The Final Product (almost!)

The Car

Sitting in upright position in the car, determining where the seat is going to be mounted, where the fuel cell will be placed and the motor... The height from the ground (ground clearance) is about 200mm.

Placing the top part of the skin on top of the bottom. The driver (one of our supervisours) is inside.

Making sure that the top and bottom pieces are well fitted together, but more ribs are required inside the car to keep the width of the car as it should be, because the skins are very flexible. Once everthing is fitted inside the body the body will automatically be stiffened.

Skins are fitted together and driver gives the "Okay".

Rear Wheel

The brake calliper bracket is welded to the fork that is holding the wheel. This brake calliper is aligned and then bolted to the brake calliper bracket.

                                   

Two flat bar pieces are welded to the rear rib on the one end and bolted to the steering assembly on the other end.

The shaft (steerer tube) supported with two ball bearings to assest with the steering. This assembly is kept together by the bolt on top which is fastened with a nut which is welded inside the pipe.

Removal of material at the bottom of the car for the movement of the wheel.

Front Wheels

The front shaft is a pipe that is welded to the front rib. The front rib is fastened to the skin using glass bubble. To make this bond stronger a strip of glass fibre was put over the bracket.

At the end of the front shaft there are axles slotted into the pipe.

The wheels are slotted on the axles and then tighten by the a bolt. The wheel hubs have two bearings inside which fit on the axle.

The brake calliper brackets are aligned and welded onto the shaft, then the calliper is bolted to that bracket. The brake disc is already mounted to the hub of the wheel.

Mould

We made the datum line and made a lip from sheet metal, this is done to enable one to split the two moulds apart. After sanding down the plug and filling in the space between the sheet metal and the plug, we applied several layers of wax on the body to get it as smooth as possible. Then blue gelcoat was applied on to the body.

Now applying 4 layers of glass fibre on top of the blue gelcoat - just after the gelcoat become tacky. The Sheet metal lip was taken out just before applying the glass fibre layers at the bottom side of the plug. Timing with these materials are very important!

The bottom mould is taken off. 

Top mould also has been taken off, but there was pollyfilla attached to the mould and we had to take it off before cleaning the mould. The white pieces seen in the picture is the pollyfilla which had stuck to the mould.

The two moulds on top of each other. Someone is inside...

 

What we have learnt:

- After shaping the body out of the high density foam - JUST APPLY PVA PAINT!

- Sand it down after several layers of PVA, if there is still bumps or holes, paint it again and sand afterwards until extremely smooth.

PVA paint

We are joined by the Dutch students while drying the PVA paint using a heat gun blower and hair dryers.

Also having our supervisor from electrical and mechanical engineering getting thier hands dirty with sanding.

Group Members

Mechanical Engineering

• Mr. T. van der Schyff (Supervisor)
• Ms V. Cain (Supervisor)
• Mr. P. Humphreys (Supervisor-AMTL)
• C. Nijeboer (Group Leader)
• M. Ruperti
• E. Labuscagne
• S. Lebatlang

Electrical Engineering

• Mr. R. Pentz (Supervisor)
• Mr. B. Groenewald
• L. Schmids (Group Leader)
• W. Volschenk
• D. Tolken

Industrial Engineeing

• G. Coetzee

Brag Poster

The poster indicating how far we are, busy with the plug. There is still Modelled vehicle to come soon.

Hydrogen Fuel Cell

SPECIFICATION

• Type of fuel cell PEM
• Number of cells 72
• Rated Power 1000W
• Performance 43.2V @ 24A
• H2 Supply valve voltage 12V
• Purging valve voltage 12V
• Blower voltage 12V
• Reactants Hydrogen and Air
• External temperature 5 to 30ºC
• Max stack temperature 65ºC
• H2 Pressure 0.45-0.55bar
• Hydrogen purity ≧99.995﹪ dry H2
• Humidification self-humidified





• Cooling Air (integrated cooling fan)
• Weight (with fan & casing) 4500 grams(±100grams)
• Controller 400 grams(±30grams)
• Dimension 21.5cm x 12.5 cm x 30cm
• Flow rate at max output* 14 l/min
• Start up time ≦30S at ambient temperature
• Efficiency of stack 40% @ 43.2V
• Low voltage shut down 36V
• Over current shut down 30 A
• Over temperature shut down 65℃
• External power supply** 13V(±1V), 5A~8A



Prop Construction

Steps to follow:
1   -   Foam shaping
2   -   One layer PVA spray
3   -   One layer Fibre Glass
4   -   Sanding
5   -   Bodyfiller
6   -   Sanding bodyfiller
7   -   PolyFilla
8   -   Sanding PolyFilla
9   -   Filling spots
10 -   Sanding
11 -   Primer
12 -   Sanding
13 -   Clear Coat
14 -   Polishing

Mission

What
-Hydrogen powered vehicle

Why
-To win the world Class event

How
-Using the state of the art technology

When
-Prototype finished by the end of November 2011 and participate in May 2012

Where
-CPUT (South Africa)

Vision

• Promote the use of alternative energy resources.
• Involve schools to create interest and to up the standard in the science and technology department.
• Improve CPUT's collaboration with The Hague Hogeschool
• Sturdy of latest composite materials

Glass fiber

The fiber glass was first cut out as a long strip and then 4 pieces were cut out of that strip.

Mixture of epoxy resin and hardener components. The two components must be mixed thoroughly.

The car was covered with one layer of fiber glass to make the foam blocks sturdy.



Polyfilla

 After the shaping process the car is sprayed with 3 coats of PVA white paint.  Each new coat is only done if the previous coat is dry.  The PVA is sprayed on to allow the glass fibre to grab onto the foam.  The foam absorbs the PVA clogging the pores and sealing the foam, which help us using less epoxy with the glass fibre process.

The holes in the car which was used to insert the steel pipes are closed up with polyfilla and let to dry.

Polyfilla is aslo used to fill the gaps between the foam and hardboard.

  

The polyfilla have been sanded using 80 grit sandpaper. 

 

Shaping process

 

Different glues where tested to find the most suitable glue for the application. It was found that glue sticks (Hot Glue) which is applied with the glue gun is the best to use and the most cost effective adhesive. 

The skeleton of the car (The Hardboard Sections) from the back and front view

After the sections have been glued together the car is shaped with wood rasps and sandpaper.

Shaping continues...

The final shape of the car!

Foam

The sections are cut out from drawings and pinned on the high density foam blocks.  A band saw is used to cut the sections out of the foam.

Sections are cut slightly bigger than the drawing allowing a bit of extra foam for trimming purposes in the final shaping stages.

A small drill bit is used to make pilot holes in the foam at the reference points.  After that a large (25mm) drill bit is used to make the holes to the required size (The size of the pipes). Now the sections are pushed onto two steel pipes of 25mm diameter.  These pipes are used to keep the sections aligned.

After each foam section the corresponding hardboard sections is placed in. These hardboard sections are put in place as a guide and to make the shaping easier.

Hardboard

The drawings are removed from the foam and pasted onto hardboard with pritt.

                                      A jigsaw is used to cut the pieces out to the exact size.

hardboard pieces cut out to exact size.