Brad Johnson
Member
A circular wing, to a layman, would have said appearance, thus my proposition.
Brad
Need a Rocket Scientist!
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A circular wing, to a layman, would have said appearance, thus my proposition.
Brad
GarandOwner
Member
From the original post:
The layman discription of it shows it is an engine nozzle. A circular wing to a layman would look like a cylinder.
The layman discription of it shows it is an engine nozzle. A circular wing to a layman would look like a cylinder.
I have a rocket scientist if you still need one. She's the '73 model.
Low miles, and still in great shape.
P.S. - marry a woman considerably smarter than you are at your own risk.
Back to topic: that's an interesting concept, but it seems it would only be practical for linear/stationary firing. It might be possible to compute lead/drop with a targeting computer, but it would have to be pretty sophisticated to aim any uncontrolled projectile that actually accelerates once fired. That would seem to limit its practicality firing from airborne/moving platforms.
Low miles, and still in great shape.
P.S. - marry a woman considerably smarter than you are at your own risk.
Back to topic: that's an interesting concept, but it seems it would only be practical for linear/stationary firing. It might be possible to compute lead/drop with a targeting computer, but it would have to be pretty sophisticated to aim any uncontrolled projectile that actually accelerates once fired. That would seem to limit its practicality firing from airborne/moving platforms.
Brad Johnson
Member
True.
Looking at his description of the item in question there is another possibility. Presume the object were made of something very dense and hard, say depleted uranium. Fill the cavity with a much softer material. It's almost a reverse of the current HEAT rounds. Would there be enough energy in a round at 4000 fps to turn the softer material into a plasma for use in cutting through armor?
Brad
230RN
2A was "political" when it was first adopted.
I was thinking a thermit-filled hollow bullet would be ignited by the gases of firing.
Like a tracer round.
After burnout, the now-hollow bullet would be hot enough to transfer energy to the incoming gases, resulting in the ramjet effect.
There would be some straightforward rocketing effect (like the Gyrojet), but the ramjet effect would take place after the thermit burnt out and left the projectile as a hollow tube.
And we are not talking about sending the thing around the world. Perhaps only a few milliseconds of ramjetting would observably enhance the performace.*
Whether it is "practical" is not part of the question. Obviously, it is an R&D project. Many things are learned during experimentation --perhaps even how best to shape the cavity so that an internal high-density shock wave picks up the maximum amount of heat from the body of the bullet, eh?
At one point in history it was impractical to mount an internal combustion engine on a glider.
At one point, someone told Dr. Braun that if you put an electric motor on a razor it would slice your face to ribbons.
At one point, someone told Dr. Land that a self-developing, self-reversing photographic film was impossible.
At one point maybe somebody said, "I wonder what would happen if a bullet were hot enough and hollow, so it would act like a ramjet?"
--------
* Somebody said, "I've got a novel idea. Why not just put more energy behind the bullet?" There is a theoretical limit to how fast one can drive a bullet with combusting powder in a case behind it. IIRC it is around 6000 fs, but don't quote that number.
Like a tracer round.
After burnout, the now-hollow bullet would be hot enough to transfer energy to the incoming gases, resulting in the ramjet effect.
There would be some straightforward rocketing effect (like the Gyrojet), but the ramjet effect would take place after the thermit burnt out and left the projectile as a hollow tube.
And we are not talking about sending the thing around the world. Perhaps only a few milliseconds of ramjetting would observably enhance the performace.*
Whether it is "practical" is not part of the question. Obviously, it is an R&D project. Many things are learned during experimentation --perhaps even how best to shape the cavity so that an internal high-density shock wave picks up the maximum amount of heat from the body of the bullet, eh?
At one point in history it was impractical to mount an internal combustion engine on a glider.
At one point, someone told Dr. Braun that if you put an electric motor on a razor it would slice your face to ribbons.
At one point, someone told Dr. Land that a self-developing, self-reversing photographic film was impossible.
At one point maybe somebody said, "I wonder what would happen if a bullet were hot enough and hollow, so it would act like a ramjet?"
--------
* Somebody said, "I've got a novel idea. Why not just put more energy behind the bullet?" There is a theoretical limit to how fast one can drive a bullet with combusting powder in a case behind it. IIRC it is around 6000 fs, but don't quote that number.
At supersonic speeds nozzles become diffiusers and vice versa. It could add to the speed, but it would be still consuming some fuel inside the cavity and only adding to it, not really making its own, just making it's own fuel burn more efficiently, IIRC correctly, plasmas are very efficient utilization of energy. It would add some acceleration beyond the traditional propellant behind said projectile in said barrel. This would be some darn interesting research. Once the fuel in the cavity is consumed, acceleration would stop. This could add significant range with only a few milliseconds of burn. Neat concept, but without dragging out some books, that's all I have. Now it's time to read all six pages.
