Stage one
The final product of this production will be a small Co2powered car made out of a balsa wood block which is propelled down a 20 metretrack. 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 putyour car through a virtual wind tunnel which allows you to see the weak pointsof your car and where you can improve on your aerodynamic shape. The car isshaped and made from this program which then connects with a Denford millingmachine which allows your design to be cut out of the balsa wood. Once the carhas been cut out you can also make your own wheels using the 3D printer whichyou make a design of a wheel and this machine can produce your wheels to goonto your car. the task has been given a due date which it is to be completedwhich 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.
As the name suggests the first type of car thatcomes to mind is to design it with the same concept as a formula one car. Thereare multiple features to this design which could be great for example, downforce, low to the ground and light weight. The down force is a great design forwhat 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 nottoo much otherwise the car would waste the power upwards instead of down thetrack. Having the car low to the ground gives it stability and betteraerodynamics which essentially makes it go faster. To get maximum speed out ofcar is to have it light as possible, this allows the car to have more of thepower that is has to be used not wasted in frictional forces down onto thetrack. Something that it doesn’t have to do though is turn like a formula onecar, the product is to go down a small straight line track so this means thatthe wheel setup will be different and that of the down force. It isn’t drivenby its own wheels either so that is another reason for not having as much downforce.
Another design which has a few similarities to that of thetask is a drag car. This is because it has to go from a stop still too fastspeeds in a small time frame and only has to travel down a small track whichscaled down is much like that of the car being designed. The shape is a littlesimilar of low at the front and slowly gets higher towards the back; this is becauseof the Co2 canister which is required to propel the final product down thetrack. It is possible to have small wheels at the front and large ones at theback but due to the fact that the lower it is the better the aerodynamics areso it is best to have the same size wheels front and back. Instead of the rearwheels driving the car much like that of a drag car it is a Co2 canister at theback 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 handis 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 weightand for straight line speed. Instead of a Co2 canister it is powered by jetengines at the rear which are the main source of power which propels the cardown the road. Relative to its size it is low to the ground which keeps theairflow around it at a minimal, which is required for the task. Again relativeto 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 productslook for straight line speed to get the fastest speed out of it possible. Oneof the factors that do make them different is that the land speed record carhas a longer time to get up to speed and doesn’t need the acceleration whereasthe product is to have it accelerate at a rapid pace.
The name of this competition is F1 challenge in schools, thename suggest that it is a small formula one car but after looking at thefeatures it is nothing like a formula one car because our car does not have toturn it only needs straight line speed. Essentially the end product should bedesigned like a land speed record car because, much the same they don’t need toturn, 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 caris that they are also powered by a jet engine which is much like a Co2 canisterwhich will propel our car. At the same time though it need the qualities of adrag car which looks for a small distance which is travelled and needs a greatamount of acceleration. It is possible to take features from each design, lightweight of the formula one car, shape and source of power from the land speedrecord car, and the acceleration from the drag car at for a short distance.
A huge factor that needs to be considered with this productis aerodynamics, this changes the way the car is designed and has to be thoughat with great detail to get it right. Aerodynamics is measured in dragcoefficient and the lower the drag coefficient is the better the aerodynamicswill be so essentially the better your aerodynamics the faster your car willgo. For example the worst shape for aerodynamics is that of a cube with 1.05drag coefficient. Whilst the best aerodynamic shape is that of a streamlinedbody shape, also known as a tear drop, with a drag coefficient of 0.04. As youcan see it is big difference in drag coefficient so this tells us that the bestshape to go for to resist drag is to try and get a tear drop shape. It has beenproven though that if the tear drop shape is not perfect it can be just as badas a sphere which has a drag coefficient of 0.47. The next best shape thatcould be used is a half tear drop which has is 0.09 drag coefficient. To getthis shape with the product it is best to have the tear drop shape on the topof the car and then on the bottom side of the car having it just a flat linewhich makes the shape of a half tear drop. Apart of the competition one of the biggest part of thecompletion is to get sponsors and create a marketing structure which draws theattention of people and depends on how many sponsors you might get in thefuture. Essentially your car needs to match your marketing design so the samecolours 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 ofgold on it. The original plan was to have the car being black with red and goldstripes on it much like the V8 supercar that HRT are a part of. After the carhad been cut there were some problems which had occurred and in result it meanta quick paint job which didn’t have many features. The black paint had been allused up so I had to turn to plain silver because it was the only colour leftand there was no time to do any stripes or decaling. As well as the differentpaint designs some stickers were going to go onto the car. It was going to havetwo HRT stickers on the sides as well as two formula one logos on the frontwing.
If you are to succeed in the competition organisation isrequired 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 andproducing of the car from week to week descriptions of what is needed for theproduct to be finished. The first week of the designing process was to write upthe first section of the design brief and research section. After this was completedit was time to design the car using Autodesk on the computer. This was doneafter the research of different car designs because this then gave us the bestway to design the car. This took another two weeks to get the car right on thecomputer. It was then time to cut, this took a total of two weeks due to thefact that the machine was being used by other people cutting out there car. itwas then time to cut the designed car and this took one double lesson so thisis one and a half hours. After the car was cut it is another double lesson tosand the car back and get the finish smooth ready for paint. The next week andhalf was taken up by painting the car with different coats and then sanding itback with wet rub to get the finish the best it can be. Once it has beenpainted it is time for the wheels and axles to be made. This will take twoweeks to get them cut to the right size and specifications for it to fit thecar. Once the wheels and axles are fitted to the car it is time to get back tothe drawing board and write about the process used and what worked and whatdidn’t. This will all be done a week before the due date to allow for mishapsthat 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.
