Build Blitz Robot Reveal - Team JVN

[Aren_Hill]

Originally Posted by Ether

I thought that might be the answer. Your new numbers put the BAG in a happier place on the motor curve :-)

Yeah, I'm looking forward to next year with the new PD board with current monitoring built in, we did test some with a clamp on ammeter and saw ~12amp peak draw for the windback.

[Richard Wallace]

Thanks for that bit of data, Aren. Seems like the mini-CIM BAG is a bit oversized for this mechanism, electromagnetically speaking. I like that.

[Thad House]

Originally Posted by Richard Wallace

Thanks for that bit of data, Aren. Seems like the mini-CIM BAG is a bit oversized for this mechanism, electromagnetically speaking. I like that.

We are currently looking at testing a choo-choo, and we are planning on using a 775, thru a 63:1 versaplanetary, then a similar 18:84 ratio. At 25 amps, it should spin at about 30 rpms, and pull about 350 lbs at a point 2 inches out from the rotation. Overkill a little, but more speed and power is always the answer.

[Ether]

Originally Posted by sst.thad

We are currently looking at testing a choo-choo, and we are planning on using a 775, thru a 63:1 versaplanetary, then a similar 18:84 ratio. At 25 amps, it should spin at about 30 rpms, and pull about 350 lbs at a point 2 inches out from the rotation.

How did you calculate the 350 lbs number ?

[cbale2000]

What did team JVN use for surgical tubing on the launcher (and where do you get it)? The tubing we've been prototyping with has been less than effective.

[Aren_Hill]

Originally Posted by cbale2000

What did team JVN use for surgical tubing on the launcher (and where do you get it)? The tubing we've been prototyping with has been less than effective.

Just black Latex tubing from McMaster.
http://www.mcmaster.com/#latex-tubing/=q9fexw

I think that stuff was 5234K46 (1/2" OD, 1/4" ID)

[Ryan Dognaux]

I don't remember seeing this anywhere so I figured I'd ask - what material are the ball holding posts made from and is there a vendor where we could pick up a few?

[Aren_Hill]

Originally Posted by Ryan Dognaux

I don't remember seeing this anywhere so I figured I'd ask - what material are the ball holding posts made from and is there a vendor where we could pick up a few?

Ryan,

Those are chunks of McMaster part# 87235K81
We just shoved it over some standoffs made from 1/2" HEX stock.

-Aren

[KevinG]

What material did you use for those flexible black rods?

[Aren_Hill]

Originally Posted by KGenson

What material did you use for those flexible black rods?

1/2" Black Delrin rod, but many things will work, we just happened to have it on hand.

[Dan Oelke]

I love the choo choo. What I don't understand is how you did the pivoting joint between the parts of the linkage. Guessing from the video looks like about 1/4" x 1/2" bar stock and I just don't see how you can do a pivoting link in that 1/4" thickness.

Can you give me any pointers or diagrams or ?? about how that joint is put together.

Thanks!

[Aren_Hill]

Originally Posted by Dan Oelke

I love the choo choo. What I don't understand is how you did the pivoting joint between the parts of the linkage. Guessing from the video looks like about 1/4" x 1/2" bar stock and I just don't see how you can do a pivoting link in that 1/4" thickness.

Can you give me any pointers or diagrams or ?? about how that joint is put together.

Thanks!

In our case I essentially made a shoulder bolt that tightened into the first strap and captured a bushing which the other strap spun on, I "handcrafted" the attachments due to limited time and not having shoulder bolts of the proper size on hand.