Every now and then I play with numbers. Here's another numeric doodle.
Do people design guns any longer, or has it all been done before?
It seems to me that there's only one purpose for a mounted gun in combat and that's to place bullets onto a vehicle, APC, helicopter or plane in sufficient numbers to put it out of commission. That requires the bullets to go to an area with a defined height and width, spread to sufficiently overlap the actual location that aiming errors are irrelevant.
So, how can we do that differently. Without a rifle.
Assume we're trying to place bullets specified as Raufoss Multipurpose (armor-piercing, explosive, incendiary) Ammunition. They need a muzzle velocity of approximately 915 m/s and have a bullet mass of 43-47g. Let's round the figures up to 1000m/s and 50g.
A horizontally mounted disc of 160cm radius spinning at 6000rpm has an edge speed of 2.pi.r.rpm = 1000 m/s. It could be any orientation, I just say horizontally to define vertical and sideways from now on.
Assume it has 50 "magazines" running radially (like the spokes from the hub of a wheel) from 30cm out from the hub to the edge of the disc, each an inch wide and capable of holding around 100 bullets (without cartridges) taken one at a time from a feeder 30cm from the hub as they pass it. That's a simple transfer from a rotating geared feeder that matches the rotation of the disc. The feeder dispenses 5000 bullets a second, the disc rotates 100 times a second, there's 50 magazines. The sums add up so far.
Centrifugal force drives the bullets down the magazine at which point they are held until the end of that magazine engages with a release catch at one point on each revolution of the disc. The release catch spins the bullet (on the same axis and to the same extent that rifling in a barrel would) and disengages it from the magazine into free flight toward the target. During the remainder of the revolution the bullets in the magazine fall centrifugally toward the edge making room for the feeder to inject another.
The release catch can be moved back and forth to vary the angle at which release occurs. If this traversing is, say, 20 degrees a second, it has the same effect as traversing a rifle barrel by the same rate to spray a target area from side to side.
The entire disc can be swivelled back and forth on its axis to vary the vertical angle at which release occurs, the effect being the raising and lowering of a rifle barrel. A combination of these movements on these two axes uniformly sprays the target area as a rectangle of specified height and width for a given range.
This mounted gun fires 15 tons of bullets - not rounds, bullets - in a minute (that's 300,000 armor-piercing, explosive, incendiary bullets). Obviously it's suited to short bursts rather than emptying the truck it's mounted on that quickly. Assuming the target area is 50m wide and high, that's one bullet per 9 by 9 cm square. Reducing the burst duration or increasing the target area decreases that density proportionately.
I mean, we could scale it down with fewer magazines but why would you? Well, there's a reason as it turns out. The energy needed to accelerate that weight of metal - 15 tons - to that speed - 1000 m/s - suggests to me that my initial idea of powering the gun with a standard V8 Ford engine throbbing along at 6000 rpm isn't going to work because it's underpowered by some margin. The power unit's perfect, the number of magazines has to be trimmed to just two. At that point the disc spins, the engine runs flat out and the gun fires only a miserable 200 bullets a second. I'm guessing as regards the numbers in this paragraph, I've not done the sums for it, I'm just going by feel. My initial question was whether it could be done without an explosive cartridge tacked onto individual bullets and without a barrel to accelerate them and I think the design does that.
Bullets without the bang
Bullets without the bang
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
My gun is my finger pointing out and my thumb up:wah: Bam, bam, your dead:wah:
Bullets without the bang
That'll teach me not to let my mind wander then. Ow.
The cat wasn't impressed either.
The cat wasn't impressed either.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Just tired tonight I guess. Long week, etc. I don't even own a gun.:wah:
Bullets without the bang
Nasty things, guns. I don't own one either.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
And no desire to own one either.
Bullets without the bang
Hoss;974401 wrote: It's all mechanical, there's no explosives correct?
What stops the disc from spinning to accelerate the round into an aim-able motion? How do you counter that force?
A Gatlin type mechanism free spins continuously, but your rotating disc must stop to launch the round correct? Or am I missing something?
I think youd have to add stabilzers to the projectile to track it to a target.
Why not simultaneously load 50 barrels in a grid sufficient to hold them in a desirable pattern like a figure 8, place the explosive rounds into each barrel with an open back blast, insert the an electrical charge to ignite the rounds and fire all 50 rounds at once.
