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About A_Mysterious_Stranger

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  1. A_Mysterious_Stranger

    Help me understand tank suspension

    Well there's different kinds of suspension that have evolved since WW1 and they offer different tradeoffs (although some have been superseded) such as cost, simplicity/reliability, effectiveness, etc. but I also think there may be an element of semantics to it (how people define such things, which is where the sources you use and quality of that source) probably applies. Also there's going to be more issues than just 'speed' to consider in your suspension choice. For example on page 319 of Jane's: It would seem tradeoffs and design (complexity, protection, weight, internal space) are drivers over 'good' or 'bad' decisions as how it is implemented (possibly getting back to the 'semantics' again?) Speed will matter too since that affects comfort/safety/stability of the crew and vehicle vibration and such matters as Collimatrix described (the better a suspension can cancel out the bouncing/shaking of rough terrain, the faster you could in theory go.) but it's still going to be about tradeoffs in the end (including speed.) Also, the suspension itself is just part of a larger system (Wheels for example, which is also discussed in Janes) which can also play a role and probably shouldn't be ignored. Differences in engineering and metallurgy (especially over time) probably affect things too. Sorry if that isn't answering what you're specifically asking I'm trying to guess at it from your words and where in Janes you're alluding (unless you mean the Damping section?) Edit (again after many): Maybe this is what you're referring to from 13.4 in Jane's? https://imgur.com/a/Et56F
  2. A_Mysterious_Stranger

