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Gripen287

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  1. Recognizing that our Sioux Scouts are expected to operate in the diverse environments of the Dakota Union, the engineers at our Rapid City munitions plant have developed a new cartridge to aid the Scouts in carrying out their duties. That cartridge is the .246 “Sweet Pea.” We believe that Scouts of today and tomorrow will put this cartridge to good use in the granite hills, wooded valleys, expansive prairie, and increasingly vibrant and prosperous towns of the Dakota Union. While some Scouts may judge its performance at 600 yards as merely being adequate, Scouts skilled in the arts of stalking and evasion will appreciate the Sweet Pea’s light weight, energy at closer ranges, extremely flat trajectory to 300 yards, and outstanding terminal performance on targets both large and small. A partially-exposed, steel “arrowhead” penetrator conveys an intimidating appearance that hints at the devastating wounds the bullet is capable of, particularly at closer ranges. It is true that the Sweet Pea’s meplat may be larger than that of some its target-shooting oriented contemporaries, but the Sweet Pea’s wider meplat aids in penetrating into the target rather than merely glancing off it when striking at an oblique angle. Stress relief channels pressed and cut into the bullet’s bearing surface help ensure long barrel life despite the Sweet Pea’s deep penetrating steel core. The middle channel also promotes generation of larger, deeper penetrating jacket fragments in tissue. Even though the Sweet Pea is optimized to end fights quickly and humanely kill game at the ranges our Scouts find themselves having to use their rifles most often, the Sweet Pea’s relatively long ogive and aerodynamic boat tail ensure that our Scouts will not have to shy away from taking shots out to 600 yards and beyond. Official magazine capacity is 22 rounds, although enterprising Scouts have been known to find room for 23. Moreover, even actuaries far from the frontier can take comfort in the Sweet Pea’s economy. At a mere 5.70 cents per round, the introductory 88 grain “ball” round is largely constructed from mild steel components, save for its bullet jacket, and therefore, the Sweet Pea will not overly impede the ongoing effort to rebuild the Union’s electrical infrastructure. Furthermore, the near total elimination of lead in the Sweet Pea’s construction will eliminate the expensive and onerous precautions that the workers in our munitions plants must endure when working with this toxic substance. Our engineers are optimistic that the cartridge will be entirely free of lead if efforts to redevelop the lead-free primers of an earlier time are successful. For additional information, please consult the materials provided. We hope that you too will discover why this new cartridge truly is a “sweet pea.” .246 Sweet Pea Data Sheet .246 Sweet Pea Renders and Performance Estimates
  2. Is there a specific deadline for this competition? Progress on the .246 Sweet Pea has been good so far, but there is still room for improvement. Also, can we expect any guidance as to how the requirements will be weighed against each other?
  3. Do you like pontificating on the infantryman's load? Want to see how different gear choices affect said load? If so, check out this spreadsheet including an itemized list of "best of breed" (IMHO) gear! Download it and customize to suit your own preferred equipment. The "Configured Totals" section should auto-calculate weights and ammunition totals for your selected items, and you can copy and paste "Configured Totals" values into the light and heavy load sections for comparison. I've tried to provide a fairly comprehensive list of gear for the rifle squad and machine gun teams. A few items are notional, and those should be noted as such. I've also tried to balance both lightness and capability. I, however, mostly intend this spreadsheet to serve as an outline and handy way to calculate total values for any items you choose to add or change. While I'm sure there are a more than a few errors, this spreadsheet is merely intended as a starting point for your own explorations, and I am NOT likely to maintain this particular version. Enjoy! Infantry Packlist Spreadsheet
