capi3101

Wasmic's got it. To be sure that's what's happening, install a mod called RCS Build Aid. Among its many useful features is a marker that will show you where the center of mass of your plane will be when the fuel tanks are empty. If it shows that the CoM will shift further aft, then wasmic has the problem dead on, and has given you the instructions you need to fix the problem. I think he's right anyway, but RCS Build Aid can verify it for sure.

I use RCS Build Aid; I find it an exceptionally useful tool for building planes in general. The big feature of the mod is the dry center of mass calculation - it'll tell you based on your current craft design just exactly how much your center of mass will shift as you burn fuel and it will show you where the CoM will be at that point. With that information you can set a center of lift that will keep your plane's flight stable in all configurations, or use it to make adjustments to reduce (or better yet eliminate entirely) the amount of the shift. The other thing it'll show you is how much torque your thrusters and engines will produce. That's the crucial bit for VTOLs, of course; if your vertical engines produce too much torque, your flight won't remain stable. I haven't played around with this feature of RCS Build Aid all that much as far as building VTOLs, but it does come in handy for small craft with which you want to conduct rendezvous and docking operations. Something you might consider as you build your VTOL - turn the thrust limiter on your horizontal engines down to zero as you're placing the vertical engines; that way your center of thrust indicator will show you only what's going on with the vertical engines. That will help you find the spot where they need to be placed. Just don't forget to turn the thrust limiter on the horizontal engines back up when you're done. Having a 100% balanced plane helps as well, though you're generally okay if the shift is minimal (say 0.02 meters or so). DocMoriarty's KSP Space Plane Construction and Operation Guide has a section on how to build, test and fly VTOL craft. It's from 0.24.2 so there are a few things about the guide that are out of date, but mostly it's just data about the lifting body (aka Mk. 2) aircraft parts; the general principles it contains remains sound. Just if you need ideas or pointers there.

Farted around with trying to get that GT 620 I installed in my box to work properly again. Everything's working - the motherboard recognizes the card on POST, I'm getting a signal through it - except that it's not; Win7 is telling me that one of the PCI standard PCI-to-PCI bridges doesn't work and that "Your computer's system firmware does not include enough information to properly configure and use this device." Solution is apparently to update the BIOS. Fine and dandy except that's not working either; I've got the right files for my motherboard for sure but I keep getting the message that the files are "invalid" when the existing BIOS checks them (and no re-flash occurs, which has probably saved me from bricking my home desktop). At this point, I'm ready to put a discount brick through someone else's computer (it being a tremendous waste of money to put said brick through my own computer, of course). Until I get this fixed, I can't run KSP. And I reallllllllllly want to run KSP at this point...... I don't suppose there's anybody out there with any ideas for what else I can try. I'd hate to take the card out (and go back to nVidia 7200-equivalent onboard suckville on graphics) but it's looking like my only option at this point.

You're wanting to do an Apollo-style Mun mission, eh? I'd suggest looking at the Apollo 11 tutorial on the wiki; the data is a bit out of date right now and the booster was unstable even when it was last seriously revised in 0.20, but it'll get you started on your own design (particularly with how the staging is set up) and the CM/LEM produced are both perfectly usable (add some OX-STAT panels to the sides of both and you're golden - and consider Skippers on the upper two booster stages).

What's your current reputation like? If it's too low, you might not get any new recruits.

Sent an intrepid crew of four up in Mute City 7, the first structure of a new Mun base and an attempt to fulfill two contracts at once (the other being a flag-planting mission). All went well except for the final landing; the structure tipped over and broke off two solar panels in the process. Fortunately the crew survived (and it was intended to be a one-way trip anyways), and both contracts were fulfilled. Also sent Albatross 7, a Turbojet-equipped airplane, on a mission to conduct seismic readings on sites near Kerbin's north pole. I thought the sites were on the ice pack; they were actually on the nearby Tundra, so the ground was not as flat as I'd originally thought. Still, the plane-become rover-become plane again performed beautifully; after a 65-minute (real-time) flight the craft returned to the KSC Runway. Didn't hit the center of the strip but I didn't break anything off either, so that all went well. At the moment, I find myself unable to play KSP - I did a set of computer upgrades yesterday, including the installation of a new set of memory chips (doubling my old capacity) and a new video card. All indications are the video card is working but there is an issue with a PCI-to-PCI bridge that will require me to re-flash the motherboard's BIOS with an updated version. Meantime I have video wherein DirectX doesn't want to work at all, looks like. I'm hoping the re-flash works; I'd very much like to finally be able to use a DX11 video card and have a box with more than sufficient memory to play KSP at full (or at least normal) graphics settings. You know, to ditch texture mods...