Talk about a long range flat shooting bullet.
Talk about a long range flat shooting bullet.
230RN
2A was "political" when it was first adopted.
One of the reasons there are six pages is that people do not read all five, then four, then three, then two, then one page(s) to assess antecedent concepts and therefore keep bringing up stuff that's been dealt with previously.
Pardon my frustration with this.
Let's start over with this scenario:
1. Some crackerjack at Aberdeen or Redstone wakes up one morning and says, "Gee, I wonder what would happen if we fired a hot hollow projectile so it would act as a ramjet? The heat energy for accelerating the gases flowing through it would come from the heat of the projectile itself."
2. He mentions this to three people in the think tanks at Aberdeen or Redstone who pooh-pooh the idea.
3. Eventually word about this concept gets to a superior who got to be superior because he does not automatically dismiss "way out" ideas.
4. The superior commissions a study group to investigate the notion. After all, their job is to improve and invent weaponry-related things.
5. The study group comes back with the idea that not enough is known about the dynamics of the concept to pre-assess whether it would work or not.
6. The idea is turned over to a group of hotshot engineers who begin investigating what would be necessary to determine the variables associated with the idea --in other words, "How might we make it work?"
7. Some months later they decide on a basic form for the tunnel inside the projectile. They sublet manufacture of this prototype to some local machine shops.
8. Some machinist notices the weird internal shape of the prototype projectile and wonders about it to a friend.
9. The friend brings up the subject on THR.
10. Some discussion about "what it is" ensues.
11. 230RN tries to reverse-engineer what's going on, based on the meager information available to the OP. 230RN does not claim to "know" what's going on, and admits that his theory is not the only possible explanation. However, people get stuck on two ideas: (1) such a ramjet effect would not significantly enhance the ballistic performance of the projectile, forgetting that this is a feasibility study and that any enhancement is a proof-of-concept, and (2) you need a "fuel" to do this, not seeing that "fuel" is not needed, since somehow, by thermit or some other means, we get the projectile hot enough to heat the incoming air to produce a ramjet effect, however slight.
12. Six pages on THR ensue.
13. The FBI investigates the "leak" of this information, and comes to visit 230RN at oh-dark-thirty, since it appears he knows some intimate details about this secret project, including its genesis, and forcibly wants to know "how come you know all about it?"
14. 230RN mysteriously disappears from the board.
How's that?
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GarandOwner
Member
This actually isn't true, the bullet is still heated after it leaves the barrel by the air around it, that is heated by the shock wave.
..........basically you said the same thing in these 3 "steps" except you glorified yourself in 11. by saying you also are trying to reverse engineer it.....thats what we all are doing....in 6 pages.
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230RN
2A was "political" when it was first adopted.
I'm not claiming to be the only one who can reverse engineer the problem. I'm just frustrated with the fact that when I present the idea that it is misunderstood (my fault) or objections are made based on another poster's misunderstanding or the lack of reading all posts before venturing an opinion.
Happens a lot on a lot of boards.
I'm not married to the ramjet idea anyhow.
I apologize for the "Now it's time to read all six pages" follow-on remarks. They came out a little more forcefully than I thought when I typed it. The old rule about edit twice, post once pertains. Mea culpa.
Happens a lot on a lot of boards.
I'm not married to the ramjet idea anyhow.
I apologize for the "Now it's time to read all six pages" follow-on remarks. They came out a little more forcefully than I thought when I typed it. The old rule about edit twice, post once pertains. Mea culpa.
the naked prophet
Member
And where does that thermal energy come from? That's right, it comes from the mechanical (kinetic) energy of the bullet, being slowed down by friction with the air. Converting that thermal energy back into kinetic energy is a waste - it would be better to just design a more aerodynamic bullet in the first place.
And what generates that shock wave? The shock wave and friction are the processes by which the kinetic energy of the bullet is converted to thermal energy - ie the bullet is heated up because it slows down. Trying to use that thermal energy to speed up the bullet is ridiculous.
The idea of making the inside of the hollow bullet shaped like a jet or rocket engine is feasible, so long as you have some source of heat, such as fuel (I calculated using thermite III in an earlier post on page 5).
But "spending" the kinetic energy of the bullet to create plasma, or to heat the bullet, or to heat the incoming air, in order to use that energy to accelerate the bullet, is just not possible. It would be like trying to make a more fuel-efficient car by using a gasoline engine to turn an alternator which supplies the electricity to crack water into H2/O2 for use as a fuel to generate electricity to run the electric motor.
