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Pulsar Ballistics

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Re: Pulsar Ballistics
Post by cthia   » Sun Nov 01, 2020 8:28 am

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TFLYTSNBN wrote:
tlb wrote:It sounds as though the only purpose of that story was to make fun of the teenagers that were hunting with you, otherwise it was a waste of meat and ammunition.



The story wasn't exactly complimentary to the teenagers, but they were on their first elk hunt.

It does serve the purpose of demonstrating what the difficulties of having some type of recoilless pulsar would be.

Fortunately; Weber's descriptions of pulsar weapons suggests that while they are hypervelocity weapons, they fire relatively low mass projectiles which keeps the recoil impulse within the realm of what is common for conventional firearms.

Anyone who shoots (as Weber dies) understands that the reciprocating mass of the slide (telescoped bolt) on a semiautomatic pistol reduces the felt recoil as compared to a revolver or bolt action pistol. Your can take this principle even further by having the entire barrel as well as the bolt and bolt carrier assembly reciprocate to absorb recoil. The Barrett semiautomatic, .50 caliber rifles use this type of system as well as a muzzle brake to reduce the recoil force on the shooter.

You could also utilize the counter recoil principle in which the bolt, bolt carrier and barrel assembly are restrained until firing then released to move forward under spring tension then the projectile is accelerated at nearly the full forward position. The momentum exchange stupid the forward travel of the bolt, bolt carrier and barrel assembly and pushes them back again. The are issues with maintaining accuracy.

All of this discussion ignores the reality that Honorverse Pulsar weapons are hypervelocity but the projector masses are very small plus there are no propellant gases to add to the recoil. As a result, they would probably be no more difficult to shoot than conventional firearms.

A major issue with Pulsar weapons would be areodynamic drag. Drag force is roughly proportional to velocity squared. (The drag coefficient varies with velocity). A closer approximation of that velocity decreases with distance as an exponential decay function. Think of it as analogous to respective decay but with a half distance rather than a half life. As an example, certain 12 gauge shotgun slugs will lose about half their kinetic energy during the first 100 meters of travel and half of their muzzle velocity within about 200 meters. However; they are still traveling at about 700 feet per second at 200 yards which will make them very lethal. More areodynamic projectiles with higher sectional densities of the type used by rifles have much longer half distances.

Honorverse Pulsar projectiles will trend to experience far more areodynamic drag because they are jupiter velocity. However; Weber describes the projectiles as long, slender days which have low cross sectional area and very low drag coefficient. I would expect a pulsar dart that has a muzzle velocity of say 5 kilometres per second to stop be doing along at about 2 kilometres per second at 1,000 meters.

It isn'tt exactly complimentary to you either. I'm part Indian and I understood long ago why my people hated White Skins hunting on Indian land. A bunch of novices who totally disrespect nature. What a shame. Wasted life and meat. You may as well use rocket launchers to hunt just as you use explosives to fish. I could catch the elk and bring him home ALIVE! Before I was a yr-old in teenage skin.

****** *

tlb wrote:@cthia: it would be best to stick to those lines, rather than trying to invent what mechanism would actually be used in the Honorverse.

I can agree with that. As an engineer, a major hindrance is not knowing what materials or methods are available for use.

My point is that in the HV the application of all the laws of physics would be mated to futuristic materials and manufacturing techniques and applied to the principles we have learned thus far. With nothing short of magical results. The same mechanisms bearing the same name in the HV will only have "the name" in common.


Arthur C. Clarke wrote:“Any sufficiently advanced technology is indistinguishable from magic.”

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Pulsar Ballistics
Post by Jonathan_S   » Sun Nov 01, 2020 10:16 am

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TFLYTSNBN wrote:Anyone who shoots (as Weber dies) understands that the reciprocating mass of the slide (telescoped bolt) on a semiautomatic pistol reduces the felt recoil as compared to a revolver or bolt action pistol. Your can take this principle even further by having the entire barrel as well as the bolt and bolt carrier assembly reciprocate to absorb recoil. The Barrett semiautomatic, .50 caliber rifles use this type of system as well as a muzzle brake to reduce the recoil force on the shooter.

