Zeiss Ikon

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About Zeiss Ikon

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    Senior Rocket Scientist

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  1. This depends on how old the toilet is. Jet-assisted siphon bowls came along when the effort started to reduce the amount of water used for each flush. When I was a young fellow, no one cared if you used 19l (5 gallons) of water to flush the bowl, so the simplest design was preferred; the water just poured in from the rim until the level rose enough to start the siphon, then enough additional was included in the cycle to keep the bowl running long enough to remove all the waste. Next to no momentum involved. You can spot these older bowls by two marks: first, they'll invariably taller than modern ones, because the height was needed to give enough head inside the bowl to reliably start the siphon; and second, they don't have the small jet hole in the front side of the lead-in to the trap. Once people started wanting/needing to reduce water consumption, there was a generation of really bad toilets that would clog at the slightest provocation (sometimes on just a few sheets of tissue). These had been modeled after pressure-flush bowls from public restroom designs, but there wasn't enough head in the tank to reliably start the siphon if there was material in the bowl -- unless you mounted the tank on the wall, a meter or so above the bowl. This produced very positive flushes, much like the pressure flush type, but eliminated the ability to store items on the tank lid. Finally, the modern pressure-assisted siphon bowl came along, starting with premium brands and working its way down to the point where the cheapest stool you can buy today flushes better than the best one did back in the 1990s. These use an improved pressure jet design which, yes, uses momentum to get the siphon started, and will reliably flush even a very heavy load with less than 3.8l (1 gallon) of water -- I've seen bowls that were rated as low as 2.5l in the last couple years. Hint: if you have one of these modern low-flow toilets, don't try to save even more water by putting bricks or a full jug in the tank -- they will not work if you cut their water use by even as much as 10%.
  2. Wow, seriously? I just barely (like, last week) got 1.7.3 running with RSS/RO/RP-1 and Principia. Kerbalism and Test Lite, this time (instead of [X] Science and Science Alerts Re-Alerted, TAC LS, and Test Flight). By the time I get anywhere in an RP-1 career, I have to stop updating Principia because they've stopped supporting the base KSP version I'm on...
  3. Even if you figure these asteroids are only about 50% solid (i.e. similar to a pile of pebbles, lightly vacuum welded together, hence why they break up and don't produce a crater on the ground), the overall density should be close to twice that of water or solid ice -- so a 1.5 m spheroid at 5.5t is pretty reasonable.
  4. So, this is basically a Dyson bladeless ring-fan, with as much power as the design can handle? I seem to recall discussion (somewhere) leading to the conclusion that this is a terrible way to build a fan, in terms of energy efficiency. Which would imply it's also not a good propulsion system.
  5. Not sure, but there might be a 12 step program for that...
  6. If you're trying to decrease build times, either spending KCT upgrade points at the VAB to increase build rate, or optimizing parts choice and tooling everything you can will cut the number of game days from clicking the "launch" icon in VAB until you can actually roll out for launch. VAB upgrades also slightly reduce rollout times. If you're concerned about the player time while the vessel loads onto the launch pad after KCT is done with it, probably only a computer upgrade to a CUP with higher single-thread performance, or switching from a platter hard disk to SSD is going to help...
  7. It's still not going to pass for a flight sim, but it's better than the stock aero, hands down.
  8. The Space Shuttle had a specific system for this, Terminal Energy Management (TEM). They used the only available strategy, with very limited drag brakes (split rudder only), gear that couldn't be retracted in flight, and a drag chute, also of limited effect: they reentered on a path to be a little high and hot, then used what amounted to S turns in the last minute or two of descent to dispose of excess energy. And then they landed on long, long runways...
  9. I saw a fireball over northern Idaho back in 1980 -- greenish, bright, and traveling south to north. We figured then it was probably a satellite burning up after its orbit decayed. Those don't generally get bright enough to be visible in daylight, though, never mind to flare a camera sensor in daylight... @Vanamonde Average meteoric entry speed is something like 20 km/s, as I recall -- compared to ~1 km/s for an SR-71 going all out...
  10. @nepphhh I have the Kerbalism RO config -- I followed the RO/RP-1 installation instruction page very carefully, after wasting a week of evening spare time and getting it wrong once. I'm now getting data, it just takes a long time to complete each experiment -- but as long as data from multiple flights is added together (it is) and I get the partial Science to spend before completing the entire data set (I do, for instance, 0.1x completed for Supersonic Flight Analysis was good for 2.5 Science points), so i can start R&D working, it works well enough. At this point, around January 1952, with half a dozen launches under my belt, I've got most of the temperature and pressure scans completed for the biomes around Canaveral, and for Space Low; telemetry similar, about 2/3 done with Superonic Flight Analysis, and after three flights on "Space Biological Science" contracts, about 2/3 of the bio sample data -- and I haven't even built an A-4/RD-100 class vehicle yet.