Yes, it's all mechanical and there's no explosives. The edge of the disc is travelling at the speed a bullet starts at and the bullet's just let go at the right point on the way round. The tips of propeller blades often go that fast. The disc never stops, each time a bullet gets to that position it's let go and flies straight instead of being dragged further round the circle it was going in. Once the bullet's in free flight it's exactly the same as one fired from a Browning M2, the same velocity and the same stabilizing spin. The bullet's spin-stabilized just as though it came from a rifled barrel.
The aim's to evenly coat a target area with a spread of bullets, not to get them to all go to the exact same place. That was one of the World War Two problems with the British Bren gun, by default it was too accurate.
One of the reasons for not using explosives is that the truck mounting the gun only needs to carry bullets, not the heavier cartridges with propellant in them.
What stops the disc from spinning to accelerate the round into an aim-able motion? How do you counter that force?
A Gatlin type mechanism free spins continuously, but your rotating disc must stop to launch the round correct? Or am I missing something?
I think youd have to add stabilzers to the projectile to track it to a target.
Why not simultaneously load 50 barrels in a grid sufficient to hold them in a desirable pattern like a figure 8, place the explosive rounds into each barrel with an open back blast, insert the an electrical charge to ignite the rounds and fire all 50 rounds at once.
Yes, it's all mechanical and there's no explosives. The edge of the disc is travelling at the speed a bullet starts at and the bullet's just let go at the right point on the way round. The tips of propeller blades often go that fast. The disc never stops, each time a bullet gets to that position it's let go and flies straight instead of being dragged further round the circle it was going in. Once the bullet's in free flight it's exactly the same as one fired from a Browning M2, the same velocity and the same stabilizing spin. The bullet's spin-stabilized just as though it came from a rifled barrel.
The aim's to evenly coat a target area with a spread of bullets, not to get them to all go to the exact same place. That was one of the World War Two problems with the British Bren gun, by default it was too accurate.
One of the reasons for not using explosives is that the truck mounting the gun only needs to carry bullets, not the heavier cartridges with propellant in them.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;974425 wrote: What holds the bullet on the disc until it 'lets go'? Am I missing this?? Was this theoretical for the fun of the math? LOL, if it was I don't think this is fun. :-3
No, I don't think it will work, how do you compensate for arc? The round when it spins off the disc will arc or curve like a baseball does depending on the rotational force of the thrower, more rotation more curve. The arc cannot be aimed unless the distance is predetermined.
That's not how a slingshot works - when you let go of a stone from a slingshot it goes straight, it's no longer attached to the sling so there's nothing pulling it sideways any longer.
The bullet's held at the end of the magazine by a latch. The latch releases when the magazine reaches the release catch which spins the bullet and lets it fly free.
Yes, it was the math, seeing whether a mechanical design with no explosive charge could put a bullet into the same release state as a rifled barrel can.
No, I don't think it will work, how do you compensate for arc? The round when it spins off the disc will arc or curve like a baseball does depending on the rotational force of the thrower, more rotation more curve. The arc cannot be aimed unless the distance is predetermined.
That's not how a slingshot works - when you let go of a stone from a slingshot it goes straight, it's no longer attached to the sling so there's nothing pulling it sideways any longer.
The bullet's held at the end of the magazine by a latch. The latch releases when the magazine reaches the release catch which spins the bullet and lets it fly free.
Yes, it was the math, seeing whether a mechanical design with no explosive charge could put a bullet into the same release state as a rifled barrel can.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
JAB;974441 wrote: 
Do you guys actually understand all this stuff without googling it? :-3
I was invigilating a three and a half hour exam this morning and I sketched it in a notebook to see how the numbers panned out.
Do you guys actually understand all this stuff without googling it? :-3
I was invigilating a three and a half hour exam this morning and I sketched it in a notebook to see how the numbers panned out.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;974448 wrote: But the stretchy part isn't spinning in a slingshot. It’s linier. Not horizontally spinning. If you spun the disc and dropped water off of it, it would curve off not spin out straight. I think you’d have to barrel it so that it released in an anticipated moment for straight flight, but to do so would mean a dead stop to release the bullet. Let it speed up inside a barrel mounted on the disc, then at the proper speed, take it to a dead stop to transfer the energy from the rotation into the barrel for an aimed trajectory.