You could also utilize the counter recoil principle in which the bolt, bolt carrier and barrel assembly are restrained until firing then released to move forward under spring tension then the projectile is accelerated at nearly the full forward position. The momentum exchange stupid the forward travel of the bolt, bolt carrier and barrel assembly and pushes them back again. The are issues with maintaining accuracy.
The problem is these methods work by spreading the recoil force over time, and that's harder to do as the cyclic rate goes up. Honorverse pulser (pistols) are not only described as having (lightweight) hypersonic darts - but also being capable of full auto.

I haven't found the cyclic rate of the pulsar pistol, but when Captain Yu opened up with his during HotQ it was described hyperbolically as a "hurricane of destruction" and "a tornado of darts". The slowest rate I did find for a larger mounted/crew-served pulser was 1,000 rounds per minute. (The big pinnace mounted ones were 30,000 rounds a minute!)

Having something as small and light as a pistol remain even somewhat controllable under full auto is a lot harder to engineer than making the recoil more comfortable for a single shot because everything has to happen so fast in order to be ready for the next round.


However I did find a pulser (pistol) muzzle velocity while looking for cyclic rate - in HAE when comparing Honor's Colt 1911 to a pulser we see "2,000-plus MPS at which a modern pulser punched out its darts".
That's definitely fast, beyond Mach 5 at STP, but not as fast as some may have been speculating. (Though the rifle, the crew served, the heavy tribarrel, and the pinnace mounted pulsers all probably have even higher muzzle velocities)
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Re: Pulsar Ballistics
Post by cthia   » Sun Nov 01, 2020 10:26 am

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Strategically placed high-tech gyroscopes.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Pulsar Ballistics
Post by tlb   » Sun Nov 01, 2020 11:23 am

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Jonathan_S wrote:However I did find a pulser (pistol) muzzle velocity while looking for cyclic rate - in HAE when comparing Honor's Colt 1911 to a pulser we see "2,000-plus MPS at which a modern pulser punched out its darts".
That's definitely fast, beyond Mach 5 at STP, but not as fast as some may have been speculating. (Though the rifle, the crew served, the heavy tribarrel, and the pinnace mounted pulsers all probably have even higher muzzle velocities)

I originally said 3km/s (almost 9 times the speed of sound, perhaps 8 times the speed of a regular 10mm pistol bullet (my guesstimate)), because that was the number I found when searching for the meaning of "hyper-velocity". Upon your correction I found a table in the search for muzzle velocity, which gives this:

The United States Army defines different categories of muzzle velocity for different classes of weapons (any speed greater than high velocity is considered to be hyper-velocity):

Weapon_________ High velocity
Artillery cannons_ Between 914 m/s and 1,067 m/s
Tank guns_______ Between 472 m/s and 1,021 m/s
Small arms______ Between 1,067 m/s and 1,524 m/s

So 2km/s is hyper-velocity based on this table. The 10mm pistol bullet has a muzzle velocity of about 400m/s to 500m/s and is only about factor of 4 or 5 less (so my guess should have been a factor of 6 or so).

Based on the earlier estimate of the weight of a hand pulser dart of one sixth the weight of a 10mm bullet, that gives about the same momentum and 6 times the energy for the dart over the bullet.
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Re: Pulsar Ballistics
Post by TFLYTSNBN   » Sun Nov 01, 2020 12:54 pm

TFLYTSNBN

I'm amused that a certain someone trotted out that noble savage bovine scatology. As a general rule, Native Americans used bows and arrows to hunt large game. Sometimes they used spears. If you have every been bow hunting, then you know that arrows are almost never promptly lethal. The arrow wounds the animal, hopefully in the chest cavity but maybe in the abdomen if your son is bad or a twig deflects the arrow. You then have to wait, sometimes for hours, for the animal to either bleed out or aphixiate. There is a high risk that the animal will remain ambulatory during this time. You dare not move in for a follow up shot. If it runs off, you will not be able to track it down soon enough to use the meat.

Top many modern vote hunters emulate the native American hunters. If they mortally wind an animal and can not catch it, they just move on to find another animal to kill. There have been more than a few times when I've found arrows in animals as I'm gutting and skinning them.

