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Gripen287

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Everything posted by Gripen287

  1. Some naval aviation and arresting gear resources. REVIEW OF THE CARRIER APPROACH CRITERIA FOR CARRIER-BASED AIRCRAFT PHASE I Carrier Suitability of Land-Based Aircraft The Influence of Ship Configuration on the Design of the Joint Strike Fighter CVN FLIGHT/HANGAR DECK NATOPS MANUAL Arresting Gear: Metallurgical Analysis of Arresting Gear Deck Pendant Failures Development of [Arresting Gear] Cable Materials Modern Sandvik 11R51 Alloy Datasheet Analytical Study of Aircraft Arresting Gear Cable Design Mark 7 Arresting Gear Training Manual Useful Figures:
  2. For the PBY Catalina lovers out there who are/where rich bastards with some class. Flying Yachts
  3. Have at it! How do I make a FOIA request?
  4. No it doesn’t. No F-35 model has any CAT 1A deficiencies at present. Are you surprised to learn that POGO and the media either don’t bother to differentiate CAT 1A from 1B deficiencies (the program office’s metrics) or use the Air Force’s definition of CAT 1 that is a lot broader and includes less serious deficiencies than those that represent a serious risk to the aircraft? Are you purposefully trying to conduct an impossible analysis to justify your preconceived notion that the F-35 is crap? Can you go back in time and apply today’s level of oversight and risk averseness to legacy programs? I’ve already given you more of my time than you appear to deserve. You don’t seem to have realistic expectations or a realistic frame of reference. So rather than submit a few hundred FOIA request hoping to get that nugget of releasable info that will surely, surely change your mind, I’m going to enjoy the rest of my day.
  5. So in your clearly learned opinion how would you rate the F-14? Yeah, you might say sticking TF30s in the A-model birds was a "small problem." Only something like 375 or so TF30 A models made into the sky to try and kill their crews for staring at the throttle the wrong way. Every single Super Bug that will likely ever fly has gigantic, toed-out pylons because of unanticipated store separation issues. It's not even clear if your criticism is with issues due to specific engineering decisions that are liable to occur in any new aircraft program, let alone three as with the F35s, or with the general configuration of the aircraft. To the latter possibility, why is it even useful to compare the F-35 to the F-22, Su-57, or J-20? They all have very different design criteria, different missions, and fight in different organizations. I bet you're fun discussing WWII armor too. And like, dude, Kopp was trying get F-22s for Australia. Have you noticed that APA stopped trying to stir shit up after F-22 production ended in 2012?
  6. What do you expect? What value, even if only entertainment value, do you think you've added? All you've done is trot out "arguments" from nearly a decade ago, or more, and slapped some CYA language over them lest someone hold you to the implications of advocating for those positions. Are you even aware of the rebuttals to the Kopp/Sprey drivel? I suggest you take a week or two to catch up on the Chip Burke debates/testimonials and the wealth of information and context here before getting back to us with a comparative analysis informed by a modicum of understanding of the compromises inherent in fighter aircraft design and the trajectory of air combat. Try googling "F-16 GAO." Try googling "F-15 GAO." Try googling "F-18 GAO." FYI, POGO was only established in 1981. As OSC said, I think you'll be shocked to find that agencies tasked with finding problems to justify their existence end up finding them. Oh, and don't forget to role in all the problems with legacy, podded sensors and systems that are integral to the F-35. Have fun!
  7. 10 years to get this baby ready!
