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Everything posted by nelso

  1. Congrats, 3000m/s at 3:48 is definitely a sign this is record breaking early on, and 24:32 is by far the best. I would give you a recommendation for that. Think it could do even better though, perhaps by 30 seconds by not doing the loop at the end. I also did another run with a craft that can carry 32 passengers, in under 30 minutes. Trying to optimize takeoffs and landings, and getting decent at quick landings. This craft has all the requirements of OP but it's a little hard to board passengers from the ladder.
  2. In my experience the descent is really critical and can shave 1-2 minutes from the time. It's also possible a reverse powered descent is optimal, which would mean the backward-moving COM isn't so bad. It is a more complex maneuver and closer to what spacex wants to do with the starship. I've also considered using an inflatable heat shield as a nose cone.. superior heat resistance (3500k) but don't know about the aerodynamics. Also if inflated it can't be deflated. Very nice and congrats. I was trying an automatic takeoff for my most recent huge craft, but I couldn't get
  3. Those are some good ideas. I did not know that about MK2 parts. I did manage to roughly tie your time (about 26:29) with a vertical ascent and landing craft and cruise maxing out at 3250.5m/s (at ~18:48) (with comfortable heating, just didn't have the fuel and thrust to go faster). It lands on the tail, not quite on the runway but close. I had shock cone intakes closer to the central axis of the craft which I believe greatly reduces the heat. For the nuclear engines, I used shock cones and 2 ncs adapters cause of their heat tolerance. There is another optimization which is to use
  4. Very nice and congrats! I guess you fly upside down because the drag from the tail fin helps rotate down, and optimized drag to maximize the use of the nerv. Craft looks great too and it looks like you really tweaked it. Guess I will have to try some new approaches to get faster than that, but it will certainly be tough.
  5. Thanks, this was fairly challenging and took quite some time (many failed approaches in ship design), although after a while I got a sense of how fast I needed to be going early in the run: 2650m/s at 3 minutes was my goal, with about 20 minutes of nuclear fuel remaining. My goal was less about going faster during the cruise - every 50m/s faster is only about 30 seconds off the final time, but consumes a lot more fuel. Also note this was 43 tons so in the higher mass category. It was easier to balance numbers of engines, intakes, fuel/engine weight balance, and aerodynamics, and had a h
  6. My best yet: 28:45. 43 tons starting mass. I went retrograde, used 2 nuclear engines and 4 rapier engines which I used for orbital insertion and brief boosts at takeoff, and I found rapiers to be the best for this purpose. Instead of a nose cone at the front I used a fairing which has higher heat resistance for this critical part. Mainly it was a combination of a good ascent and descent, and going retrograde which lessens lift needed to keep below 35k, allowing significantly higher speeds for the same thrust. I only recorded a video, which does have an edit for an autosave towards the end.
  7. I gave it a test in reverse and got significant savings on fuel, approximately 40% less at cruising for the same surface speed (@ around 2560 m/s surface, circular orbit ~33km). I was able to test this precisely with my kos script. It does take stronger engines to get into orbit, since you need to go faster to start feeling weightless, but the fuel consumption is so much less for the cruise, it enables options like using higher power rocket engines for the ascent. Question for more experienced players - do wings create any drag if they are headed straight in the prograde direction (any
  8. My best with actual landing: 34:19. I wrote a kOS script to maintain a near perfect flight for nuclear engine types, much better than Mechjeb was doing. It sets throttle based on an estimate of orbital energy, and has a quite stable altitude control. I only used half the fuel so it may need a redesign. More in this album https://imgur.com/a/LPmim7w and video of kOS altitude maintenance and landing. I went into a few intentional spins to slow down to land: Similar thoughts here, and air speed appears to be the ultimate limit, so to get beyond that, as you
  9. For anyone wondering how to do nuclear engines for this and approach the 33 minute range, here's a video of an ascent and getting auto throttle control. The craft is kinda cheaty, with the nuclear engine inside the main fuel tank, and was very unstable when the fuel ran out. The mechjeb autopilot can work for speed, but takes some babysitting to manage altitude.
  10. Nice! That is a nice optimization to put everything inline and put the nuke backwards. There is another potential time save, by going into retrograde orbit instead of prograde, so KSC gets closer to you while in flight instead of farther. It means going ~340m/s faster relative to the air, and a harder ascent, but by rough calculations it would reduce time by 3 minutes. It would use more fuel but that is hardly a concern since while in orbit, the only loss is drag and mass doesn't matter very much.
  11. The heat was a problem, but mainly the craft was too heavy to keep the height up. With a small redesign, I was able to get into "orbit" with help from rocket mode from the rapier engines. This orbit was ~2166 m/s surface speed at ~34k, so to go any faster it would have to thrust downward to keep from going into space. At this point I could use very little thrust to maintain speed. Just based on kepler's laws, it should be a significant amount faster than kerbin orbit in space). I did manage an actual run in about 35 minutes, though I got my altitude too high at some points, I overshot
  12. Not an official run (no command seat), just experimented with using nuclear engines and RAPIER. 57 minutes roughly. I used the nuclear engine to jump out of thicker atmosphere repeatedly (up to 35k), thinking it would allow higher speeds. The nuclear also helped quicken the initial ascent, as well as some spare oxidizer. I'd turn off the nuclear when the RAPIERS turned back on, and flew it all manually. The nuclear is tilted downward slightly, the theory being the plane could point forward and the nuclear would keep it up, but my assumption is probably wrong there. More pics: https://img
  13. I did this at level 4, trying to be smart about it, using rhino engines for the majority of the burns (better ISP than vectors), and with ISRU on Gilly and on Eve. Used a powered descent to Eve, and using default game settings. For the initial launch from Kerbin, I took advantage of all the Vector engines needed for the eventual Eve ascent and could put some enormous tanks on. I took 3 kerbals, the big ore converter and 2 drills. I also took a module to allow a surface sample, though that didn't work out. Didn't do any docking so that meant taking more mass on the whole trip. I initially
