basizeland wrote:
The official world record is 1.020 seconds but the unofficial world record which is the Australian record is 0.985 seconds. We got a run of 1.046 seconds which is the second fastest this year because out of all the state finals only one team has beaten it with a 1.040. Our car kept breaking at the end of the track because the towels that they used to stop the car were very heavy which stop the car very abruptly causing it to break. Once the car broke its times were around 1.080 so if it hadn't of broke it may have got faster because it only had 2 runs before it broke.
I'd be willing to bet that the faster times are due more to environmental conditions than car design.
I'm thinking mainly of temperature- surely how hot the can is when pressurized and how hot it is when discharged will make a huge difference. I haven't read the rules, but surely the best way to increase performance would be by preheating the can in some way- whether you stick it hot water, the microwave, or heat the car (to transfer heat to the can).
I guess atmospheric pressure would also have some impact, but probably not that huge.
One other approach I'm surprised no-one's tried is to get rid of the wheels altogether. Obviously you will need them to be within the rules, but from the point about ceramic/steel bearings, sounds like rolling resistance is a major factor.
Why not build it as an ekranoplan? It'd be dead easy to use some of the gas from the can under the body (mount the can at the front maybe) or perhaps just do a true ekranoplan design. Reducing load on the wheels would mean lower friction from the bearings. If the car could actually take off at maximum speed, even better.
Damn I wish my school had done this, sounds like a fantastic physics + engineering challenge.
