So I have been working on our catapult this winter break and I have added stoppers for it and figured out the right amount of rubber bands, but now I’m stuck on the bucket. I really don’t know what type to do after testing a couple different ones. Any ideas?
Thanks,
68031B
First thanks for at least testing first. Anyways are you just having trouble making a decision on 2 that worked in testing or none of them worked and you want another idea
None of them really worked, I am thinking the angle that the catapult stops at is a factor in why it isn’t shooting far. Thoughts?
What are you replacing it with? If I were to go with that design wouldn’t the triball pretty much be going straight down?
yeah definitely going with what @Gigahertz.t said if the catapult is completely up when releasing it will cause the triball to have a mix of downward and forward force. Meanwhile stopping halfway or so will have forward and upward force causing it to go further.
Many of the top teams I have seen use a large square and the point of the triball sits into the hole in the center.
It is more complicated than a bucket but if you get it right it can greatly reduce the movement of the triball when launching and also allow you to add certain plates to automatically align the triball when it is placed.
Thank you for the sketch, where do you think my angle would fall under? I made a temporary bucket (or holder) and the triball needs to go a little farther. I can’t add more rubber bands because of torque reasons and I can’t make the arm bigger because of space (I am adding a blocker today so if it’s any bigger it will hit the blocker)
Thanks,
68031B
If you have a video/gif of it throwing a triball on the field, that would help as I can’t guess from just a pic. However, as a quick patch-up for now, you can use a small arm or string that deploys in the matchoad zone and drive away a little bit like @javaskrypt 's bot
This’ll give you a few extra inches, but later you should address the underlying problem with the cata
That looks like a good angle. Make sure that your bucket is rigid. Those bent plates you are using look a little flimsy. I use standoffs and they work great. My shots are very consistent and easy to tune. I will include pictures of my catapult.
I hope this helps!
Thank you for the input! I will add standoffs ASAP
Here is a gif of it shooting
Thanks for the gif! That is a good angle for shooting.
However, I looked closer at one of your images, and it seems you are running a blue 600 rpm motor 36:84 for a 257 rpm cata. That is really fast, and probably too fast. I would recommend changing the cartridge to a green 200 rpm (which is about 86 rpm in the end) and doubling the band number (seeing as those motors are hot swap this should be a quick fix). 86 is towards the low end of the average, but it is quite competitive especially since it can hold quite a few bands.
I was thinking about changing the motors too, I wish there was a way to make it shoot farther without losing speed. I’m also using 2 blue motors for the cata btw (Not sure if you saw). And the gear ratio is a 12 to a 36 to a 84 (I’m not good with gear ratios so it could be exactly what you said) Is there any other way to make it shoot farther? The only other way that I can think of with keeping this current configuration is by making the arm longer.
Ohh 12:84 gear ratio then. That should be able to hold about 5 or 6 bands at least.
The last thing I can think of is shave off less teeth on the slipgear so there is more of a retraction (and hence more time to accelerate).
For motor purposes, use a ratchet on your cata. This takes a lot of stress off the motors and can allow for a couple of additional bands.
Are you sure it can’t hold more bands? You can add another band mount closer to the cata so the additional bands don’t add too much stress to the motors.
Only if you use a basic single slipgear. My slipgear catapult is 20 rpm. It lets me have a 1 motor catapult even with a lot of rubber bands and no ratchet. However, with a triple slipgear (which we are about to implement instead of our older double slipgear) you can achieve 1 shot per second. More torque and more speed.
What do you mean by a ratchet? (Sorry I still don’t know everything about catapults
We have really strong rubber bands “Tactical Rubber bands” (Also our team name) Apparently they can be used for airsoft so they are pretty strong.
I can try adding another mount closer and see if that will add any more power without making the motors not be able to retract the catapult.
So are you saying that more slip gears = more torque and speed? Sorry if this is a dumb question I’m still learning. Pictures would be greatly appreciated if you have them
It’s alr
A ratchet only allows the gears to spin in one direction. By doing so, it prevents the cata from backdriving the motors and takes the stress of holding the cata off of the motors
Here are a few examples:
