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Everything posted by bewing
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Planning bi-elliptic interplanetary transfers
bewing replied to Laie's topic in KSP1 Gameplay Questions and Tutorials
If you look at a porkchop plot of near-hohmmannly tranfers to anywhere, you see that the dV cost increases really fast when it's slightly non-optimal. I promise that it continues to increase really fast even off the edges of the porkchop plot. Just for fun one time, I turned on infinite fuel and flew to Jool on a fairly direct and fast intercept ... I calculated the final dV cost of the experiment at somewhere around 26km/s, IIRC. To leave Kerbin at a non-optimal time, you have to redirect your vector using a gravity slingshot from a flyby of Eve or Duna. There is no other practical way without expending hellish amounts of dV. -
The problem is generally microbouncing. The gear sink a little way into the ground and then are forced back upwards with excessive force. This means that the entire craft tends to "float" a fraction of a centimeter above the ground for a few percent of each second -- while all the gear is in the air. Obviously this means that there is no friction during that period, which allows rotation and movement. Unbalanced forces can even cause uphill microbouncing. It was supposed to have been improved in 1.8, but I haven't tested it out again -- I haven't bothered used landing legs/wheels for spacecraft since 1.0.5.
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When a Kerbal dies, there are two possibilities. KIA and MIA. If they are KIA, they never respawn. If you have the setting for "no respawn", and then they die, they get marked KIA. If you then turn on respawn -- they stay KIA. MIA is always supposed to happen if they die when respawn is active.
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Kerbal characteristics
bewing replied to jimmymcgoochie's topic in KSP1 Gameplay Questions and Tutorials
Courage actually does have a bit of an effect on G force tolerance. -
Getting from Mum polar orbit to minimus
bewing replied to TanDeeJay's topic in KSP1 Gameplay Questions and Tutorials
No, it's more like Roger Rabbit. We're just seeing whose willpower breaks first. Shave and a haircut, .... -
Getting from Mum polar orbit to minimus
bewing replied to TanDeeJay's topic in KSP1 Gameplay Questions and Tutorials
Correct. Pretty much, but to get back to kerbin you want to be going retrograde along the Mun's orbit, rather than prograde. But yeah, if you are in a polar orbit then you can really only leave twice during a Munar month. -
Getting from Mum polar orbit to minimus
bewing replied to TanDeeJay's topic in KSP1 Gameplay Questions and Tutorials
Important info: If you fly to the Mun and directly dock your minmus station to your mun station, then undock -- then your minmus station will no longer be "new", and your minmus contract will fail. You can do the minmus contract first, then fly the whole contraption to the mun and do the docking and that will cover both contracts perfectly. But if you go to the Mun first, then you have to be very very careful not to ever dock your whole minmus station to the mun station. You would have to decouple a hab section from the main craft without docking, then dock the hab section to the Mun station while it is in free flight -- and it would just get complicated and annoying. But yes, as 5th horseman basically said, to get from the Mun to Minmus takes very little deltaV but you have to time it right. You would want to go when your orbit is parallel to the Mun's velocity vector, and that vector leads the position of minmus by about 90 degrees, as I recall. And the trip takes about 15 days. -
Or add moar boosters!
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Bug in the ship, or bug in the game?
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
Since you are using mods, there is always the possibility that it's a bug in a mod. -
Generating 2,500 'units' of electricity in space?
bewing replied to GungaDin's topic in KSP1 Gameplay Questions and Tutorials
Are you sure you have to generate it? Most station contracts require storage, not generation. -
Spaceships lose connection no matter what!
bewing replied to Fenceingmadman's topic in KSP1 Gameplay Questions and Tutorials
Red almost always means you ran out of electricity. -
The map view model of the CB is just a model. Yes, it is known that none of the models precisely match the CBs. You should have seen the differences between the models of Gilly and Bop and reality before they got fixed a few versions ago -- those were really really bad. They were off by kilometers. It's one of the reasons why the typical "suicide burn" technique is so dangerous -- you're trying to create a maneuver node in map mode on the CB's surface, but you can't trust what appears to be the surface in map mode.
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Retractable radiators cool your entire ship. It doesn't matter where you place them. But no, you can't attach anything directly to a converter -- you'd have to attach all your stuff to the little ore tanks.
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You're not losing thrust. Getting from 330 m/s to 400 m/s is the game's Mach 1 barrier, and that is where drag is highest. Your problem is drag, not thrust. Somehow, either you've made a little tweak to your craft that increased drag a little bit, or there has been a slight change in the version of the game and the aero calculations have changed a little bit. It does not take much of a change to make a working spaceplane suddenly not get past Mach 1 anymore. You have a hell of a lot of little goodies radially attached to the outside of your craft. It looks like you also have a cargo bay. You need to take most of the radially attached thingies (radiator panels, gigantors, science experiments, antennas) and move them into your cargo bay. Yes, it'll be a little tricky making it so they still serve their functions and deploy properly after putting them in a cargo bay, but that's definitely the easiest way to cut your drag by a lot.