    Documents Repository: Small Arms

    It's amazing what you can find on DTIC, isn't it?
  3. A_Mysterious_Stranger

    Documents Repository: Small Arms

  4. A_Mysterious_Stranger

    Gun Science Library

  5. A_Mysterious_Stranger

    Gun Science Library

    I've noticed there is no repository for ballistic science documents the way there is for the Mechanized or the infantry forums (for example) so I decided to fix this. My first offering is dtic stuff from the past on some weird and novel ways to extend the L/D ratios of spin stabilized projectiles. I originally learned about this from someone I was having a discussion with years back and hunting lead me to one of those discussions about bringing back the battleships on navweaps discussion boards where one of the posters (Zenmastur) laid out his master plan for Battleship resurrection. Which included the aforementioned 'higher than 6:1 L/D ratio spin stabilized projectiles'. It took awhile to hunt down but I eventually found some of the original documents that focused on novel projectile shapes (for a large improvement) and non-conical boat tails (for a much smaller improvement) Obviously this went nowhere insofar as I am aware, and I suspect they had drawbacks nobody addressed (like most do) but it's an interesting thing to look at anyhow. Much of this is the work of one Anders S. Platou, who seems to be as prolific as the RAVEN guy. AN IMPROVED PROJECTILE BOATTAIL AN IMPROVED PROJECTILE BOATTAIL. PART II. Improving the Flight Performance of Projectiles MUZZLE-BLAST-INDUCED TRAJECTORY PERTURBATION OF NONCONICAL AND CONICAL BOATTAIL PROJECTILES THE EFFECT OF VARIOUS BOATTAIL SHAPES ON BASE PRESSURE AND OTHER AERODYNAMIC CHARACTERISTICS OF A 7-CALIBER LONG BODY OF REVOLUTION AT M = 1.70 YAWSONDE FLIGHTS OF 155MM NON-CONICAL BOATTAIL PROJECTILES AND THE 155MM M549 PROJECTILE AT TONOPAH TEST RANGE-OCTOBER 1977 YAWSONDE FLIGHTS OF 155MM NON-CONICAL BOATTAIL PROJECTILE-B CONFIGURATIONS AT TONOPAH TEST RANGE--MARCH 1978 AEROBALLISTICS OF 9ORKSCRE1 PROJECTILES (12 page document) AEROBALLISTICS OF CORKSCREW PROJECTILES (36 page document)
  6. Wow those are a gold-mine of info and not just for the tungsten carbide stuff either (there's tons there too, like penetrator images, the implied cost savings, etc.) There's also stuff in their about the dual-purpose grenades and body armor and a different (interim?) lightweight case. From the FY2018 brochure Ramlaen posted: tungsten carbide penetrator: https://imgur.com/a/mXmcY Light weight casings (10% only) https://imgur.com/a/9hE43 I'm guessing the FY2016 link is the 'before' image (with a penny for scale) and the FY2018 image is the finished product (which resemble the EPR arrowheads) I wonder if it would be possible to derive anything about the proposed round from this?
  7. So just sharing a bunch of aforementioned links that may be of interest: First batch are a series of technical reports about a Knox Engineering company cartridge design for lightweight 5.56 NATO centering around 'enhanced propellant' and 'alternative cartridge case' (basically a straight-walled design): ENHANCED PROPELLANT AND ALTERNATIVE CARTRIDGE CASE DESIGNS DEVELOPMENT OF A LIGHTWEIGHT AMMUNITION CONCEPT USING AN ALTERNATIVE CASE MATERIAL AND ENHANCED PROPELLANT They're very similar but many of the ideas seem to overlap with what we know so may be of interest even if they are over a decade old. ... Component Technology Investigations for Light Machine Gun Applications - 2005 NDIA presentation on LMG technology concerning lighter barrels and various catridge concepts (including the Knox one above, and aluminum cases.) ... Lightweight Small Arms Technologies (Formerly known as…Lightweight Machine Gun and Ammunition) - 2005 presentation on LSAT for NDIA concerning machine guns. Like alot of it more than a decade old, but the details are interesting all the same I think as far as internals and tradeoffs go. ... ALTERNATIVE CARTRIDGE CASE MATERIAL AND DESIGN This one is more about polymer case designs and the challenges. more than a decade old but may still be of interest again. ... A new machine gun - the right weapon for today's environment A General Dynamics 2012 presentation on Machine gun improvements and design and seems focused on the LWMMG concept. Warning includes at least one mention of 'Tactical Overmatch' ... LIGHTWEIGHT AMMUNITION DESIGN - 8550 - 2009 presentation by Colt on a 'hybrid' cased/caseless 'modular' design and a polymer spiral case for .50 BMG ammunition. Interesting for the 'modular' design being a 'caseless' cartridge inside a brass case with two giant holes cut in the side. ... SHOULD THE U.S. ARMY ADOPT NEW 5.56MM AMMUNITION CARTRIDGE DESIGNS TO REDUCE OVERALL AMMUNITION WEIGHT? Found this in with what I was digging through, decided to keep it anyhow since it is something Sturgeon has interest in, although he may have already seen/read it. Does cover some of the concepts mentioned above though as well (the colt modular concept, as well as aluminum, steel, polymer, telescoped, etc.)
  8. Sorry for the delay, I was digging for info after reading the replies. As usual I end up with more than needed because I find new stuff that distracts me* I think you're right on the gun pressures but I haven't bothered checking lately. I find this interesting too given that a few weeks back on TFB there was a mention of the army Looking into combustible cartridges for small arms - whether the SBIR produces anything or not it's still an interesting coincidence, especially given Sturgeon's comments below. You've got me interested, but my own mind draws a blank. Could I persuade you to elaborate? Oops, you're right. My bad. That actually sounds like a big deal if they can pull it off. With the previously mentioned insulating qualities of CT ammo you have quite a few options for propellant (something closer to tank propellant impetus for example? I think 'specific impetus' or 'force constant' are the correct terms.) and helps explain CT requiring less propellant than modern ammo (or improve performance for the same amount of propellant.) Do you know if the Carbine uses the same internal mechanisms as the light machine gun? I can recall seeing a few different ideas for CT feeding and I know Textron had a particular one it went for. You've mentioned Minisi and the Magnum round before on TFB so I can see the correlation and association with others like DocGKR. Newill is a new name but a search did turn up a few possibly interesting things like a design on small caliber ammo ballistics and a magazine article on small arms ammo design. Unless it allows fire on the move won't that impede mobility (further) and add more weight? It's also interesting given mention of the third arm project: https://www.army.mil/article/201229/army_researchers_advance_third_arm_project_to_next_testing_phase A device to allow troops to carry heavy guns and 20 lbs shields matches what the Army has been hinting at. But also makes it sound like they're partly/totally abandoning mobility in favor of range and firepower. In other news I see another update on TFB about the NGSAR with more info: http://www.thefirearmblog.com/blog/2018/03/05/us-army-calls-next-generation-squad-automatic-rifle-prototypes/ The interesting bits from the Product Opportuinty Notice as posted on TFB: That sounds like to me they are emulating the Marine's ideas with the M27, but also aren't that attached to obscene 1200m ranges either. On the other hand, didn't they try to make one rifle do everything with the M14 before? I also turned up this NDIA (I think it's the one referenced in TFB update) https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2017/armament/Beal.pdf * I'm not kidding. I actually 'rediscovered' a bunch of links I'd lost whilst digging and ended up with a ton of stuff that is only slightly relevant. I'll post it after this on the off chance it might be of interest, but if not then it can be more easily split off where it belongs if it doesn't belong here (apologies if it doesn't)
  9. http://www.dtic.mil/dtic/tr/fulltext/u2/a007151.pdf This is one of those things you always find when you do diving into DTIC or some other site for unrelated purposes but is still interesting - a 1975 study on extending ranges of US artillery. It's one of those interesting reads because it highlights cold war era thinking. Whether it has merit today or more than historical interest I'll leave up to others. It does have some really interesting charts though (like the velocity/momentum a artillery round needed for a given range)
  10. A_Mysterious_Stranger