Aye, one day the Great White Ass Kraken bit me good leg off at the knee, so I stabbethed the foul beastie up his blowhole!!! (Not mine, but I did drop such a mission for the KSP Game Challenge; that pic is Jean Deaux's "proof of victory"...).

Gonna go with time warp set accidentally at 5x. When I encounter the same problem (craft not responding when it should), that's the most common culprit in my experience. Something to check anyways. Beyond that, I can't offer anything constructive that hasn't already been thrown out there.

^^^ This. It works if you're "close enough"; the Kerbal doesn't actually have to be touching the seat before he can sit down.

Yeah, go ahead and provide the craft file - I did go ahead and build a replica of your craft from the series of screenies this evening and I need to verify something major about the design. Had a screenie of my own all nice and ready to go - or at least, I thought I did. Coulda swore I hit the F1 key anyways. Anyways, I use a mod called RCS Build Aid when I build planes (someone may have mentioned it already; I'm not going back through the thread to say one way or the other). Among its many, many useful features is a marker that will show you where your craft's CoM will be once all the tanks are dry, and an "average" CoM position between dry and however you have your fuel loaded at the moment. This is accompanied by a measurement telling you just how far the CoM shifts from "wet" to "dry". Optimally you build your plane so that the CoM doesn't shift at all - and it's for this reason that I use the mod. Seriously, I'd recommend it to anybody wanting to get serious about planes; it can save you a lot of headaches. For the replica craft - which was built using the same parts in the same* positions with the same amounts of fuel indicated in your screenshots - RCS Build Aid was showing that the CoM shifts aft during flight by close to half a meter. That's not that much mind you, but given how close you've got the CoL to the CoM in the design it is sufficient to put the CoL up front. Between that and the high drag caused by the nose intakes, that's probably what's causing your issues. Again, this is all for the replica; I might've got some things wrong in the process of construction, which would make these observations completely invalid, but does heighten the need for a second glance at the original. I should mention that I lost control of the replica at roughly the same time, around 30,000 during the process of switching over to the nukes.

Right. I'm not trying to be a jerk here; just asking an honest question. If I was a complete newbie to the game, how would I have known about using the R key in the VAB/SPH?

Ka-ching: http://forum.kerbalspaceprogram.com/threads/100334-SSTO-Why-u-no-fly?p=1546536&viewfull=1#post1546536 Spoiler - I'm not adding much to the table that hasn't already been said...a mere three posts into the thread... On the other hand, not much changed spaceplane-wise in between 0.90 and 0.25 except for the Mk3 spaceplane parts, and none of them are lifting bodies (unlike the Mk2 spaceplane parts), so any advice that mentions 0.25 is still sound as of this post.

If rocket performance and low part count are your main concerns, may I (in lieu of the 48-7S/24-77 combo I suggested earlier) suggest you go with LV-T45s? You'll wind up with 400 kN rocket thrust, keep the part count the same as what you have, and still wind up saving about a tonne on the mass of the craft you've got. I too also play KSP on a Byzantine computer setup (2.9GHz Dual Core w/ 2 GB memory and an onboard video chip with the processing power somewhat less than that of a Dorito), so I can sympathize with wanting to keeping the part count down. Again, that doesn't address your initial issue, but it might prove useful. Actually, I've been considering replicating your design to see if there's any other pieces of advice I can give you from trying to fly it my own self. For the record - the recommended engine ratio for Turbojets is 15 tonnes per engine, for Basic Jets it's 10 (and to be wholly honest I've never even come close to making orbit on Basic Jets). I've heard 1.3 bandied about as an initial takeoff TWR for spaceplanes; couldn't tell you where that falls on mass-per-engine, though, as Turbojets don't hit maximum thrust until they're already 15-20k up in the atmosphere...

