pic: Team230 Damaged Frame Rail

[MamaSpoldi]

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[JohnFogarty]

What thickness tubing is that? What kind of wheels did you use?

[Jay H 237]

Looking at that I'd guess that adding a spacer in there would have helped by not allowing the walls to fold in and tear even with the same thickness aluminum material. Those thin walls were the only thing supporting the axles.


I was at Waterbury both days and some of those robots hit the defenses at high speed and caught air at times. You really don't know at times how well some parts will hold up until you give them the real live test!

[AndrewMorrison]

At least it wasn't caused by us this time!

[electroken]

Originally Posted by JohnFogarty

What thickness tubing is that? What kind of wheels did you use?

That's 0.062" wall thickness 6061-T6 tubing. The drivetrain is 6WD, 8" pneumatic tires in a WCD (cantilevered) configuration.

It was the ramparts that did us in, with that big shot to one wheel at the start of each crossing. We told our driver to drive it as if he stole it, and he did not disappoint.

A spacer within the tube may have bought us time, but failure was inevitable. the other side of the tubing has significant stress cracks. As it was, the thing made it halfway through its 17th match before it failed. The new frame ( 0.125" wall thickness) seems bulletproof so far. We would have started off with that if we'd fully understood the brutality of this game.

[electroken]

Originally Posted by AndrewMorrison

At least it wasn't caused by us this time!

Not his time, but district champs are coming up.

[JohnFogarty]

Originally Posted by electroken

That's 0.062" wall thickness 6061-T6 tubing. The drivetrain is 6WD, 8" pneumatic tires in a WCD (cantilevered) configuration.

It was the ramparts that did us in, with that big shot to one wheel at the start of each crossing. We told our driver to drive it as if he stole it, and he did not disappoint.

A spacer within the tube may have bought us time, but failure was inevitable. the other side of the tubing has significant stress cracks. As it was, the thing made it halfway through its 17th match before it failed. The new frame ( 0.125" wall thickness) seems bulletproof so far. We would have started off with that if we'd fully understood the brutality of this game.

Yeah all of the teams I work with are using 0.125" frame rails and we haven't seen any damage at all.

[PayneTrain]

Originally Posted by electroken

That's 0.062" wall thickness 6061-T6 tubing. The drivetrain is 6WD, 8" pneumatic tires in a WCD (cantilevered) configuration.

It was the ramparts that did us in, with that big shot to one wheel at the start of each crossing. We told our driver to drive it as if he stole it, and he did not disappoint.

A spacer within the tube may have bought us time, but failure was inevitable. the other side of the tubing has significant stress cracks. As it was, the thing made it halfway through its 17th match before it failed. The new frame ( 0.125" wall thickness) seems bulletproof so far. We would have started off with that if we'd fully understood the brutality of this game.

You said this drivetrain was in a WCD configuration, but you seem to have described a timebomb.

Source: built a timebomb in 2014. It was not fun.

[chrisfl]

Now that the season is over, could I ask how well the 1/8" wall tubing held up? Would you need bearing blocks with the 1/8" tubing like with 1/16"?

[Billfred]

Originally Posted by chrisfl

Now that the season is over, could I ask how well the 1/8" wall tubing held up? Would you need bearing blocks with the 1/8" tubing like with 1/16"?

I can't speak for 230, but 4901 never replaced any of their 1/8" wall tubing through two competitions and demos. The final exam would be next weekend at SCRIW.

[JohnFogarty]

We've also been doing some playing with our 2016 robot at off-season outreach events quite a bit. I can say with some certainty that 0.125" wall tubing holds up without bearing blocks.

[Eric Scheuing]

.125 tubing checking in, we're good with no blocks and no spacers.

[nathannfm]

MOE also used 1/8" wall but with press fit rings bridging the gap between the inner and outer bearings, still runs great after 80 matches and a few miles of parade route.

The drive is not something you want to take...lightly...

[mott]

1619 ran an 8WD with 6" pneumatic wheels/tires in a West Coast config with bearings pressed directly into .1" VEX 1"x2" tubing with zero issues. Our machine competed at 2 regionals, Champs, IRI and a handful of "street demo" events (where our students decided to use curbs and parking barriers as makeshift Defenses).

Running spacers inside the tube wouldn't have been an option for us because we run a chain-in-tube set-up.

[chrisfl]

Thank you all for the insights. Our team has been looking into trying a west coast drive this fall and this really helps. What other tips or tricks do you guys have in regards to west coast drive?