Dual Post- DR4B help, and Ringle Plunger ideas?


After today’s Tournament, I have decided to scrap the whole ring idea. I might have a small 4 bar, or six bar on the side, but i am now focusing on the Mobile Goal side of things. at least from what i have seen, the rings are really insignificant when it comes to most matches. in some, people win by 1 or 2 points because of the rings, which is why i want a small lift on the side specifically for that, but MoGos are so much more important from what I have seen. All of the tall MoGos just get knocked over. Now, I have a new question. is the cascade type the best of the MoGo lifts?

End of Update

HI All! I have 2 different questions involving my teams DR4B, and a Ringle Plunger.

Q1. Does anyone know of the best steel to aluminum ratio for the DR4B? I have seen a couple different designs use steel for the base piece, and the first 4 bar. we are struggling with support, 1 side being higher then the other, and it swaying. we are going to be rebuilding our DR4B and base after this tournament(We are currently in one) as we have 3 months before our next tournament, and we want to do it in the best way possible.

Q2. Does anyone know any way to make the basic Ringle Plunger design, without pneumatics? I have seen a couple people say a couple things, but I do not know many engineering terms, so much of what they say sounds like gibberish to me, but still is very valid and may work.

Thank you for reading this very long message!

you don’t necessarily need steel for a dr4b; in fact most of the time youll get better stiffness with aluminum. vex alu channels are made of 5052-H32, which has a tensile strength of anywhere between 20ksi and 30 ksi and has a density of about 2.7 g/cm^3, while the steel channels have a tensile strength of about 40ksi and a density of around 8 g/cm^3. as such the aluminum channels have a better strength-to-weight ratio (at least in tension). but if you run into volume restrictions, steel will work great because it’s more dense and can have more strength in a smaller amount of space. other than that id stick with aluminum.

anyways regardless of what material you choose- cross braces help a ton. boxing your arms helps too. in general just focus on maximizing beam stiffness (think about moment of inertia and increasing the cross sectional area of the supports) and you’ll be fine

a passive lexan plunger design could work. think pilons ITZ


DR4B Tutorial by 333A
This may help some when it comes to strengthening your DR4B.