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SanderB

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Posts posted by SanderB

    Stock Payload Fraction Challenge {1.3.x Reboot}

    in KSP1 Challenges & Mission ideas

    Posted

    27 minutes ago, ATEC said:

    @Laie Fixed the rules, Nerv's now also count towards unlimited and not rocket only

    Can you compare my 29.4% craft and Laie's craft? I think they are easily different enough to qualify as different submissions. My payload is made of unshielded ore tanks with a fairing on top, I use only 2 engine types, have fewer stages, my vessel is released from launch clamps and has very different starting mass; to name a few differences.

    Stock Payload Fraction Challenge {1.3.x Reboot}

    in KSP1 Challenges & Mission ideas

    Posted

    29.2% achieved. This rocket uses 14 vectors 2 nerv engines and I completely made it up myself after reading Laie's posts. I can launch it pretty consistently.by pointing it prograde at 50m/s airspeed. Some tilting up is required to maintain enough upward vertical velocity and you do actually need to do a 2nd pass through the atmosphere, but... improvement has been achieved. Or at least, I have attained the fraction that I said could theoretically be attained with Laie's craft.

    craft file: http://www.filedropper.com/004fpayloadfractionchallenge

    And I still had 19m/s dV to spare at the end, so further improvement yet again is possible...

    Stock Payload Fraction Challenge {1.3.x Reboot}

    in KSP1 Challenges & Mission ideas

    Posted · Edited by SanderB

    41 minutes ago, Laie said:

    @SanderB: Whoa, that's neat. On my best attempt I had like 10m/s left, on the others I could barely eke out 90x90 on vapors. Considering the number of "almost but not quite" designs that preceded this, I dare say that 0.2% is a great improvement.

    Also: Whenever I take screenshots it becomes a failed attempt; I do have video of a successful launch, but have spent the last hour trying to figure out a workable compression that's still intelligible (I'm hosting my own files, hence bandwidth is a bit of a topic). Your upload solves that nicely. Thanks!  And anyway, independent confirmation is always great. Double thanks!

    All I did to improve the scores was to not fly your rockets sideways on into the airstream :rolleyes:.

    Actually after getting the right ascent trajectory and hitting prograde SAS, all I do is stage. It took me about 10 attemps to get this result.

    I use Open Broadcaster Software. The files that it produces are only about 9MB per minute with my settings and they upload handily and very quickly to youtube within 20 min of recording.

    Stock Payload Fraction Challenge {1.3.x Reboot}

    in KSP1 Challenges & Mission ideas

    Posted · Edited by SanderB

    1 hour ago, Fauble2000 said:

    Awesome, <a href=http://www.filedropper.com/missingsomething><img src=http://www.filedropper.com/download_button.png width=127 height=145 border=0/></a><br /><div style=font-size:9px;font-family:Arial, Helvetica, sans-serif;width:127px;font-color:#44a854;> <a href=http://www.filedropper.com >file upload storage</a></div>

    just post the link normally

    Laie's craft:

    . There is 2 tons of unspent liquid fuel in 90kn LKO so it is theoretically possible at least to get 0.2% more.

    Stock Payload Fraction Challenge {1.3.x Reboot}

    in KSP1 Challenges & Mission ideas

    Posted · Edited by SanderB

    I've slightly exceeded Laie's exceptation and got to 27.2% (120,875/444,928) with a slightly modified version.

    I expect that 0.2% perhaps 0.3% can be added by adding more to the payload, staging as efficiently as a KOS script would and not exceeding the ap by more than 1  meter.

    Craft file. Flying instructions: Turn on SAS, stage, SAS prograde at 110m/s airspeed. (stage twice whenever an engine cuts out.) Once pitch is less than 10 degrees, maintain pitch at 10 deg. When AP is 90km, cut off engines. Circularize at AP.

    I think more efficiency might also be achieved by not forcing pitch to be no less than 10 deg while thrusting but I can't be bother to try.

    The Definitive KSP Speedrun.

    in KSP1 Challenges & Mission ideas

    Posted

    4 minutes ago, MoeslyArmlis said:

    Ah yes I was trying for humor; from wikipedia  "Four minute barrier".

     

    That would certainly shave minutes.

     

    the problem I've encountered with a perpendicular landing is that it takes me a while to line up my ascent from the mun with return trip from the mun to KSC, because you have to time your descent to about 6 hours so KSC will be in the same place as when you set up your return maneuver, so you can set up your return. Without trajectory prediction it's going to always be very tough. The mk1 pod with 2 tons of fuel and a terrier engine (and 3 landing legs and 3 aerobraking flaps) is capable of a little bit of atmospheric flight (ie. gliding at up to 30 degrees pitch in any direction) but only from ~10km altitude onward.

    The Definitive KSP Speedrun.

    in KSP1 Challenges & Mission ideas

    Posted

    that was very interesting to watch.

    The only way I can see to improve that time by a lot is by not passing LKO on the return from mun, but instead land perpendicularly straight into KSC. You'd have to burn off ~1km/s of velocity before reaching 40km altitude and manage to do a precision landing without orbiting, but it is theoretically possible.

    The Cheap and Cheerful Rocket Payload Challenge 1.0.5

    in KSP1 Challenges & Mission ideas

    Posted

    I think the smaller fuel tanks generally are less efficient per fuel unit and it never changed ever as far as I remember. I wonder how efficient a 1.25m cross section launcher can get (ie, a sustainer stage with LFO engines not exceeding 1.25m in diameter). I might be wrong but I believe 830$/t is the best achieved so far under the previous ruleset. I've been looking things over a little and it'll have to be more expensive because of how less efficient the engines and fuel tanks are in several ways.

    The Cheap and Cheerful Rocket Payload Challenge 1.0.5

    in KSP1 Challenges & Mission ideas

    Posted

    (1,590 + 3,700)/6.389 = 828$ / t if my calculations are correct, which if they're not they can be recalculated with the numbers KER shows. No tail fins, 80km orbit. I think this is it. Launching it is pretty simple once you have it tilted correctly in the VAB; launch, stage at burnout, maintain prograde (20 degrees) minimum pitch, circularize at 80km and separate payload. The tilt is the hardest part to design because the slightest change results in drastic differences to the ascent profile. If you change the payload only a little, everything changes.

    My design can be currently gotten here: http://www.filedropper.com/03expendablelauncher

    If I'm not mistaken this design is the most cost/t efficient for of all the vehicles with a 1.25m cross section (even though there is not a separate leaderboard for them as far as I know). There is space for a bit more efficiency but I didn't want to spend the time to fine tune it THAT much.

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