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Posts posted by ARS

  1. 7 hours ago, K^2 said:

    You are dealing with low pressure, so it's much harder to generate lift. You then either have to greatly increase the wingspan - the U-2 route, or greatly increase speed - the SR-71 route. Traditional swept-wings are critical for flight in the transonic region. We're talking Mach 0.9-1.1 or so. Airliners dip into that region, so they...

    With such a low-pressure environment, if we're looking for hypersonic realm of speed (from engineering standpoint, strictly about speed, not about it's application on hypersonic ordnance), which altitude is preferrable? Low or high? Since at low altitude, the higher air density makes hypersonic engine (ramjet, scramjet) easier to use since there's plenty of air to feed it, but the aerodynamic heating would be deadly, while at high altitude, the heating might not be as severe as in low altitude, but the thin air might impede the engine's performance

  2. What's the design consideration specific for aircraft operating at extreme altitude? Because one one hand, we have the slow-moving aircraft with near-glider like characteristic such as U-2, but on the other hand, we have a literal speed demon with overkill engines like SR-71 or MiG 25/31

    Also, does this statement correct?: "A material with high melting point is stronger in terms of mechanical characteristic than material with low melting point"

  3. I've seen multiple times on works set in WW2, be it games or movies, that everytime there's a soldier carrying a flamethrower, if a bullet struck a backpack he carries, it usually blows up in a massive fireball, engulfing the user and anyone nearby. Is this true to real-life? Because AFAIK, military grade-flamethrowers does not use gas-based fuel, only liquid (because it sticks better to enemies), and liquid is not compressible, so if a bullet pierced the tank, the contents inside is not under pressure, so there's no sudden expansion that can cause the whole backpack to rupture. And if I remember, military flamethrowers are specifically designed to be slow-burning and hard to ignite to maximize the burn effect and only burns when you want it to burn

  4. I wanna ask some stuff about Outer Space Treaty:

    1. If country A build a moonbase, then country B landed a rocket nearby and also build their own moonbase. Both (technically) didn't violate each other's territory since it was a neutral territory to begin with (and as long as they behave peacefully with each other)

    2. Since the OST only specify WMDs and nukes that's prohibited to be placed in orbit, that means regular ballistic weapon (cannons, railguns, autocannons) and non-WMD weapons (missiles) are still allowed right?

    3. If a country didn't participate in the OST (non-parties), does it mean they are exempt from the WMD rule? (aka, they can place nukes and WMDs in orbit)

    4. What actually constitutes as contaminating space? Does a spent shell casings, discarded booster rockets, defunct satellites and missed railgun shot that continually travels out of solar system count as 'contaminating' it?

    5. If we take a sci-fi tech such as phase technology (i.e technology that allows phasing between realspace and phasespace) and place a nuke in phasespace, technically it isn't a violation of OST right? (since the nuke isn't in realspace (actual space))

  5. In many sci-fi settings, there's a lot of plot points of mining asteroid or planet to satisfy the demand of precious metals, and just now, I saw an article about 2 high-density ore asteroid that's supposedly could satisfy global demand of precious metal. If we take a real-life logic to this situation, is it worth setting up a space mining operation (orbital operations, spaceflight, the mining, and logistic transport) for ores with jacked up market price just to satisfy economic demand? (assuming that space travel is still limited, like today)

  6. 4 hours ago, K^2 said:

    Oh, man, layers upon layers. Optimization is a huge topic. Very broadly speaking, if we limit it to games, you are looking at one of the following categories...

    I know that setting a system on high-performance (the usual setting for playing high-end games)demands more power, does it means supplying more power can compensate for low-end hardware? (within a certain limit of course)

  7. How does software optimization actually works? I played a game back then in 2019 on my laptop and it's laggy as hell, with stutters and choppy framerate that makes it nearly unplayable even at lowest setting, but 2 years later, a definitive edition came out and I tested it on the same laptop. A same game, same laptop but it's far smoother than the 2019 version, even at medium setting. How does the optimization worked?

  8. 5 hours ago, FleshJeb said:

    I've heard the arguments that it's REALLY the procurement officers screwing things up by writing unrealistic requirements, but you know, I work for a small-time engineering firm, and we tell our clients NO all the time when we think their ideas are infeasible

    Why I felt this starts to look like WW2 German wundewaffe project in a nutshell, history repeats itself

  9. On 10/17/2021 at 7:31 AM, mikegarrison said:

    I find it depressing how many people play a game like KSP and instantly want to add weapons. It would be so nice if we didn't have to militarize everything. (And I say that despite working for the world's biggest defense contractor.)

    For me, the thunderous roar of SRBs during a liftoff or the roaring plasma during reentry still gives me satisfaction comparable to watching artillery battery going off. I rarely make military stuff in KSP, but if I make something, it has to be BIG (dunno why, but I always find it fascinating to build big stuff)

  10. 1 hour ago, K^2 said:

    Are you just trying to build a chain? Or do you need at least one tower visible from every point on Earth? Even in the later case, you can come up with a space-filling pattern that's more efficient. Think a branching out fractal-like structure. Simply filling all space with a grid of tower is not the optimal solution if you're trying to build fewer towers.

    Just need one tower visible, it doesn't have to chain into an entire network

  11. 23 minutes ago, Gargamel said:

    I'm ignoring your fundamental question, of is my math right, but I want to investigate the idea behind this question more.    I think we need to define Line of Sight here.    Do we mean A human standing on the top of a tower can see another tower?  Or do we mean a radio (EM) signal of some wavelength can reach...