  4. A little off topic, and something I've tried to bring up in another thread, but before we go about haraming all belt-fed SAWs, I think there is at least one part of the belt-fed design space that could use a little more exploration, i.e., something inspired by the HK21/23, OTS-128, or Czech URZ with quick change "belt-mags." Maybe throw in a little XM248 DNA too. The HK21/23 proves that belt-fed levels of suppressive fire and a useful semi-automatic capability are not mutually exclusive if firing from a closed bolt. The HK21 also easily integrates variable-power optics (and potentially clip-on night sights with an extended rail/mount). Secret squirrel types value the HK21E for these reasons. If I were Sheikh for a day, I'd declare spare barrels haram within the rifle squad since the squad can't carry enough ammo to the point that they're required anyway. I would however retain one or two belt-fed SAWs, chambered in the standard rifle caliber, within the rifle squad. If chambered in 5.56 or 5.45, the SAW gunner probably gets two 200 round "belt-mags" for when close ambushes are likely and for covering the guys trying to throw grenades into a defensive position, but otherwise, the SAW gunner mostly fires on semi-auto from 60-100 round "belt-mags." The old "belt-mag" would retain that pesky empty link from the expended belt, and the new "belt-mag" would present the first round in feed position, so the SAW gunner can just extract the old one, retain it (or not), and insert a new one, including at night and while moving. Conceptually, the "belt-mag" is like attaching the HK21 feed mechanism and feed tray cover to each ammo box/drum and rocking the whole thing in like an AK drum. I've always been intrigued by these inverted belt feed systems, but I've never been able to find much information on the OTS-128 or URZ. There doesn't seem to be much out there on the XM248 either, apart from the Weaponsman series, a few patents, and the technical manual. Any idea why these inverted belt feed systems haven't received more attention?
  5. Upper Vortex Flap - A Versatile Surface For Highly Swept Wings While several types of leading edge devices exist for enhancing vortex lift at high angles of attack, the interesting thing about "upper vortex flaps" is that they also work well at low angles of attack. The CV variant of the X-32 had these inboard of its conventional leading edge slats to provide better low speed handling characteristics (e.g., lower AoA at approach and landing speeds) given it's initial pure delta configuration.
  6. Actually, it appears that that is the case in those two examples. I think the Borg Warner system IS described by the "incomplete" wiki figure, albeit laid out a bit differently (i.e., the balance shaft and idler gear perform the same function as the "steering input" bevel gears). The Borg Warner video is kind of confusing because it appears that the rotor of the TV motor rotates in the opposite direction of the "vectoring torque." As I understand it, the TV rotor drives a second, coaxial sun gear within the right wheel ring gear, the second sun gear driving a second carrier having planets that engage both a support member and the ring gear of the right wheel planetary gearbox. Accordingly, when the TV rotor spins CCW torque is vectored to the right wheel as depicted in the video by the CW "vectoring torque," and vice versa. The balance shaft and idler transfer and the reverse the direction of the "vectoring torque" with respect to the ring gear of the left wheel planetary gearbox. I think the clutch in the Borg Warner system is just there to improve efficiency when the propulsion motor isn't in use at all. That MUTE system is a fair bit more complicated, but it appears to work using the same, simple principle. I couldn't really tell what was going on in the YouTube video, but I did find this paper. Figure 5, reproduced below, has a diagram of a further evolution of the system depicted in the YouTube video, which seem to mostly differ in how the "superimposing electric machine" is integrated. In Figure 5, the left wheel is directly driven by the carrier in the spur gear differential, the carrier being driven by the planets depicted as hashed lines (I'll refer to these as the "primary left wheel planets") that interface with the ring gear, which driven the via the electric drive motor gear train. The spur gear differential planets represented by the solid lines (I'll call these the "primary right wheel planets") rotate with the carrier and in doing so drive the sun gear connected to the right wheel. The superimposing electric machine drives the interconnecting