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NikkyD

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  1. NikkyD
    Aphobius is explaining gravity assists and NOT oberth. Oberth in simple means, u change ur orbit the most (stretch ur AP) if you burn in the PE. Pick some orbit, create a node with 500 m/s prograde. Now circle this node around the orbit (it should be a non circular orbit). In the AP the resulting orbit has the least distance traveled and in the PE it has the most distance traveled (because of most gain in kinetic energy and stuff). The whole effect simply describes what changes ur orbit the most.
  2. NikkyD
    Staging can do miracles. Lots of fuel (and thus boost) is needed only for the first 10 km to 20 km.
  3. NikkyD
    FLT400 without oxi is more efficient than the mk1 fuselage
  4. NikkyD
    You will always reach terminal velocity just before impact, which usually means about 100 m/s. So all you need to land is 100 m/s delta_v(atmos) and good timing or mechjeb. Sometimes not using a chute but some fuel can increase overall d_v
  5. NikkyD
    Just some hints Turbojets have a maximum speed of 2400 m/s, rapier has only 2200 m/s (both lose a lot of thrust above 2000 m/s but rapier faster n harder) Turbojets 225 kN vs rapier 190 kN. Weight 1.2t vs 1.75t You will not get as fast and high with a rapier as u will get with a turbojet. Space ISP of the rapier is 360, that is "ok" at best. There is the aerospike with almost 400 and the lvl 909 with 390. For noobies the rapier has a lot of advantages. But once you want "more" you are not getting anywhere with it. In space it has bad ISP for longer trips (may be ok for a mun trip) and in the atmosphere its just not as powerful as a turbojet. Keep in mind that in space, you have lots of time, so thrust doesnt really matter (to a point) but ISP does. 1 turbojet and 1 lv909 weigh 1.7t and give you the best performance in atmosphere and 390 ISP in space. (as a sidenote, you will have trouble building a stable ship with only one of each as you cant really center the thrust)
  6. NikkyD
    It was just a first prototype. I kind of despise those cubic struct things, the rocket/plane should look like one object and not like bad-LEGO. Also the LV1 with 1,5 thrust... gnaaa
  7. NikkyD
    Yes, i'd prefer that as well. Intake + housing + engine, thats it. Would be less to argue then.
  8. NikkyD
    a 70 / 45 orbit i already managed. Would have been 70 / 50 with more fuel. With crazy amounts of intakes something close to 70 / 70 is probably possible but to reach a stable orbit, in principle, you need to burn at the AP that has to be in space. Storing air inside a closed intake sounds kinda shady. Why would the air have the necessary airspeed ??? Whats the point of airintakes storing air anyway ?
  9. NikkyD
    Good to know. Btw, Are wings actually useful at all ? Im thinking about building a bigger plane for my personal projects... is there a variant where forward thrust + wings results in better uplift than just rocket-style flying straight up ?
  10. NikkyD
    I cant build a craft with a manned chair with vanilla game. I can place a chair on the craft but i cant assign a kerbal to it. Using a 2nd craft to switch crew is imho against the rules, because you use a 2nd craft. @ redshift With jets alone i can reach AP of about 130 to 150, my best "almost" orbit was 70 AP / 45 PE. Its not stable but that would be jets alone. Im pretty sure you could achieve a stable 70/70 orbit with pure jets, LOTS of time and lots of fiddling. I did try this: http://imgur.com/9A7P3Wz its ugly as hell, qualifies for a plane only with both eyes shut but... does the job (poorly). I do need 100 kg more fuel with it. Ok, i implemented several things, but the start alone takes 5 units of fuel because of the higher drag at sealevel. So can vs cockpit may have saved 200 kg, but i definitely need more fuel. So the variant with plane cockpit is more fuelefficient.