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SSTO spaceplane not gaining speed
bewing replied to mbound's topic in KSP1 Gameplay Questions and Tutorials
You are in "MK2 hell". MK2 parts (while pretty) have enormous drag compared to their performance. They have two benefits on reentry (high drag and high temp resistance), but on ascent if you cannot brute force them through the sound barrier (at about 370 m/s) then you will never reach space in the first place. So, redesign your plane and throw away every last MK2 part on that craft. Replace them all with equivalent MK1 parts. Fly your craft easily to space. Then wonder why it seemed so hard the first time.- 13 replies
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Radial attached and drag
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
For node attachment drag, translation has no effect. So a 180 degree rotate will have no drag. -
FYI for the future: Spaceplanes veering on takeoff is actually a very common problem. You will probably see it again. It is common enough that it is included in the FAQ on this forum. It is actually a real engineering problem, but it comes from many different causes. It can come from flexing of the landing gear or whatever parts the landing gear is attached to (wings), or from wheelbarrowing, or from not taking into account "ground friction". So the next time you have this problem come back and read the FAQ and then ask again here. We can all go over the possibilities and fixes with you.
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Radial attached and drag
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
The thing that makes the difference is the shape of the part compared to the airflow, and also compared to the part "in front" of it. If you take a 1.25m cylinder, and put it underneath another 1.25m cylinder and fly them through the air exactly prograde, then the lower cylinder is completely shielded from drag by the upper cylinder. If you rotate the lower cylinder 180 degrees, then it is still exactly the same shape, and will still have zero drag in the same circumstance. If you only rotate it 90 degrees, then the bottom cylinder is no longer the same shape as the upper cylinder, and will suffer some drag, but will be partially shielded from drag by the cylinder above it. -
As mk1980 said, the An and Dn shown on your target orbit are relative to your current craft's orbit. The Longitude of Ascending Node listed in the contract is in the absolute coordinate system of the galaxy, and is completely irrelevant to anything that you need to do. To complete the contract, hover your cursor over the An or Dn on your target orbit. You want that number to go to zero. You make the number go to zero by burning either Anti-normal just before the An, or Normal just before the Dn. You generally do this before you make your final adjustments to your Pe and Ap. You adjust your Pe and Ap by burning prograde or retrograde. If you ever really do need to move your An on your orbit, the way to do it is to burn prograde just before or after your Ap. The Ap will rapidly move away from your current position in your orbit, and this will move your An. Similarly with your Pe.
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Radial attached and drag
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
For each part, the game uses an aerodynamic modeling to generate something called a "drag cube" and stores the info in the part database. Depending on the orientation of the part, it has some drag coefficient calculated for it. If the part is radially attached, then the drag cube causes drag, depending on the orientation. If the part is node attached, then the drag cube of the part is reduced by the drag cube of the part that is next closest to the front of the craft, before calculating its drag (any offset is ignored). -
Can someone explain an SSTO flight profile?
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
When you launch a spaceplane, you always turn SAS on first -- unless you want to fly it with a joystick (which is usually annoying). So the function of the F key in that case is to momentarily turn off SAS. If your spaceplane is built to be stable then flashing the SAS to "off" for a moment should always cause the nose to drop. You can watch your "pitch" control indicator to make sure you always have positive pitch control. -
Can someone explain an SSTO flight profile?
bewing replied to Jestersage's topic in KSP1 Gameplay Questions and Tutorials
There are two philosophies of SSTO spaceplanes in KSP. There are designs with plenty of wing, and designs with very little wing. Your ascent profile depends strongly on which philosophy you follow. However, it sounds like you are climbing too fast. It's best if the Ap stays in front of you always. If you get too high while you are still too slow, then you will start to fall back down into denser air again -- usually that will really kill your rocket performance. I go for the big wing philosophy myself. Which leads to an ascent like this: after launch, only use the F key to adjust pitch. Climb at a little over 10 m/s until 5km altitude, at low thrust and less than 5 degree pitch. Go to full thrust, break mach 1, climb 1km for each 100 m/s of speed, at 14km start bringing the nose down to allow a mostly horizontal speed run in airbreathing mode. As the jets approach max speed, allow the nose to rise. At just past peak speed, activate the rockets. Allow the nose to rise naturally and the jets to flame out. Then the key is to keep just enough pitch on the nose to climb while still increasing your speed. Then all you need to do is climb fast enough to avoid overheating and melting. Above 40km altitude, lock to prograde and finish the climb to orbit. This whole process can easily take over 15 minutes of flying time, but will get big payloads to orbit with very efficient fuel usage. The small wing philosophy is totally different. It goes something like: raise your pitch to 45 degrees, go to full thrust, and coast then circularize when your Ap gets above 70km. This takes much more in the way of engines, and is therefore not so good for payload fraction.