Stage one
The final product of this production will be a small Co2
powered car made out of a balsa wood block which is propelled down a 20 metre
track. The car will be firstly made on a 3D Computer Aided Design (CAD)
program; this program is called ‘Autodesk’. From this program you can also put
your car through a virtual wind tunnel which allows you to see the weak points
of your car and where you can improve on your aerodynamic shape. The car is
shaped and made from this program which then connects with a Denford milling
machine which allows your design to be cut out of the balsa wood. Once the car
has been cut out you can also make your own wheels using the 3D printer which
you make a design of a wheel and this machine can produce your wheels to go
onto your car. the task has been given a due date which it is to be completed
which is Monday week 7 of term 2, which gives us time to do an investigation,
planning, design, produce and evaluate our finished product to be marked.
Research
As the name suggests the first type of car that comes to
mind is to design it with the same concept as a formula one car. There are multiple
features to this design which could be great for example, down force, low to
the ground and light weight. The down force is a great design for what it does
expect it isn’t the biggest factor that is needed for the design. For the task
it is best to have little down force and little up lift but not too much otherwise
the car would waste the power upwards instead of down the track. Having the car
low to the ground gives it stability and better aerodynamics which essentially
makes it go faster. To get maximum speed out of car is to have it light as
possible, this allows the car to have more of the power that is has to be used
not wasted in frictional forces down onto the track. Something that it doesn’t
have to do though is turn like a formula one car, the product is to go down a
small straight line track so this means that the wheel setup will be different
and that of the down force. It isn’t driven by its own wheels either so that is
another reason for not having as much down force.
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Another design which has a few similarities to that of the
task is a drag car. This is because it has to go from a stop still too fast
speeds in a small time frame and only has to travel down a small track which
scaled down is much like that of the car being designed. The shape is a little
similar of low at the front and slowly gets higher towards the back; this is because
of the Co2 canister which is required to propel the final product down the
track. It is possible to have small wheels at the front and large ones at the
back but due to the fact that the lower it is the better the aerodynamics are
so it is best to have the same size wheels front and back. Instead of the rear
wheels driving the car much like that of a drag car it is a Co2 canister at the
back and that is all no extra motors to the wheels it is purely Co2 powered.
The final car design which is relevant to the task at hand
is that of a land speed record car, the similarities between the two are endless.
The designs are almost identical, jet powered, low to the ground, light weight
and for straight line speed. Instead of a Co2 canister it is powered by jet
engines at the rear which are the main source of power which propels the car
down the road. Relative to its size it is low to the ground which keeps the
airflow around it at a minimal, which is required for the task. Again relative
to its size it is light weight, even though the rockets at the rear are heavy,
compared to the power that they put out it out weighs itself. Both products
look for straight line speed to get the fastest speed out of it possible. One
of the factors that do make them different is that the land speed record car
has a longer time to get up to speed and doesn’t need the acceleration whereas
the product is to have it accelerate at a rapid pace.
The name of this competition is F1 challenge in schools, the
name suggest that it is a small formula one car but after looking at the
features it is nothing like a formula one car because our car does not have to
turn it only needs straight line speed. Essentially the end product should be
designed like a land speed record car because, much the same they don’t need to
turn, only in a straight line to try and get the fastest speed possible.
Another reason why your car needs to be designed around a land speed record car
is that they are also powered by a jet engine which is much like a Co2 canister
which will propel our car. At the same time though it need the qualities of a
drag car which looks for a small distance which is travelled and needs a great
amount of acceleration. It is possible to take features from each design, light
weight of the formula one car, shape and source of power from the land speed
record car, and the acceleration from the drag car at for a short distance.
A huge factor that needs to be considered with this product
is aerodynamics, this changes the way the car is designed and has to be though
at with great detail to get it right. Aerodynamics is measured in drag
coefficient and the lower the drag coefficient is the better the aerodynamics
will be so essentially the better your aerodynamics the faster your car will
go. For example the worst shape for aerodynamics is that of a cube with 1.05
drag coefficient. Whilst the best aerodynamic shape is that of a streamlined
body shape, also known as a tear drop, with a drag coefficient of 0.04. As you
can see it is big difference in drag coefficient so this tells us that the best
shape to go for to resist drag is to try and get a tear drop shape. It has been
proven though that if the tear drop shape is not perfect it can be just as bad
as a sphere which has a drag coefficient of 0.47. The next best shape that
could be used is a half tear drop which has is 0.09 drag coefficient. To get
this shape with the product it is best to have the tear drop shape on the top
of the car and then on the bottom side of the car having it just a flat line
which makes the shape of a half tear drop.
