energy producing experiments

[Brad]

You throw mass off wheel, get big weight from velocity increase (mass not same as weight, yes ?), all you need is rewind for get weight return mass to release position. Is using CF.

[nicbordeaux]

I am rather surprised that nobody has picked up on the most sensible comment made by dabbler Brad. But maybe most people don't know the difference between mass and weight ?

So Pequaide, what are you doing now, throwing bricks ? Any progress ?

[pequaide]

Weight is a force that earth’s gravity exerts upon a mass. For instance; a 2.2 pound weight is a force not a mass. You can’t plug pounds into the kinetic energy formula because a pound is not a mass.

A counter weight is an out of balance force, so I think here the term is used appropriately. But it would probably be easier to stay in the SI system and use kilograms (mass) and newtons (force).

My trebuchets throw further than the property on which I throw them. So I am trying to throw straight up. I am also breaking 50 lb line with these trebuchets so the centrifugal force is getting quite high. So I am working on tether strength and direction.

Check out “multiple rotations trebuchet� on the internet. It is highly interesting.

[DrWhat]

Sort of on topic! Crazy!

http://www.metacafe.com/watch/447938/cr ... trebuchet/

[pequaide]

http://www.physics.ohio-state.edu/~durkin/treb2.htm

[nicbordeaux]

Very interesting Peq, thx. The guy has some good analysis, but misses the point of the sling : it's like another wheel, giving more acceleration. I guess that between us we could beat 25 meters by a mile with 2 kgs and a 40 gram ball :-)

[Trevor Lyn Whatford]

Hi Nic,

this is why bike wheels are so good, you would not what all that on your front and back wheel would you : )

http://www.physics.ohio-state.edu/~durkin/treb2.htm

PS still not convinced until I see a creator test of the big weight and the small weight to see which is doing the greater actual work, if a little weight was placed under the big weight and allowed to hit the ground then maybe you need a spade : ) good to see you posting again though.

Regards Trevor

[pequaide]

An Atwood's and a Trebuchet

[greendoor]

That looks impressive Pequaide! I don't understand it though ... the cast iron weight on the left is heavier than the weights in the bag? Which one is being launched and which one is accelerating the Atwoods?

[pequaide]

The bag launches under the wheel to the right, traveling paralleled to the surface of the Earth. The bag is on a string that is looped over an Allen wrench at 3 o’clock.

[pequaide]

This Atwood’s Trebuchet gives you control of several important variables. You can place a small object in linear motion using the preexisting linear motion of two larger objects; or the initial motion can be mostly rotations. You can arrange the initial motion to be somewhat fast at 4 to 6 m/sec or so slow that it would hardly work. This machine will yield some very useful information.

I used a smaller BB bag and the motion was so intense I could not pick up the bags trajectory, I heard a whirr and a thud on the lawn, the longer tether had launched almost straight down. That would be over 270° beyond the shorter tether launch direction. You can of course mechanically release in any direction you choose.

The important part is that the entire motion of the system can be stopped by the bag.

Did you notice that there are two wheels bolted together; a wooden one and the bigger aluminum one? The drive wheel is 12 inches and the throwing wheel is 18 inches. This is how the two strings keep from tangling. It also gives a mechanical advantage; which is another interesting variable.

[greendoor]

Thanks Pequaide - brilliant. I like the idea of incorporating gearing into the flywheel, and that's a very elegant solution.

[Trevor Lyn Whatford]

Hi Pequaide,

I have looked over some of my posts on this thread and they are very negative, not fitting for the work and time you have put into this concept, this I put down to the difficulties in being able to tap the energy gain, as most of the time it is lost in the impressive height gain (work against Gravity), if the same experiment was done at height and the projectile was thrown to the ground then I am shore these experiments would be more positive as a crater test would prove, the velocity would be far greater if the projectile did not have to slow down first. I do like the direction you are now going in, as I feel that the greater degree of control in your experiment should give us a better insight how to tap this phenomenon, and hopefully provide some answers that can transfer to a working wheel.

I do sometime wonder if you could throw these objects ( like A bowling ball ) into a big wheel that with the right gearing ratio there could be a system reset. Edit, I know this is not possible in real terms because of the friction losses of a big wheel, but the maths could be done.

Edit, without experiments there would be no new discoveries.

I wish you well and good luck.

Respectfully yours Trevor

[nicbordeaux]

Hi Peq. Nice work, but the bottom line is that the closer to the rim your weight is placed, the greater the speed at 6, the faster the acceleration from 0, this for a given weight. Using bigger weights on a smaller hub at best gives you the same result once ratio is accounted for as a rim weight.

What would be interesting is variable gearing. How about elliptics ?

[pequaide]

The main reason for the choice of the smaller 12 inch plywood hub is that I found a 12 inch wide piece of plywood in my scrap box. If I had a full sheet of plywood I probably would have made the plywood wheel with an 18 inch diameter. But I am always willing to try something new and I was curious how a smaller drive wheel would perform.

Yes; I am very interested in an elliptical hub. The many variations are all interesting.

I am working with mass and tether length right now.