Jod

Thank you, Captain. We've established that several times on the first page. As I said, the problem with ion engines is the inability to counter Drag. With the current Lift model we can counter gravity acceleration all day using a matchstick for propulsion. Looks like it's back to LV-Ns for me. Though I'm pretty sure their weight will screw things up with this ridiculous Drag equation. What bugs me the most is it probably would have been possible(a dry to full ratio of just around 1/5) to SSTO Eve if it had no atmosphere. Aerodynamics are useless. Does anyone have an elevation map of Eve in its current form? I've been watching Scott Manley videos and noticed it took him only 8000 delta v when taking off from 10 000m. I'm aware that the plateau is gone, but is there anything close enough?

I've found my problem with Drag. According with a formula from the wiki - if you have around 2000m/s speed and 4 tons of mass, ion engines will be entirely unable to compensate for Drag below 40 000m on Kerbin and below 70 000m on Eve. So it's not a question of at what altitude to deploy solar panels but at what altitude the drag won't eat up all the ion engine thrust since the latter is much higher.

I'm guessing around 40 000m. With small craft - you can pave wings in OX-STAT provided it is noon and you have a small craft where less than 300 OX-STAT(enough for 8-12 ion engines max) are enough. The problem is battling drag and actually stabilizing when switching to ions, I've yet to do it on Kerbin. Also - I am getting weird results for lift and drag at high altitudes. Can you compensate for Drag with Lift in KSP? As in - add more wings? And how exactly is the Drag vector oriented? Pointing to retrograde?

I have a bit of a progress regarding aerospikes. I tested a TWR of 1.6 on Kerbin and it took around 4600 delta v to put in orbit. Almost no drag losses. Question is - will 4600 delta v be enough to lift ion engines on Eve up to an altitude where solar panels can be deployed? It should still be able to operate in 1.7 gravity, though the atmosphere density could be a problem. Here's my proof of concept, consisting of 23 stock parts: And here it is in polar orbit(it was not controllable very well, i literally whipped it up in an hour or so) Notice the 2 half-ton landing gear on the wingtips. I could optimize that for more ion engine load.

Why is there only SSTO for Kerbin? There are a lot of places I've visited with my SSTO craft(Eve orbit, Mun/Minmus). I've even seen people take SSTOs to Duna/Laythe surface and back, without refueling. Though I can see how it can get confusing what exactly an SSTO did in that SOI...

True, I have problems with that during reentry, but there are workarounds for that. Placing most fuel tanks near the CoM helps. As well as pumping fuel to forward tanks if you have heavy engines in the back. Also, you haven't mentioned the Drag force. If the craft has a lot of air intakes, it is possible to bind them to an action key to close/open when additional stability is needed. Wing lift indeed is completely inaccurate in KSP. Don't even get me started on this one, I had an exam on aerodynamics recently.

Decided to document one of my SSTO launches yesterday: http://forum.kerbalspaceprogram.com/showthread.php/34689-First-kerbal-to-space-In-style The exact cargo mass is 9,26 tons. Landed on runway. Nothing groundbreaking, just a good, mostly stable, mission flight, one that I didn't have many of recently.

