Rotating weapon pre-approval

We're designing our first beetleweight robot, it's a vertical spinner. The rules require that robots with spinners that meet two of: longer than 500mm, heavier than 20% of the total robot weight, or faster than 500RPM, need pre-approval from the event organisers.

How does this process work? It is pretty much a formality for competitions that allow spinners? Does the likelihood of getting approved scale with how much the weapon breaks these barriers? Does this occur over email? Are there tests that we can perform to show that the mechanism is safe, i.e. that the weapon is constrained to the axle and so cannot shoot off? The robot is currently a 3D printed prototype, can we get pre-approved for a competition before building the finished robot?

The current design of weapon is 363g i.e. 24% of max weight, but that doesn't include the axle, pulleys, fasteners or bearings - which would all add some considerable weight - so maybe as much as 450g of moving mass. The final speed also isn't set, but I believe ~5000RPM is somewhat typical of similar robots.

I couldn't find a similar post on here on this subject, although I'm sure others have asked. I'm not sure how to make best use of the search function.

Ultimately, it is up to the event organiser to determine wherever or not your weapon is safe for the arena it is being ran in. Telling them about your robot, especially when new to the scene (i.e. a new build) will help determine wherever it is safe for your robot to compete. In this context, photos of the way it is attached and the expected stats via a e-mail conversation or similar, as you've laid out, will help.

The tech check process, at the event itself, will also help determine if it is safe to run (noting that pre-approval doesn't override this - all robots have to pass tech check). Not at the same weight class but at the Antweight event I run, I have spinners demonstrate safe control in the arena during tech check itself. From memory, I think the last time I went to the BW Championship in 2019, I think the same thing happened there too.

Thanks very much. This is excellent information. I'll do that.

I have queried that rule in the past as I found it confusing considering full combat arenas should be able to hold all types of spinner, and most spinners would likely exceed both the 20% and the 500rpm points on a regular basis. If I remember rightly, the response I received was that these stipulations only applied to Grade 3 arenas and below (aka, arenas that are not designed to hold robots with spinning weapons), so if building for a full combat event you'll be fine; I think it's more to regulate something like 360 degree electric lifters. However as you are new builders, pics and specs sent to the EO won't go astray.

Thanks for the information, everyone. I contacted Bristol Bot Builders and the person that I spoke to said that they cared about three things:
1) Theoretical tip speed of less than 250mph
2) Spin down time of less than 60 seconds
3) Pass safety inspect at the competition

https://bristolbotbuilders.com/guides.html#beetle this information is reproduced at the bottom of this page.