Canopy Windshield Designs and Materials

Owned by Ace Choi
Last updated: Mar 24, 2022 by Tania Lai
2 min read

Ideal Canopy Shape

Canopy is an extrusion in the basic body shape which has drag force associated with it. It should be kept low in height and long in length in order to blend into the main body smoothly.

An ideal canopy when viewed from front should be blended into body with small radius to minimize projected frontal area (A). When viewed from side, it should blend in with larger radius to reduce interference drag and avoid flow separation. Looking from the top, it should have a teardrop shape to minimize aerodynamic drag.

Interference drag is the drag force generated by the mixing of airflow streamlines between the canopy and main body.

 

Ideal Windshield Material Properties

  • Strong

  • Able to Withstand Fracturing

  • Moldable

  • Transparent

  • Affordable

Most Commonly Used Plastics

  • Acrylic or Polymethyl Methacrylate (PMMA)

  • Polycarbonate (PC) ← Ideal for use in the solar car windshield as PC is tough, stable, and transparent. PC is often used in many engineering applications due to its strength and design flexibility (moldability). PC is 250x stronger than glass and 50x stronger than acrylic.

  • Polyethene (PE)

  • Polypropylene (PP)

  • Polyethylene Terephthalate (PETE or PET)

  • Polyvinyl Chloride (PVC)

  • Acrylonitrile-Butadiene-Styrene (ABS)

Source: Types of Plastic | Learn What is Plastic Made Of & Different Types of Plastic - A&C Plastics

Types of Polycarbonates

  • Clear Polycarbonate ← Best option for solar car windshield applications

  • Coloured/Tinted Polycarbonate

  • Mirrored Polycarbonate

  • Bulletproof Polycarbonate

  • Abrasion-Resistant (AR) Polycarbonate

  • Anti-Static Polycarbonate

  • flame Retardant Polycarbonate

  • FDA-Approved Polycarbonate

  • Multiwall Polycarbonate

Source: Types of Plastic | Learn What is Plastic Made Of & Different Types of Plastic - A&C Plastics

Types of Clear Polycarbonates

  • Polycarbonate Clear SL Sheet ← In terms of affordability and properties, SL sheets would be the ideal material to use for the windshields for the solar car. Also sold in various thicknesses to suit our needs.

  • Clear TUFFAK SL2 Polycarbonate Sheeting

  • TUFFAK GP Sheeting

Source: Types of Polycarbonate Sheeting - Guide to the Different Polycarbonates | A&C Plastics

 

What makes a feasible canopy windshield design?

  • Aerodynamics

  • Ease of Manufacturing

Types of Polycarbonate Forming/Molding Techniques

  • Vacuum Forming (Thermoforming)

  • Pressure Forming (Thermoforming)

  • Twin-Sheet Forming (Thermoforming)

  • Injection Molding

Note: The polycarbonate forming techniques used is dependant on the complexity of the windshield shape. More complex windshield/canopy shapes would require pressure forming while simpler shapes would require vacuum forming.

Source: Polycarbonate | Thermoforming and Injection Molding

 

Types of Windshield Designs/Shapes

  • Cockpit (Vacuum Forming)

  • Backfin (Pressure Forming for back windshield due to sharp edge)

  • Bullet (Vacuum Forming )