  8. FEA of M855 FEA of Lightweight Ammunition Materials Cartridge Case-Chamber Interactions
  9. Space Shuttle Technical Conference, Part 1 (601 pages of Space Shuttle Development Documents) Space Shuttle Technical Conference, Part 2 (another 537 pages of Space Shuttle Development Documents)
  10. CONFIDENTIAL From: Aldo Griffin, Chief Engineer, Ammunition Development Task Force To: The Second Joint Committee For Cartridge Development, Dakota Union Cartridges and Ordnance Department March 2, 2223 Re: Progress on .237 Antidote Mk.2 In response to the Committee’s request, I am pleased to report that the Task Force is finalizing details for the Capability Production Document (CPD). I know everyone is anxious for the Mk.2 CPD so that low-rate initial production and operational testing can commence. I can assure the Committee that the Task Force is proceeding with all due urgency with respect to Operation Shangri-La. It has been a long road, but I think even ol’ Big Bore would be content with what we’ve accomplished, if not entirely satisfied with the .237/.243 caliber. I do not believe the Scouts should have too much to complain about with this one. And they may not have been wrong about Mk.1. Not only have we equaled the long-range performance of their 175 grain .308 load, as the Scouts requested, we have surpassed it. While not as inexpensive as Mk.1, Mk.2 still beats the .308 on cost, bulk, and recoil. The move to the .435 case head has paid real dividends. Not only have we increased performance, at the behest of Mr. Lewis I believe we have successfully de-risked production of the General Purpose (GP) and Armor Piercing (AP) natures. As will be reflected in the CPD, GP Mk.2 and AP Mk.2 have experienced a slight increase in weight. Prototype samples weigh slightly more than 87 grains. The GP Mk.2 projectile comprises a partially exposed 24 grain, nickel-plated, 4340 alloy penetrator sitting atop a 36 grain, 1018 alloy core. The AP Mk.2 projectile comprises a partially exposed 59 gn, nickel-plated, D7 tool steel penetrator. The Task Force has elected to dispense with the cup-and-nose architecture in favor of a more conventional reverse-drawn CuZn5 gilding metal jacket. Like the Mk.1 and Mk.2 lead-cored projectiles, the GP Mk.2 and AP Mk.2 jackets include an integral rotating band to reduce barrel wear resulting from the full-length steel components. The Long Range (LR) Mk.2 projectile has experienced a slight reduction in weight to bring the boat tail length back to that of the GP Mk.2 and AP Mk.2 projectiles at one caliber. Prototype samples weigh approximately 101.5 grains. The LR Mk.2 projectile comprises a 4 grain, nickel-plated, 4340 alloy tip and a 68 grain Pb97Sb3 core. The LR Mk.2 jacket is pure copper to maximize sectional density and includes an integral rotating band. Performance of all three natures is outstanding. All three retain the .618 i7 form factor and outer mold line that was so successful during Phase 2 trials. The G7 GP Mk.2 and AP Mk.2 BCs are .342, and the G7 LR Mk.2 BC is .397. The slight decrease in BC for LR Mk.2, at least as predicted using the Task Force’s sub-standard equipment, is more than made up for by the significant increase in velocity provided by the .435 case head. The newly developed .435 - 1.85 inch, lacquer-coated, steel cartridge case is loaded with 36.1 grains of propellant irrespective of projectile nature. The .435 case provides GP Mk.2 and AP Mk.2 with a muzzle velocity of 3185 ft/s and a muzzle energy of 1966 ft-lbs when fired from a 22 inch barrel. The .435 case provides LR Mk.2 with a muzzle velocity of 2980 ft/s and a muzzle energy of 2001 ft-lbs when fired from a 22 inch barrel. The increase in velocity provided by the approximately 10 grain increase in propellant charge weight substantially increases down-range performance. A drop of 96” occurs at 800 yards and 775 yards for GP/AP Mk.2 and LR Mk.2, respectively. A drift of 36” occurs at 900 yards and 950 yards for GP/AP Mk.2 and LR Mk.2, respectively. Down-range energy reaches 700 ft-lbs at 1025 yards and 1175 yards for GP/AP Mk.2 and LR Mk.2, respectively. Additionally, GP Mk.2 and AP Mk.2 meet the 12” pine penetration requirement out to approximately 1400 yards at predicted muzzle velocity and approximately 1250 yds at 200 ft/s under predicted muzzle velocity. Most impressive of all, LR Mk.2 achieves 12” penetration at over 1500 yards, predicted muzzle velocity and 1500 yards, -200 ft/s. Recoil remains mild at 5.8 ft-lbs and 6.6 ft-lbs for GP/AP Mk.2 and LR Mk.2, respectively. Senator Brown’s predicted FY23 budget should be able to accommodate the modest increases in material cost, which is mostly attributed to the increase in propellant. Respective cartridge material costs for GP Mk.2, AP Mk.2, and LR Mk.2 are approximately 5.52 cents, 6.65 cents, and 6.317 cents. Respective cartridge weights for GP Mk.2, AP Mk.2, and LR Mk.2 are 15 grams, 15 grams, and 16.17 grams. Despite the modest increases in cost, bulk, and weight, the Task Force’s testing demonstrates that all three natures of .237 Antidote Mk.2 provide an as of yet unrivaled level of efficiency and performance. The Task Force is confident that .237 Antidote Mk.2 is the right choice given the terrain, temperatures, winds, and long sight lines that the Scouts and our new force of Rangers are likely to encounter in Operation Shangri-La. Moreover, Mk.2 will meet the Ranger’s call for a 30-round magazine for the new semi-auto having a stack height of less than 7” (Mk.2 30-round stack height is 6.74”). The Committee can expect the finalized CPD within the month. The Task Force looks forward to the Committee's decision, and hopes to bring this successful Engineering and Manufacturing Development Phase to an end while spooling up the Production and Deployment Phase along with Mr. Lewis and Rapid City Union Ammunition Plant. Regards, Aldo .237 Antidote Mk.2 Engineering and Manufacturing Development Phase Data IMAGES PERFORMANCE CONFIDENTIAL
