The Slingshot Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hello everyone! Let's get straight to business- here is my entry for Joerg's design challenge!

Here is the breakdown:
Section A: Linear acceleration, where upper and bottom rails constrain the card. Length can be adjusted by arbitrary amount, but twice the card's length looks reasonable.

Section B: Card is free to start rotating and starts to gain rotation. This section should not be much longer than one length of card in this design, otherwise loop could slip out of card's notch.

Section C: The flick. Loop is captured by two hooks located on outer side of the stabilising panels (so as to not collide with the card inside). The hook is there to ensure that the flick motion is quick and fluid, without stuttering which could be caused by friction of loop against groove.

Additional notes on design elements:
1 and 3: Card has two notches, which are symmetric to maintain centre of balance. They work both as rubber attachment point and engage with trigger in loaded position.

2: A rod can be placed through this central opening to allow card to be pulled back, while between the stabilising panels.

4: Hook's geometry and radius of rotation may need to be modified, to make sure that card is properly ejected and that card's notch does not catch on loop at end of the flick.
 

Attachments

·
Registered
Joined
·
28 Posts
Interesting idea! Could the strength of the rubber have any impact on the length of the barrel? Rotation? How will the car run through the barrel without repetitive damage or lose of velocity?
 

·
Premium Member
Joined
·
5,803 Posts
That is a really good idea, even though I think the contraption needs to be turned upside down.. plus the axis of the hooks needs to be lower than the card so it does not jam the card. I might try that once I am back home!
 

·
Accident-Prone
Joined
·
1,513 Posts
Looks interesting, a bit overcomplicated for me to try, but that's not saying too much:D. At position four it looks to me like the card will be caught in between the rubber and the hook, maybe something to fine tune during the actual build phase. How big are the "cards" you plan on using?
*edit: I just looked again and I see a huge design flaw! There's no handle;)
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #5 · (Edited)
I am glad you like it, Joerg!

You are quite right about the rotation axis. I think it could also be made to rotate by a larger degree. Instead of going 90 to 0 degrees, it could swing maybe as far as 90 to -20 degrees if the rubber and hook have enough inertia.

Flipping it the other way up would make it a whole lot easier to maybe construct a magazine-fed version in next iteration! On top of that, it would be reminiscent of underhanded knife throwing, which it badass.

Interesting idea! Could the strength of the rubber have any impact on the length of the barrel? Rotation? How will the car run through the barrel without repetitive damage or lose of velocity?
The damage and loss of velocity which could happen as a result of card starting to rotate inside of the barrel and jamming itself between the top and bottom rails? Yes, it's something to look out for, but with good, right fit inside the barrel and bevelled edges on the card it should be fine.
 
1 - 5 of 5 Posts
Top