No worries 230RN, I know the drill, all is forgiven. But the IIRC from popular science or the Scientific American, the RAMJET theory still involves some sort of fuel source, it's the plasma phase of the matter that makes things ridiculously efficient and scoops up the available gases and ionizes them to form the plasma. Plasma is not entirely simple, but it's not overly complex either. A flame, for example, is a plasma.
I think something has to be in that hole initially to keep the propellant in the cartridge and the enviroment out of the propellant. Namely moisture, which leads to corrosion and reliability degradation. Said material is some sort of secondary propellant, the "rocket" end of the bullet, right?
So, from what is described, the open nose of the projectile is simply feeding the fuel oxygen, nitrogen and other elemental gases from the atmosphere. The propellant burning time and the ramjet effect would be transitional, and as you state, milliseconds or less depending on the projectiles size.
Like the space shuttle booster rockets, those babies burn liquid oxygen. It the shape of the nozzle and rate process that controls the burn. In this case, it's the projectiles propellant, likely a solid like sodium perchlorate. And form factor, the shape of the innards of the projectile. The induction of the air into the projectile tip would force the burn to take place much more quickly, adding even more thrust.
Effectively, this sounds like a little rocket used for a bullet. You launch it with traditional powder like propellant, or whatever they use in big artillery type guns, not sure, no background here. This ignites the solid rocket fuel in said projectile and adds thrust. The open tip just helps things burn faster by providing extra oxygen to speed up the process and not entirely rely on the solid propellant alone as is the case in many rockets. This is why a flare burns under water for instance, or they can lauch missiles from a sub while it's still entirely submersed underwater. In this case, the open tip would contribute to the rate process, like a rocket on steroids.
From this statement, I can't see where they are gaining energy purely on speed, I would suspect they are creating this plasma not only from the air itself, but it's mixing with some sort of solid propellant also. Beyond that, all your standard energy arguments apply.
When we create plasma through etch and deposition processes in semiconductors, we are ionizing a gas with RF energy, making the plasma form. We use Nitrogen, Oxygen, Argon...the list goes on. The electrical bias in this case accelerates the ions (positive or negative charged atoms) towards our target at super duper high speeds and we are effectively beating the surface with these charge ions. Remember, an ion is only a charged particle in this case. Like an oxygen molecule with a plus charge rapidly attracted to a negatively charge wafer chuck with the wafer in the way. This oxygen plasma stream is likened to a bead blaster on the atomic level, but instead of being accelerated via air like a bead blaster, it's accelerated with the charge differential between the ions and and the chuck. In this case, I suspect, a solid propellant of some form or another is providing the ionization energy analogous to the electrical bias in an etching process in semiconductors, and the speed is such that there a lot of energy being contributed in that regard also. I still don't see it purely turning air into fuel and accelerating until it overheats or disintegrates
Beyond that, we are discussing MS and PhD level physics here and beyond. Even then, it's so focused on specifics we can't do much more than guess without more data about not only the projectile's form factor, but what resides in that cavity of the projectile. I really don't think that cavity is just empty. And once projectiles move into supersonic speeds, there's a different set of equations that get used regarding friction, nozzles and a minutiae of other things. Neat concept, but incredibly complex physics could be taking place. Sure, the application may seem simple, but getting there isn't. Rocket science is some pretty heavy stuff man.
I think something has to be in that hole initially to keep the propellant in the cartridge and the enviroment out of the propellant. Namely moisture, which leads to corrosion and reliability degradation. Said material is some sort of secondary propellant, the "rocket" end of the bullet, right?
So, from what is described, the open nose of the projectile is simply feeding the fuel oxygen, nitrogen and other elemental gases from the atmosphere. The propellant burning time and the ramjet effect would be transitional, and as you state, milliseconds or less depending on the projectiles size.
Like the space shuttle booster rockets, those babies burn liquid oxygen. It the shape of the nozzle and rate process that controls the burn. In this case, it's the projectiles propellant, likely a solid like sodium perchlorate. And form factor, the shape of the innards of the projectile. The induction of the air into the projectile tip would force the burn to take place much more quickly, adding even more thrust.
Effectively, this sounds like a little rocket used for a bullet. You launch it with traditional powder like propellant, or whatever they use in big artillery type guns, not sure, no background here. This ignites the solid rocket fuel in said projectile and adds thrust. The open tip just helps things burn faster by providing extra oxygen to speed up the process and not entirely rely on the solid propellant alone as is the case in many rockets. This is why a flare burns under water for instance, or they can lauch missiles from a sub while it's still entirely submersed underwater. In this case, the open tip would contribute to the rate process, like a rocket on steroids.
