RogueTwo Robots

**RogueTwoRobots** · 4th April 2015, 22:15

Oh, and forgot to mention that I popped the higher kv brushless motor into Drumroll yesterday and gave it a spin-up. 11,000rpm of fun

**overkill** · 4th April 2015, 23:30

The motor change has made quite a difference; apart from the speed boost, it seems smoother and quieter now. What was the reason for changing from all steel armour to steel & HDPE?

**GlenR** · 5th April 2015, 00:13

Would it not have been better to use the angle the other way round so you didn't have to weld filler bits into all the gaps :P

**overkill** · 5th April 2015, 00:36

Its probably to help hold the HDPE in place - I figure we will just vaporise it anyway.

**Mouldy** · 5th April 2015, 09:19

**RogueTwoRobots** · 5th April 2015, 11:22

Copycat you say?

If it's any consolation, I'll be bending the HDPE with a heat gun which means it'll be more curvy than angular, so the final result will probably be closer to this, shape-wise:

(possible photo credit to Nick, can't remember if this was one of yours from RG08?)

Didn't do anything to bearings or drum setup when I swapped the motor over, but I didn't start the spin-up as slowly in that second video so that's perhaps why it sounds a little better.

Couple of reasons for going from all steel to steel/HDPE. Last year Drumroll took a hit from NST that buggered the bulkhead. Stupid design flaw aside, I couldn't hammer it back into shape at the event and had to get it flattened in a fly press. The hardox was also slightly bent out of shape but was able to just force it back into line using the bolts that held it on. However if that hadn't worked, I'd have been unable to reshape it at the event.

Contrarily, Carcinus took hits from a variety of spinners, including NST, and despite the claws suffering damage, the HDPE armour absorbed the brunt of the impacts and the chassis remained relatively unscathed. Additionally any damage on the HDPE could be sorted out with all manner of hand tools there and then.

So basically the steel frame is there to lend some strength but the HDPE should take the blows of spinner impacts without it having too detrimental an effect on the chassis, and as most of the damage should be on the HDPE, I can just clean it up, or unbolt that section and replace it with another piece, all at the event and without needing any special machinery.

You're right, Glen. It would have been more beneficial to bend the angle the other way, but I want as little steel exposed as possible, again for the reason that if a vertical catches it, it's more likely to gouge and toss the robot slightly if it gets the HDPE, whereas it would probably bend the steel as well as sending the robot flying.

Whether all that works in practice remains to be seen, but it works in my head. Although I have a substantial track record of engineering faux pas