What is the most efficient projectile launcher?

[greendoor]

The most efficient way to launch a projectile? As far as i'm concerned, this would have to be an elastic collision, as seen in Newton's Cradle.

Imagine the mass was a football, and the goal was to lift the football over a tall goal post. You could do this any way, such as lifting it with a fishing rod and winching it up manually. Or launching it with a cannon. Or levitating it in a plastic tube with water pressure, or sound waves. Or lifting it with a hot air balloon, or a model helicopter ... there are so many ways to lift a mass.

But I would argue that the most efficient way to lift a football over a goal post would be a well aimed kick that sends it right up and over within seconds.

So if an elastic collision is the most efficient way to launch a mass, what is the most efficient elastic collision? We know that inelastic collisions waste energy in the form of heat and sound - so what is the most elastic material? elasticity, in physics, is pretty much 'stiffness' - ability to deform and then return - measured in Young's Modulus (units of Pressure). Basically, steel is pretty good. Tungsten is better. Diamond is the best.

"A hammer receives many blows" perhaps??

I'm a fan of the Force x Time theory, and the requirement to transfer momentum between masses by sharing Force x Time. Very obviously, this requires a physical connection followed by a disconnection, so elastic collisions are a fundamental part of this action. Even if considering Bolas or Cylinder & Ball type transfers, these all start with a collision of some sort, and the elasticity of the materials involved is an important factor in the efficiency of the transfer.

I could also add that I believe the most elastic 'material' in the universe is Aether, the massless substance out of which all mass is made. But that would probably lose most people here ...

[jimmyjj]

I have posted up the design i am working on. One of the weighbts i am considering using is a super bouncy ball " made of amazing zectron " with "50,000lbs of compressed energy" lol.

Thank you for the replies and my apologies Jim for the earlier confusion.....

I shall have to think about how to incorporate a compound bow into the wheel

although i feel a compressed air type piston device may be more efficient than the spring design i have illustrated.

[nicbordeaux]

But I would argue that the most efficient way to lift a football over a goal post would be a well aimed kick that sends it right up and over within seconds.

If I read you right greendor, a impact is more efficient (you did say efficient, not "easy) than a throw ? Power delivery form or curve is of great interest. Like for example, it's easier to knock a nail into a piece of hardened oak with a hammer rather than by sitting on the nail, even though the total amount of force involved on sitting on the nail could be considerably greater than that delivered by a well timed and aimed hammer. Regardless of considerations of peronal injury.

I could also add that I believe the most elastic 'material' in the universe is Aether, the massless substance out of which all mass is made. But that would probably lose most people here ...

Quite correct, you have me lost, and I think you are lost too, you are confusing elasticity and plasticity :)

[wheelrite]

allways found Besslers 'the bow twangs' comment thought provoking, that and the springs do imply a tensioning/relaxing(or firing) cycle, in the rotation. tensioning /relaxing would seem easier than a a tensioning/firing arrangement, for that you need a latch/sear mech etc. and that is more friction/complication.
Jon

[greendoor]

IMO, an Impact and a Throw are different variations of the same thing. Basically, we have one Mass that has Momentum, and we want to transfer that Momentum to another Mass. In physics, this is called an Impulse, described as Force x Time. The difference between hammering a nail and sitting on a nail are just variations in Force x Time.

Text book physics is always a vast oversimplification of reality. An impulse is virtually never a simple application of constant Force over a period of time. The Force can vary all over the place. Just like the Speed of a car can vary all over the place during the course of a Journey. We can plot the variation in Speed over time, or we could look at the rate of Acceleration over time ... or we could look at the rate of change of Acceleration over time, etc, etc.

It's similar with Impulse ... we can describe different rates of change of that impulse. That's where Jerk and Jounce and other physics terms can be used. But personally, I think that's too nerdy by far. I'm a musician, and i'm used to viewing acoustic waveforms on a screen. Drum hits or piano notes or strings, whatever, are basically Impulses with different shaped waveforms.

IMO, the transfer of momentum can be thought of as a waveform. At the end of the day, the amount of Momentum transfered is the area under the graph.

Nicb - what makes you think i'm confusing elasticity with plasticity? I said steel, tungsten and diamond have extremely high elasticity? Do you consider any of those materials to be highly plastic?

Aether theory is too radical for many people to consider, and not really a subject for this forum. But some basic concepts I consider to be true:

Space is not empty nothing. Space if full of electromagnetic energy over a massive range of frequencies/wavelengths and contains massive amounts of energy (even when completely devoid of all mass).

