Note: usual rotation of postings is off kilter this week. It happens sometimes...
Tasks for the build session were as follows: Strengthen steering assembly for crash resistance. Finish wiring the steering actuator. If time permits, install brake. And test, test, test.
The good news is that failsafe test went as expected. Turn off the transmitter, or drop it, or drive out of range, or swallow the frequency crystal....and power to the drive motor cycles off.
So, all we really needed to do was get a feel for the machine as it drives under (hopefully) steering control.
It drives with a very light touch. The first couple of kids only got 30 feet or so before bouncing off the hallway walls. The control stick just needs gentle nudges when the dragster starts to drift. Later kids did better, getting maybe 80 or 90 feet before I told them to power off. There was one brief collision with a projecting bit of masonry while the 8th grade principle happened to be watching, but only a few plywood splinters. The steering reinforcement held.
But then the ranges started getting a little longer, the steering corrections a bit harder. One test driver was doing very well, perhaps the best run of the day, when I told him to power down the drive.
Unfortunately he did not have his finger on that control so he had to look at the transmitter for just an instant.
The dragster veered to one side, and hit the wall of the girl's bathroom at a freak angle. Darned if it did not snap the half inch plywood right behind the battery mount! Of course this is a weak spot since it became necessary to saw a hole in the dragster for a bigger drive pulley.
Back in the pit area:
And here a privacy rules compliant moment of silence by part of the build team:
Of course the kids generally felt badly, and the ill starred driver worst of all. But actually this was a good thing on almost all levels.
-More testing always shows you more ways to improve.
-We have one full build session left.
-The steering held.
-It will only take about 15 minutes to fix this...just screw a couple of support struts onto the bottom.
-It provided considerable amusement to all adults in the vicinity!
-The kids learned something today. The hard way, which is often the most durable form of learning.