While launching my SSTO probes to Eve orbit, it occurred to me that I've yet to launch a single kerbal to space. And I have a refueling station right in Kerbin orbit with cosy 4-person apartments too. So I took my freighter variation SSTO, the KASA Moth IX-C and attached a cupola module with some RCS to the cargo port. It is a rather old design that doesn't use LV-Ns for some reason, instead it has 2 aerospikes for space maneuvers and a Skipper for boosting through higher atmosphere. Nevertheless, I hoped it would get the job done. And I took off right after attaching 4 parachutes to the command pod(just in case). Jebediah bravely volunteered to be the pilot/passenger. (click the images to enlarge, 50 full res images would probably lag weaker PCs) I completely forgot how well the cargo variant flies, it took off like a feather right from the end of the runway. I really need to balance my fuel tankers this way. Getting 9 tons of cargo to space was a breeze, 8 turbojet engines had more than enough power to push it half the way up to 1500 m/s. And we got to space with some fuel to spare. And it flew straight up the equator too. Now, let's detach the cargo and... watch it fidget relentlessly. Jebediah! Why have you not reminded me we need ASAS on the cupola modules?! Argh... I'd hate to use exploits but it looks like that without time warping to stabilize heading we are not going anywhere. Note to self - never trust Jebediah to fly anything straight. But wait - I have a small orbital tug docked to the station. Maybe I can use this.... If it hadn't a fuel tank permanently stuck to it! After several minutes of trying to undock the pesky fuel canister I decide to just haul it along. And here we are! This might work yet. Wow, that looks almost as if it was intended to fit together. Jeb, what do you say we not mention the whole ASAS incident and split the credit, eh? Anywho, now that we can maintain heading we can finally dock to the station! Now that Jeb is accommodated - it's time to return the freighter back to base. First step - open the air intakes to increase drag and stability on reentry. Step two - transfer remaining fuel to the front to compensate for slight mass center shift and heavy engines in the back. Step three - do it again during reentry because you obviously messed up the first time. As you can see, I burn retrograde right near the large crater on the other side of Kerbin to get periapsis all the way down to surface. It works well enough in most cases. I also select some craft debris near the landing strip as a target to get a sense of direction. Though it deselects after entering atmosphere for some reason so i have to select it again. And there's the rest of the journey. Textbook reentry and landing right on the landing strip. Craft handles like a charm, ASAS tries to nose-up for some reason but with most fuel spent it is easier to fly manually anyway. Managed to lose control and do one nose-up loop on the way but stabilized easily, no screenshot of that because panic. Also - completely forgot to track speed relative to surface until the last moment. Come to think of it - I really should've documented the ascent like this as well, but I was more concerned about Jeb's life at that point. In any case - Jebediah was transported to space with no casualties on the first try, the craft returned to base and is ready for refueling. Mission successful! Yay I will go sleep now I totally wasted several hours on this huge post.

The only bad thing that can happen in a community with mods is when people start making cults around them and force their opinions on others. Doubt it will happen on the KSP forums anytime soon. Install what you want and don't care about what anyone says.

Unfortunately, I don't think there is a way of refueling SRBs... As for liquid fuel - I'm getting immence drag due to huge fuel tanks required, which pretty much rules out aerospikes as an initial ascending engine. So the real problem right now is getting to at least 15 000m height, after which LV-Ns work semi-well. Can anyone post links of good Eve ion planes? I am still considering that option.

Thanks, I've already glanced through the Drawing Board. The docking tutorial was helpful when I was assembling my space station. I will look into the Mission Report section. I've already posted one of my missions in an unrelated SSTO topic, will probably move it there.

Good day, I am Jod. I am currently obtaining a masters degree in aviation engineering and instead of preparing for exams I've been playing KSP for the past couple of weeks. I like all sorts of winged contraptions, engine noise, and shiny things. Currently I'm going for a 0 stage aerospace game(everything is built in the aerospace hangar, no decouplers allowed), with SSTOs, space station modules, clampotrons etc. But there are several problems, mostly with Eve, which I hope I will solve eventually. On the upside, I've already perfected my first SSTO to the point where 40% of fuel is left after reaching low Kerbin orbit.

Currently testing a low TWR 7000 delta-v(calculated with an average 500 Isp) aerospike/LV-N combination on Kerbin. It can get to space, but atmospheric drag eats a LOT of delta v, which is my prime concern. Does anyone know how terminal velocities work? How much does meeting terminal velocities improve burn efficiency? Low TWR planes don't look very promising at this point.

Unfortunately, my PC can't handle more than 400 small solar panels(ones that don't break in atmosphere) and the PB-NUK are too heavy, so looks like the ions are not an option for me. Trying with an aerospike and LV-Ns. Math says it's gonna be close.

I shall waste ALL my time trying! Though I did the math and looks like I'm stuck with Ion engines and LV-Ns as means of propulsion... It won't be fun flying this thing. Will post the thing if triumphant. Probably will even if not.

Lol I forgot to mention I am making a glider. I'm making everything in the aerospace hangar as I haven't even touched the vehicle assembly building once. Drop tanks are out of the question, it won't be an SSTO with them. And without drop tanks, for liquid fuel the dry mass is at least 1/9 of the full mass, which rules out any engine with an Isp less than 600. Ion engines have really, really low TWR, but flying with them is not a problem, the problem is accelerating within reasonable amounts of time. So if they can get a fuel tank+nuclear engine to 20 000m in less than 30 minutes I think it is possible to pull off. I will try this on Kerbin and see how it goes.

