We are currently using wood to prototype and we were thinking of making a hood, how could that be done without excessive fabrication but could still be precise?
I would suggest 1/8th inch Hardboard, its the same stuff used on the team version of the half and minimal fields to produce a curved chute.
One option (although I have not tried it personally) is to use standard hardware store “pegboard” to form the side plates. you can drill bearing holes in that for your (more) rigid shooter geometry that may exist. From there you can use the peg holes to insert cheap woodworking dowel pegs to bend a strip of 1/16" poly carbonate into hood profiles (to play with different compression rates, etc).
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Polycarbonate is decently priced, flexible, and can be fastened down in a number of ways to the angle you want, depending on thickness. Recommend looking into it for prototypes especially. Once you’ve got your dimensions worked out, you can go for something more rigid if you feel it is necessary.
We just got our hooded shooter prototyping working today. Here’s how we constructed it.
Frame:
We used plywood for the plates, with 2x4s joining the plywood. The curved part is a piece of perforated lexan attached to the 2x4s. We can move the 2x4s strategically to change ball compression and the curve of the hood. Running 0.5" compression right now.
Powertrain:
Driven by 2 NEOs. We connected the NEOs into VersaPlanetaries using the CIM adapter so that we can get a 1/2 hex output. The VPs don’t add any reduction and connect to the flywheel shaft via meshing 30T gears. No actual reduction.
Flywheel:
We are using 3 4" Colsons with the ends shaved down to get them closer together.
Pics/videos:
Disclaimer: the shot in the video is only with one NEO powered and the distance was around 25ft.
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We are close to finishing our prototype made of wood tomorrow. We used wood side plates that were hand machined because they didn’t have any complex curves on them. We held them together with a square made of 2 by 4s to simulate a hole in the bottom. The rails that guide the ball were originally going to be routed mdf due to the difficulty of hand making the curve. However, we decided to try and 3d print it and hopefully it will be strong enough for the prototype. I’ll try to send pictures to better explain next time I’m in the shop.
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The ball will be compressed against the surface of the hood and will spin as a result of this. Since it is likely that you would be using polycarb for this part of the hood in your competition assembly, you may as well use polycarb for this part of the prototype since other materials will react to the ball differently.
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Some pictures of how we decided to go about prototyping the shooter. The shot we made was about 25 feet to the port. We ran two 775s at 1:1 with a 4 inch hi grips wheel and 2 inches of compression.
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We often use versaframe to prototype
To make the hood, just use lexan or thin plywood. Bend it to where you want and screw it in / rivet it in.
Do you get issues with the motors heating up? We’ve run a single 775 on a 36:42 belt reduction and the motor gets fairly hot but we aren’t exactly sure what’s causing it.
We’ve had some warm motors but we never really ran it continuously enough for them to actually get hot. Having only one motor means you have half the torque though so that might be the reason.
May I get a picture of the hood?
The lexan broke when I tried to bend it, do you have to heat it first?
If your “lexan” broke when you tried to bend it, it’s probably not Lexan™. It’s probably acrylic, aka Plexiglass™
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I mean a little bit of foam mounted to the stronghold shooter works as a prototype for us
We didn’t use an actual hood. Instead, we cut out curved rails from plywood and bolted them onto the side plates with standoffs. The rails guide the ball similarly to a hood but they keep the ball centered between the two tracks. Here is an example since I can’t get a better picture of our setup till Monday:
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I think it was just a little too thick.
Here’s what we tried this weekend using 1/2" Lexan cut on our CNC router. If we want to make new side plates, wood might work just as well. In fact a really large kerf bandsaw blade might be the move for rapid iteration.
Did you just bolt the hood on in that shape? Did you need to heat the lexan first?
How squishy is your power cell? How hard is it to compress it by hand?