First high speed weapon test

This is our 15 lb combat robot running the weapon at high speeds for the first time. This was at about 70-80% speed on the throttle and the lowest settings for the mamba monster. The rpm is about 7,000-8,000 rpm. The batteries are 3s2p A123s.

Category:

Science & Technology

Tags:

• robot
• battlebot
• robobot
• thunder
• lighting
• mamba
• monster
• max
• A123
• cells
• castle
• creations
• snow
• battery
• carbon
• fiber

[MullinPerformance]

So the beater spins on the shaft instead of having the shaft and beater as one peice spinning on a bearing/bushing? I was going to key the beater (with 1/2 shaft) and have it running thru a bushing on both sides.

[MrPizzaman09]

YES YES YES. If you have every built a battlebot before, you will quickly realize that bronze bushings and spinning shafts are REALLY hard to line up and spin freely. I was using a CNC machine for my brackets and it still didn't line up well. If your frame bends just a fraction of an inch, your weapon will seize up real fast. Mine idea worked really good and I couldn't be happier. Bolt your sprocket or pulley to the side of your weapon and it will work just fine.

[MrPizzaman09]

Chech out my extreme electronics test video, as it shows what i did fairly well. I tried what you had suggested on my Lancerbot with the spinning shaft and bronze bushings, and it only caused problems. In all of my bronze bushings, I have had to drill them out to a larger size to they work.

[MrPizzaman09]

A 1/2" shaft should work well if the weapon bushings are close to the frame. I once saw an eggbeater who bent a shaft and one who broke it's weapon. The latter was caused by two eggbeaters going in opposite directions, which wasn't very smart.

[MullinPerformance]

I was thinking of using bronze bushings instead of needle bearings because I have seen them explode before. Yea I was leaning towards the beater because i think it's easier and a better design. I have a huge peice of 1/2 cutting board material I was going to use for sides...not sure how well it will hold up.

[MrPizzaman09]

I made mine out of one solid piece of steel, about 1/2" sides all around and large radius's on the inside. I used a lot of bronze bushings. You definitely should use a shaft that does not spin. My shaft was a 60 rockwell steel 1/2 shaft. At first it was a 5/8" titanium, but the weapon seized to it because there was no bearing. Make sure to design extra metal around the shaft holes for extra strength. I did some prototyping on 3d cad software and found the weak points ( around the holes).

[MullinPerformance]

ok, thanks for the info...

[MrPizzaman09]

Also, maybe try some steel rollers for the front instead of 4 wheel drive.

[MrPizzaman09]

I tried cutting some 1/8" cf with an axe one day and I could not cut through it. But it is really pricey (90 cents a inch^2).

Eggbeaters also can hit from the side, drums can't. I would use about 15,000 rpm as a super extreme maximum rpm for an eggbeater, but only if it is designed right. Also a cf or steel timing belt with pulleys instead of chains. Mine at 50% would work for any situation, but if you want to be the best, use a mamba monster combo with 4s A123 pack and 3:1 ratio.

[MrPizzaman09]

It depends on what you can machine. Also, a drum is harder to mount teeth. My egg beater only has a sharpened edge, which will grab anything. The eggbeater will tend to have a larger diameter and a better bite. I would strongly suggest the use of needle bearing for your weapon because of their light weight and robustness. I think I have the fastest and most powerful 15lb (actually 13.6 lb) robot out there. My sides are 1/2", which is WAY over kill. If you have any money, us carbon fiber.