sun gear, and thus the primary left wheel planets and carrier) via the planets of the right-most carrier in the superimposing gear (I'll refer to these as the "secondary left wheel planets/carrier"). The planets of the left-most carrier in the superimposing gear (I'll refer to these as the "secondary right wheel planets/carrier") are connected to the secondary left wheel plants by an idling ring gear. Because (i) the primary left wheel planets only interface with the "interconnecting sun gear" and ring gear and (ii) the primary right wheel planets only interface with the right wheel sun gear (although both are carried by the carrier directly driving the left wheel), the right and left wheels can rotate at the same speed when driven by only the electric drive motor and at different speeds when torque is added/subtracted via the superimposing electric machine. Torque can be vectored to the left wheel and away from the right wheel by running the superimposing electric machine in a first direction and a vice versa by running in a second direction because the idling ring gear reverses the direction of the applied torque between the secondary left wheel planets/carrier and the secondary right wheel planets/carrier. I think/hope that makes sense. I think passenger vehicles like these systems seem to be designed for can get away with the fatigue loads that these systems will likely place on the drive shafts, as opposed to isolating wheels/sprockets via multiple differentials/clutches, because the duty cycle and loads are probably relatively light. Trying to turn a 20+ ton tracked vehicle is an entirely different proposition. I'm sure you could do it with beefy enough components, but I can see why adopting a bit more complex and sophisticated system would start to become appealing. Standby for a post and document dump covering split torque transmissions as applied to helicopters as soon as I can get around to writing it up. I think moving away from planetary reduction gear boxes could open up some interesting possibilities as far as helicopters, particularly compound helicopters, are concerned.
  7. I'm no expert, but according to wikipedia , this drawing is incomplete. Wikipedia says this is, " [a] Differential steering mechanism, either double-differential minus the clutches, or triple-differential minus the brakes. More specifically, I believe they mean a Maybach double differential with clutches to disconnect the "slowed" (i.e., not sped up) sprocket when steering torque is applied. Alternatively, the diagram could depict an "ordinary" double differential transmission, but the diagram's "epicyclic gears" are not correctly drawn as differentials, as in the transmissions depicted here or here. To depict a triple differential transmission, the steering torque is input into the steering half shafts via yet another, third differential (the diagram is missing a carrier having idler(s) between the steering half shafts) and brakes and/or clutches on the steering half shafts selectively engage and/or disengage to effect a steer. If you haven't already, you might want to revisit Coli's link. So, yes, you are correct in that the diagram does not include means for controlling the reactive torque applied to the drive input by the slowed sprocket when the steering input is driven. If the drive input and steering input were independently driven, you might be able to get away with that kind of set up for a while, maybe.... But the various multi-differential transmissions differ, more or less, in how to address the issues you have raised.
  8. It's actually being developed by a Québécois company, but close enough. That's the Mawashi Uprise exoskeleton. It was also discussed here at 3:42:30. I want me some "Ranger legs"! The whole episode is great.
  9. With these long-ogive, EPR-style bullets, how far does the shank of the penetrator extend relative to the cannelure? The steel penetrator and copper slug of M855A1 and M80A1 seem to mate up right at the cannelure for whatever reason. For M855A1 it appears that joint is slightly below the cannelure such that the neck of the cartridge reinforces that joint a bit, but it looks like that joint is slightly forward of the neck and cannelure for M80A1. Is there any sort of limit on how far forward of the neck that this joint can extend (e.g., to provide sufficient structural integrity)? Or is it just a matter of balancing the mass of the components that determines where that joint ends up?