  11. NikkyD
    The atmosphere may fall off at an exponential rate, but the drag increases at v^2*m*d [...]. I did calculate some drag at 30k with 2000 m/s and it was somewhere 32 kN with a coeff of 0.17. So if i have less weight, then i can use an even smaller ascent angle to battle less gravity, but mechjeb doesnt allow floats so im somewhere in the 1 digit degrees area here at the altitude. Edit: http://imgur.com/WchCzD1 simplified model, assumes perfect conditions etc. Not sure if all the calculations are in order, but there pretty close. It only calculates up to 45 km, because of my phones resolution horizontal is speed in 100 m/s steps
  12. NikkyD
    I need to finish my program to simulate different possibilities regarding grav vs drag. Im not so worried about the lower atmosphere. I go straight up like a rocket, im more worried about final speed n altitude, because thats what really saves me delta-V for creating a stable orbit. I admit, that here there is a benefit of having less weight (small caps) but ill have to see how much v-max it costs me. The wings, tbh i just took the best normal wings and accepted it. I realized later that i dont really need them... i just want it to look like a plane, at least a bit. A can with 2 winglets just reminds me of comic book rockets
  13. NikkyD
    Why would u suggest that ? have u done the math ? its worse with the landing can because of its drag coeff 600 kg * 0.2 = 120 1000 kg * 0.08 = 80 edit: didnt mean to be rude, but what u are suggesting is worse than what i have
  14. NikkyD
    Those tiny crafts are unmanned! And as i wrote, i dont want to use glitches or part-placements what can only be achieved by using tricks.
  15. NikkyD
    So... i got to a point where the game is limiting me. I replaced my rapier for a turbojet and put 2 48-7S aside it. I removed 2 of the swept wings and reduced the fuel to about 40 Units liquid and 20 Oxi. With the turbojet alone (with 3 intakes) i can fly up 90° like a rocket, turn 5° at about 20km and accelerate to 2100 m/s surface (reached at somewhere 25 to 30 km), which at this point would be 2300 m/s orbit. With mechjeb managing the intakes and throttle i can thrust to about 40 km but its merely 5 kN thrust or less, but thats enough to fight any drag that still exists at that height. My projected AP is about 100 km with a PE of -20 km. Thats pure Turbojet at this point. At the AP i need just a 5 sec burn or so with the 2 rockos to achieve a rock solid 100 km orbit. Decending requires about 60 m/s retroburn and the rest is aerobrake and glide. If i could, i would drop so many more parts to make the thing lighter... but its impossible to attach the still necessary parts to the ones that remain. Thank god the cockpit is so huge, that gives me plenty of mountpoints for the wheels and wings. The lightest mount for intakes unfortunately is a small fuelcan, even if that can is only filled to about 30%. Which means the 1/9th of container weight turns into 1/4 th. So i would need the next flattest version of a fuel can. Because the engine makes about 40% of the total weight, my center mass is at the very rear, which makes it difficult to place the gearbays and wings so far back that it allows for stable flight and more importantly LANDING. I wish that all parts would come in "tiny" size as well. With reasonably weighted engine housings (300 kg for a thing that does NOTHING is a joke)... tl;dr; With only vanilla parts at hand and no glitching/cheating i cant improve my vehicle any more and its almost perfection and i doubt that anyone can do any better so the game sets the limit for this challenge which makes it less of a challenge :/
  16. NikkyD
    Does any one know the exact formula of Ram Air Intakes ? I just figured out that it makes no sense to accelerate to more than 2000 m/s because thats were the thrust critically drops. I want to calculate my maximum altitude but i cant find the formula for the intakes. During the flight it says "Units" of air and sometimes my engines still can breath with 0.00 intake air resource
  17. NikkyD
    No, the budget to the mun is pretty much what i remember. I had a tweaked ascent so reaching mun with 2nd stage still having 100 m/s or more left was always the case. It's the mun descent and ascent that throws me off. I could swear it was less than 800 m/s for both... or somehow i didnt need that much or... i dunno
  18. NikkyD
    So i played around a bit and the budget seems to be way off... i dont get it The lander stage with about 1500 m/s on its way too the mun, landing, getting back up and "crashing" into kerbin was somehow possible but now, i really need the 800 m/s to land AND again to go back up... how did i pull this off in .21 and before ?! I do remember that the last change was switching a 909 out for a 48-7s, as it was new at that point. And im not sure if the rocket was still operational with the 48-7s. But if i switch back to a 909, even if i double the fuel on top... im off by far. Maybe it wasnt working in .21 but in .20, i stopped playing for quite some time so i cant be sure. But was there any major change from .20 to .21 that would explain this ?
