Quote:
Originally Posted by John Neun
#25 chain is great, but for final drive, we learned the hard way that it is too light. We actually broke links in half at the "neck" in their cross section. ... be very careful with #25 on final drive. I'd love to show you the brooken pieces; I would not have believed it if I had not seen it.
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I've also seen a few broken #25 chains coming off of hard driven traction systems. Like John, I think the cause was shock loading. A #25 powertrain can be sized appropriately for stall conditions and still fail when shock loaded. Such a failure becomes more likely when load conditions get more aggressive, as usually happens during elimination rounds.
A team might ship its robot thinking that #25 chain is plenty strong enough based on practice driving at home, and continue to believe that through Thursday practice rounds. Most of the broken chains I have seen came from robots that were designed for offense, but switched to being defensive specialists in the eliminations.
__________________
Richard Wallace
Mentor since 2011 for FRC 3620 Average Joes (St. Joseph, Michigan)
Mentor 2002-10 for FRC 931 Perpetual Chaos (St. Louis, Missouri)
since 2003
I believe in intuition and inspiration. Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research.
(Cosmic Religion : With Other Opinions and Aphorisms (1931) by Albert Einstein, p. 97)