Okay...so you're wanting to move 20 tonnes to the Mun. I'm assuming the 20 tonnes is going to include whatever delta-V you need to land it. So you just need a transfer stage capable of getting to the Mun and a booster capable of getting that into Kerbin orbit. So...whip out the delta-V map......you need 1170 m/s of delta-V to go from a 70k LKO to a 10k LMO. If you want a one-way trip craft, you can put that together with a Rockomax Decoupler, a single nuclear engine and an X200-8 fuel tank; that will give you 1,238.5 m/s of delta-V, plenty enough for a one-way trip. If you want to be able to deorbit the thing afterwards, you could add an OKTO-2 probe core and 2 Z-100 battery packs; that would add only 0.05 tonnes and cost you 2.5 m/s of delta-V. Total mass will be 27.45 tonnes. Now, getting 27.45 tonnes to LKO. A classic asparagus design will do the trick. Using Temstar's guidelines, you should expect a total rocket mass of 183 tonnes with a total of 2869-3049 kN of thrust at launch, with 631-670 kN in the core and 372-396 kN in the boosters, assuming a 4-stage to orbit asparagus design (i.e. 3 booster pairs and a core). I'd tackle that with a set of seven Skippers; leave the core Skipper set to maximum thrust and set the thrust limiters on the external booster stages to about 59-60% or so. Total engine mass of seven Skippers is 21 tonnes, you've got 27.45 tonnes of payload, say two tonnes of asparagus support equipment (a stack decoupler, an array of six radial decouplers, a sepratron per booster, maybe a probe core and some batts to deorbit the core)...from your 183 tonne rocket, you're left with 132.55 tonnes for fuel tanks; divvy those up evenly and it comes out to 18.9 tonnes of fuel per asparagus stack. An X200-32 tank weighs 18 tonnes, so just go with thems. You can add an FT-200 to the boosters if you really need the extra fuel. I'll have to play around with the design when I get a chance (to see if it can land and make it back to Kerbin on its own). The info I gave you should be enough to get you started, though. What level is your launch pad at? 183 tonnes is an estimate; you can get into orbit with a lighter rocket if your asparagus is good. I'd just hate to see you try to put the design together and not be able to launch it due to the Level 2 mass limitation...three tonnes short......

I'll admit to it having been quite some time since I looked at the game's basic craft construction tutorial; has the ability to switch between radial/mirror symmetry been added to it in 0.90? If not, that's something that should probably be addressed for 0.91; I wouldn't have known about it myself if I didn't visit the forums on a near-daily basis.

That's arguably the most attractive aspect of KSP - every single item in it is A) readily accessible and given the right set of conditions, highly explosive...

Last night I knuckled down on getting my current set of contracts finished. Sent a science probe out to the Mun to satisfy both a satellite contract and a "sci data from Mun" contract. Got the thing in the orbit I needed, went to collect the sci...and suddenly realized the damn instrument I put on the probe was a seismometer, not a gravioli detector. #facepalm. Second attempt at the sci data went better but I was annoyed for having to make the trip. Sent Jeb and Bob out in the direction of Minmus, chased by a probe that will be heading into a tundra orbit. Probe at 5,000 m/s of delta-V in its own right (i.e. not including the booster phase), so I would certainly hope it's got enough to cover the inevitable screwups. That one should all go okay as long as I don't hit Minmus in the process of putting it in the right orbit. Put a satellite around Kerbin for a contract. That one went alright; got credit for it, which was good considering it was going to encounter the Mun on its next orbit... Last but not least I remembered how to build a proper Turbojet/rocket combo SSTO and sent up Tamlin Kerman in Turtledove 7 to rescue Richemonde Kerman. Complete success on the mission there, though I was worried about the landing there for a while. Being off-center on the Level 2 runway is most definitely NOT a good thing. Still, I didn't tear anything off, which is more than I can sometimes say about landing craft on the Level 3 runway... Took on a whole bunch of new contracts to replace the ones fulfilled, of course. Got missions to put a space station up around Kerbin and ground bases on Mun and Minmus, one to collect EVA data from the Munar surface and a flag planting Mission (three for one, there), and a mission to do some ground exploration on Minmus (will try to combine that one with the mission I've got to Minmus at the moment - not sure I can do that since the contract was accepted after the prior mission was launched). Got the Astronaut Complex and Administration Building fully upgraded at this point. I think I'ma gonna go for Level 3 Runway next and definitely Level 3 R&D when I can get to it. I plan to use the science from the Minmus mission (once again, it's a Geschosskopf Sci Bomb design) to grab nukes, at which point it'll be time to think about going interplanetary.

Whack a Kerbal is pretty much just for fun. If you're looking for something more specific to do with it, here's something to try: 1) Put a stack of about ten S3-14400 fuel tanks out on the launch pad, arranged in a rough triangle. 2) Back the camera up to the VAB - there's a little line there at the start of the crawlway; make sure it's in view. 3) Set your whack-a-kerbal settings up for a Sphere, a good small to medium size and whatever weight you want. Set whatever speed you want to. 4) Aim carefully for the tanks on the launch pad. Fire when ready. 5) Count the number of pins you blew up. If you get all ten, it's a strike. If there are any left, shoot again; if all ten are destroyed after the second sphere, it's a spare, otherwise it's an open frame. 6) Revert to launch. Score as high as you can for ten frames. If you blow up the launch pad, it's a foul. But at least it's a foul of awesomeness. Been thinking about turning that one into a proper challenge for a couple of versions now......

