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Rotary Racer - Car Performance
Castle Combe 2014-09-29
Results
Superb weather with absolutely no wind and warm, perfect racing conditions. Practice went very well and the new drivers are getting better. Our first practice stints data logs showed that the car was going exceptionly well using about 16Amps at full speed. The caculated gearing was 2.82 but this assumed 20km/H of wind. The reduced wind and probably the improved cockpit sides that the students had made allowed us to gear up a bit further. First F24 race was very good, we were worried a bit as the car was way ahead on the first lap, but data telemetry was saying all was ok and even with a few slowish lpas we managed to win. The F24+ went well as well, Jet was running exceptionaly as usual, but there was a real battle for 2nd and 3rd with the Renishaw andSilesian University car's. We managed to get up 2nd in the later stages of the race. We were pushing the batteries to do this, the set was not as good as the others. The second F24 race was again excellent and we managed to win with a suprisingly good margin.
Car Computer Log
This shows the main items measured by the Rotary Racers car computer. They are:
| Item | Description |
|---|---|
| Throttle | The position of the twist grip throttle from 0 to 100% |
| MotorCtl | The motor power output setting. The Car computer sets the motor power based on the drivers throttle position, the speed of the car and the current being used. There is a software algorithm to implement this "drive by wire" system. The Car computer drives the PWM (Pulse Width Modulation) Motor Speed controller with a duty cycle proportional to this value. 0 - 100% |
| Speed | The speed of the car in Km/H calculated from the magnetic read switch pulse generator by the Car Computer. |
| Voltage | The batteries voltage under load. |
| Current | The current being taken from the batteries. |
| Charge0 | The charge left in the battery pack 0. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery. |
| Charge1 | The charge left in the battery pack 1. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery. |
| Charge2 | The charge left in the battery pack 2. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery. |
| BatPack | The battery pack in use (0, 1 or 2), the turbo button (4) and the Pitstop warning (8) . We generally change the battery pack with each driver change. |
| Temp | The Temperature of the motors casing in degrees C. |
| GPS | GPS position, speed and time together with lap position information |
| Misc | Other items describing the operation of the control system |
The graphs show the overall data, the actual ASCII data log files are also available, from the links below, for detailed analysis.
F24+
F24 Race 1
F24 Race 2
Practice Laps Data
Notes
- After practice testing we used an 18:48 gear ratio in the F24 and a 21:48 in the F24+
- F24+ driver was: Tom.
- F24-1 drivers were: Jacob, Tristan, Louise.
- F24-2 drivers wereL Louise, Joe, Jacob
- F24-1 Batteries were: RR15/RR16 (ok)
- F24+ Batteries were: RR17/RR18 (bad)
- F24-2 Batteries were: RR19/RR20 (good)
- The batteries in general were not as good as the sets we have been using for the rest of the year.