Similar to when a sling shot slows down to release the stone.
LOL! this is when my dad tells me about a factor I haven't considered yet. Want to fill me in?
The water comes off a spinning disc in a straight line too - get your buzz saw out and try it with a bowl of water. Don't electrocute yourself. Actually, don't, it sounds really dangerous. The only curvature you'll get is from gravity.
Slings don't slow down to release the stone, you let go of one end of the doubled material and the stone carries on in a straight line - gravity will curve it downward but that happens to everything in free flight.
If something's gripped and spun in a circle it's dragged round in a curve. Once the grip's removed it goes straight. There's nothing left to drag it to one side or the other. Newton has a law about it: "An object that is in motion will not change its velocity unless a force acts upon it". Velocity's a description of something's speed and direction. Before it's released from a sling, the sling's applying a sideways force. After it's let go the only force left acting is gravity.
Similar to when a sling shot slows down to release the stone.
LOL! this is when my dad tells me about a factor I haven't considered yet. Want to fill me in?
The water comes off a spinning disc in a straight line too - get your buzz saw out and try it with a bowl of water. Don't electrocute yourself. Actually, don't, it sounds really dangerous. The only curvature you'll get is from gravity.
Slings don't slow down to release the stone, you let go of one end of the doubled material and the stone carries on in a straight line - gravity will curve it downward but that happens to everything in free flight.
If something's gripped and spun in a circle it's dragged round in a curve. Once the grip's removed it goes straight. There's nothing left to drag it to one side or the other. Newton has a law about it: "An object that is in motion will not change its velocity unless a force acts upon it". Velocity's a description of something's speed and direction. Before it's released from a sling, the sling's applying a sideways force. After it's let go the only force left acting is gravity.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;974486 wrote: I just tried it, I have a spinning painter. You put a card on it and drop the paint out on it and centrifugal force moves it to the outside in a straight line if it’s spinning fast enough.
But it does curve if it’s too slow to move the paint drop. It spirals out till it reaches the end of the card.
How do you aim it though? There’s no telling where it comes off the edge of the card, or disc in your weapon.
I do understand force and velocity.
I see the puzzle - yes it curves on the card. It's once the paint flies off from the edge of the card that it's free to go in a straight line. The curve when it's on the card is because it's resisting the acceleration as it moves outward and the only thing pulling it in the direction the card's travelling is friction. it moves outward a bit, it's going slower than that part of the card so it drifts back until the friction's sped it up. Then another bit outward and a bit more slip. The air resistance drags it along the same backward spiral as well but even in a vacuum it would take the same shaped path.
On my disc the magazines are straight, like spokes on a wheel. The bullets go in near the hub and are kept straight from there to the edge of the disc by the walls of the magazine pressing against it. To the bullet it feels like being in an aircraft accelerating down a runway, the bullet gets pushed in the back all the way down which is why it speeds up.
The release catch that flips the latch on the end of the magazine isn't attached to the disc, it's fixed to the gun mount. The bullet's let go when the end of the magazine reaches that point in the circle. Every bullet gets released at the same place, pointing in the same direction, with the same speed on it, just as with a normal barrelled rifle. If the release catch is moved back or forward around the edge of the disc then the release point's advanced or retarded and the direction the bullet flies moves to the left or the right.
But it does curve if it’s too slow to move the paint drop. It spirals out till it reaches the end of the card.
How do you aim it though? There’s no telling where it comes off the edge of the card, or disc in your weapon.
I do understand force and velocity.
I see the puzzle - yes it curves on the card. It's once the paint flies off from the edge of the card that it's free to go in a straight line. The curve when it's on the card is because it's resisting the acceleration as it moves outward and the only thing pulling it in the direction the card's travelling is friction. it moves outward a bit, it's going slower than that part of the card so it drifts back until the friction's sped it up. Then another bit outward and a bit more slip. The air resistance drags it along the same backward spiral as well but even in a vacuum it would take the same shaped path.
On my disc the magazines are straight, like spokes on a wheel. The bullets go in near the hub and are kept straight from there to the edge of the disc by the walls of the magazine pressing against it. To the bullet it feels like being in an aircraft accelerating down a runway, the bullet gets pushed in the back all the way down which is why it speeds up.
