How to wrap bumpers around the corner?

#1

Any construction hints on how to build bumpers that wrap around the corner like this?

image

I don’t want to compress the noodle so much that we fail inspection, but I would like a tight, crisp corner.

Thank you for your help!

#2

We usually cut the pool noodles at a 45 degree angle at the end and put those together for a 90 degree angle. Stick it together with either tape or hotglue and then wrap the bumper material around it.

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#3
#4

This is what we do each year. Personally, I like how crisp these types of corners look, versus the corners you get with other solutions (wrapping the noodle, vertical noodle, or extending one noodle all the way across). Doing your corners this way can make reversible bumpers easier, as well - do the fabric separate on each noodle, and that joint gives you a place for the fabric to tuck into, such that you won’t have any of the wrong color showing, and it lets you make nice, straight stitches without worrying about rounding the corner.

And Tom - if you want to bring the bumpers to breakfast on Saturday (presumably just wood and noodles at that point), I can take a look at them and let you know what I think.

#5

We personally like rounded corners, both for aesthetic and functional purposes . Your robots total diameter decreases when you round the corners of your bumpers by about 1" which could be marginal, but we’ll take whatever we can get to fit through tight spaces. Rounded bumpers also help you slide across things rather than getting caught on the corner. Typically we take a noodle that is 5" tall and place it vertically at the corners. This has worked really well for us, and it allows you to use up those short pieces that you have accumulated over the years as well.

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#6

The rules specifically permit noodle compression around corners, so if you go this route you will be okay.

That said, it looks way better to either have mitered noodle ends, or have one side’s noodles stick out in front of the other. Use some masking tape or something to hold them snug against the wood before stapling the fabric in place.

#7

We just wrap the noodle around the corner, it’s faster than cutting 45 degrees or putting a vertical noodle in the corner and let’s your robot get past defense easier than having a larger corner. You also don’t have to deal the vertical noodle possibly sagging down as the fabric stetches during the season. Nothing special to how you do it, lightly tape one side, fold the noodle to the other side and lightly tape. We have been doing it this way since at least 2014.

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#8

There is inconsistency in how this is inspected. While the blue box this year does say that wrapping a noodle around a corner is ok. However the rule specifies that the cross section should remain consistent. If wrapping the noodle around the corner results in a significant change in cross section, you may be called on it by some inspectors. And it will at a minimum cause you hassle and stress.

I would recommend making sure that the noodle is not compressed enough that the cross section, measured diagonally from the point of the corner, is significantly different from the cross section of the uncompressed noodle. This could be accomplished by cutting reliefs on the inside of the noodle so that when it turns the corner the outside of the noodle is not under as much strain. As long as the reliefs are closed in the process of bending the noodle you should be good. Or just miter it or use the vertical noodle in the corner.

#9

You can also cut the noodles to the length of the wood backing, then add a 5" long noodle vertically in each corner. Or you can have one side overhang the 2.5". You can do just about anything as long as there is a noodle in the corner.

#10

The rule specifically allows for wrapping the corner, but it doesn’t allow for cutting relief slits in the noodle, I wouldn’t do that and never have when instructing teams and my team to build bumpers.

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#11

True it doesn’t allow relief cuts specifically, however it does allow beveling, and since the noodles are covered and this would make sure that the cross section stays consistent, it is unlikely that anyone will say anything other than to compliment you on your lovely looking bumpers. It would of course be prudent to ask Q&A if relieving the inside of the noodle at the corner in order to ensure the cross section stays the same is legal.
Merely wrapping the noodle around the corner often results in a severely compressed noodle at the corner, which will be picked on by some inspectors. And which does not serve the purpose of the rule which is to provide a given level of padding at all points around the robot.

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#12

“Picked on by some inspectors” is the exact reason this rule is written the way it is this year. I had a discussion with Al last year after a LRI rendered my team’s bumpers technically illegal at a regional by making the team open them up and cut the noodles for going around the corner, then TAPE the covers (which was OK for temporary repairs, not a full regional of competition, per the rules). Then I see other teams with these nice round corners built the exact same way we did ours and there are no issues.

By the way, I take issue with your interpretation of the purpose of the rule. I believe you are referring to the 2008, 2009, and 2010 bumper rules. If the purpose was to have a given level of padding at all points, there wouldn’t be a 6" from the corner of the perimeter requirement, there’d be a X% of the frame perimeter AND Y" from the corner requirement. No. The purpose of the bumper rules, and I recall hearing this a few years back from someone in the know, is so that a BUMPER will be the part contacting bare metal, regardless of point of contact, even if contact is not bumper to bumper. As such, a corner wrap-around isn’t going to affect the purpose of the rule.

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#13

I agree with Eric - the rule was changed from 2018 to 2019 to explicitly allow noddle compression in the corners for the purpose of wrapping the noodle around the corner. The updated Figure 10-7, and blue box clarification of R31-C show/state that compression of the noodles for the purposes of rounding a frame perimeter corner is not considered deformed.

R31-C Blue Box Clarification
Noodle compression as a result of smoothing BUMPER fabric or rounding a FRAME
PERIMETER corner is not considered deformed. Any compression beyond that, e.g. for
the purposes of flattening the noodle, is deformation and a violation of R31-C.

I’m glad to see this rule revised to explicitly allow rounded corners in this manner. We had the pleasure of re-building both bumpers overnight (stripping fabric off, re-noodling with mitered corners, and re-wrapping) at district championships last year. Our inspector insisted we had compressed the noodles in the corner too much, despite other teams at the same event passing with the same bumper method. Escalation to the LRI got the response that it was a ‘soft call’ due to how the rule was written, and recommendation that we report the issue to FIRST in the end-of-year survey - which we did. Glad to see FIRST is still willing to evaluate and make sensible changes to improve the team experience.

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#14

As a note, the rule actually changed (in Team Update 3 of this year) based on discussion at LRI training the weekend after kickoff. While compression in the corner is clearly allowed, it’s not clearly stated how much compression is allowed. At what point does the noodle go from “compression due to rounding” to “compression because it was pulled extremely tight at the corner to gain an advantage in game play”? There’s still too much “judgement” required for the call for my liking - I prefer rules that are clearly back and white, which this still isn’t.

#15

Thanks for the additional insight, Jon. I overlooked that the change was made in Team Update 3.

Hollow round noodles (the most readily available) easily collapse when wrapped around a sharp wood corner - and will be much thinner at the corner even with light wrapping of fabric just enough to pull wrinkles out. I suppose per the last sentence of the blue box this could be considered by some to be ‘flattening the noodle’, even if that wasn’t the intent.

I actually like the above suggestion to notch (relief cut) the noodles, so it can make the turn without as much internal tension in the outer wall causing it to flatten - thus better preserving the cross-section around the corner. To me, this meets the spirit of the rule, but violates the letter.

I agree it’s best if rules are quantifiable and black-and-white. There’s already such incredible variability in legal bumper materials and construction methods that I think it would be difficult to define acceptable compression at the corner in a way that wouldn’t further exacerbate inspection issues. We’ve already got 7 pages of bumper rules, and even still teams get caught up in them - and have to scramble to rebuild in order to get practice field time or not miss matches.