Apart of the competition one of the biggest part of the
completion is to get sponsors and create a marketing structure which draws the
attention of people and depends on how many sponsors you might get in the
future. Essentially your car needs to match your marketing design so the same
colours and sponsors on each. Currently the plan is to get Holden Racing Team
(HRT) to sponsor the car so this means to have the car red with some touches of
gold on it. The original plan was to have the car being black with red and gold
stripes on it much like the V8 supercar that HRT are a part of. After the car
had been cut there were some problems which had occurred and in result it meant
a quick paint job which didn’t have many features. The black paint had been all
used up so I had to turn to plain silver because it was the only colour left
and there was no time to do any stripes or decaling. As well as the different
paint designs some stickers were going to go onto the car. It was going to have
two HRT stickers on the sides as well as two formula one logos on the front
wing.
If you are to succeed in the competition organisation is
required to keep structure within the whole designing and producing of the car.
To have good organisation having a plan for all steps of the designing and
producing of the car from week to week descriptions of what is needed for the
product to be finished. The first week of the designing process was to write up
the first section of the design brief and research section. After this was completed
it was time to design the car using Autodesk on the computer. This was done
after the research of different car designs because this then gave us the best
way to design the car. This took another two weeks to get the car right on the
computer. It was then time to cut, this took a total of two weeks due to the
fact that the machine was being used by other people cutting out there car. it
was then time to cut the designed car and this took one double lesson so this
is one and a half hours. After the car was cut it is another double lesson to
sand the car back and get the finish smooth ready for paint. The next week and
half was taken up by painting the car with different coats and then sanding it
back with wet rub to get the finish the best it can be. Once it has been
painted it is time for the wheels and axles to be made. This will take two
weeks to get them cut to the right size and specifications for it to fit the
car. Once the wheels and axles are fitted to the car it is time to get back to
the drawing board and write about the process used and what worked and what
didn’t. This will all be done a week before the due date to allow for mishaps
that might occur.
The final product was not all that was expected due to few
mishaps that occurred along the way. The first thing that went wrong was that
when the car was about to get cut out and was doing the process to set it up to
the machine so that it would cut. The Co2 canister was too high off the ground
for what was already cut out of the block which is the starting product. This
meant that the height of the canister had to be changed on auto desk. Once this
problem was resolved the car was set up to begin cutting for the second time
and after a few passes it looked that the canister was too thin for what the
regulations provide of 3.5mm. Once again it was resolved on auto desk again and
instead of starting anew block it was continued from the existing block so that
materials were not wasted. Once the car was finished cutting out it looked
really good except for the fins that were located on each side of the canister,
they were very thin and had to be sanded back. They weren’t sanded back all the
way but enough so that it didn’t look tacky. After the car had been sanded it
looked even better and was time to paint it. After it had about three coats of
black paint it was wet rubbed and here was one of the few problems that made
the whole final product looking incomplete. At the front of the car there was a
thin bit of wood which helped the air pass over the wheels and without taking
enough care it broke off in the process of wet rubbing the paint. To try and
resolve this problem it was glued back on with wood glue but unfortunately it
did not hold and broke off again and again. After considering options to take,
including that of cutting out a whole new car the wing was glued back on using
a hot glue gun. This did not work the best and made the finish a bit lumpy at
the front but there was no more time to cut out another car so it went back to
paint and had to be left there. Even though the car was not fully up to the
standards that were hoped for the holes were drilled for the axles to go
through. This was not done up to standard due to the fact that it was done on
the drill press and not held straight so this meant that the axle hole was not
straight and meant that the axle would be on an angle which will cause more
force which was not wanted. The original plan for the wheels were to make them
out of balsa wood, they were but in the end had to resort to using the wheels
that were provided. This is due to one, not having enough time and two, it
would have taken too long to make sure that the wheels spun evenly and with
ease. If it was possible to start the car again and possible to make more
changes it would have happened, starting with making the front splitter thicker
and moving the front wheel wells further back to allow it to by stronger. The
fins on the side of the canister would have been made thicker so that it would
be able to take full advantage of its purpose there to give it a small amount
of up lift. Take more care towards the finishing of the car which is painting
and having more patients with it.
