This is how fast 7:1 speed is:

and this is torque:

This is how fast 7:1 speed is:

and this is torque:

I’ve been testing some and it seems like a 2 motor (high torque) 1:5 would work. Probably… however, the testing I did was only on an rd4b that spans about half of the 18 inches so that it will work with my robot design and I didn’t have time during my test to attach bearing blocks so it was a little shaky but it seems like it would work. Tuesday my school should start slowing down so I may try prototyping a bit more with a more realistic test

Not enough. 1:5 turbo it is

Keep in mind that the lift speed/torque allotment is influenced by how long the arm is, not just the ratio. Connecting two four-bars together like this effectively doubles their length, doubling the speed and halving the torque compared with a single four-bar (which is similar to a two bar for Starstruck folks). So if you’re still thinking in terms of what a ratio would do on your Starstruck lift, it will actually be twice as fast at the same ratio assuming your ITZ lift is basically two of those stacked on one another.

Do you know if those are speed or torque motors?

I’m thinking that if you only need to lift four mobile goals only a few inches off the ground, a faster gear train would work if it doesn’t burn out.

Do you guys think that two motors is enough for a decently fast DR4B if it doesn’t lift the base? I was a noob back in skyrise so I never experimented with DR4B’s, but it seems like that should be enough.

First video I linked was with speed motors, second was with torque motors.

You might want another part of your lift geared slower (or shorter) for lifting the bases, rather than trying to pick them up at the end of the cone lift.

Two motors will probably be enough for single cones, unless you’re going for some insane speed.

The torque motor DR4B speed isn’t too bad, however in order to win you must be fast. This is where I’m stuck - between full-on speed and use high speed motors and tension it like crazy to see if it can lift a mobile goal, or use torque motors and tension it so i won’t have to worry as much for torque.

Basically I’m stuck between getting a lot of cones stacked, or focusing on heavy lifting extremely valuable mobile goals, since you can get around 50 points if you get one 20-point and three 10-point mobile goals.

You could have a separate base lift on the back/mid section of the cone lift, which would lift half as high (still way higher than is needed) and with twice as much torque. You could probably come up with a way to give it even more torque. I don’t think you should be lifting bases with the same thing you use to lift cones, as the huge difference in weight will make any “one size fits all” ratio way slower than would be ideal for the cones.

I was bored in english, and calculated out some numbers for a rd4b with 35 long metal (without friction and assuming you balance the rd4b with rubber bands) with 2 motors also operating at stall toqur, so i leave some leeway in there. The max useable ratio i ended up being confortable with is a 3:7 torque ratio with high speed internals. Its really agressive, but theres never been game objects this light, especially if you can only hold one. You end up with about 2 ft/lbs extra, and i think thats within the range of comfort of friction and inertial heating (having to deal with the momentum of the metal)

It had no rubber bands, bear in mind. Also, 1:5 turbo is a leap. You have 1:5 speed and 1:7 turbo in between.

@Infinity Minus 1 you also have to consider the update rate on the motors is 15 ms, so… you’d have trouble controlling the lift at all, let alone with driver conrol. Going 1:1 is crazy, and thats a catapult, not a lift.

I know what I’m doing tomorrow

Speed ratio???

@Infinity Minus 1 yeah, but the balance issues would be so bad, i think im sticking with 2 motors because threres not an effective way to transfer power to the other side without 360 degrees of slop

Theoretically possible != actually possible

You don’t want to be anywhere near the stall torque of the motors, as they will slow down significantly and heat up quickly. These calculations also don’t take into account friction, gear inefficiency, elastic inefficiency, etc. You’re right about how ridiculously fast and impossible to control it would be if it did work.

A one motor lift is interesting and might have some potential. Keep in mind that you won’t always be lifting to full height, on average you’ll be lifting to half height. 5:1 for torque with speed motors should be more than fast enough and already difficult to control, if that could work with 1 motor (I’m a little doubtful, torque might be better) then it opens up some interesting possibilities.

Just a question, I don’t even know what I should do calculation wise, but is it practical to have two claws? One at the top for cones to reach, and one halfway to lift mobile goals. Depending on gear ratios and motor distribution, would there be more lifting power at the lower claw? Just a random thought

@LHS Team 598B yeah, that would work, but on a rd4b the middle section is generally about slightly lower than the lift towers are, so it’d be up pretty high,(side note the equation you use for torque is feet/pounds, so 1 pound at the end of a 1 foot arm is 1 ft/lb. So then the motors have a torque of 1.23 ft/lbs so you multiply it by your gear ratio like 5:1 you’d multiply it by 5)

Does anyone think 2 lifts would work : 1 for the cones and 1 for mobile goals?

I think so. I was actually looking at the ratios, and lifting 0.25 lbs (cones) 45 inches and lifting 3.75 lbs (goals) 3 inches is an x15 gearing difference, so ignoring the weight of the mechanism and friction, you could have two lifts geared off of the same motors at different ratios.