How can a 'wave' traverse "nothing"? There has to be a fluid medium to wave. You can invoke the concept of a photon for example, and say that light is a particle that has some mass. But if you were to do that, you need to invoke mass particles for all possible wavelengths. I choose (like many others past and present) that space if completely filled with a massless fluid that can be vibrated or waved.

Mass then becomes compression waves within this fluid. Similar to waves in a swimming pool. You can see waves in a swimming pool, and you can knock physical objects about with waves. You can create stationary 3D patterns with combinations of waves ...

Empty space displays the Casimir Effect, which is a good reason to believe in Aether. Magnetic fields in a vacuum are another good reason to believe in an Aether. I don't have time and this isn't the place, but there are many reasons to believe in Aether theories.

http://www.anti-relativity.com/ is a good place to start, but don't stop there ...

If all Mass is composed out of Aether, then Aether has remarkable properties. That is why I think that the ultimate elastic substance for efficient energy transfer is probably Aether ... perhaps magnetic fields?

Fortunately, I don't think Bessler required exotic materials or technology, hence my interest. I think he had plenty of surplus energy to afford wasting a lot in friction and less-than-perfect materials.

[nicbordeaux]

Thx grendoor, I 'll check the link out. Most of what you are saying seems sensible/logical, and much like what Tesla was working on.

Just by the way, why won't Audacity work with windows 7 ? Do you know of any easy to comprehend freewares which are compatible ?

On a silly down to earth note, are you awarethat the "distance" travelled by a bicycle from point A to B in a straight line can vary quite a bit with tire presure ? As in 8 bar some thin sewups rockhard and you'll get bounce from road irregularities which don't register on the speedometer/distance counter ? The more airborne you are, the less distance the tires travel ?

[greendoor]

Just by the way, why won't Audacity work with windows 7 ? Do you know of any easy to comprehend freewares which are compatible ?

On a silly down to earth note, are you awarethat the "distance" travelled by a bicycle from point A to B in a straight line can vary quite a bit with tire presure ? As in 8 bar some thin sewups rockhard and you'll get bounce from road irregularities which don't register on the speedometer/distance counter ? The more airborne you are, the less distance the tires travel ?

Audacity is pretty cool open source audio software. Beta 1.3 should work in Win7 now. 2.0 will be fully Win7 supported, so it's just a matter of time. I think it's your best choice. If you hadn't said "easy to comprehend" I would be recommending you check out Reaper. Reaper is very advanced though - good enough for serious studio work.

I have a completely different theory on why tyre pressures might affect odometer distance ... I don't think you would really get much "air time" with most road bikes - maybe with mountain bikes ...

How about this for a theory: high pressure tyres are highly elastic and therefore more efficient than low pressure tyres, which are less elastic. Therefore, if the tyre pressures are low, the rider has to supply more energy to overcome friction, and tends to get more fatigued. When a rider gets fatigued, they are much more likely to sway from side to side, rather than travel in a straight line. The reason, I believe, is because swaying from side to side makes it easier for arm muscles to get involved, which is a significant energy source we instinctively use, and the effect of swaying is similar to dropping down a gear, which also makes things easier.

So my theory is that the odometer is correctly recording the actual distance the tyre travels. With tight, bouncy tyres, you go faster in a straight line ...

[jim_mich]

As in 8 bar some thin sewups rockhard and you'll get bounce from road irregularities which don't register on the speedometer/distance counter ? The more airborne you are, the less distance the tires travel ?

A speedometer registers less distance with higher tire pressure because the circumference of the tire gets bigger with higher tire pressure.

Any vehicle with larger tires moves farther during each tire rotation. Thus the speedometer seems to not register the full travel distance of the vehicle with higher tire pressure.

[nicbordeaux]

Greendoor and Jim, whilst your points are both valid, actual scientific testing done rigourously by people like scientists and Grate Branes (cf Molesworth) indicates beyond doubt that a bounce factor is involved if the air presure is very, very high. The odomoeter does actually register less ditance travelled once variables such as tire deformation and actual tire circumferance are taken account of. It's not a great amount, sure. Also, contrary to popular belief, the thin hard tires aren't necessarily faster for the rider because getting what is known in scientific circles as goollie bashing tends to make you ride gingerly on uneven surfaces. Plus there are issues of contact pattern which though varied in shape are pretty much consistent between tires.

Still, the point I wanted to lead to was that, possibly, a "bounce" drive, eg partial during the rotation, might be a way of making a working wheel. Using the elastic properties of something like a tire.