wumpus

Members
  • Content Count

    2,775
  • Joined

  • Last visited

Community Reputation

976 Excellent

3 Followers

About wumpus

  • Rank
    Spacecraft Engineer

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Sure it could, but if you simply lockout any lead slower than the fastest British Vne you don't have to worry about IFF (assuming you are only targeting V-1s).
  2. Which sure enough mentions a British use to target German aircraft responding to their own IFF. The technology just wasn't there to make the encryption fast, light, and strong enough at the same time. But apparently it didn't stop them from trying (and of course British vs. German air battles were typically fought at night where visual identification was far, far, worse. So they pretty much had to try).
  3. True, and a gun optimized to hit a V-1 is unlikely to hit a spitfire (wrong lead times). But I doubt that electronic IFF (identify friend or foe) was a thing during WWII. Somebody had to see the aircraft and decide shoot/don't shoot.
  4. I've heard this a number of times about multiplication of Roman numerals and am shocked it is still repeated (I'm not sure how Egyptian multiplication worked). But Roman multiplication is even easier to learn than with Arabic numbers: n| I V X L C -------------------------------- I| I V X L C V| V XXV D CCL D* X| I D C L* M L | L CCL L* MMD* D** C| C D M D* M** (tack on an extra order of magnitude [base 10] for "*" values. In practice, it appears the Romans didn't need them). Just do multiplications on each number via the multiplication table for each roman numeral. No need to worry about position, just group the whole batch up. Then sort and reduce (by converting groups of numbers into larger ones, etc). But still, you only need to remember a multiplication table 1/4 the size of our own. And far easier I might add. The only thing I know about Egyptian division was that they really only had "proper" fractions (that is 1/some denominator). Possibly, they could figure out that 5/6 would give you 1/6+1/6+1/6+1/6+1/6, but they never had a good way to call it "5/6". And simple tricks like that won't scale well when a scribe has to do some real accounting. But multiplication was never as scary as historians say it was. I won't say that division is even possible with roman numerals. What is psuedo-phonetics? This sounds like the old "ideograms" bit that was an early published attempt to read hieroglyphics. Once it was shown just how much it resembled the modern (might be dead now) Coptic language, it was pretty clear it was reasonably phonetic (Spanish is phonetic. Can't say the same about English). There are something like 5 giant pyramids. King Tut (and any other Pharoh within 1000 years or so of him) was buried in an underground chamber. No "condo made of stona" for him. So unless you are talking about Ramses II or similar Pharoh (I think he clobbered the Hittites at some point), the pyramids had nothing to do with it. Also don't trust trust the hieroglypics painted on temple walls claiming they brought back those spoils of war. They were probably started before the chariots left and finished before word of how the battle ended (or otherwise not changed to reflect reality). They were meant to be impressive (and perhaps act as propaganda to anyone who could read them). Trust the papyruses written in the scribes' shorthand. That will tell you how many chariots came back without riders (of course the chance of finding both writings for number of chariots leaving and returning is almost zero, but sometimes you can get a good idea). Pretty sure they had bronze (although they presumably had to trade/raid for it. Thus Ramses II in the lands of the Hittites [who didn't invent iron smelting like I was taught in school]). It really isn't clear at all if large scale iron production happened anywhere in the first bronze age in the ancient Middle East (the period that ended with the sea people and the fall of every civilization nearby. Except Egypt). Lastly, my father is convinced of this "Egyptians made the pyramids via canals/locks" theory. Without understanding that locks simply aren't ever used unless you have a supply of water higher than the object you want to move (moving the water yourself is far, far, heavier than anything you want to move. Let alone all the water pressure issues). Dear old dad believes strange things (dragged me at a young age to see Chariots of the Gods when I was 5 or so. Found a paperback of the book it was based on while studying biology in high school and couldn't believe just how many trivial, show stopping errors it contained). Still, he would take me to the Smithsonian and gawk with me at the mighty rockets. That and a love of science that includes asking the questions needed to debunk some of his most cherished beliefs...
  5. While it isn't an issue for the Phalanx weapon system (which controls the Navy's big gatling guns), before jets took over those AA guns were controlled/fired by hand and the gunner had to identify friend or foe visually and quickly. Early in WWII, the US found itself shooting down more friend than foe through AA guns (by the time Yamato deployed, they really didn't have enough zeros for this to be an issue). This was eventually corrected, but the techniques to do this became obsolete with jet aircraft (and fortunately published. Far too many are lost since secrecy was maintained by shear habit). For Heinlein fans, much of this was done by one Samuel Renshaw who shows up as "inventing a super memory training device" in several of RAH's works. Pre-google, this took nearly an hour to track down all the information you could get in a single google search, and all day (a trip to the Library of Congress) to confirm no other material was published).
