FAKA Trebuchet

This is supposedly one of the most efficient trebuchet designs. It was also a pain in the rear end to build correctly and then a bigger pain to adjust so that it fires at all. But the three triggering systems were tuned, it launched a tennis ball 235 feet with 20 lbs, then 237 feet with 30 lbs, then 240 feet with 40 lbs. At 40 lbs, the oak rod holding the weights snapped in half. we replaced it later with a metal one. The tennis ball didn't have enough mass for its drag so that's why it didn't throw much further for twice the weight as the initial toss. I'm going to one day adjust the lever arms, counterweight arms and trigger timing to see how efficient I can get it. As of now, it tossed the ball 11.75 feet/pound. But that ratio would go up if we dropped the weight a little more.
Enjoy.

Category:

Science & Technology

Tags:

• trebuchets
• catapult
• FAKA
• floating axle

[njkelton]

When it is initially set how many triggers are there...? How is it free standing while leaning forward? I am building one however that is the only piece that I cannot understand, the triggering mechanism... some people say 1 some people say 2. How did your trigger mechanism work?

[TheMockingbirddude]

@njkelton There are technically three, but don't let that overwhelm your thought process. The reason I say there are three is because there are three "triggers" that have to be adjusted all separately to make the ball throw correctly. I'll describe them in order of their sequence. The first trigger is the actual one that I physically pull out to let the weights fall. That trigger is a pin that is locking the pivoting weight arm to the other half of the throwing arm...

[TheMockingbirddude]

@njkelton That is why you see half the arm fall when the pin is pulled out. The second trigger is also a type of pin that locks the throwing arm down, which explains why the weights can be held up and even slightly tilted forward. This trigger is the hardest to adjust and it is the most crucial for an efficient throw... an unfortunate combo. It is also "self-releasing" in a way so that the weights falling down are what provide the pulling action of the pin.

[TheMockingbirddude]

@njkelton This is done by a string attached to the falling weights which will eventually pull the string which will pull the pin. The third trigger is the typical throwing arm release on the end that controls the release angle. If you need more info, I will try even harder to explain... Thanks for taking an interest in understanding it!

[asdfasdfasdfasdf789]

hey. Great FAKA trebuchet. Would you be able to provide any plans that you used to build this? like dimensions of all the parts and such? Also, got any more videos?