  10. Hydrogen's energy density (about 10 MJ/L for liquid hydrogen) may be on the order of 2-4x better than the best batteries, but it's still pretty much crap compared to other gaseous and liquid fuels (diesel is about 35.8 MJ/L). And hydrogen comes with a side of severe storage headaches regardless of whether it is stored as a liquid or high pressure gas. If you have access to a power grid, water, and stuff that'll burn, and aren't that concerned with overall process efficiency, there are plenty of well-established ways of producing methanol, ethanol, methane, and various other synthetic fuels from those feed stocks. And if you count among your citizens a billionaire or two with plans to harness in-situ resource utilization for manned missions to Mars, perhaps they can figure out how to fit a synthetic methane plant (22.2 MJ/L) into a handful of shipping containers. Methanol (15.6 MJ/L) does a little worse than methane in terms of energy density but is also relatively simple to produce and, conveniently, is a liquid at room temperature that can be blended with other liquid fuels to stretch their supply. In something as volume-constrained as an AFV, as opposed to something that is more mass-constrained (like a rocket), hydrogen is a particularly poor choice. Hydrogen, however, is also a fantastic cryogenic coolant. Railgun augmenting coils and coilgun drive coils happen to like cryogenic coolants because they reduce resistive losses and/or raise the critical current and critical fields of any superconducting materials used therein. The general rule of thumb, even for HTS materials, is that useful operating temperatures max out at about 1/2 the critical temperature, except for very low field/current applications. Accordingly, liquid hydrogen at 20-ish K and supercritical hydrogen at 33-ish K are attractive coolants for HTS materials. A good setup might be to use a first stage liquid or supercritical helium cryocooler to cool the coils directly and to use cryogenic hydrogen as fuel and as a cryogenic heatsink for the first stage helium cryocooler. In any event, you're still probably talking about some sort of 120+ ton, 60 foot articulated MBT monstrosity or the worlds most expensive 120mm mortar carrier.
  11. Which seems to be exactly what BAE is doing with their "Dispensing" charge. There's barely any room for explosives anyway Things might get more interesting with larger bore rail and coil guns due to the scaling factors of the various components. This paper contemplates a 12" coilgun firing projectiles 155mm in diameter, excluding the fixed control fins. The guidance package volume fraction isn't nearly so bad.
  12. As a platoon commander, would rather have to ask company command for those attachments or ask company HQ to look after your CGs and GPMGs while you're rifle squads are on some sort of ninja mission? I'm not saying that the platoon would be 60 guys forever and always. CG rounds weight 6+ pounds each. Your'e going to need several bodies to lug a useful number around. While we're at it, why not distribute the load of a GPMG team amongst 5 guys instead of 3 and give them a DMR? Assaulting a small hamlet (e.g., 2-4 structures) after maneuvering on foot through restrictive terrain? Those 60 guys could give you two GPMGs on tripods in a support by fire position, two 15-man assault squads with 2 fireteams and a CG each, (i.e., two 15-man squads) and a 10-man squad in reserve. Battalion 81/120s or Brigade 105/155s drop smoke during the initial assault. The CGs accompanying the assault squad take out any fortified positions that could not be observed during initial reconnaissance or lay smoke if the respective assault squad needs to make a hasty retreat. IDK, I'm just an interested amateur. My interest is mostly motivated by figuring out how we might best incorporate the CGs that seem like a much better solution than whatever the current flavor of interim XYZ is that DOD wants to foist on the "light" infantry to achieve "overmatch." Additionally, I'm trying to think of ways to keep combat loads under 60 pounds or so.
  13. Fair enough, but a USMC platoon with the 13-man squads is already at 43 men. My 60-man platoon gains 17 men because of a slightly larger platoon HQ and two 5-man CG teams. Is it better to expect a 12/13-man squad to lug around a CG in addition to everything else or expect a platoon commander to employ a couple of dedicate CG/mortar teams? I arrived at the "super-platoon" solution in order to incorporate a couple of CGs without overloading the squads. And if, for example, it make sense to delete the two drone operators or one drone operator and one medic from the platoon HQ and add an assistant platoon commander to give that 22 year-old a bit of experience in the assistant role, , and maybe add a platoon staff sergeant, I'd have no objection. Precisely, so is the 60-man platoon I laid out above a super-platoon or miniaturized company?
