Talk:Electrothermal-chemical technology

Muzzle energy versus accuracy improvements

I know ETC technology is primarily researched for improvements in muzzle velocity, but the reduction in projectile exit time variability also improves accuracy. Increasing the muzzle velocity is a bit tricky, but ETC guns without MV improvements still have the improved accuracy. Unfortunately, I don't still have the link to an article about a built and tested ETC gun with improved accuracy and not MV, but reduced projectile exit time variability is well documented. Ergbert 02:26, 4 November 2006 (UTC)

Every source I have, including those that I used to write this article, state that the primary consideration in ETC technology is to increase muzzle velocity given that increase in accuracy is not only due to the use of ETC. All "official" testing that I know of have increased both muzzle energy and muzzle velocity. Given that the majority of sources, including various articles in Armor Magazine, Military Technology, Armed Forces Journal, Armada International and Janes say that the principle reason ETC is used is to increase muzzle velocity/energy I believe that this should be the purpose of the article, not accuracy. JonCatalan 02:44, 4 November 2006 (UTC)

Furthermore, there has been no serious effort to date to test ETC with liquid propellants, therefore for the time being it should be solid propellants since that is the mainconsideration. JonCatalan 02:46, 4 November 2006 (UTC)

I know the driving reason behind ETC R&D is an increase in MV, but that is only effected with great power input, while the improvement in accuracy is, I believe, immediate. I recently read a paper with some information regarding the difficulties in achieving significant boosts in muzzle velocity solely by using ETC technology, but considering how many papers I have, finding it again could take a while...I just remembered the article I mentioned previously referred to a reduction in ignition jitter as the cause for the improved accuracy, but searching for that phrase on Google does not provide the article in question. I'll get back to you if I dig up anything.

IIRC, Ogorkiewicz's Technology of Tanks actually only mentions LP ETC technology, so I think the early research probably focused on that, although it is true that most recent research seems to be focused on SP. Ergbert 03:59, 4 November 2006 (UTC)

Okay, I was partly wrong in the first sentence of that reply. The first paper I found was Experimental and Modeling Studies of Plasma Injection by an Electrothermal Igniter into a Solid Propellant Gun Charge by Michael J. Nusca and Stephen L. Howard, which says in the summary "the ignition delay is lengthened, even to the point of a non-ignition event, when the current that is input to the ablation capillary is reduced". This paper also mentions accuracy as a reason for ETC technology in the introduction. Ergbert 04:08, 4 November 2006 (UTC)

Well, not necessarily. You don't need a great power input. The idea is that the plasma will regulate the expansion of the solid propellant after ignition, meaning it will expand much more smoothly. That's what the entire technology does, therefore an increase in muzzle velocity/muzzle energy is inherent within the design! You cannot increase accuracy through the design without increasing muzzle energy given that increasing accuracy requires a much smoother expansion of the propellant and a much smoother release of the penetrator, which will increase muzzle energy simply because it will receive more pressure from a better expanding propellant! As for that PDF. Thanks for linking it! I have a problem with the introduction. It states future engagements require 'improved range and accuracy'. It has been proven already that APFSDS, even with some sort of ramjet propulsion, will not necessarily be able to engage at ranges greater than 4-8kms; AFAIK, ramjet propulsion for APFSDS is being researched to keep high velocities for a longer period of time, increasing penetration at ranges between 2-3kms. On the other hand, accuracy seems like a handy side effect of ETC technology since inherently accuracy will improve along with muzzle energy given how the design works. But that's just a nitpick. I think we can agree on dropping the 'potentially' on either case. JonCatalan 17:36, 4 November 2006 (UTC)

Yeah, the intro to that paper isn't perfect, but the MV increase w/great power input & accuracy improvement w/low power input are backed up by other papers, too, such as Spectroscopic Measurements During an Electrothermal Plasma-JA2 Solid Propellant Interaction by Michael D. Ryan, Noel T. Clemens, and Philip L. Varghese (from the introduction: "The original objective of plasma ignition was to increase muzzle velocity over conventional ignition. However, without a prohibitively large plasma energy input, it has been shown that the only way to increase muzzle velocity is for the plasma to increase the burn rate of the propellant. Unexpected benefits of plasma ignition were a reduction in ignition delay and delay jitter over conventional ignition as well as temperature compensation for the propellant. These benefits increase gun accuracy over a range of environmental conditions."). I have to go now, but I'll keep looking later. Ergbert 22:20, 4 November 2006 (UTC)

