Here are my thoughts for discussion.
1. Types of Records - I think distance and speed records are the two things that would be of interest and could continue to be increased. The driving a course once its done is done really. Maybe also a class system like you have for the rockets ie: Single bottle 1.5L and an open class ie: unlimited capacity. There would probably need to be some rules for not allowing super heated steam powered rocket cars as this is a different class altogether.
2. Electronically verifiable - I have tried a bike computer to get speed reading and distance but they are unreliable on both counts. The speed reading has a maximum limit of the reed switch as it will only record so many rpm's, anything beyond that it just cant handle, for bikes with 22" wheels its fine because it would mean the bike is traveling at 100km/hr doing that many rpm's, but for our rocket car with smaller wheels it max's out at 21km/hr at this same rpm. It also doesn't record the distance traveled for the times when its actually traveling over 21km/hr, which gives incorrect distance readings.
We are going to try the low cost radar guns to see if these give a reliable speed reading. We will report back on the success of these.
For distance we currently just step it out. I use this method a lot for work (for wireless surveys to dimension buildings ) and know my step is 1.05m but this is not really verifiable. I looked at the option of using a GPS reading from my Nokia N95 at both ends of the run, then using Google earth to calculate the distance. The gps co-ordinates themselves (even with 13 decimal places of accuracy) we not accurate enough as when I put these on Google earth they didnt correspond exactly to where i was when I took the readings. The measured distance was at least 10m out. I may try some further tests with this method to see if my initial tests had induced human errors .. ie: me
Although maybe not everyone has access to an accurate GPS device.
I checked a launch distance using the ruler feature on Google earth and its pretty accurate, within 2m, so this method may be able to be used with video evidence and a Google earth kml file of the location to verify a claim. I have looked at lower priced laser distance devices but most of the cheaper ones max out at 30 or 50m which is not good enough for distance records. I think the simplest way will be to use a tape measure and record the measurement on videotape. You can buy a 100m tape measure for A$45 (or 50m for A$39) on eBay. As long as the entire measuring process was on tape this should be sufficient for accurate measurement, the Google earth file and video evidence could be used as an additional method to check the claimed distance.
3. Ground Slope - I know from experience of looking for flat areas to launch the car, that its virtually impossible to get a long stretch of perfectly flat surface without some slope. Usually there is some slope for drainage, the flattest areas we have found are basketball courts, but we have outgrown them now and need to use roads / carparks. A couple of options available here are possibly
a) require a run in both directions and take the average distance
b) Only allow up to a certain percentage of gradient on the road. I know my N95 has an app that uses the accelerometer to measure the gradient of the road, but this technology may not be available to everybody.
I think option a) is probably the fairest as it cancels out the issue of surface gradient
Interested to see what other people think as well. Ive attached a pic of a 100m tape measure ... measures in feet too
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