Any idea on where I could find the correct size string for such an old bow? I dont really know that much about bows.

yes u could def's use fiberglass that would be an easy soultion but it mite take a while
oh and when adding stuff to the bow allways add it the the back so that it is being compressed not puled apart cos this dosent work just wastst time( trust me i no)

When you say the back, you mean the side ...

What if I cut the barrel in half? The arrow might be flexing and hitting the walls of the pipe....

So what if I cut a pipe, any pipe will do, in half and tried that? I am afraid that the arrow might not stay on the ball though.


On the other hand, I do not know the maximum amount an arrow will ...

I believe the bow is at max draw... I did think about just forcing it past that, but again it is old and I do not want to over do it.

My teammate is in the process of shortening the arrows tonight.

OK OK i might have and idea........... just get some sort of thin sheet metal like tin or something and stick behind the bow part (the flexibale part, forgot what this is called cos don't do archry any more) and scru it in

this should work
i did this once with a old bow cos it was the only bow ...

I cant build an air cannon because I have already done extensive work on inventor drawings and a finalized report.

There is absolutely no way I could build another project, draw it, and make up a report in the remaining time. Especially considering it is near the end of the semester with finals ...

So far I am thinking,

Shorten barrel
Shorten arrow
Lightly lubricate barrel
Lubricate the pulley of bow
Overextend the draw of the bow.
Make a stronger frame to set my bow on and hopefully reduce energy lost to vibration.

I have an old compound bow, and I decided to use it for a golf ball competition. The bow and arrow is pulled back, and held by a release at a given point. The arrow is released and basically pushes the ball through a metal tube that is only slightly larger than the ball.


I am needing to hit a ...

I like the Foam sabot made from a swim noodle. I had an idea of using some window and door foam, but scrapped the idea as I thought it would not compress evenly and would throw the ball off.

I then came up with the idea of making a piston out of wax. Cheap and can be molded to any shape.

The competition is not until early December, so I have a lot of time to work on it.

Cool thanks for the help.

I gave this a shot modeling the Marshmallow cannon in GGDT.

In your marshmallow cannon what are you using to seal the pin you pull back to release the quick dump valve?

The current plan is to use a crossbow from wal-mart that costs $25. Sounds cheap to me, but I havent seen it yet. Anyways we ...

The team has decided to go with a ballista style setup with a crossbow. I dont know all the details atm, but when I get some more info I will let you know.

Thx for the help thus far.

Accuracy and precision are the only problems.

How are sling shots the best? Quite a bold statement w/o any evidence or even an argument.

Is it the best because I can make one in an hour? Or because it is the most accurate? How about precision?

So is the idea to keep the angle constant and to only vary the distance you pulled the sling back?

I would have to question the accuracy of a home made sling shot even if we had a perfect person shooting it. I would think if you are off on the length of either of elastic bands by even a small ...

A decent regulator is going to be fairly expensive. The accuracy of the reg doesn't matter much. What does matter is how accurately you can read it and set it.

How about a different approach. Instead of a compressor with regulator how about a propane cylinder? The pressure is constant for a given ...