  6. If you absolutely can't afford both (and are set on waiting for KSP2) I'd at least recommend looking for the free demos. There were at least two: .18 (demo) [.02-.18 were also freely available and presumably stuck on a thread somewhere]: this was the game right before it went into "open access". Expect all the weird features you may have heard about "old school KSP": needing aspargus staging to for any large craft, aerodynamics really don't matter and flat, round spacecraft made much sense, and the means to orbit is straight up to 10k, then hard West. 1.0.0 (demo) learning this at least won't require learning KSP(1) again, assuming you find KSP1 on an extreme sale. It has the aero model (both drag and stability. Stability will be the biggest problem if you cut your teeth on .18) and most of the major improvements for release (but is likely more intentionally limited than .18. In .18 I doubt there was any real limits on what you could asparagus together with tiny little rockets). Be warned though: plenty of gamebreaking bugs will be present that weren't really stable until 1.0.3 (if your demo says 1.0.3 then breathe a sigh of relief, but I'm pretty sure it was only 1.0.0).
  7. One thing is that the speed of light has an inverse square relationship with the electric and magnetic permeability of vacuum. So if you reduce the speed of light, you increase the strengths of magnetic and electric fields. This would do wonders to chemistry (probably immediately extinguishing all life) let alone such obvious issues as electronics and electrical devices. And of course the reverse would be likewise true (except for the effects on life of course). The math is beyond me, but I've been told that altering the universes' constants tends to result in a boring, trivial universe that can't support life, and probably can't really support matter as we know it. That said, I highly recommend Vernor Vinge's "A Fire Upon the Deep" and later books that takes this idea (speed of light is variable by location) and runs with it.
  8. I worked for a company that made drones in the early 90s (unfortunately they were out of business before drones really took off), and they made one of their prototypes out of kevlar. Thing once ran into a tree (they were fixed wing "aircraft", not quadcopters) and only the propeller (and possibly engine) was damaged. On the other hand, cutting the fabric was so hard (even with the special shears) that they weren't interested in making more. I have to wonder if you can laser-cut those things... So kevlar isn't as tough as steel. But if you have to accelerate the mass to orbit, you might prefer kevlar.
  9. Detonation of gasoline/oxygen mixtures in cars is not unknown, and common enough to have a name: "knock". Granted, if your engine starts knocking you pull off, turn the engine off, and have it towed to a mechanic (that much knock may well destroy your engine before it gets there). So getting the energy the engine was designed for in a shockwave is rarely instantly fatal. I'm not even sure if nitroglycerin has more energy than properly mixed gas/oxygen (nitromethane does, or at least at mixtures that fit in the same sized engine). High explosives typically don't have as much energy, just the ability to easily lose it all at once. And while I haven't worked out the math, at least one thread here was reasonably convincing that the main point of Orion wasn't to capture all the *energy* of the explosion, but the *momentum* of the explosion (well, the momentum of the material hitting the plate). Momentum is the key to rocketry, and Freeman Dyson and co took advantage of that.
  10. As far as I know, that was why they initially believed that the radiation and various isotopes would not return to Earth: nearly all the explosions happened when it was sufficiently sideways to miss the Earth. Unfortunately, if you aren't near the poles the magnetosphere can typically grab them and bring them back. No idea what the initial blasts were supposed to be, I'd just assume they were dialed back to survivable levels.
  11. But your Isp is effectively infinite. So when you see claims that "reactionless engines" are impossible, that isn't true. Just that all known reactionless engines have really low thrust. Of course, your Isp wouldn't really be infinite. There is a theoretical loss in mass (E/c2) just to produce the energy that produces the photons.
  12. Same as on Earth, the air would follow the ground, with a certain small amount of "constant wind" counter to rotation. So anything dropped would be slowly grabbed by the wind as it got closer and closer to "ground". No idea if anyone has determined how to deal with such airflow in an O'Neil cylinder (they were talking about them long before computer simulations were feasible). I suspect that width and baffles would be key to such construction.
  13. I've heard it pushed it back at least a year. But using the Apollo1 design plus Apollo1 schedule, the most likely landing scenario involves lithobraking.
  14. Toxic and likely explosive. Plus, low gravity planets would "quickly" (at least by geological time) lose their atmosphere. The atmosphere would have to be brought by settlers and not expected to last (I'd assume mass nuclear alchemy creation of oxygen). Pretty much the only way you will get winged humans. And menances from Earth.
  15. In the original Star Trek series (1960s), at least one of the episodes having a space battle with the Romulans was based on a US/Japanese submarine battle (from googling, I'm guessing "The Balance of Terror"). I don't think steering against a medium made much of a difference. The main issue in the battle was using sensors to try to detect the enemy (presumably sound with submarines, Sci-Fi sensors [presumably resembling electromagnetic sensors] in Star Trek). But yes, Star Wars was basically fairy tales with semi-modern fighter pilots. Not science fiction at all.