Sunday, June 15, 2008
X3 testing today - 81 mph
Today's testing went very well. I was able to get my Eagle Tree eLogger V3 working with the 5Hz GPS module. I wanted to be able to get data on amps, volts, watts, speed and motor rpm. There are a couple interesting things to point out about the data. If you take a look at the detail of the 81mph run data, you can see that the GPS measured a max of 77.7 mph. The radar measured 81 mph. As far as I know the GPS is more accurate in speed (.1 knot) compared to the radar. But since just about every one who is doing these r/c speed runs is using the same type of radar, and I have been using the same radar since I started I will say 81 mph is the max speed reached in this testing session.
I also tried some belted rubber tires instead of the foam tires I have been using since I got this car. They worked very well and they felt like they had more traction than the foams. The problem is that they are slightly smaller in diameter than the foams. This means with the same gear ratio, I will go slower with the rubber tires than the foams because of this smaller diameter.
Since the accident with Greg's leg last week, I reinstalled the vertical stabalizers. These are a huge help at high speeds. The importance cannot be stressed enough. The car feels like its on ice without the vertical stabalizers. They make driving the car much easier and controllable. There was no evidence that blowover was going to happen at these speeds so higher speeds can be tried next session. We are going to have to increase our space were we use to test. The run up area has plenty of room, but the slowdown part of the testing track is getting too short with these higher speeds. We're going to have to move down the track into the "prepared" surface of the drag racing track. This will cause some problems during the runs when the driving surface transitions from the prepared surface to the bare concrete of the shutown area. Hopefully it wont become an issue. We will find out during our next session.
The "X3" should be able to reach into the 90's with this setup on 8s. As soon as I can reach the limits of this 8s setup, I will upgrade to 12s and push the limits of that setup. Since this last weekend of testing, the car feels nice and stable and I will be able to punch it 100%. Check back soon for details.