The elk that I shot at such extreme range was mortally wounded and effectively crippled by my first hit. It wasn't going to suffer for a significant period of time nor was it going to get away. I certainly wasn't going to go out and shoot another animal.
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Re: Pulsar Ballistics
Post by tlb   » Sun Nov 01, 2020 1:06 pm

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Don't forget the very effective method of buffalo hunting by stampeding a herd over a cliff.
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Re: Pulsar Ballistics
Post by TFLYTSNBN   » Sun Nov 01, 2020 1:10 pm

TFLYTSNBN

Jonathan_S wrote:
TFLYTSNBN wrote:Anyone who shoots (as Weber dies) understands that the reciprocating mass of the slide (telescoped bolt) on a semiautomatic pistol reduces the felt recoil as compared to a revolver or bolt action pistol. Your can take this principle even further by having the entire barrel as well as the bolt and bolt carrier assembly reciprocate to absorb recoil. The Barrett semiautomatic, .50 caliber rifles use this type of system as well as a muzzle brake to reduce the recoil force on the shooter.

You could also utilize the counter recoil principle in which the bolt, bolt carrier and barrel assembly are restrained until firing then released to move forward under spring tension then the projectile is accelerated at nearly the full forward position. The momentum exchange stupid the forward travel of the bolt, bolt carrier and barrel assembly and pushes them back again. The are issues with maintaining accuracy.
The problem is these methods work by spreading the recoil force over time, and that's harder to do as the cyclic rate goes up. Honorverse pulser (pistols) are not only described as having (lightweight) hypersonic darts - but also being capable of full auto.

I haven't found the cyclic rate of the pulsar pistol, but when Captain Yu opened up with his during HotQ it was described hyperbolically as a "hurricane of destruction" and "a tornado of darts". The slowest rate I did find for a larger mounted/crew-served pulser was 1,000 rounds per minute. (The big pinnace mounted ones were 30,000 rounds a minute!)

Having something as small and light as a pistol remain even somewhat controllable under full auto is a lot harder to engineer than making the recoil more comfortable for a single shot because everything has to happen so fast in order to be ready for the next round.


However I did find a pulser (pistol) muzzle velocity while looking for cyclic rate - in HAE when comparing Honor's Colt 1911 to a pulser we see "2,000-plus MPS at which a modern pulser punched out its darts".
That's definitely fast, beyond Mach 5 at STP, but not as fast as some may have been speculating. (Though the rifle, the crew served, the heavy tribarrel, and the pinnace mounted pulsers all probably have even higher muzzle velocities)



Well this is disappointing. Only 2,000 meters per second muzzle velocity from a pulsar pistol. Heck, the sabot rounds from an Abrahms tank is about 1,400 meters per second.

It is interesting as well as easy to estimate the average recoil force from a full auto Pulsar. They come in various calibers and projectile masses. Assume a projectile mass of about 23 grains or about 1.5 grams, a muzzle velocity of 2,000 meters per second, and a fitting rate of 600 rounds per minute or 10 rounds per second.

The mass flow rate is then 15 grams per second or .015 kg per second. Multiply by muzzle velocity of 2,000 meters per second and you get a recoil force of 30 Newtons. This is the equivalent of a 3 kilogram weight in a one gee gravity field.
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Re: Pulsar Ballistics
Post by TFLYTSNBN   » Sun Nov 01, 2020 1:13 pm

TFLYTSNBN

tlb wrote:Don't forget the very effective method of buffalo hunting by stampeding a herd over a cliff.



Why do mammoths have flat feet?
To trample slow ruining Neanderthals.

Did you notice that all of the mammoths and other megafauna in the Americas died out within a few thousand years after a bunch of illegal aliens exploited the Bearing straight land bridge for their invasion? The animals should have built a wall.
Last edited by TFLYTSNBN on Sun Nov 01, 2020 1:16 pm, edited 1 time in total.
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Re: Pulsar Ballistics
Post by ThinksMarkedly   » Sun Nov 01, 2020 1:13 pm

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tlb wrote:Don't forget the very effective method of buffalo hunting by stampeding a herd over a cliff.


Buffalo buffalo?

Buffalo Buffalo buffalo buffalo?
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Re: Pulsar Ballistics
Post by tlb   » Sun Nov 01, 2020 1:35 pm

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tlb wrote:Don't forget the very effective method of buffalo hunting by stampeding a herd over a cliff.

ThinksMarkedly wrote:Buffalo buffalo?

Buffalo Buffalo buffalo buffalo?

North American buffalo as it is commonly called; technically it is a bison. But remember, William Cody was known as "Buffalo Bill" and not as "Bison Bill".
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