How can I measure the speed of a Hot Wheels car?
There are a few products on the market produced by Mattel for HotWheels cars to measure the ‘speed’ of model diecast cars. Some like the Rev’n’Launch product that has a speedometer gauge don’t even measure the speed! Even the products that ‘measure’ speeds, do not measure the ACTUAL speed of the car. For example, the Hot Wheels® Track Builder Digital Speedometer Accessory measures “your car's “Hot Wheels Speed”. But what is “Hot Wheels Speed”?
The Hot Wheels ID system released in 2019 (product was discontinued in 2022) also relied on scale speeds. These systems did not measure the real speed of the car, but an unspecified scale speed of the car. Hot Wheels models are 1:64 scale. This means each 1cm on the model is equivalent in a real world size of 64cm. It also means that if a model car is travelling at 1 km/h, the equivalent scale speed would be 64 times faster, or 64Km/h. As Mattel provides no detail on the methodology they used, we have to assume real model car speed x 64 was the speed these systems displayed. That is ‘Scale Speed’.
Is measuring the scale speed of your Hot Wheels car sensible?
No! Diecast model cars are capable of travelling at scale speeds far in excess of a real world speed. In the YouTube video showing the Hot Wheels Rev ’n’ Launch system, a real speed of a Hot Wheels car of 23.35Km/h was recorded. That is a scale speed of over 1494 Km/h (928mph or 1.2 Mach [1.2 times the speed of sound])! The real world Land Speed Record currently stands at 1227 Km/h by ThrustSSC driven by Andy Green in October 1997. Obviously, a real world version of a Hot Wheels road car model could not beat the land speed record! Also any errors is measuring the time or distance are magnified by using scale speeds. So considering the car’s scale speed is nonsensical.
The early prototype version of the Cook’s Projects Race Timer and Speedometer used to measure real car speeds with the Hot Wheels Rev ‘n’ Launch system.
But using the real speed of a car is useful. Real speed can show just how quickly a car is going and how any tweaks or changes to the track layout or launch system have changed the speed of the car. Real speed can also be used to show how much energy has been ‘consumed’ by the car and track. (The Law of Conservation of Energy states that energy cannot be created or destroyed - it can only be changed from one form into another. When we refer to energy used, we are referring to the amount that one energy form has been ‘consumed’ to change into another measured energy. For example, the energy required to make a car travel at a certain speed.)
How can I measure the speed of my model car?
Speed is defined as distance travelled divided by time. So if you know how far the car has travelled and know how long this took, you can easily calculate the speed of the car. The problem comes in the units that we use and the accuracy that can be measured! We are familiar with speeds being measured in Kilometres per hour, or Miles per hour, but when dealing with model cars and tracks, measuring tracks in kilometres and speeds in hours gives us a problem. The decimal places are huge! Any measuring errors are also magnified by 1000. Because the distances and times that need to be measured are so small, tiny errors in measuring them will lead to massive discrepancies in the calculated speed of the car. For example, if we have a 1m track, measured to 1mm accuracy, and measure a car travelling through this section with a stop watch we would be lucky to get a time within 0.1s. This would give a 10% variation in speeds.
Race Timer, Start/Finish Line and Speedometer
Using the Cook’s Projects Race Timer and Speedometer the time is measured in microseconds. That is 1 millionth of a second! So the measuring errors are reduced significantly. The Advanced Race Timer version can measure times so accurately that the errors are reduced and typically measure within 0.25% of the real car speed. And even the basic model can achieve less than 1% variation.