Missed the fact that the OP was just going to orbit with the design. Yeah, the nukes are overkill there. You don't necessarily want nukes unless you plan to go interplanetary with the design - I wouldn't use them for the final ascent, my own self. At best you might want a set of rocket engines that'll give you a launch TWR of 1.0 (and that's being conservatively high; I suspect by the time you need them a 0.8 TWR would do the job but I need to do more experimentation; the idea behind saying 1.0 is to have a little overlap in case you botch the jet portion of the ascent and have to have the rockets take over earlier than you'd like). A combination of 24-77 and 48-7S engines will easily do the job and save you some serious mass in the process. For your original 34 tonne design, you want somewhere between 272-340 kN rocket thrust. A pair of 48-7S engines accompanied with six 24-77s each will give you 300 kN rocket, and have a total mass of 1.28 tonnes - this compared to two nukes providing 120 kN thrust with a mass of 4.5 tonnes. Remember, after your spaceplane is done being an airplane, it's a rocket; the same considerations still apply once it's up there. 8 24-77s would give you 380 kN thrust - a greater than 1 TWR, and still only another 0.36 tonnes in mass. Of course, seeing as the OP has abandoned the original design, this information might not be all that useful for this particular case. The nukes didn't have all that much to do with the original question, either...

I'd recommend Navyfish's Docking Port Alignment Indicator - hell, I'd recommend that one even if you were just doing single-port to single-port. One of those mods that's so useful it should be stock, IMHO. Back in the day (prior to the release of the Sr. Docking Port in 0.20), getting docking ports that wouldn't wobble was a major problem that folks tended to overcome by putting multiple normal Clamp-O-Trons on their craft, so yes, it is possible to do. The tricky bit, as has been mentioned, is to get them all to line up so that they all suck each other in at the same time and make a solid connect (otherwise you wind up with only one properly connected and then the thing is just as wobbly as it would've been had you just used one port). The most common solution back in the day was to put the ports on both craft on a Tri-Coupler - the triangle shape was the easiest one with which to eyeball the alignment, and it made a pretty solid connection. Tri-Adapters would also work for the same purpose (but of course, they were released in 0.21 and by then Sr. Docking Ports were in use). Whether you're adverse to mods or not, using the tri-coupler or tri-adapter is probably your best bet.

Related question: is there a button on the GUI that switches between radial/mirror symmetry? If there is, I've missed it; I didn't remember the "R" key last night when I wanted to put on a set of 24-77s with 6x symmetry in the SPH.

Cancelled a visual survey contract; the two surface EVA bits were in the mountains in an area with a serious grade (one of those where getting out of the capsule was a fatal act in and of itself). Pay wasn't all that great anyways - but I was annoyed at the rep hit. Sent Jeb and Bill to go explore Minmus and sent a science probe in the direction of Mun. Trying to kill two birds with one stone on the Mun probe. Also accepted a tundra orbit contract for Minmus - the pay on that one was just too good to pass up for the program I've got in the stage that it's in. Going to be interesting to see if I can get it in position without crashing it into Minmus... I also seem to have forgotten how to build a proper Turbojet-rocket combo SSTO; got too used to working with RAPIERs...

Pretty easy: 1) Go to the VAB 2) Pick a probe core, or if necessary a Mk1 Capsule as the pod. 3) Attach the item to be tested on the underside of the pod. If it's an engine (particularly an SRB), set the thrust limiter to zero. 4) Send this very basic, 2-part assembly out to the launchpad. 5) Hit the staging button. The test will automatically carry itself out (except on certain parts such as the Small Gear Bay or LV-1 engine; for those, right click the part and select "Run Test"). 6) Recover the craft. 7) Profit.

Probably the best way to do it stock is to set up a maneuver node at the point of closest approach. Look at your target relative velocity (click on the speed gauge until it says "Target"), and set up the node for a retrograde burn equal to that amount. You should get a burn time estimate from the maneuver node; start the burn when you're an equal number of seconds away from the node (unlike a regular burn, where you want to split it 50/50 on either side of the node) and stop when you get pretty close to zero. This will at least get you reasonably close to the closest approach distance you had with the target originally, and travelling at a much slower relative velocity, making the approach part easier. EDIT: Ninja'd, twice.

I got a thread locked down on me on Saturday going after this information...thanks for posting it. So yeah, a class E ranges about that much. You can plan for 1808 tonnes but it sucks if the rock turns out to be heavier. Frankly the notion of sending a sounding probe first makes sense for Class D and E given the wide range of possible masses, less so for Class A through C. I've done that sort of thing on an E before; added Vernors to it to steer the thing. They wobbled hard enough I thought they'd break off, but they did do the job. This link will definitely help on that particular score.