Pnuematic Catapult limits

Does anyone have an educated guess as to how many times (at most) a two tank system could launch balls across the full field before running out?

Our guesses: My friend says 5, my other friend says 10, and another kid said 40.

I don’t think you could get any or maybe 1

So how many of those are educated :stuck_out_tongue: Just kidding…thanks for asking around.

So with a sample size of 4 our average is 14 with a standard deviation of 17…

Any other guesses?

I’m no expert on pneumatics, but from what I know about them, I’d be amazed if someone could shoot all their driver control loads using only 2 air tanks. I’m very confident that you would run out of air well before 40 shots.

Well, people were not getting very many big ball launches during toss up. I would say ten launches was a lot for that game. (and you could have as many tanks as you wanted)

The balls were bigger and heavier, but I still don’t think you will be able to launch enough NbN balls with pneumatics to be successful.

You could potentially use pneumatics as a ‘trigger’ to release stored energy stored in rubberbands from a motor, but other than that, I don’t see pneumatics being useful for ball launches.

Elevating partners on the other hand…:rolleyes:

I actually should have been more clear. Not me personally (your probably right about me). I was wondering about someone who know what they were doing… More of a what’s possible kinda question…

That’s not exactly how I meant it. Sorry if it sounded rude. I was more thinking how many times you could get it into the net. Otherwise, I seriously think 5 is a reasonable max # of shots with that distance.
The Toss Up balls were heavier, but people also weren’t shooting them very high or far most of the time.
Also I kind of hate pneumatics, so luck would provably lead to 0 or 1 in multiple matches even if you could theoretically get more :slight_smile:

I agree pneumatics are probably not that useful for launching balls this year, however, generally speaking pneumatics are very reliable and efficient if used well.

I for one don’t think it would be out of the question to launch 60+ balls with 2 reservoirs. The trick would be launching 4 at a time. If you launch 4 at once and you want to launch 60 balls that’d be 15 launches. One toss up ball was .9 lbs and four NbN balls would be .44 lbs so its about half the weight. Two pistons on a forward launcher system could work with the right testing. The only problem is that you’ll get the same launch distance every time minus a few at the end due to air loss so you would only be able to do full court shots otherwise it would go over the net.

Good luck launching 4 balls at once in a tight enough pattern to get all of those into the net from across the field

I feel that the balls would just scatter, and probably be lucky to get even one ball in per launch.

I have a Excel Sheet that will do the exact calculations you are wondering about, here is the like, so far I have not been able to get this to work, so if it doesn’t PM me and if you give me an email address I can email it yo you

on the off chance that the like does work you must download the spreadsheet, it will not work in google sheets

here is the link

https://drive.google.com/file/d/0B1LLlSCW4Hm5Nkx0X1dRVjdHTGs/view?usp=sharing

you need to input all the specifications of the vex cylinders, tank volume, pressure, cylinder volume and pressure, stroke ect. and it will spit out the speed of the piston, and the number of cycles to drop tank below 60 PSI, which is where you start to see performance drop off. the numbers I have so far for 2 tanks at 100 PSI, using a single acting cylinder is 40 shots

I know this doesn’t quite answer the question, but I don’t think full court shots are smart. It wastes air (exponentially more per foot, btw, because of the high effect of air resistance and height issues on balls this year), and is way to inaccurate. Half or quarter shots are much smarter, with a fast drive these would be much more accurate and likely be able to get more points simply because it doesn’t miss.

Full court shots also won’t be needed as there are only preloads a full field away. Most shots would therefore be half court or less. I would not be surprised if you could get as much as 40 to 50 shots. I know several toss-up robots managed 25-40 full degrading to half field shots on the big balls.
I am guessing less force is needed for each ball, about 1/9 as much. Assuming an error margin based on the material, maybe 1/5 as much force per distance. with the pressure regulators, you could greatly lower the force pneumatics would extend at. you could maybe, with luck, get 65 full degrading to half court shots (based on the 4- 2 cylinder limit from tossup to now).

With two tanks? I would need to see it to believe it. Remember, in Toss Up some teams literally had dozens of tanks on their robot.

I find it hard to believe that with 2 tanks anyone will be launching 40-60 NbN balls a sizeable way across the field.

I’d love to be wrong though. Maybe my students can prove me wrong.

The “full degrading to half court” part is a big problem. That’s a lot of chances for mistakes. A shooter should be consistent and repeatable for an entire match. Otherwise you are always relying on a bit of luck.

4 at a time could have problems such as 1 ball hitting another in the air which would knock 2 balls off course…
Also the trajectory of each ball would be very slightly off and it could mess up some launches

I still think it is possible to launch 4 at a time. It would require lots of fine tuning but I think if you gave some of the more experienced teams the whole summer and fall to work, by the end of winter I think we could see it happen.

Four scored in the high goal at once? If I’m measuring correctly on Inventor, the high goal is ~15.75" at the WIDEST. (please correct me if I’m wrong). Seems unlikely?

Here is pastoral invasion: https://www.youtube.com/watch?v=GMjoGzxHLNU they had 4 tanks (which i accounted for when i gave my answer as to the amount of shots needed) with more than 28 shots.

While the degradation is not ideal, it will be noticeable during gameplay and therefore possible to deal with. Note that i am not planning on using pneumatic launchers, i was simply pointing out the efficacy of them.

It will be possible to do 60 shots, which may seem like a lot, but is theoretically possible.