    Okay, I should add other things to consider about my question. Assume the earth-sized planet, with little to no variations in geographical features. Line of sight is defined from the top of the tower

    28 minutes ago, Gargamel said:

    Next, why only 50m?   That's relatively short.  As the height of the mast goes up, the distance to the horizon would also increase.   I don't know the ratio, but there's probably a reason that building 500m+ tall radio towers are a thing, instead of a small network of shorter ones.   Let's assume cost of materials is our biggest limiting factor, there's a...

    From practical, safety ad economic standpoint, which one is better? A network of 10 towers with height of 50m or a single 500m tall tower?

    30 minutes ago, Gargamel said:

    And then there's the topography.   On a local scale, it's fairly easy to play around with potential layouts and find a near optimum layout.  But on the scale of the whole planet, this is a really complicated problem.   I would think plugging our various preferred features of the towers and applicable GIS data into the appropriate...

    If we just assume an earth-sized planet with smooth surface area, how many towers it takes to do it? (basically ignoring the variable terrain topography)

    32 minutes ago, Gargamel said:

    And final question would be, why would a series of towers be superior to a low orbit cloud of satellites (a la Starlink)?  I don't know the intended use of the towers, so satellites might not be a good option. 

    let's just say I'm writing a semi-realistic sci-fi story where in a nutshell, space launch has become impossible due to... Over-kesslering the planet?

  12. So I got something to ask...

    Build towers across earth. Each tower must have a line of sight to at least 1 other tower and 1 tower must be directly on south and north pole, whether the tower is placed on ground or sea doesn't matter, each tower has a height roughly 50m

    Considering that earth's surface area are roughly 510 million km2, and the distance to the horizon is roughly 5 km (which means there must be another tower within a radius of 78.5 km2 for each tower), the formula for the number of towers required would be: 510,000,000/ 78.5=6,496,815 towers

    Is this correct?

  13. On WW2-era vehicles, especially tanks and ships, we can see coincidence rangefinders mounted on it, from small, portable unit used by tank crew, mounted on tank's cupola, integrated on tank's turret, and then we have the one mounted on fire control unit on destroyers, all the way up to a massive duplex rangefinder mounted on Yamato's fire control tower. All of those are from the smallest to the largest, so what I want to ask is, does the length of the 2 viewports (aka the width of the unit) corresponds to the maximum range that can be measured? (thus the effective firing range of the unit using it) Because the small ones are mounted on tanks since it's expected to engage other tanks at an average range of 1-2km , while the larger ones are mounted on ships because destroyers might engage each other at 5-10km+ range while battleships at over 15-20km+ range

  14. On 9/1/2021 at 12:24 PM, SOXBLOX said:

    However, I think it could still be detected, mostly because, to the receiver, it would be a notable blank spot in the sky.

    Wait, so there's a difference on what appears on radar screen between 'looks like nothing there (because there really is nothing)' and 'looks like nothing there (because something is stealthing from radar detection)'?

  15. 26 minutes ago, DDE said:

    Now, the article notes that typical civilain Il's have not two but six sets of fire extinguishers. However, if all of them are in the nacelles I'm not sure jow it would help.

    I doubt it'll help. Fire suppression system are usually mounted on the engine nacelle simply because that's the area that's more likely to catch fire and the inward air movement into the engine usually enough to put off any fire after the system is activated. If the aileron actuator cable melted but the fire has been put off before spreading too far, best case scenario, you can still glide away to land, but considering the circumstances of this crash, it's likely the pilot tried to turn back to land the plane, but only one aileron are functional, causing an uneven lift on one side and send the whole thing crashing down

  16. So I got few things to ask... and it's about stealth, specifically radiation-absorbent material (RAM):

    1. If RAM can reduce a radar-cross section of an object, does it also works when applied on non-stealth design? For instance, using RAM on 747 instead on B2, does it reduce 747 radar cross-section even though the 747's design is a non-stealth design?

    2. Does the radar cross-section reduction effect is affected by the size of an object? Let's take an example, if there's a RAM that 100% absorbs any radiation emission (including all spectrum of radar), and apply it on independence day city killer mothership (or any other gigantic flying object), would that object invisible to radar? (even though it would be obviously visible to the naked eye)

  17. On 8/21/2021 at 7:53 PM, kerbiloid said:

    A little bit later the truth will reveal about the lunar race...

    Funnily enough, Apollo Program was born because USA's previous proposal to one-up the Soviets was considered nuts, since after the Sputnik debacle, USA was desperately searching for ways to top the Soviets in the space race, and a proposal was made that an atomic bomb be detonated on the Moon (just to send a message). Fortunately, they decided to send astronauts to the moon instead after they realized the difference between legitimate science and cartoonish supervillainy

  18. So... while browsing for an idea about sci-fi vehicles, I saw a quote which basically sums up like this:

    "Though the bomber is unlikely to be shot down, owing to it's heavy armor and redundant backup flight systems, the highly classified nature of it's existence means that the enemy must not be allowed to recover any remains of it should one of these get shot down. As such, this aircraft is fitted with sophisticated systems that it is designed to detonate and combust on impact, should it crash, melting the structural airframe and destroying any hardware designated as classified asset. Guaranteeing that none of it's remains are left in a condition that allowed the enemy to obtain any information about it."

    Now, logically speaking, does it make sense to put such a system on actual top secret military hardware? The one that completely destroy the asset to prevent the opposing side to gather intelligence of it? (not counting espionage and defection of course) Because AFAIK, even the modern day stealth bomber like B2 doesn't have a system like that (mainly from that 2008 B2 crash near the runway, the wreckage is still there after it went lithobraking)

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