The release catch that flips the latch on the end of the magazine isn't attached to the disc, it's fixed to the gun mount. The bullet's let go when the end of the magazine reaches that point in the circle. Every bullet gets released at the same place, pointing in the same direction, with the same speed on it, just as with a normal barrelled rifle. If the release catch is moved back or forward around the edge of the disc then the release point's advanced or retarded and the direction the bullet flies moves to the left or the right.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;974502 wrote: Got it, thanks, now I 'see' what your saying.
I like it. It is recoiless, and smoke free. Is there anything like this in production or trails?
Look at this web site: http://www.metalstorm.com/
I watched the metalstorm video - yes, it's the same end result. The rounds still need propellant though so there's no weight advantage in the way I was attempting, the weapon's rounds still need to carry the explosive charge to get each bullet up to speed in the barrel.
I liked the bit about no misfires. I wondered about the variable muzzle velocity that comes from having the rounds at different depths in the barrel as they each go off. I did think there'd be alternative problems to bent firing pins like maybe the battery running out or water shorting an electronic component, it's not going to fire if that happens.
Mine matches the rate of fire even for their 40mm grenades - they quote a quarter million rounds a minute, my maximum configuration allows slightly more. All I'm missing is an adequate power unit. A mobile turbine plant would do the job. I bet there's nobody working on producing what I sketched though. What amazes me is that it could have been in production as I describe it before World War One, it's shockingly simple to build.
I like it. It is recoiless, and smoke free. Is there anything like this in production or trails?
Look at this web site: http://www.metalstorm.com/
I watched the metalstorm video - yes, it's the same end result. The rounds still need propellant though so there's no weight advantage in the way I was attempting, the weapon's rounds still need to carry the explosive charge to get each bullet up to speed in the barrel.
I liked the bit about no misfires. I wondered about the variable muzzle velocity that comes from having the rounds at different depths in the barrel as they each go off. I did think there'd be alternative problems to bent firing pins like maybe the battery running out or water shorting an electronic component, it's not going to fire if that happens.
Mine matches the rate of fire even for their 40mm grenades - they quote a quarter million rounds a minute, my maximum configuration allows slightly more. All I'm missing is an adequate power unit. A mobile turbine plant would do the job. I bet there's nobody working on producing what I sketched though. What amazes me is that it could have been in production as I describe it before World War One, it's shockingly simple to build.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;974511 wrote: Did you see the small helicopter video? I thought that concept was very interesting.No, just the one on the front page. I'll dig around the other pages and see what other mayhem they're offering.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Shall I bring this to its conclusion? I've done the sum for the final paragraph and now I understand why guns use explosive propellant instead of a Chevvie engine.
The energy needed to fire one bullet is 50,000 joules (mass times the square of the velocity)
So firing one bullet a second needs a 50kW power source.
A Cadillac supercharged Northstar V8 is rated at 350 kW. Running flat out it can fire seven bullets a second. It just goes to show the energy a flying bullet carries, it's orders of magnitude higher than I guessed in that opening post. All the power of a flat-out supercharged V8 held in just seven bullets a second.
With thirty magazines in action, pushing out 3,000 bullets a second, the power needed is 150MW.
Taking a normal 150MW ship's gas turbine without the gearing reduction, say a Westinghouse 501, the engine weight is 339 tons and it burns 3.5 gallons of diesel a second. That would power the gun with a thirty magazine load and fire 180,000 bullets a minute but it's scarcely an infantry platoon weapon. Which is why an infantryman carries rounds instead of bullets, because they have all that energy packed away in the explosive cartridge.
Back to the drawing board, eh?
The energy needed to fire one bullet is 50,000 joules (mass times the square of the velocity)
So firing one bullet a second needs a 50kW power source.
A Cadillac supercharged Northstar V8 is rated at 350 kW. Running flat out it can fire seven bullets a second. It just goes to show the energy a flying bullet carries, it's orders of magnitude higher than I guessed in that opening post. All the power of a flat-out supercharged V8 held in just seven bullets a second.
With thirty magazines in action, pushing out 3,000 bullets a second, the power needed is 150MW.
Taking a normal 150MW ship's gas turbine without the gearing reduction, say a Westinghouse 501, the engine weight is 339 tons and it burns 3.5 gallons of diesel a second. That would power the gun with a thirty magazine load and fire 180,000 bullets a minute but it's scarcely an infantry platoon weapon. Which is why an infantryman carries rounds instead of bullets, because they have all that energy packed away in the explosive cartridge.
