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Everything posted by ARS

  1. The most critical problem is cooling system. By default, SSME uses fuel flow through the main fuel valve into regenerative cooling systems for the nozzle. Considering the heat the engine needs to withstand (aside from the hot gas from the engine itself) from launch into reentry, it's A LOT. The pressure (and temperature) of the gas remains very high all along the spike surface in order to maintain the consistent engine performance across all altitudes, and the sharp tip of the engine design itself leaves very little room for cooling systems, unlike the bell-shaped nozzle of SSME. Some other problems includes the fact that SSMEs are not exactly fully reusable, since despite being advertised as reusable, the engine needs to be swapped for each new launches, and considering the cooling problems above, it would considerably jack up the maintenance cost
  2. Is there a reason why muzzle brake constructions are wildly different? On one hand, we have the muzzle brake that vents the gas sideways, on the other hand, we have star-shaped muzzle brake that vents the gas circularly on 5 directions, and on the other hand we have the one with multiple smaller holes around the tip of the muzzle like a mic. Does "it works as long as it has holes on the muzzle" (so for example you can use assault rifle muzzlebrake on sniper rifles) or it's specifically tailored with set parameter for specific gun (meaning the one for assault rifle is inefective or useless when put on sniper rifles)? Also, does putting muzzle brakes beneficial if you're gonna fire that gun in space?
  3. What is the actual advantage and disadvantage of having an arm-mounted sword (as in a full-size sword mounted on the wrist) versus sword that's held normally on the handle?
  4. Does modern military helmet actually bulletproof enough to resist firearms to prevent headshot or it's limited to just protecting the head from impact and splinters?
  5. So, imagine this scene in an actin movie: You're thrown away, whether by explosion, punch or from being kicked off a helicopter taking off and you landed on the classic "glass roof" on top of the building. The glass is cracked (but didn't break) when you impact it, and now you have to get out of the glass area. Realistically speaking, if the glass is already cracked, which position should be used to get away from it (while minimizing the disturbance that could break the glass): -lay down and slowly crawl away to safety -get on all fours and slowly get away -try to stand on your legs and carefully take each step to get away
  6. Is it possible to reenter the atmosphere stealthily for undetected planetary insertion (to the extent of visual and radar invisibility) with proper controlled deceleration in orbit (and during reentry) to minimize atmospheric friction and heating (that creates a highly visible plasma) with the combination of radar and visual countermeasure (optic camo, anti-radar coating, etc.)
  7. In video games, there's often a case where a different weapon with same type has different attack power despite using same type of bullet. I know this is for the sake of game balance, but what I want to ask, does this kind of difference also true in real life? A same bullet used in 2 different (but same type of gun) has different penetration, force, and destructive power (note: not ballistic properties like trajectory/ grouping, etc.) for example, using .50 cal bullet on different anti-materiel rifle produce a result where one is more powerful than others, or instead, using the same bullet is just as effective as shooting it from different gun
  8. Yeah, I mean larger. The smaller planet has much more mass and stronger gravity than the larger ones
  9. Is it possible for a planet to have a moon that's much larger than it is as long as the planet in question has much more mass (and stronger gravity)? For example, a rogue planet that wanders the universe entered a system and gets captured by a planet much smaller than it (but has much more mass and stronger gravity). Or is there an absolute limit of moon's size related to the parent planet it orbits?
  10. Does the flight trajectory of an object is affected by the rate of acceleration and how the atmospheric drag behaves during the flight? For example, there are 2 projectiles launched into space at suborbital trajectory. Both has the same delta-V, same mass and same angle of launch. However, projectile A is launched normally using rocket engines while projectile B is shot using mass driver. In this case: 1. Projectile A has a gradual acceleration to max speed and atmospheric drag that steadily rises as it flies through atmosphere before it finally reached space 2. Projectile B has instantaneous acceleration to max speed and the atmospheric drag is instantaneously jumped to max before it finally reached space Assuming these 2 have the same delta-V (but different flight characteristic), does the trajectory produced are identical to each other?
  11. If I want to break the speed record, which one of these environment that would put the most and the least strain on the vehicle at high speed? (ignoring the difficulty of attaining high speed in that environment, assume we can go as fast as we want) -sky: flight speed record (vehicle only interact with air) -ground: land speed record (vehicle interact with air and ground) -sea surface: sailing speed record (vehicle interact with water and air) -underwater: submarine speed record (vehicle interact only with water)
  12. I see, thanks for your advice. I'm planning to buy a new PSU at the end of March. Hopefully it would solve my problem
  13. I am planning to buy a new PSU, should 650w enough? Or should I go higher?
  14. Thanks for the response. Here's my spec: I'm still thinking whether I should: -Increase house voltage to reduce the margin of power fluctuation -Buy a voltage stabilizer with higher range of power output -Buy a UPS (should I use UPS and Stabilizer at the same time?)
  15. Guys, I need some help So I recently bought a PC for my 3D print design and modeling need (because my laptop are no longer sufficient). It's a mid-end computer, and it did it's job properly, however, there are things that's bugging me since I used it. So, the electricity in my house is kinda unstable (but still sufficient), with the voltage frequently rise and fall erratically. Here's what happen: 1. At first, I plugged the power cable of the PC directly into wall socket. The result is, everytime there's a power fluctuation, the computer just freeze, that is, the cursor disappear, any sound stopped and the screen just freeze in place with no way to recover it, necessitating a hard restart 2. Then I bought a voltage stabilizer to at least make the power flow consistent (that was the only conclusion I can gather). The result is, yeah, everytime there's a power fluctuation, the PC no longer frozen in place, as the stabilizer whirrs to stabilize the voltage. However, now it exhibit an annoying habit: Everytime I worked on it, especially those that involves heavy rendering of 3D objects on screen, or doing something intensive that requires heavy GPU use, the PC frequently start to just turned off (screen goes black) and then restart on it's own (without me touching the buttons), often, such event are accompanied by a soft screech from the voltage regulator (p.s the regulator output is 220v, and my PSU range is between 170-230v) Should I increase the power voltage in my house? Is it the problem with PSU? Should I bought UPS? Thanks for the answer, I know this is not a tech support forum, but I'd like to hear your thoughts about it
  16. Could MANPADS locks on grounded aircraft? (Either with engine turned on or not) is there a minimum altitude limit where MANPADS couldn't lock to aircraft? and if the missile is heatseeking type, could it be aimed at tanks with running engine to be used as a makeshift (albeit ineffective) AT missile?
  17. If a stealth aircraft such as F-117 or B2 is taken into WW2 era where the radar is still during it's early age, would it be completely invisible to the radar?
  18. Double that number just in case the yield is less than 1kg
  19. If the outer space treaty said that space isn't really owned by everyone, if colonies are built close to each other, let's say colony A and B are built in such a close proximity, does colony A still have sovereignity claim to what's inside their colony? That is, inside their pressurized structure area, not the soil outside where inhabitants from both are free to place anything outside with no such things as territorial border
  20. @kerbiloid, @monophonic K then. Thanks for the answer
  21. I wanna ask for you who lives in a country with winter season. Which one is better for navigating snowy environment? Wide off-road wheels (chains optional)? or caterpillar track with additional grousers? or heavy duty rotary screw propeller? Does it also effective on wide flat of ice terrain (not soft snow)?
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