Motors on a DR4B

Would you guy advise putting 4 motors on the mid section or two on the mid section and two on the tower and why?

i would do just four on the mid section because in starstruck i noticed a team use a double reverse four bar with just four motors
(1-7 ratio)

Both work. Just depends on how you want to attach to tower, and how much room you have for the towers.

Could 2 motors work? This year, all you’d need to lift would be the weight of the lift plus a quarter pound, while in previous years, you’d need to lift 4 pounds of extra weight (4 skyrise cubes) or 3 pounds of extra weight (3 stars and a cube in starstruck).

@puzzler7 and mobile goals?

You only need to lift the goals 3 inches up, it may be better to design your DR4B to lift just a quarter pound, save two motors, and use those to build some mechanism for the pylons, as that would greatly speed up your DR4B.

well from my opinion four motors is safest way to go but then again its your opinion

When 9571 ran a 4 motor 7:1 in skyrise we used two on the drive base chained to the tower for space and then two on the mid section of the lift. We tried both 4 on the mid and four on the base, but we found spacing them out worked best for us. Also we found that having the lower shaft on the mid section high strength did wonders for stability.

3885 is going to prototype a two motor 7:1 to see if it will work.

It would be safer, certainly, but I think it may be beneficial to speed up the lift and have a separate mechanism for the goals, especially as you’d need to carry them.

Here is a robot I worked on with team BNS
Used 2 motor rd4b because it only had to lift skyrise sections.

Thanks! Do you remember how much a skyrise section weighed?

@puzzler7
Here is the excerpt from the skyrise field specs. A little over a quarter of a pound.

Anyone have any idea how much weight 4 strength motors, 1:7, dr4b would be able to hold?

It totally depends on how high you want to lift. The bar lengths are an important part of the torque equation.W

What if we just wanted to lift it 2-3 inches above the ground? This is a really broad question, but we are just looking for an estimate

Like I could make a rd4b at that ratio to lift something a few inches off the ground that could lift 30 pounds.

Alright thanks

@tabor473 In the video you posted, where exactly are the two motors? Are they on the midsection that is lifted up? I can’t seem to pinpoint exactly where they are.

Hmmm it looks like the bottom. Usually I prefer the middle but that robot was designed to be really skinny so I guess we didn’t do middle.

@tabor473 Why do you prefer putting motors in the middle?