  11. Are those small yellow blocks the Thuds are mounted on Lf/O tanks? If they aren't, the Thuds don't have any fuel to draw from. Fuel ducts will pull Lf/O from their supply end to keep tanks on their output end filled as long as there's supply -- but that assumed there's something for the duct to keep filled.
  12. (1.7.3 RSS/RO/RP-1/Kerbalism) It's September of 1951, and we're at the height of the sounding rocket era. Meet Sixpence B. The initial vehicles in this save were Tiny Tim II (one guess what engine than one had) and Copper A, a 305 mm vehicle with a first-generation Aerobee engine burning Anline/Furfuryl with IRFNA. We got a couple contracts out of that one, but it quickly became apparent that it wasn't adequate to meet the contracts that were being offered -- even with no payload, it was only good for around 120 km. Fortunately, the R&D folks pretty promptly released an upgraded engine version, designated XASR-1, with a slightly shorter burn time rating, but nearly double the thrust. Even that wasn't enough to send instruments and payload into space proper, however, and early simulations suggested that the larger diameter of some of these payloads was part of the problem. Well, then, let's stage one to another, and build the whole thing to minimize drag as far as practical. Here's the result. Wups, looks like we're headed for Tampa (in fact, the payload section landed in the Gulf a couple kilometers offshore, and a similar distance north of Tampa Bay).
  13. @nepphhh Yeah, but I've got a couple of those decision points where my answer is "yes, but I wish I were better at it." I guess that's what practice is for, but if I were a *good* money manager, I'd probably be living better in real life...
  14. Well, for whatever it's worth, I found the buttons for activating the science instruments (in the VAB, even, though I presume that would be a mistake if you're running on batteries and need to take data for a contract after several days in flight -- like, say, a Lunar flyby). If they have buttons in the VAB, they can be bound to Action Groups, so I can manage my science collection. And even better, partial data nets partial science. After bankrupting my first save in the new install (bought one too many KCT upgrade points), I started a new one, and was able to see in the Kerbalism status window as the data added up in whatever biome my sounding rocket flew over. A minute, two minutes, and I'd get 0.1 of the available science. After a couple flights into the Upper Atmosphere, I was able to unlock the entire first (1 point) tier and start one or two nodes in the next. I'm not sure I agree with the Kerbalism model entirely -- reading out a thermometer or barometer is pretty much instantaneous, and the data you get ought to be pretty small -- a couple bytes, plus a short header, should be able to encode temperatures from liquid nitrogen up to boiling water (likely easiest to just send as Kelvins, in binary or BCD, and at this tech level 0.1 degree resolution is plenty). Same is true of the pressure readout -- zero to a couple hundred kPa, in tenths of a Pa (one Pa is close to a hundredth of a millibar, if you're more used to weather than physics) would be three or four bytes. My telemetry unit is supposed to be able to send 32 bps, or ~3 B/s (including start, stop and even or odd parity), and redundancy can stand in for error correction, just keep sending over and over. If you have four instruments, you queue their data in a preset order and sort it out on the ground (with 1950 tech, this would be effectively WWII radio teletype with frequency shift keying, or equivalent of modern 80m ham RTTY). I don't see it taking more than about ten seconds to get a good temp, pressure, and a recording of the signal that will let you analyze atmospheric (or exo-atmospheric) effects on the signal -- yet multiple flights that spent a minute or so in a particular biome didn't get fully completed temperature and pressure scans.
  15. I made my first two launches in a new RSS/RO/RP-1 career, with a fresh install of 1.7.3. I installed with Test Lite instead of Test Flight, Real Antenna instead of Remote Tech, and Kerbalism instead of Science Alert Re-alerted, [X} Science, and whatever else (it also gives "reliability" management for non-engine parts, and tracks the overall health and mental well being of Kerbals on long missions, rather than just making sure they have food, water, oxygen, and electricity as TAC LS does). Unfortunately, I found that the need for science experiments to run for a protracted period introduces some issues in the sounding rocket era. If it takes 30 minutes to complete a Supersonic Flight Analysis, and your rocket's total flight time (launch to impact) is only about ten minutes, does the data get saved and added to that from the next flight? If so, how is one supposed to remain solvent when it takes five or so times as many launches to get the science for the next engine/tank/etc. upgrade node? I know it's possible; other people are doing it -- but it's not very well documented (in terms of telling one how to go about getting science early in the career).