I can't get that paper because I have to go through AIAA, and I don't normally buy from them, but it seems strange. From what I've read the act of burning the propellant much more smoothly will increase muzzle velocity alone; all the sources I have infer that the increase in muzzle velocity is inherent in the design because of that fact. In fact, a quicker ignition, a reduction of ignition jitter and the reduction of temperature sensitivity should all do its part in increasing muzzle energy. Of course, the change in propellant in the DM63, from the DM53, is what we can attribute a slightly higher muzzle velocity from a L/44, I would think - at least, in cases were temperature would make a difference. I'm sure that it increases gun accuracy, but it all seems that it would attribute to an increase in muzzle energy, as well. JonCatalan 18:26, 5 November 2006 (UTC)

The paper I mentioned is included in the file available through here (There's lots of neat stuff at http://stinet.dtic.mil!) on pages 27-37. I'm not saying there's no increase in MV with low power input, but as I understand it it's very small. I could be wrong, though; if you could share any of your sources, that'd be great. Ergbert 00:44, 6 November 2006 (UTC)

The paper I was thinking of earlier may have been Optical Measurements of the Interaction Between Electrothermal-Plasmas and Solid Propellants, on pages 17-26 of that file. From its introduction: "Early studies did find increased muzzle velocities, although the ~5% increase was lower than expected. However, these and other tests discovered additional benefits from plasma ignition in the form of reduced ignition delay and jitter as well as temperature compesnation of the propellant.". Ergbert 00:55, 6 November 2006 (UTC)

I uploaded the principle paper used for this to my server for a limited amount of time (the file is fairly large and I run a forum, and it's not exactly legal either ;). You can find it through this link: http://pdfdirectory.modernwarstudies.net/pdf/Electro%20Thermal%20Chemical%20Gun%20Technology%20Study.pdf Unfortunately, all the other sources I used I have on paper and not in pdf form. However, I'll be glad to send you future sources when as they come - if they are in pdf form. JonCatalan 15:45, 7 November 2006 (UTC)

Ok, thanks. :) Ergbert 16:15, 7 November 2006 (UTC)

Gun Comparison Chart

Can somebody double check those numbers? My number for mass for the DM63 has to be wrong; I got it through the KE equation, assuming a KE of 9 MJ for the penetrator, and 12 MJ for the entire round. I would appreciate it, thanks. JonCatalan 18:32, 4 November 2006 (UTC)

But as I understand it the 12 MJ of the M829A3 is of the complete projectile too?--MWAK 12:24, 6 November 2006 (UTC)

It's most probable that this is the case. My information is based off this site which says it accelerates a 10kg projectile at a velocity of 1,555m/sec. The entire cartridge weighs 22.3kg. At 10kg I get 12,000 joules. JonCatalan 15:31, 6 November 2006 (UTC)

But then the chart compares the projectile weight of the M829A3 with the penetrator weight of the DM63, which is rather confusing.--MWAK 17:33, 6 November 2006 (UTC)

No, the projectile weight of the M289A3 is said to be 10kg on that site, while the entire projectile weighs 22.3kg. My weight for the DM63 is based off 12MJ for the entire projectile, and 9MJ for the projectile - the difference in mass might be because dU is denser than the tungsten alloy used in newer German ammunition, although I'm not completely sure. Hopes this clears things up. Regards. JonCatalan 20:31, 6 November 2006 (UTC)

I now see the point of confusion. I'm using projectile weight for everything; I should have been more careful. 10kg refers to penetrator weight. JonCatalan 20:31, 6 November 2006 (UTC)

The M829A3 has a 22.3kg complete cartridge and a 10kg projectile. I think the actual penetrator is 6-7kg, but ATK doesn't say. Ergbert 00:23, 7 November 2006 (UTC)

I dropped a message at TankNet, but nobody has responded yet. JonCatalan 15:41, 7 November 2006 (UTC)

The muzzle velocity for the DM 63 from the 120mm L55 is "over 1,750 m/s" according to Rheinmetall. Ergbert 03:26, 9 November 2006 (UTC)

Muzzle Velocity to KE

Wouldn't it be exponentially given that the relationship is the square of the muzzle velocity? JonCatalan 19:09, 5 November 2006 (UTC)

No, exponential functions are of the form c^x, with c being the constant and x the variable. The quadratic function is of the form x^c — with the constant in this case of course having the value 2. It's a polynomial. For some reason people never speak about polynomial ratios ;o)--MWAK 12:16, 6 November 2006 (UTC)