Back to the drawing board, eh?
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
spot;974839 wrote: Shall I bring this to its conclusion? I've done the sum for the final paragraph and now I understand why guns use explosive propellant instead of a Chevvie engine.
The energy needed to fire one bullet is 50,000 joules (mass times the square of the velocity)
So firing one bullet a second needs a 50kW power source.
A Cadillac supercharged Northstar V8 is rated at 350 kW. Running flat out it can fire seven bullets a second. It just goes to show the energy a flying bullet carries, it's orders of magnitude higher than I guessed in that opening post. All the power of a flat-out supercharged V8 held in just seven bullets a second.
With thirty magazines in action, pushing out 3,000 bullets a second, the power needed is 150MW.
Taking a normal 150MW ship's gas turbine without the gearing reduction, say a Westinghouse 501, the engine weight is 339 tons and it burns 3.5 gallons of diesel a second. That would power the gun with a thirty magazine load and fire 180,000 bullets a minute but it's scarcely an infantry platoon weapon. Which is why an infantryman carries rounds instead of bullets, because they have all that energy packed away in the explosive cartridge.
Back to the drawing board, eh?
I also suspect that you'd have problems with strength of materials - and manufacturable disk carrying that much weight at that velocity would fly apart from the stress.
The energy needed to fire one bullet is 50,000 joules (mass times the square of the velocity)
So firing one bullet a second needs a 50kW power source.
A Cadillac supercharged Northstar V8 is rated at 350 kW. Running flat out it can fire seven bullets a second. It just goes to show the energy a flying bullet carries, it's orders of magnitude higher than I guessed in that opening post. All the power of a flat-out supercharged V8 held in just seven bullets a second.
With thirty magazines in action, pushing out 3,000 bullets a second, the power needed is 150MW.
Taking a normal 150MW ship's gas turbine without the gearing reduction, say a Westinghouse 501, the engine weight is 339 tons and it burns 3.5 gallons of diesel a second. That would power the gun with a thirty magazine load and fire 180,000 bullets a minute but it's scarcely an infantry platoon weapon. Which is why an infantryman carries rounds instead of bullets, because they have all that energy packed away in the explosive cartridge.
Back to the drawing board, eh?
I also suspect that you'd have problems with strength of materials - and manufacturable disk carrying that much weight at that velocity would fly apart from the stress.
Bullets without the bang
Bryn Mawr;974958 wrote: I also suspect that you'd have problems with strength of materials - and manufacturable disk carrying that much weight at that velocity would fly apart from the stress.
Propeller blades manage that tip speed, the "disc" needn't be any more than the magazines themselves with a reinforcing band at 30cm and the edge. Genuine suspension spokes could keep the bands from bending and the magazines could be aerodynamic. The magazines weigh, oh, maybe 8 kilos each fully loaded including the release latch.
Those bullets I specified are around five times heavier than normal 7.62 ammunition, they're half inch heavy machine gun armour-piercing. In some countries it's illegal to fire them at people - though not, I hasten to add, in America.
Propeller blades manage that tip speed, the "disc" needn't be any more than the magazines themselves with a reinforcing band at 30cm and the edge. Genuine suspension spokes could keep the bands from bending and the magazines could be aerodynamic. The magazines weigh, oh, maybe 8 kilos each fully loaded including the release latch.
Those bullets I specified are around five times heavier than normal 7.62 ammunition, they're half inch heavy machine gun armour-piercing. In some countries it's illegal to fire them at people - though not, I hasten to add, in America.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
spot;974967 wrote: Propeller blades manage that tip speed, the "disc" needn't be any more than the magazines themselves with a reinforcing band at 30cm and the edge. Genuine suspension spokes could keep the bands from bending and the magazines could be aerodynamic. The magazines weigh, oh, maybe 8 kilos each fully loaded including the release latch.
Props are not carrying the weight of the magazines or the bullets. As originally described you were talking a quarter of a tonne of bullets. Even if you figure out a way to pick up bullets at the hub whilst it is rotating at that speed, you're still talking about fifteen kilos of bullets minimum giving you a firing rate of two hundred bullets per second.