  14. Found an old screenshot from 2014 in version .23, think it was meant to drop the orange fuel tanks on things.
  15. After about 150 more attempts and lots of craft redesign, I got down to about 1:00.7 (judging from the first frame I got in the desired orbit). This was pretty hard to get. I used 4 "boosters" in onion staging, each consisting of 2 mammoth engines and 2 kerbodyne s3-7200 fuel tanks (plus 1 nose cone, 1 strut, 1 fuel line, and 1 decoupler), to accelerate off the ground really fast but still have a good amount of fuel. I used a more vertical launch profile, and also cut the engines for a few seconds while approaching the point to start thrusting sideways/downwards to get into orbit, because u
  16. The Kerbal budget meeting is in 2 minutes and you forgot to build any rockets all year. You need to get to a nice looking circular orbit as fast as possible to impress everyone. This is a fast challenge of piloting skills and quick thinking, and using a much different launch profile than you're used to. The circularization step is the hard part - a test of your understanding of changing orbits under pressure, as well as a game of "chicken" when to start circularizing, so you don't drop your periapsis or apoapsis below 70k in the process. It was inspired by various other challenges.
  17. This looks kinda stock but is it? Looks cool anyway.
  18. Did a mission to test the Vector engine landed on minmus. I used this funny looking craft which took off with 2 kickback boosters strapped to it. Coming back from minmus was where it got interesting, since I had only 200 m/s delta v in orbit of minmus which isn't enough to get back to Kerbin directly, so I used a mun gravity assist to get into a low kerbin orbit, so it took about 110 m/s instead of 300 m/s. Unfortunately due to bad time warps I had to revert it, but I got screenshots. Using mun to get to kerbin since I had almost no delta v.
  19. Did a bunch of missions in the Jool system. I used the nuclear engines and I can't say I'm too fond of them, although they served their purpose and let me be lazy in maneuver planning. My main vehicle was a modification of one I landed on Tylo, so it had all the bells and whistles. The launch vehicle & staging. It's a mammoth engine and 8 kickback SRBs. My final launch had nosecones on the SRBs which stopped them from colliding with things upon decoupling. A decoupler on a structural support on the fairing was the attachment method I used. Bop refeuli
  20. I had problems with scatterer crashing in 1.7.3. Removed it and haven't had any crashes since.
  21. I did the challenge in OP, orbit kerbin and return, but with 6 parts not 10. I used the biggest SRB, a decoupler, a swivel (for elec generation and gimbal), mk1 command pod and small parachute (best aerodynamics I found for takeoff). My initial orbit was a bit high but was able to land. The main challenge was getting the ascent right with only reaction wheels in the command pod, but after a bunch of tries I got it, pretty much hold right. For descent, I used the swivel to stay retrograde and also burn the engine so the parachute would activate. Fun challenge using only the 1.25m parts
  22. You mean this? The engineering sounds insane. I'm interested how well the stock electric props do, but I imagine solar panels could introduce a lot of drag which is something his ship tried to avoid.
  23. Mission plan was a single stage from Kerbin orbit, land on Tylo and back, using ISRU on Pol first, then Tylo. I used 6 Terrier engines for the low TWR burns, because they're pretty efficient (345 ISP). For the tylo landing and low altitude "oberth effect" burns I had a single Vector engine (315 ISP). Since it was already pretty heavy, it was easy to stick all sorts of accessories on it. Delta V was about 4500 for terrier engines alone, and 4200 when adding the Vector. Landing on Tylo it's best to have a pretty high TWR so you can approach fast and not pick up too much vertical speed on th
  24. I did a straightforward mission to Ike and Duna which costed 260,000 for the vehicle and rewarded about 4,000,000. One of the 3 missions was transporting about 3000 ore from Ike to Duna which I planned into the mission. It also needed to support 11 kerbals for another mission. The main stage had enough fuel to circularize around Kerbin, but not enough for the burn to Duna, so I had filled all the ore tanks prior to launch, and converted ore to liquid fuel while waiting for a good transfer window to Duna, then converted the rest while on the way to Duna. The Ike and Duna landings were prett
  25. Finally got a very cheap first mission home from Jool, no ISRU and only about 3000 delta V at LKO, using mainly gravity assists to get to Jool and back. Didn't take screenshots of the first part, but I took the Kerbin-Eve-Kerbin-Kerbin route to get to Jool (seems to be the easiest), so the initial burn was only about 1000 m/s to get the initial Eve encounter from LKO. More delta V spent fine tuning encounters. Used Tylo to reverse gravity assist into Jool orbit, and was able to do science and crew reports at a few of the moons, resulting in a lot of experience and science for a cheap pr
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