  14. I think you're overstating the difficulty of storing a handful of extra weapons systems in a COP or gun truck and understating the difficulty of "simply" adding the manpower (and the logistics that come with it) of a weapons platoon to the company. Moreover, a weapons platoon might train together, and they might move together, but they're hardly ever going to fight together because every squad leader is going to be clamoring for support from a GPMG, CG, or mortar team. To keep the company at around 200 men, my company would have three 60-men platoons and a HQ but no weapons platoon. The weapons platoon is essentially distributed amongst the maneuver platoons. I think that has a few advantages. First, company HQ doesn't need to constantly make decisions as to which requests for weapons platoon assets get approved and which don't. Second, each platoon leader has an all-arms, all-effects combat team that should let him steamroll enemy squads, even if they're dug in. Third, I think my the maneuver squads would have a chance to develop better teamwork with the GPMG team and CG/mortar team that'll be supporting them. It's not as if they must be trained on the additional weapons systems. It's also possible that one grenadier might be certified on the CG and the other might be certified on the commando mortar (likewise wrt the gunner and assistant gunner on the CG/Mortar team). I view giving the Joes/Grunts a couple more goals to work towards as being an advantage. This stuff is small potatoes compared to requirements for artillery shells, fuel, and water. It might be a challenge to provide all of hit, but hardly insurmountable.
  15. In this scenario, is there any meaningful difference between a 12/13-man USMC squad with one SAW-equipped fire team and a 9-man Army squad with an attached 3-man MG team? The only one I can think of is that the USMC platoon commander knows that that the de facto MG teams are “his” and not toys that the company commander is passing around. IMHO, instituting a more flexible platoon organization and arms room concept would address these deficiencies way better than merely throwing gear at the squads. If I were SecDef Mattis for a day, I'd change the TO&Es such that the infantry platoons, Army and USMC, include at least a couple 5-man MG teams and at least a couple 5-man CG/Mortar teams. I like 5-man building blocks because they make it easier to go all Generation Kill and have each squad roll around the AO in a couple of humvees or together in a single 10 + 2 APC. My notional 60-man infantry platoon that might look something like this: (3) x 10-man Infantry squads including: (1) x squad leader (1) x assistant squad leader (4) x riflemen (2) x grenadiers (2) x assault gunners (2) x 5-man MG Teams including: (1) x team leader (1) x machine gunner (1) x assistant gunner (1) x ammo bearer (1) x marksman/spotter (2) x 5-man CG/Mortar Teams including: (1) x team leader (1) x CG/Mortar gunner (1) x assistant gunner (1) x ammo bearer (1) x marksman/spotter (1) x 10-man Platoon Command Section (1) x platoon commander (1) x platoon sergeant (2) x RTOs (2) x drone operators (2) x medics (2) x runners/drivers I’d give the platoon commanders and/or squad leaders a good bit of flexibility to decide how they want to organize their squads at the fireteam level. In close terrain (e.g., urban environments), they could organize each squad into two balanced 5-man fireteams with the squad leader leading one fireteam and the assistant leading the other fireteam (team leaders might be designated on an ad-hoc basis or based on experience). In more open terrain (e.g., Afghanistan), they could organize into a 5-man fireteam including both assault gunners and another 5-man fireteam including both grenadiers. The “arms room” concept would be desirable because the assault gunners and grenadiers could be equipped differently in each scenario. In the balanced fireteam scenario, each assault gunner could carry something like a Knight’s LAMG or M27 IAR and each grenadier could carry M320s on their hips. In open terrain, the assault gunners could draw a GPMG from the armory, with one assault gunner acting as the assistant gunner, and the grenadiers could similarly draw a CG or 60mm mortar from the armory. I figure the GPMG would probably be used as an LMG on a bipod and the 60mm as a “commando" mortar. On top of flexibility at the fireteam level, the platoon commander would also know that he can count on having at least a couple of MG teams and a couple CG teams to play with. Like the grenadiers, I’d give the CG teams the option of drawing CGs or 60mm mortars from the armory but employing the 60s off the tripods were possible. I'd put a couple of gunnery sergeants at company level to oversee training of the MG and CG/Mortar teams, essentially acting as respective MG and CG/Mortar platoon leaders on training evolutions.
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