Rotary Racer - Car Performance

Castle Combe 2009-09-13

Results

This was the second race with RR8. We had an excelent race and managed to win the race ! The first first place for our new car.

• Lap Times
• Our Lap Times

Car Computer Log

This shows the main items measured by the Rotary Racers car computer. They are:

The graphs show the overall data, the actual ASCII data log files are also available, from the links below, for detailed analysis.

• Car Data File

Practice Laps Data

• Car Data File

Battery Voltages

These are the battery voltages measured with a multimeter at the end of each change. The readings were taken as soon as possible after the batteries were taken out of the cae and placed back in the battery area.

Notes

• The Car was RR8b. This was the cars second race. Some minor modifications to the aerodynamics had been done and the tyres had been changed. The faults that appeared during its first test race had been fixed and the wheel tracking was better aligned.
  
• In the race we used a 18:49 (2.72) ratio on the chain drive. the new tyres were 1cm greater in diameter giving a 2% gear ratio reduction.
  
• The Castle Combe circuit is 2.977Km long and has a slight hill with sweeping corners. There was a slight wind on the day (18Km/H ?).
• The Car Computers "Average Current" setting was at first 25.00 Amps, the Control Speed was 38 Km/Hour.  The software was car15.
• Drivers were: James Alington, Gareth Barnaby, Tom Alington, Ben Millar, Dan Dando.
  
• The drivers drove excellently again, the drivers performance was well matched. The pit stops were much better with the limited practice we had had. We managed a 1:01 driver/bat change. Also when we came in for a last minute battery change we managed a 39 second battery change time.
  
• The car ran excellently, there were no problems during the race. The motors temperature kept below 45 degrees.
  
• The CarComputer and MotorSpeed controller worked very well with no issues on the day. The telemetry link worked over more of the circuit than at Goodwood.
• The new seating arrangement was buch better, but could probably do with some improvement.
  
• The current average over the race was 24.1 Amps. The live charge calculations stated we had 5% and 5% left in the battery pairs. However the battery voltages had got down to 10.5 and 10 volts. At Goodwood we averaged 25.4 Amps and the terminal voltages where 10.5 under load. So it looks like the battery capacity for both battery sets was about 5% down on Goowood. It was probably slightly colder at Castle Combe but I suspect that the batteries are now starting to show their age (2 and 2.5 years).
• At the start of the race the speed control was on slightly. It was effectively set off for the second part of James drive and the start of Gareths drive as the current useage looked Ok. During the later part of Gartehs drive the seconday batery monitoring system was suggesting that the battery capacity was lower than the main charge level indicators stated so we lowered the power levels. As the race progressed it started to become clear that the batteries were not holding up well so we eased the power off more. It was touch and go at the end of the race. We did a last minuite pit stop to swap batteries to get a little more out of the other set and managed to finish still travelling relatively quickly.
  
• The new Pit Stop warning light and message worked well, there were no missed pit stops.
• The average speed was 49.2Km/H (taking into account the wheel size change) and the peak 63.24Km/H (40.5 MPH). The fastest drivers (where the power level was at full) were lapping at about 3:20, this is about 10% faster than at the Castle Combe the previous year with the old car.
  
• An excellent result for the team and its new car.