I need to build a catapult -- HELP!!

[Odie1]

Oil the marshmellow.

But what oil to use?

Running for cover now...

Odie1

 

[DannoXYZ]

Oil the marshmellow.

But what oil to use?

Running for cover now...

Odie1

full-synthetic for most slickness of course...

 

[Slammer]

The "Boys" say...: "Hold our beer!"

grand tour trebuchet fake - Google Search

www.google.com

 

[naedlaen]

I helped my eldest build one a couple of years ago. We did the basic bungee cord one. One thing I noticed that impacts distance is release point. Where is the "basket" in the arc of travel when it stops. It needs to be before being perpendicular to the ground.

This is very important. Stopping the arm at 45º will give about 70% of the arm velocity to both vertical and horizontal directions. At 60º (from horizontal) the horizontal velocity is about 86% while the vertical is about 50%. The trick is to find the point that gives the most horizontal velocity the longest time to be active. So start with 45º and slowly increase the angle from there. (again, from horizontal). Measuring arm speed on the basket is possible, but difficult on the size that you are building. Ask if you want more info on trying to measure the speed.

Neal

 

[flyfisher]

Use a fiberglass arm on the flinger....tent pole, fishing pole that kind of thing to get a snap to the launch

 

[ddemair]

Use a fiberglass arm on the flinger....tent pole, fishing pole that kind of thing to get a snap to the launch

That's the basic principal of an atlatl (ancient throwing stick). That could add tremendous speed, but probably a lot of trial and error to get the physics right.

 

[flyfisher]

Yeah project is probably due Monday......

 

[Skunkape]

How about some sort of fly/inertia wheel that could be spun up real fast using a high ratio crank. Get it spinning then engage. It wouldn't have to be too big or heavy since it's only a marshmallow. Might snap the arm because of initial acceleration.

 

[SMSW]

Use a fiberglass arm on the flinger....tent pole, fishing pole that kind of thing to get a snap to the launch

Might snap the arm because of initial acceleration.

Carbon fiber arm solves both issues. Better yet, just get a golf club and cut it down to the appropriate arm length. Don't forget to remove the head...this is not a putting contest.

Oil the marshmellow.

Nonsense. They put dimples in golf balls for added loft and range. Only question is, how do you dimple a marshmallow?

 

[Willsmotorcycle]

Nonsense. They put dimples in golf balls for added loft and range. Only question is, how do you dimple a marshmallow?

Pencil point

 

[flyfisher]

Considering the size restraints on this thing golf shaft no good too stiff....and the rules apparently allow no modification of the projectile {marshmallow} This isn't david and goliath stuff

 

[SMSW]

Considering the size restraints on this thing golf shaft no good too stiff....and the rules apparently allow no modification of the projectile {marshmallow} This isn't david and goliath stuff

Guess we are back to clandestine mods, like Larry's ball bearing.

 

[flyfisher]

You're gonna shoot your eye out…

 

[Larry Fine]

Only question is, how do you dimple a marshmallow?

Golf ball mold, of course.

 

[Slammer]

That's the basic principal of an atlatl (ancient throwing stick). That could add tremendous speed, but probably a lot of trial and error to get the physics right.

That is one of the great mysteries. Why would a device such as the AtlAtl, a contemporary to the sling, a weapon that was superior to the hand-thrown spear and used even before the bow and arrow was invented be so utterly forgotten?
Also it was a leaver, along with the wheel one of mankind´s first inventions. If the technology had been developed further we could have had the Honda ST in the middle ages.