More destructive air tank testing from 95

[Andy A.]

Originally Posted by FrankJ

I noticed the 7.62 slug had an exposed lead tip. I am pretty sure that would be on the list of prohibited items for your robot.

Interesting study. thanks.

That'd actually be gray paint which denotes something about the bullet weight and intended use. For the curious, I believe it is a 184 grain FMJ bullet with a lead and steel core. Muzzle velocity is around 2400 to 2500 FPS. It was loaded in Hungary in 1977.

I agree- not FRC legal!

[Andrew Schreiber]

Originally Posted by JamesCH95

Andrew-

We could drop ~140lbs from some height onto a tank, with some representative strike surface to hit the tank (1x1 aluminum tube? 1/4in aluminum plate?). We could also strap a tank onto one robot and crash it into another robot, but that might get more than a little hairy.

There would be much to consider in making a 'realistic' test.

This is the part where I point to my sign which reads "ignorant software engineer". I think what I had in my brain was less of a more realistic test more of a more realistic appearing test. It's REALLY easy for me to rationalize away the risk right now because to me a bullet is far more destructive than our robots. Logically I know it's not but it requires and understanding of physics. A more realistic looking test would remove even that interpretation.


TL;DR - disregard if your target audience is people who actually know stuffs.

[JamesCH95]

Originally Posted by Andrew Schreiber

This is the part where I point to my sign which reads "ignorant software engineer". I think what I had in my brain was less of a more realistic test more of a more realistic appearing test. It's REALLY easy for me to rationalize away the risk right now because to me a bullet is far more destructive than our robots. Logically I know it's not but it requires and understanding of physics. A more realistic looking test would remove even that interpretation.


TL;DR - disregard if your target audience is people who actually know stuffs.

You make a very good point. I think this is where I am going to take a step back and remind myself why Andy and I did this in the first place (and state it directly if it wasn't obvious to everyone):

1) Show how inadequate most of the proposed mitigation solutions were.
2) Show, in a way tangible to a layperson, how much energy is contained in a storage tank.
3) Show how far shrapnel is thrown after a tank failure.
4) Raise awareness of the potential hazards associated with the use of plastic tanks.
5) Hopefully spark a change in the FIRST community. This was the big objective - and I consider it accomplished. I know several teams changed out their white tanks, and I'm pretty sure that Clippard's tank exchange program starting less than a week after our first video was not just coincidence.
6) Have a little fun and provide a little entertainment.

[this is where I leave on a tangent]

We never set out to be scientifically rigorous or to test failure mechanisms. We stated as much in our videos and posts on several occasions. We know that failures can, and do, happen. We consider that aspect of this topic proven empirically by the experiences of numerous teams who have had tanks fail in service. If our videos motivate or inspire another team to do more rigorous testing, hey, that's just icing on the cake as far as I am concerned.

So, I think we're going to leave our efforts at the level we always intended: a demonstration, not a scientifically rigorous experiment. I'd love to test the Pneumaire and AndyMark tanks at some point, but thus far we have no takers to donate tanks.

[Monochron]

Originally Posted by JamesCH95

The moment that there is an affordable and non-terrible high-speed camera available, I'd love to. Alternatively, if someone would lend us one, that works to.

At the moment we're SOL.

A couple of top-of-the-line phones on the market have 120 fps speeds. It's not amazing but it is double your 60 anyway. I know the iPhone 5s does it, as well as a couple of flagship Android phones. You can probably find someone who has one.