Style Question

I've know I've seen it in many locations, including some books I deeply respect, but I'm wondering if the "lead the chapter/section with a quote" style is all that appropriate for Wikipedia. I can't recall any other article using it, including any of the links in the first paragraph. My own personal feeling is that while fine for general non-fiction use, the leading quote is not appropriate for a reference work like an encyclopedia, because it lacks nessassary context and analysis. That said, I'm unaware of any prohibition in the Manual of Style as to its use. -- 15:26, 7 November 2006 (UTC)

The leading quote idea is taken from the T-34 article, which received featured article status, so I don't think there is any problem with it. The leading quote is within the context of itself, to be honest. The context of the article the quote is taken from is the same context of this article; future gun technology - it simply states that solid propellants are no longer the most effective medium of gun propulsion for the future threat, given that the ability to expand on a solid propellant gun is limited and doesn't yield the dramatic increase in muzzle energy, as explained by this article. JonCatalan 15:40, 7 November 2006 (UTC)

Thoughts on the Summary

The first part of this article, above the list of contents, describes: what ETC is supposed to do, how promising the results are, who's going to be using it in the near future, where it's being researched, and what some of the alternatives are. What it does not do, however, is to say what ETC *is*.

If there were a single sentence saying, perhaps, "ETC is a technology in which electrically-produced plasma is used to moderate the rate of combustion of propellants in a gun", it would be more useful than everything that is currently there. I'm not confident enough that I understand it to be willing to insert this myself, however - the article even mentions 'eliminating the necessity for an outside electrical source', which I can't reconcile with my understanding of the concept.

The lack of basic encyclopedic content and abundance of, to put it bluntly, hype in the article was enough to make me suspect it as a hoax. An attempt by some company to boost their stock price by promoting their technobabble, perhaps. It wasn't until I searched for other sources on the net that I grew fairly confident that the subject of this article actually exists. —Preceding unsigned comment added by 144.136.186.48 (talk • contribs) 06:17, Nov 17, 2006 (UTC)

I will try to edit the article, now that I have access to MUCH more information, and make it more encyclopedic - first thing is first; I must get rid of the quotes. JonCatalan 01:08, 13 March 2007 (UTC)

Worldview Issues

This article seems to be lacking in worldview, its written almost entirely from a NATO perspective.

I have found no information on the development of similar weapons in Russia or the Ukraine, and although there were rumors that the Merkava IV was to mount a 135mm ETC gun, these rumors turned out to be false and there's no information that I have on the Israeli ETC program. In any case, it should be noted that ETC technology was developed by NATO, and IMO solely by NATO, until recently. JonCatalan (talk) 00:58, 28 May 2008 (UTC)

In the dim and distant past I have met Israeli scientists working on ETC gun technology. I would expect that the Russian and Chinese authorities will have looked into it too. The basis ideas are very simple - getting it to work well enough to be useful under battefield conditions may be the ongoing challenge. — Preceding unsigned comment added by Knobeeoldben (talk • contribs) 10:04, 11 October 2014 (UTC)

Muzzle energy comparison chart

why there's no 140mm gun for comparison? manufacturer estimates a muzzle energy of 14 MJ (pdf). With a guessed penetrator weight of about 7 Kg the muzzle velocity is about 2000m/s -84.57.154.108 (talk) 23:35, 26 February 2008 (UTC)

There's no use guessing penetrator weight, which is the issue. JonCatalan (talk) 00:59, 28 May 2008 (UTC)

Possibility as a hand held weapon?

Is it feasible that the ETC technology could be put foreword into infantry weapons? In the article I could only find references to tank, artillery etc. guns. Is there some major disadvantage to using ETC for a rifle or pistol, such as the plasma cartridge taking up so much room that only a 15 round magazine would work? Thanks 213.78.183.91 (talk) 18:07, 2 March 2008 (UTC)

well, the problem would be the same as in every energy weapon: the weight of the energy source -84.57.170.25 (talk) 11:43, 11 May 2008 (UTC)

Question on hyphenation

Which is better, electothermal-chemical, electro-thermal chemical, or electro-thermal-chemical?

Keith Galveston (talk) 13:08, 29 June 2008 (UTC)

In the majority of my papers(especially ones published more recently) it's refered to as electrothermal-chemical. JonCatalán (talk) 12:56, 30 June 2008 (UTC)

I've followed that line and made two changes in the leading section. Keith Galveston (talk) 08:43, 17 July 2008 (UTC)

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