Props are not carrying the weight of the magazines or the bullets. As originally described you were talking a quarter of a tonne of bullets. Even if you figure out a way to pick up bullets at the hub whilst it is rotating at that speed, you're still talking about fifteen kilos of bullets minimum giving you a firing rate of two hundred bullets per second.
Bullets without the bang
I'd ask at this point where I can borrow a Westinghouse 105 gas turbine to demonstrate that I'm right but I suspect it would put me on a surveillance list.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Scrat;975001 wrote: This has been done before, the Israelis may have one in the works albeit in a much smaller version for use on their tanks.
I read some things about it as a military application but is was considered impractical for logistics reasons and the fact that a bomb can do the same thing.
Any references to a design?
I'd love to see where this concept could get to is carried through.
I read some things about it as a military application but is was considered impractical for logistics reasons and the fact that a bomb can do the same thing.
Any references to a design?
I'd love to see where this concept could get to is carried through.
Bullets without the bang
You'd need pulleys.
Bullets without the bang
Hoss;974448 wrote: But the stretchy part isn't spinning in a slingshot. It’s linier. Not horizontally spinning. If you spun the disc and dropped water off of it, it would curve off not spin out straight. I think you’d have to barrel it so that it released in an anticipated moment for straight flight, but to do so would mean a dead stop to release the bullet. Let it speed up inside a barrel mounted on the disc, then at the proper speed, take it to a dead stop to transfer the energy from the rotation into the barrel for an aimed trajectory.
Similar to when a sling shot slows down to release the stone.
All one need do is to render the disc nonsymmetrical...It makes up for having to stop the disc...
Similar to when a sling shot slows down to release the stone.
All one need do is to render the disc nonsymmetrical...It makes up for having to stop the disc...
Bullets without the bang
K.Snyder;975503 wrote: All one need do is to render the disc nonsymmetrical...It makes up for having to stop the disc...
I believe Hoss was thinking catapult rather than slingshot at the time.
The disk cannot be asymetrical because at that rate of rotation it would shake itself to pieces.
I believe Hoss was thinking catapult rather than slingshot at the time.
The disk cannot be asymetrical because at that rate of rotation it would shake itself to pieces.
Bullets without the bang
Bryn Mawr;975692 wrote: I believe Hoss was thinking catapult rather than slingshot at the time.
The disk cannot be asymetrical because at that rate of rotation it would shake itself to pieces.
Even without equal weight distribution?...
The shape would be the determining factor...
The disk cannot be asymetrical because at that rate of rotation it would shake itself to pieces.
Even without equal weight distribution?...
The shape would be the determining factor...
Bullets without the bang
K.Snyder;976276 wrote: Even without equal weight distribution?...
The shape would be the determining factor...
But the weight is distributed equally, there are many axes of symmetry in the disc. It's essential that there has to be at least one. If it were asymmetric it would destroy itself.
The shape would be the determining factor...
But the weight is distributed equally, there are many axes of symmetry in the disc. It's essential that there has to be at least one. If it were asymmetric it would destroy itself.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
Hoss;976301 wrote: That was my thought, also it would greatly reduce the rate of fire if it had to stop, recover its original speed prior to launching and stopping again. The simple spin of the disc is what makes it work.
I didn’t really have a clear understanding of what you were talking about till you mentioned the’ hub’ and ‘spoke’ model and the rounds feeding from the center outward through the 'spokes'. Then it was more obvious to me I what your designed looked like. But then I got hung up on the round leaving the disc 'straight', I had not considered the amount of speed you were talking about. It was fun though! I enjoyed that process of learning how it worked.
The major problem with keeping the speed of rotation would be the ability to pick up bullets at the hub on the fly - given that we're talking a kilogram every ten seconds minimum this, in itself, is likely to introduce severe judder into the system with a lot of resultant stress to the materials used.
The alternative is to hold all of the bullets on the disk from the start which would severely limit the firepower or, as you suggest, stop and start the disk to pick up a fresh load.
I didn’t really have a clear understanding of what you were talking about till you mentioned the’ hub’ and ‘spoke’ model and the rounds feeding from the center outward through the 'spokes'. Then it was more obvious to me I what your designed looked like. But then I got hung up on the round leaving the disc 'straight', I had not considered the amount of speed you were talking about. It was fun though! I enjoyed that process of learning how it worked.
The major problem with keeping the speed of rotation would be the ability to pick up bullets at the hub on the fly - given that we're talking a kilogram every ten seconds minimum this, in itself, is likely to introduce severe judder into the system with a lot of resultant stress to the materials used.
