Canopy

This page is from the old Trevipedia, and has not yet been tidied.

The canopy on the UniSA prototype is a single piece, free-blown from acrylic.

[[Image:UniSA_canopy.jpg|400px]]

Advantages:

* the one-piece pillarless design looks good, and gives the driver an unobstructed view of the surroundings
* side hinging gives good access to the car
* the one-piece design is easier to seal than a design with multiple pieces
* acrylic has a much lower mass than glass
* the canopy is hinged using a simple long, straight plastic hinge that mounts the canopy to the body.

There are some issues that need further consideration:

; Cleaning
: Designing a system for clearing rain and dirt from the canopy is difficult, because of the shape of the canopy and because acrylic is easily scratched. However, it is also easy to polish. Team Trev fitted a windscreen wiper and drove 28000 km in all types of weather. At the end of the trip the screen needed a good polish, but was otherwise in good condition.

; Construction
: The canopy was free-blown from a sheet of aircraft-grade acrylic by Aviation Acrylic Mouldings. This gave good optical clarity, but it took several attempts to get it right. This method restricts the range of shapes that can be achieved.

; Hinging
: Hinging on the side gives good access, but does block access to ticket machines and drive-through food.

; Expansion
: Acrylic has a high coefficient of expansion, and so a large canopy will change shape with temperature.

; Latching
: Designing and building a custom latching mechanism that can lock the outside handle but still allow the inside handle to operate is a challenge. Team Trev's latching system was adequate, but could be improved.

; Opening window
: Many people who have seen the canopy have said that they would want an opening window. Some form of controllable ventilation is required somewhere in the car.

; Strut
: Team Trev designed a folding strut to hold the canopy open. The mechanism includes a gas strut to hold the canopy open. It is simple and it works, but there may be a more elegant solution.


== Design alternatives ==


# '''Don't have a canopy.''' Use TREV pretty much as is with perhaps a small "aero" screen only.  This means that weather protection will be non-existent, but no worse than a motor bike.  This also means that many aerodynamic advantages are lost. But if Trev's operational performance criteria are set at mostly less than 60 km/h and very little greater than 80 km/h then the aerodynamic issues can be lessened. A stream of activity that can branch from this approach is to design a soft-top cabin enclosure system.  This will still require a robust, wiper and demistered windscreen system.

# '''Use the canopy approach''' but work through improved hinging, cleaning, demisting, opening window solutions.
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