From this statement, I can't see where they are gaining energy purely on speed, I would suspect they are creating this plasma not only from the air itself, but it's mixing with some sort of solid propellant also. Beyond that, all your standard energy arguments apply.
When we create plasma through etch and deposition processes in semiconductors, we are ionizing a gas with RF energy, making the plasma form. We use Nitrogen, Oxygen, Argon...the list goes on. The electrical bias in this case accelerates the ions (positive or negative charged atoms) towards our target at super duper high speeds and we are effectively beating the surface with these charge ions. Remember, an ion is only a charged particle in this case. Like an oxygen molecule with a plus charge rapidly attracted to a negatively charge wafer chuck with the wafer in the way. This oxygen plasma stream is likened to a bead blaster on the atomic level, but instead of being accelerated via air like a bead blaster, it's accelerated with the charge differential between the ions and and the chuck. In this case, I suspect, a solid propellant of some form or another is providing the ionization energy analogous to the electrical bias in an etching process in semiconductors, and the speed is such that there a lot of energy being contributed in that regard also. I still don't see it purely turning air into fuel and accelerating until it overheats or disintegrates
Beyond that, we are discussing MS and PhD level physics here and beyond. Even then, it's so focused on specifics we can't do much more than guess without more data about not only the projectile's form factor, but what resides in that cavity of the projectile. I really don't think that cavity is just empty. And once projectiles move into supersonic speeds, there's a different set of equations that get used regarding friction, nozzles and a minutiae of other things. Neat concept, but incredibly complex physics could be taking place. Sure, the application may seem simple, but getting there isn't. Rocket science is some pretty heavy stuff man.
GarandOwner
Member
Clearly you didn't read my entire post or you would have seen that I said that exact same thing. What was meant by the sentence that you quoted of mine was that I THINK WHAT THE COMPANY IS TRYING TO DO is to use the thermal energy (yes created by the mechanical energy of the bullet) that would otherwise be lost to be converted back into mechanical energy (minimizing the energy lost). Im not saying it would work, Im saying I think this is their theory.
....yes thats what I said, the bullet is heated up. I did not say the bullet would speed up, just clarifying that the bullet does not cool down as soon as it leaves the barrel.
Here showing that in order to try and use this heat you would sacrifice mechanical energy (hence decreasing aerodynamic efficiency.)
Once again here I say that it wouldn't work because of the drag created by trying to get air to flow through the engine.
One of the problems with message boards is you can't convey tone, so while some response sound hostile, they might only be meant to justify ones own comments with counter points.
Ok now on the other side of the spectrum, being an engineer, I was taught to ask not why, but why not. So here are some calculations (These are the end results, most of the long calculations were done on another piece of paper) Showing that based on the original posters description of the projectile, it would in fact increase the velocity of the air that flows through it.
Before you other physics types flip out and think I am saying this will work read the following lines
I do not believe that the implied concepts would work without some sort of propellant (Which in itself would most likely cause possible stability issues) I'm not saying that I think this design would accelerate the projectile, BUT it might be possible that it decreases the deceleration by minimizing energy loss. (In this case by reducing energy lost by converting thermal energy back into mechanical energy) These calculations just show how a supersonic nozzle works. It does not PROVE that it would work in accelerating or slowing the deceleration of the projectile. It does not show the amount of drag (which would reduce more energy than would be conserved by adding the nozzle onto the projectile), and it does not show how much energy is saved from the otherwise "lost" thermal energy. It is just my representation of what I think the developer of the experimental bullet was trying to do.
My assumption is that the original concept was developed NOT as a way to accelerate the projectile, but as a way to slow the deceleration by minimizing thermal losses. While I don't think it would work, it was a good idea.
This is part of R&D, coming up with ideas, and testing them. Sometimes things that work on paper don't work in reality, and sometimes what works in reality doesn't work on paper.
For this example I used a .50 caliber bullet (The largest caliber that I could find dimensional information on) though not nearly as big as a 37mm round.
Sorry for the messy handwriting, but Im an engineer not an artist.
On a last note, I dont want to come accross as thinking I know everything. Im not perfect and make mistakes (sometimes in calculations) I am open to any comments or corrections if you think I did something wrong. (One thing about math, they dont lie
if I'm wrong, I'm wrong)Attachments
GarandOwner
Member
On more thing, my first reason for thinking this wouldnt work is: how do you fire a hollow bullet 
Officers'Wife
Member
Hi Hendrick,
Hmm, the projectile version of battery driving an electric motor attached to a generator charging the battery. Here I was expecting string theory and end up with the laws of thremodynamics. I am soooooo disappointed.
Hmm, the projectile version of battery driving an electric motor attached to a generator charging the battery. Here I was expecting string theory and end up with the laws of thremodynamics. I am soooooo disappointed.
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