The alternative is to hold all of the bullets on the disk from the start which would severely limit the firepower or, as you suggest, stop and start the disk to pick up a fresh load.
Bullets without the bang
There's a geared feed that brings the bullet into contact with the magazine feed slot at the same forward speed as that bit of the disc's moving. From the point of view of the feeder it's just rotating into contact and injecting the bullet and pulling back, there's no pushing it in as it flies by. Imagine a rubber wheel held against that bit of the disc and the feeder being one inch of the rubber edge. Round it comes, squeeze as it touches and away it goes. The gearing makes sure the bullet arrives at the same time as the magazine's present to receive the transfer.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
Bullets without the bang
spot;976328 wrote: There's a geared feed that brings the bullet into contact with the magazine feed slot at the same forward speed as that bit of the disc's moving. From the point of view of the feeder it's just rotating into contact and injecting the bullet and pulling back, there's no pushing it in as it flies by. Imagine a rubber wheel held against that bit of the disc and the feeder being one inch of the rubber edge. Round it comes, squeeze as it touches and away it goes. The gearing makes sure the bullet arrives at the same time as the magazine's present to receive the transfer.
Then increase your power requirement to take account of the acceleration of the mass involved.
We'll get there - I'm sure there's a practical design in there bursting to get out.
Then increase your power requirement to take account of the acceleration of the mass involved.
We'll get there - I'm sure there's a practical design in there bursting to get out.
Bullets without the bang
Hoss;976341 wrote: Here we go! Lock down your seats belts, keep all your hands and arms inside the ride at all times!
I can imagine a mechanism but I don’t know if I can describe it. I'll try.
Let the round (pointy end first), enter the center of the disk as though it was a mouse popping its nose out of a hole, then let the force of the spinning disc take it from there, depending on the weight and shape of the round it could automatically move to the edge where it fires off straight by itself. No need to have anything grab and position it, let centrifugal force do it for you. No need to slow it down or time it, just push them into the spinning disc in a free float. You can vary the rate of fire independently of the speed of spin then.
The judder would get you - trying to accelerate fifty grammes dead weight to 150m/s within a very small fraction of a second would stress you out.
I can imagine a mechanism but I don’t know if I can describe it. I'll try.
Let the round (pointy end first), enter the center of the disk as though it was a mouse popping its nose out of a hole, then let the force of the spinning disc take it from there, depending on the weight and shape of the round it could automatically move to the edge where it fires off straight by itself. No need to have anything grab and position it, let centrifugal force do it for you. No need to slow it down or time it, just push them into the spinning disc in a free float. You can vary the rate of fire independently of the speed of spin then.
The judder would get you - trying to accelerate fifty grammes dead weight to 150m/s within a very small fraction of a second would stress you out.
Bullets without the bang
Hoss;976385 wrote: Just as long as I am on the aiming end and not on the target end! LOL! Let’s spin the tube that the mouse (projectile) pops its nose out? Would that change things a bit? Would that help?
My worry is that the stress would shatter the disk killing the aimer.
I quite like Spot's idea of a rubber wheel spinning fast enough to accelerate the bullet to the same speed as the hub of the disk before insertion - hell of a power drain though.
My worry is that the stress would shatter the disk killing the aimer.
I quite like Spot's idea of a rubber wheel spinning fast enough to accelerate the bullet to the same speed as the hub of the disk before insertion - hell of a power drain though.
Bullets without the bang
Bryn Mawr;976417 wrote: I quite like Spot's idea of a rubber wheel spinning fast enough to accelerate the bullet to the same speed as the hub of the disk before insertion - hell of a power drain though.It's marginal. It's 30cm out from the hub, not right out on the rim. It's... umm... a fifth of the power requirement of turning the disc, but it's a fifth of the energy requirement I already calculated, it's not extra. My initial power figure involves taking the bullets from a standstill, driving the feeder consumes 20% of it and the disc 80%.
Nullius in verba ... ☎||||||||||| ... To Fate I sue, of other means bereft, the only refuge for the wretched left.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.
When flower power came along I stood for Human Rights, marched around for peace and freedom, had some nooky every night - we took it serious.
Who has a spare two minutes to play in this month's FG Trivia game! ... My other OS is Slackware.