I am determined to make a single stage lander-lifter for Eve, and looking for possible configurations. I've gone over the math for 11500 delta-v required and it seems that only Ion engines and nuclears( >600 Isp when above 20 000m) can lift a single stage from Eve surface. At a ridiculously sluggish pace as you can imagine. Aerospikes are not even close to the needed Isp, falling short by a third or so. Has anyone tried to make this kind of craft? I would imagine a lot of nuclear engines, even more ionic ones, and a single aerospike(to at least somehow boost the craft) can pull that stunt off with 1-2 tons of cargo(some kerbals at least... i dunno, in seats?), though I have my doubts about this setup, especially if the drag eats up the really slow acceleration it provides.

I'm aiming for the orange tank payload as well. Hopefully I will someday be able to finally achieve my dream of a non-stop SSTO carrying full orange tanks to Eve surface, unloading cargo, and making it back to Kerbin.

THIS is the newest Kerbal AeroSpace Association Heavy Tanker codename "Moth" model Mark XI, Extra Fuel tank variant. It weighs 108.78 tons, made from 339 entirely Stock parts. It costs 6600 Kerbucks to fly this craft for 30 seconds. KASA Moth XI-F is a variation of a more baseline KASA Moth IX-C Heavy Cargo Carrier model, which instead of the extra fuel can lift payloads of up to 20tons into Kerbin orbit using the Large Clampotron bay near its center of mass for precise balancing. Here you see the craft leaving Kerbin on its way to the Mun on a test run without refueling. It sports two nuclear engines for interplanetary travel as well as 8 turbojets for Kerbin lift-off and a mainsail acting as a booster to reach orbit. Engine configuration is still in the works, with aerospikes being considered as a more efficient booster than the current skipper/mainsail variants. Among the high points of the craft - it can: -Refuel entire fleets in orbit -Easily transport cargo without changing position of its center of mass -Glide and land on Kerbin with no engine thrust -Fly without a kerbal pilot -Leave Kerbin orbit on 2 aerospikes without refueling -Launch medium-sized space stations -Itself be a space station Insurance does not cover rapid part separation during time warp while in atmosphere, no money back guarantee or any other form of compensation will be provided. Here are some screenshots of its test run. I'm considering making this craft public when I finally figure out the most fuel efficient configuration for getting into orbit within reasonable amounts of time and piloting effort. Do note, however, that lift, thrust and drag centers are already balanced so it handles well even during reentry, I even managed to land it right back on the space center runway once. RCS is consumed in ungodly amounts though, especially when ASAS is turned on. The test run was a success btw, so I decided to visit Minmus and leave the craft in its orbit.