    RAVEN guns; a technology that's worth watching

    So I had a bunch more links on RAVEN, these don't seem to have been posted, so I'm posting them. Dr Eric Kathe is a prolific guy: http://www.dtic.mil/dtic/tr/fulltext/u2/a435128.pdf <- this one is a 317 page thesis by Dr Kathe on RAVEN in relation to other recoilless concepts http://www.dtic.mil/get-tr-doc/pdf?AD=ADA398942 <- pdf download if you click on the link. Google cache link here:http://webcache.googleusercontent.com/search?q=cache:6eBVulAzScsJ:www.dtic.mil/get-tr-doc/pdf%3FAD%3DADA398942+&cd=5&hl=en&ct=clnk&gl=us It's another technical paper by Dr Kathe in the same vein as the above, but with fewer pages. https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2015/armament/wedKathe.pdf < - powerpoint along the lines of what you posted a few years back, but with some other differences (I think) which analyzed alternatives https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2015/armament/MondayKathe_Tutorial.pdf <- another powerpoint. With the monday/wednesday thing I think it wsa part of a larger seminar in 2015. you posted one of those originally (the Tuesday one) Some technical reports on RAVEN and the tech demonstrator http://www.dtic.mil/dtic/tr/fulltext/u2/a597442.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a591200.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a504316.pdf And another powerpoint: https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2010/armament/WednesdayLandmarkAMikeBixler.pdf I'm also fascinated by RAVEN and it has many nifty implications regarding 'light weight without losing performance' as far as recoilless technologies go. One was for improving man portable firepower (mentioned in the first pdf Collimatrix posted in the original post.
  11. Don't think this was posted yet. Not sure how much I believe since Task and Purpose seems to be the SOLE source and they seem to be mixing up details of ARs and SAWs, but still it's been showing up on alot of places: https://taskandpurpose.com/army-next-generation-squad-weapon/ 60-80 ksi vs 45 ksi sounds like quite an improvement but can be deceptive without knowing other variables like the chamber volume, and even some rough guesses suggest something that would be excessive for even a full power round, much less intermediate ones. Sounds kinda hype-y to me. That wasn't all either: That sounds odd. Are they suggesting we're going to be getting yet another new round? Which sounds like they're doing an oversized SCHV, a small bullet with a shit-ton of powder behind it for higher velocity. Except that also means more powder adding to the recoil among other drawbacks, I think? Maybe that's another reason for the tank analogy, given that KE rounds I believe tend to rely on a large propellant load comparable in mass to the projectile itself. So... smart targeting? This sounds quite heavy, and I'd worry about reliability. And proprietary? Do you really want 'proprietary' designs for widespread military use? So, yeah. I'm not sure I'd buy this without some independent verification and a huge grain of salt, but it's out there.
  12. Regarding the ADVAP stuff we've discovered (open tip EPR, tungsten carbide core) this may/may not be interesting given it's mostly speculation. A round known as the Athena/Anthena PPI which came in 7.62 and .50 caliber. I don't think anyone has posted about this before, but if I am repeating known information my apologies. powerpoint document: http://www.powershow.com/view1/1f1478-ZDc1Z/NDIA_powerpoint_ppt_presentation PDFs on the rounds from small arms review: .50 caliber: https://www.smallarmsreview.com/archive/detail.arc.entry.cfm?arcid=12779 7.62mm: https://www.smallarmsreview.com/archive/detail.arc.entry.cfm?arcid=12778 There are images on the internet (especially on cartridgecollectors if you search for 'Anthena PPI') but since photobucket decided to fuck over the internet there are alot fewer to be found. Like the DU APDS stuff that is sometimes floating around and there is alot less of too. Anyhow, whilst open tip AP rounds aren't a new thing PPI rounds are a more recent version I can recall and it may have some relevance to any 'improvements' ADVAP may provide (EPR construction is similar to PPI, and I'd bet the ADVAP core is heavier than in M993.) Just my 2 cents and take it as you will.
  13. A_Mysterious_Stranger

    Non-initiating Precursor Shaped Charges

    Hi I know this is months out of date so apologies if this is redundant but these may or may not help you: A Brief History of Shaped Charges MODELING AND SIMULATION OF SHAPED CHARGES This second one includes text from the first link as far as explaining shaped charges but it also explainsWHY shaped charges with liners are called 'cumulative.' For example: Assuming I am correctly interpreting the data the difference is the presence or absence of a liner and how that affects shaped charge behavior. That said I may be wrong: How to pierce tank armor. Lavrentiev’s theory of shaped explosive Setting aside the fact the document uses wikipedia as a source, this alternate interpretation assigns 'cumulative' to the Munroe effect (which I think is independent of a liner). In that case 'cumulative' vs 'non-cumulative' may mean focused vs non focused explosive (which isn't a 'jet' so much as a normal HE detonation. Go figure.)