits include:
Excellent draw characteristics over complex canopy shapes
Low tendency to crack during forming
Consistent wall thickness when formed correctly
Minimal shrinkage and distortion
Clarity and Appearance
PETG offers outstanding optical clarity and produces highly realistic canopies when formed correctly. Its transparency rivals acrylic while offering significantly greater toughness.
Durability and Impact Resistance
Compared to other clear plastics such as acrylic or PVC, PETG is considerably more resistant to impact damage. This makes it particularly attractive for flying models where occasional handling mishaps or less-than-perfect landings are inevitable.
UV Resistance
PETG has good UV resistance, making it well suited to outdoor flying applications. In practical terms this means canopies remain clear and serviceable for many years when compared to old PVC canopies on older models.
Continuous, long-term exposure to direct sunlight may eventually cause slight yellowing or loss of clarity.
Our Verdict
For vacuum-formed R/C aircraft canopies, 1 mm PETG is arguably the best all-round choice available. It combines excellent clarity, toughness, ease of forming and good weather resistance in a lightweight material ideally suited to both sport and scale models. Unless extreme UV exposure or maximum scratch resistance is required, PETG remains the benchmark material for producing strong, realistic and durable model aircraft canopies
White HIPS (High Impact Polystyrene)
For many years, HIPS (High Impact Polystyrene) has been a favourite material among model aircraft builders for vacuum-formed engine cowlings, wheel spats, fairings, hatches and scale detailing components. Lightweight, easy to form and simple to finish, HIPS remains one of the most versatile plastics available for hobby applications.
HIPS is a lightweight plastic that can be easily cut, shaped, sanded and glued, making it particularly attractive for model aircraft construction.
Vacuum Forming Performance
HIPS is exceptionally easy to vacuum form and has long been used by kit manufacturers for producing lightweight scale components. For most sport and scale model applications, white HIPS sheet between 1mm and 2mm provides an excellent balance between weight and strength.
Weight and Strength
HIPS is relatively lightweight while providing sufficient rigidity for many non-structural aircraft components.
While considerably tougher than standard polystyrene, HIPS is not intended for highly stressed structural parts.
Whilst this material is suitable for cowlings on electric power and glow, we would recommend glass fibre for bigger petrol engine models.
Our Verdict
For vacuum-formed engine cowlings, wheel spats, fairings and scale detailing, white HIPS remains an excellent choice. Its combination of low weight, ease of forming, simple finishing characteristics and affordability makes it particularly attractive for both kit manufacturers and scratch builders. While it lacks the impact resistance and UV durability of some engineering plastics, a painted HIPS component can provide many years of reliable service on sport and scale model aircraft.
For builders looking for a material that is easy to assemble, modify and finish, white HIPS continues to be one of the best all-round choices for non-transparent R/C aircraft components.