  11. From the age of slide rules: INVESTIGATION OF THE DRAG OF VARIOUS AXIALLY SYMMETRIC NOSE SHAPES OF FINENESS RATIO 3 FOR MACH NUMBERS FROM 1.24 TO 7.4 TRANSONIC DRAG MEASUREMENTS OF EIGHT BODY -NOSE SHAPES BODIES OF REVOLUTION HAVING MINIMUM DRAG AT HIGH SUPERSONIC AIRSPEEDS
  12. General Purpose and AP Cartridges "Copperhead" Cartridge Heavy Lead Core Cartridge Comparisons
  13. SECRETARIAL DRAFT DO NOT SUBMIT From: Chayton Jones, Lead Engineer To: Arthur Q. Lewis, Director of Production at Rapid City Union Ammunition Plant Sequestered away in the heart of the Black Hill with a copious supply of peyote, Through diligent effort over the last few weeks, my team has completed work on our entry for the Scout’s new cartridge. We believe Senator Brown and his committee will find it entirely acceptable. We call the new cartridge the .237 Antidote because it will cure all, or nearly all, of my team’s the Scouts’ troubles. We further believe that you will find the 103.2 grain loading in line with your requirements for a .260 projectile or greater. While our projectile is merely .237 in nominal diameter, and .243 in diameter at the rotating band, the 103.2 projectile and its .320 G7 ballistic coefficient approximates the performance of a low-drag, 140 grain .264 projectile. Even firing this impressive projectile, the magazines for the new semi-auto will surely fit 24 cartridges owing to the .40” rim diameter. The material costs for the 103.2 grain projectile and the loaded brass-cased cartridge are 0.95 and 5.50 cents respectively. In addition to the 103.2 grain loading, we have taken it upon ourselves acceded to the demands of the wretched accountants and developed a 85.8 grain general purpose (GP) projectile, a 85.8 grain armor piercing (AP) projectile, and a 86.5 grain expanding copper-jacketed, or “Copperhead,” projectile (CH). The 85.8 and 86.5 grain projectiles have G7 BCs of .266 and .268 and muzzle velocities of 2917 and 2905 ft/sec, respectively. For field use, my team considers these three cartridges ballistically equivalent. All natures of the new .237 projectiles are characterized by a projectile overall length of six calibers, a 3.33 caliber nose, a .243 rotating band, and a one caliber boat tail set at seven degrees. My team finds that the nominal .237 projectile diameter provides good external ballistic performance while retaining the internal ballistic performance of larger .243 projectiles. The .237 projectiles also provide slightly increased usable case capacity and lower projectile weight compared to a six-caliber .243 projectile at 2.8” COAL (without resorting to excessive internal cavities or exotic materials). Since the rotating band engages the rifling, the bearing surface merely rides along the lands. Therefore, the projectile can be kept stable within the bore, wear on the lands can be kept to a minimum, and the bearing surface/coating can possess high hardness. Apart from employing a rotating band, my team’s second great innovation is forsaking the cult of von Kármán foregoing the use of a von Kármán ogive in favor of a three-quarter power series ogive. While the von Kármán ogive is indeed very efficient in the transonic and low supersonic range of free-stream velocities, the most critical phases of flight with respect to this projectile, and modern small arms projectiles in general, occur above Mach 1.8-2.0. Above Mach 1.5 the L-D Haack/von Kármán ogive begins to lose out relative to ogives in the power series (for flight bodies having an L/D of 3). Long hours spent conjuring the spirits of the immortal aerodynamicists delving into dust covered NACA reports (e.g., Perkins et al., Report No. 1386)confirm that the three-quarter power curve, aka the one form to rule them all hypersonic optimum form, is an excellent form in at least the Mach 1.8-3.0 range. The three-quarter power curve approximates a von Kármán ogive near the meplat interface and transitions into an extremely shallow, nearly conical parabolic section at the bearing surface interface. Past research demonstrates that this form is nearly as efficient as a von Kármán ogive in the transonic flight regime and becomes increasingly more efficient as free stream velocity increases through the mid to high supersonic and low hypersonic regimes. Employing the three-quarter power curve will provide the .237 Antidote with the highest possible efficiency within 600 yards, where the .237 Antidote GP, AP, and CH projectiles are above Mach 1.7. In addition to the aforementioned innovations, the GP, AP, and CH projectiles utilize a new architecture comprising a low-carbon steel cup and a copper nose that is pressed into said cup. The half-caliber copper rotating band is