  19. NikkyD
    Thx mate, that rules that out Will check tomorrow, mechjeb is indeed fresh install and the .22 version (no .23 out yet ?! ) Lets face it, if you wanna go all "real men do..." u win, but as a programmer i would write myself a plugin that lands as perfectly as possible, but someone already did that for me, why not use it ?
  20. NikkyD
    Out of curiosity, is it "legit" for the challenges here to stack ram intakes into eachother as some do ? Ive seen some attached at the BACK or a tank but pointing forward etc. because maybe i could manage to drop one of my tanks ^^
  21. NikkyD
    I dont really remember the .21 stats :/ I searching for my papers, i wrote down all the calculations to that point but... big pile of papers What im wondering is that i am in lunar orbit with 1200 m/s left, and i remember that this was sufficient to land a craft that small and light and bring it back. I did let mechjeb do the landing and it thrusts always in the last second(s) and stop perfectly. But with .23 mechjeb keeps the engines running at 1/3 during the fall... its messing up somehow I know its little safety in this rocket, but its the end result of a lot of tweaking etc. It did the job with almost nothing left when it landed on kerbin. This includes a very tricky atmospheric braking so maybe thats why the those "rule of thumb" maps make it look closer than it actually is edit: I didnt bother for a lunar orbit on the way back, it was a straight shoot up into the sky, escape and be on an almost crash course with kerbin. Return never costs much, i just need to touch the atmosphere so much that it brakes me down into a kOrbit. Second or third braking will do the final job.
  22. NikkyD
    The major problem is the uneven thrusting. Just built a plane with 4 rapier when air was getting thin, one engine suddenly switched, the others a couple of seconds later but thats enough for the plane to spin. If they dont switch all at the same time, they are BROKEN and cant be used.
  23. NikkyD
    My personal comparison ended up with turbojets failing me at about 28k with 4 ram intakes at over 2000 m/s whereas rapier could go to 32k with only 3 intakes. I havent figured out why, yet.
  24. NikkyD
    Its driving me crazy. In version 21.1 i built a very minimalistic munar lander, removed part by part, tweaked with mechjeb and saved the rocket. Now im loading it in 0.23 and its no longer working. Rocket http://imgur.com/xp71coG The only major changes are the monoprop in the capsule and the 48-7S had a thrust increase from 20 to 30 kN. The monoprop i removed, the thrust should be massively in my favor. The idea behind this rocket is, that the biggest starter stage is dropped while still in the atmosphere so that it would return to the surface to be recovered or at least not trash my orbit. The second stage is the orbital + travel stage with the 909 engine with max efficiency and slim/short design. The third stage, the lander, lands on mun, gets back up and back to kerbin and lands there without the need for a parachute. It worked in 21.1 ! But now, the best i can manage is to get to a 100 km munar orbit with about 1300 m/s left. The latest mechjeb version that i have and use does some really weird things for munar landing, constantly burning with 1/3 thrust and stopping in a height of about 30m then drops and brakes again... wasting 800 m/s. And even if i start manually, with 400 m/s or so i cant make it back into space + munar escape! It once worked and there the lander had less thrust! The 20 to 30 increase in thrust should make the escape a cakewalk. Does anyone have any ideas what could be the problem ? Did any part change that i missed ?!
  25. NikkyD
    Lets see if i get the imgur thing straight My attempt for minimalist with Rapier, images should have descriptions and guides if someone wants to copy/improve/fool around
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