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zolotiyeruki

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Everything posted by zolotiyeruki

  1. That's a fair point about the yaw/roll coupling, although I wonder how much roll you'd actually get, given the much larger surface area of the (hypothetically fixed) rear fins.
  2. That's an interesting aside. When I've done a mk1-sized craft with a single RAPIER, near the end of the flight, it's only generating a couple kN of thrust to sustain near-1700m/s speeds at 27km altitude. An LV-909 at max thrust will burn 3.5 units/second of fuel, according to the wiki (is that LF only, or combined LF/Ox?), and produce 60kN. If it only needs to produce 5kN, that's 1/12th max thrust, so 3.5/12 ~=0.3 units/second. Two FL-T800's would give you about 800 units total LF/Ox, which would be more than enough for the 40-minute trip, assuming you use a RAPIER to get you up to 1700m/s and 27km. In fact, it's better than that, for two reasons: 1) using a rocket engine would allow you to fly at 29,900m and encounter significantly less parasitic drag 2) higher altitude and velocity means you're closer to orbital speed, and you need less lift to maintain altitude. It gets a bit nerdy, but I figured out that the amount of lift you have to provide is proportional to (GM/R^2 - V^2/R). With some hard numbers plugged in, if you're at 1700m/s and 27km, you only have to supply about 48% of the baseline lift, and at 1,900 m/s, you're down to about 36%. Note that the percentage of lift you have to supply doesn't change much with altitude. Actually, thinking about it a bit more, just using a RAPIER in closed cycle mode would probably be better, despite the Isp hit, since you'd eliminate the dead weight and drag of a second engine.
  3. I have a question: Assuming SS is passively stable in the roll axis, why would you need to have actuated rear fins at all? You could control pitch and yaw with just the canards. The best system being no system, and all that...
  4. Yeah, making it around once isn't too bad. Making it around many times, or going really fast, is where the challenge lies!
  5. Will do, and thank you for your honesty. Way back when I was participating in the 1.3 or 1.4 version of this challenge, just as a test, I stuck a shock cone intake on the back of a RAPIER, and it resulted in something like a 30% reduction in fuel burn. Crazy stuff.
  6. ...and the lower the state of battery charge, the faster it accelerates!
  7. You got to orbit. That's a huge step. The screenshot you posted appears to be setting up a maneuver node. Since you're not familiar with that, it sounds like you're pretty early into your career, and haven't upgraded much. In Career mode, you want to accept contracts to get money (to build rockets and upgrade your buildings) and collect science to unlock more parts. The wiki has a fantastic explanation of how the science system works--basically, do you various experiments and observations in various places, and return them (or transmit them) to collect science. And you spend science on unlocking parts. In terms of mods, there are two that are "must have"s for me: Kerbal Engineer (incredibly useful for lots of things, but especially useful when building rockets to see your TWR and dV of each stage) and Kerbal Alarm Clock (which you probably don't need *yet*, seeing how early you are in the game). I use a few other mods for specific situations (Pilot Assistant) or on more advanced designs (PreciseEditor and RCS Build Aid for planes), but KER and KAC are, to me, indispensable.
  8. Here are a few tips: Of all the nose cones in the game, the Shock Cone Intake has by far the least drag. If you're willing to get a little cheaty, you can stick a Shock Cone on the back of your engines, and then offset them into the engine. That way, you get the reduction of drag, without the nose cone sitting in the way of the exhaust. The game has a default calculation for drag, but some parts override that calculation, via values set in that part's .cfg file. It's also worth noting that there's drag due to the shape, and there's also skin drag. That's why a plane with a Mk1 LF tank can fly perfectly straight and level and still have non-negligible drag from the fuel tank, even if the tank is fully occluded from the airstream. Any time you change fuselage diameter, you'll pay a pretty heavy drag penalty. You may see better results if you stick with Mk3 parts for the entire length of your craft--you'll get more fuel in a shorter craft, and you'll avoid some of the drag penalty from going up and down sizes as much.
  9. True, but the mass ratio of the fuel is less advantageous (300 units for a 500kg wing) than the strakes (100 units for a 100kg wing). In an optimization challenge like this, that can make a difference
  10. Yes Last I heard, wings in KSP do not create parasitic drag unless they're in a stall, although they create some component of lift-induced drag, due to their mass. This is something that makes the wet strakes awesome--they have the same lift-to-mass ratio as other wings, but they also carry fuel, so you get fuel capacity *and* lift without the parasitic drag or additional dry mass of a normal cylindrical fuel tank.
  11. The shock cone intakes have less drag than anything else you can put on the front (or back) of a 1.25m stack. Even less, I believe, than the really-long tail connectors, which have a lower Cd but a higher surface area. If you stick a shock cone intake on the back of a RAPIER and offset it into the engine (so it doesn't block thrust), you'll see a significant reduction in drag. But it's not realistic, which is why it's specifically disallowed. Dangit, I was hoping nobody would notice the edit. Yeah, that rule should have been in place from the start, since aero and thermal seem to get tweaked between versions. I'm going to allow it under Smokey Yunick, since it was my fault that rule wasn't there. Don't worry about being annoying--there is nothing wrong with multiple entries. Your time on the leaderboard has been updated!
  12. Yeah, it all comes down to the final approach. Slow down too late or high, or too soon, and it takes a long time to get to the ground. Slow down too low, and you burn up. An extra 10m/s over a 40-minute flight adds up to about 25km, which seems like a lot, but it's only about 15 seconds of cruise flight, and it's easy to lose that much time.
  13. Rats, I just about had Bob_Saget54 beat, but at the end of the trip, I found out I didn't have enough elevator authority to stick the landing. Of course, this didn't become apparent until I was trying to land the thing at the end of a nearly-40-minute flight....
  14. Actually, the rules state: " Your craft must carry a kerbal in a cockpit or capsule. " So while a Mk1 passenger compartment would have relatively very little drag, and contain a kerbal, it doesn't count for this rule.
  15. Yeah, few days ago I was testing a craft and was wondering why it was only going 1690m/s instead of the 1750 I was expecting. Turns out I had forgotten to retract the gear. oops. Well done to Bryson, MakerTribe, and Bob_Saget54--the leaderboard has been updated with your impressive entries!
  16. I fully expect the first N attempts will be done well offshore for this reason. Several early F9 landing experiments were done over the water, rather than a droneship.
  17. How about this?: An "Honorable Mention" leaderboard, for entries that don't quite fit the rules as intended, but are still noteworthy
  18. That's some great ingenuity there, but I think that proposal breaks the spirit of the challenge a bit. The runway length imposes a uniform design constraint on all contestants, so that the challenge is more about craft design and piloting skill.
  19. Absent any dissent, your request has been granted. I'm intrigued to see what you come up with!
  20. Hmm, that's a great question, and I appreciate you asking ahead of time. I'm torn on this one--on the one hand, it automates a menial task the player would normally be expected to perform, similar to an autopilot. At the same time, the design of the craft is an integral part of the challenge, and I'm a bit hesitant to change the rules in a way that enables brute-forcing it.... Anybody else have an opinion?
  21. Yes. I believe it's only my first release (v1.4.0.1) that omits it.
  22. I've seen it called either a "turtle back" or a "fastback".
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