OK, so I was building an SSTO freighter for about a week now and here is what I picked up during this lengthy and painful process. Flying an SSTO to orbit consists of 4 flight stages(assuming a plane with wings + lots of air intakes and jet engines for the initial ascent), during which you will mess up in many horrific yet very distinct ways: 1: Take-off. 2: Up to 10 000 m 3: 10 000 - 30 000 m 4: Up to space 1: During take-off there are 2 things to look out for: -Lift center balance. It shouldn't be too far ahead of the mass center or the craft will nose up, then dive and crash. Too far back and you simply won't take off. -Landing gear placement. It needs to be very sturdy, including what it is based on, some things just won't hold it. Should usually be placed so that the wings would have at least 3 grades angle pointing upwards, 5 is best. Also there's the problem of anything behind the rear landing gear clipping the terrain and exploding. So place them as far back as possible. Possible issues: =Can't compensate for the nose up momentum, goes into a loop and crashes: +CoL too far ahead of CoM =Can't take off at all(could be any of the following): +CoL too far back of CoM +Wings are at less than 3 degree angle +Not enough lift =Rear end clips terrain: +Landing gear placed incorrectly And possibly +Too much nose up effort, ease up on the controls Preferable:configure the craft to take off of the runway, not halfway to the ocean. it is a good idea to do so and will sometimes make landing that contraption much easier. 2: The smoothest part of the flight where if you could take off less things can go wrong with good piloting. Then again: -Control surface placement. Control surfaces will apply torque. Torque depends on distance from the CoM. Place control surfaces as far away from CoM as possible for best effect(along the craft, not to the side, unless you want to do barrel rolls like crazy). Don't overdo the amount of control surfaces or the craft will twitch badly. Possible issues: =Veering off to the left/right without an ability to compensate: +Tail fins! lots of them. possibly delta wings as tail fins. and don't forget control surfaces =Twitching wildly, comes in two flavors: +Too much control surfaces, the smallest push results in a huge torque +If the whole structure is shaking you need more struts =Falling into a roll/loop without an ability to stabilize: Either: +You are a horrible pilot Or +CoL too far from CoM, which if engines are active and aligned with CoM produces a nasty loop after engine thrust is changed. Also: +Too many high drag parts in the front, move them behind CoM If you took off without going into a loop the only other possible explanation would be +Fuel tanks too far away from CoM and drained unevenly And sometimes: +Placed high lift control surfaces on the wingtips like a fool. Never place anything that far sideways. =Rolling when trying to turn: +Only one tail fin with a control surface high up will do that to you, place at least 2, close to CoM vertically and as far away from it on the horizontal plane as possible. Preferable: balance the CoL and the fuel tanks with CoM so that no nose up/down moment would be produced and an ASAS could handle this part of the flight without too much control. 3: Worst part of the flight, with increasing speed producing huge amounts of lift and drag, air density dropping and jet engines about to stop working. -MOAR air intakes, you need as many as you can get. ram air intakes work well, radial for some reason didn't do so well for me. -MOAR control surfaces. If it does not lead you into at least a small twitch at lower altitudes, it is not good enough. -Finer CoL-CoM balancing, you will really need all the stability you can get -It is important to understand that for most configurations at these speeds the nose-up/nose-down you are experiencing if trying to maintain heading close to prograde is not due to torque from balancing CoL, but probably from drag which is applied rather mysteriously to the craft. -Balancing Center of Drag, there is no indicator as to where it is, but it is sufficient to place high drag parts behind the CoM -Higher altitude allows for more velocity, reaching 1500 m/s on jet engines alone is possible at heights above 20 000 provided enough air intakes to keep engines active. Possible issues: =Nose-up/nose-down without an ability to compensate after switching engines/adjusting jet engine thrust/changing heading angle: +Not enough control surfaces, you need more at these altitudes Or +Misaligned engines, you will need them in line with CoM to get to space anyway so keep that in mind Or +Weird drag moment, you need to balance the high drag parts i.e. air intakes =Jet engines don't have enough air: +Air intakes. you need them. =Not enough speed gain, getting to 30 000m at 500-800m/s speeds: Either: +Not enough engine thrust Or +Too much lift. Yes, with too much lift you will actually lose horizontal speed in favor of vertical component. Can be circumvented by decreasing engine thrust or maintaining a very small angle to prograde provided your Drag center is behind CoM. Preferable: at least 1200 m/s before switching off jet engines, it will make reaching orbit easier. and a decent vertical speed as room for error in the likely case of losing control while switching engines 4 Finally, with the worst behind all that's left is to gain height and speed to reach orbit. -Air drag becomes minimal at about 40 000, at this point RCS becomes a valid control mechanism. Any use of RCS below 40 000 is a waste, if you can't control your craft without it below that point - go back to the drawing board, invest in control surfaces, do something. -Consider rocket engine thrust to weight ratio as well as efficiency. Aerospikes are efficient but heavy and will usually not lift you up fast enough, so other engines as an additional boost may be needed. Mainsail is a beast and can push most freighters, even the Skipper can manage this with a little worse power to weight ratio but still lighter than 4 aerospikes, for smaller craft consider Rockomax 24-77 as boosters, as highly inefficient they may be, the gain in altitude and saved time makes up for it. Possible issues: =CoM not aligned with CoT, a nasty surprise to get when you got all that way up to space: +Just... don't forget this during construction =RCS balancing: +Adjust for empty fuel tanks during construction, better yet - position fuel tanks close to the CoM. Preferable: Efficient engines for gaining speed when above 50 000m when there is enough room for slow burn and good booster engines to make that room and push past the nasty 30 000-40 000 barrier. Bonus: Landing -Again, balancing Drag. Put the air intakes in the back and you'll be fine. Don't forget to open them during reentry and you'll be safe. Upd: added info on Drag balancing, that's the last part I needed for a perfectly functional craft. Upd: added some info on control surface balancing Upd: added miscellanious info Hope this wall of text will be helpful to somebody. All these horrible things happened to me and keep happening to me on a regular basis, none of the characters and events in this post are fiction and should resemble real issues anyone can come across. Most of this post was written during KSP 0.20, but contains general physics that will probably be useful for years to come unless the space kraken invade Kerbin and all our base will belong to them. No kerbals were harmed during the production of this craft. All test models were probe-controlled and the final product has zero casualty rate up to date on its extensive duty as a Kerbin-LKO SSTO freighter.