also pressed onto the steel cup. Accordingly, it should prove relatively easily to switch production amongst these three projectile natures utilizing the same production lines. With the appropriate dies, it is likely that the copper noses can be economically produced via impact extrusion and drawing operations utilizing existing equipment. Producing the steel cups via impact extrusion, drawing, metal-injection molding, and/or milling is under investigation. Steels in the 1010, 1018, or 1020 ranges are candidate materials for the cups depending on the method of manufacturing ultimately chosen. The GP projectiles possess a 4340 steel penetrator, and the armor piercing projectiles possess a D7 tool steel penetrator. In soft tissue the penetrators will fracture the nose and provide divergent wound tracks that should rapidly incapacitate small-statured foes targets. The CH projectile includes a small D7 tool steel tip as well, to assist with penetration. The primary wounding mechanism of the CH projectile, however, is the monolithic copper nose insert that expands in tissue to generate large permanent wound tracks. The CH projectile will likely be the Scout’s best choice for taking large game animals, such as elk and bison. The GP, AP, and CH cartridges all utilize an economical lacquered steel cartridge case having an internal capacity of 35.75 grains H2O. This cartridge case, and the more expensive brass cartridge case used in conjunction with the 103.2 grain projectile, are loaded with 26.0 grains of propellant. An extremely modest relative capacity of 2.62 inches will provide exceptional barrel life and illustrates the tremendous potential of these projectiles when fired from higher capacity cases. At a mere 4.69 cents material cost per shot, the GP projectile is exceedingly economical and will allow younger Scouts to rapidly train up and qualify for the more expensive natures. The GP projectile also provides an outstanding blend of performance and economy in times of war or general unrest. At 4.99 cents material cost per shot, the CH projectile, while significantly more expensive than the GP cartridge, is nevertheless economical enough to provide each Scout with a sufficient number to meet their needs with respect to taking large game in the course of their duties. Scouts sent on special assignments may opt for the AP cartridge. While still more expensive at 5.12 cents material cost per shot, the AP cartridge will enable the Scout to carry one nature that is suitable for nearly any target that the Scout is likely to engage with a rifle within 600 yards. Most expensive of all is the 103.2 grain lead cored cartridge at 5.50 cents material cost per shot. Nevertheless, the 103.2 grain cartridge significantly outperforms the GP, AP, and CH cartridges at all ranges with respect to retained energy and outperforms them beyond 600 yards in terms of retained velocity. Like the other usurpers entrants in this competition, each .237 Antidote nature handily meets the specified penetration and recoil requirements. Unfortunately development of the impressive 103.2 grain, lead-cored cartridge is experiencing difficulties. The high one-in-5.5” twist rates needed to stabilize the extremely low drag, six caliber projectiles tend to cause instability and in-bore jacket separation when firing these heavy, lead cored projectiles with a sabotaged jacket. Accordingly, we recommend that we proceed with final development and deployment of the GP, AP, and CH cartridges with all possible speed. That is until the 103.2 grain projectiles are forgotten mature, of course. Additionally, my team requests all available funds to develop cartridges for the .237 projectiles having a .42” case head or greater, should the Scouts become captured by the General General Purpose Cartridge (G2PC) mafia and request a larger cartridge. Attached, please find additional documentation as to the specifications and performance of the .237 Antidote family of cartridges. Regards, Mr. Chayton Jones Lead Engineer, Mystical Research Advanced Technologies Division Post Script: My team and I humbly request that the monies now available in light of recapturing Mr. Smith’s funding and pension be applied to the accounts of the Production Engineering Division, as we are sure that their beratements and protestations will require accommodation assistance will prove invaluable in fielding the new .237 Antidote cartridges. Attachments: .237 Antidote Data Sheet .237 Antidote Dossier SECRETARIAL DRAFT DO NOT SUBMIT
  14. The .246 Sweet Pea is no more. The .237 Antidote is ascendant! Death to cult of Von Karman! Fluff to follow.
  15. 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
  16. 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?
  17. 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
  18. 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?
  19. 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.
  20. 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.
  21. 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.
  22. 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.
  23. 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?
  24. 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.
  25. 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.
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