holy FAKA (hah)

holy FAKA (hah)

tyler1 14 Nov 2008 02:34

I just posted in that one thread below this one.

Basically, I built a copy (sorry, its too cool!) of your Golf Ball Beast over the past three weeks. I have the frame done, but one major setback I am having is the throwing end. I have an arm, the counterweight arm, primary and secondary triggers, but i can never get the arm to stop its forward motion after it has flung. I'm hoping it will be as simple as adding a projectile, but I don't know. I guess I am just horrible at tuning.

My tuning method thus far has been to rotate between the holes I have drilled in the arm and the counterweight arm, trying to get that perfect combination, but to no avail. Any tips and or pointers?

Thanks!

Re: holy FAKA (hah)

Craig Macomber 14 Nov 2008 04:54

You are not the first.

I ask you this, where do you intend to put the energy? I suggest the projectile, but heat and broken parts are also acceptable. Have you ever keep a car engine floored with the clutch out? Tried to kick something and miss and fall down? If you try to put energy somewhere, and fail, it will go somewhere else, and considering it did not go where intended, it will go where unintended. Even if your tuning is simply imperfect, it will be violent. FAKAs are one of the hardest most complex designs to make work properly. If you don't work through the physics a bit, you won't be able to operate it. You are experiencing the "Disadvantages of the FAKA" paragraph, except you are misfiring intentionally, known as dry firing, something you should never do.

As far as the axle smashing into the front of the frame, may I suggest adjusting the horizontal momentum on the arm assembly to be less forward? There are instructions on the FAKA page.

I'll try to add some basic debugging instructions to the page as this is a exact copy of what happened to another guy.

Re: holy FAKA (hah)

tyler1 14 Nov 2008 15:32

I guess I should be building myself a sling then. Thanks!

Re: holy FAKA (hah)

Craig Macomber 14 Nov 2008 20:09

Yep! Take a look at my slings page if you haven't already.

Re: holy FAKA (hah)

tyler1 25 Nov 2008 01:39

I am having the most hellish experience with this thing. I've tried a multitude of weight and arm configurations and sling adjustments, but nothing is getting the distance or performance I was hoping for. My longest throw was only 40 feet!

Is there a template or something for that? I little sliver of information about arm to counterweight lenghts, where to drill the holes, etc? :)

I would pay you in pirate gold (assuming I ever get some)

Re: holy FAKA (hah)

Craig Macomber 25 Nov 2008 03:07

Trying a multitude of configurations is not the process. You need to make individual small adjustments, and based on the effects, choose your next adjustment. Considering the range you're getting, I have to ask, this wouldn't be your first trebuchet would it? You don't start math by simply memorizing and using calculus equations (you don't even do that in calculus!). You need to understand what you are doing before building the most complex design you can find.

First you need to figure out the things you can adjust (I suggest sling length, pin angle and secondary trigger timing), and determine the effects of them. Then determine whats wrong with your machine and choose adjustments to fix it.

Read tuning and the details on floating-axle-king-arthur.