Claw

If I had to guess, I would say numerobis' comment about having a reference point is because the game forcebly sets the camera to the CoM. So if your frame of reference is the CoM, rotation around any given point will always appear as rotation about the CoM because of camera movement. The nav ball is incapable of anything besides rotation. It isn't going to show translational forces imposed on the CoM from rotation about an arbitrary point. And it's pretty easy to repeat the experiment by hacking gravity. Then the ground provides a fixed frame of reference. As for game logic, I have no idea how they are actually implimenting the math. Gyros and flywheels have all sorts of other wacky reactions to being turned and moved. I sort of like the simplified model of "apply torque here, watch things move."

Ahh yes, this is a different problem. Based on your pictures, I thought you were about the Center of Lift in the SPH. If you can, post a picture of your ship with the Center of Mass, Center of Thrust, and the Center of Lift shown. What you are saying is probably true. Although I am less familiar with some of the mods you are using.

Are you talking about it nosediving in flight? Or just asking why it does it in the SPH? In the SPH, it just shows the direction. So once you go into negative AoA it points down. If you level your ship and put on wings that are pitched down, it will do the same thing. It basically assumes the relative wind will be going down the axis of the body and shows you the resulting lift direction.

When you pitch things in the SPH, it shows you the resulting lift as if it were Angle of Attack. So if you pitch it down by 5 degrees, then the lift line acts as if you have put your aircraft in -5 degrees of AoA. At negative AoA, wings in KSP produce lift downward instead of upward (because they are symmetric).

I'm sorry, I completely forgot to address this question in my post. Perhaps this will help you if you haven't seen it. This will show you the dV required to get from the surface to orbit for each of the bodies. For example: if you look at Minmus, it takes about 240 dV to get from the surface of Minmus to a 10km orbit.For Kerbin, it takes roughly 4550 m/s to get from the surface to an 80km orbit. If you want a suborbital for your lifter stage, then aim for a little less dV than that. Hope that helps. Here's another one that includes orbital plane changes, but that doesn't really address your question about dV to orbit.

That isn't dumb, it feels intuitive. But I generally find that torque and moments are not necessarily intuitive. It sort of defies the standard mass, fulcrum, lever concept that most people are used to. Your question can still be misinterpreted. As Kasuha said, the torque is definitely applied at the point where the SAS modules are. However, the torque causes the whole ship to move around the CoM. All of that stress of moving around the CoM passes through whatever part the SAS units are attached to on the way to the CoM. Weak parts = bad results. If you spread out the torque or put it near the CoM, you will have less bending to deal with. Just be thankful that you don't have to contend with all the actual physics. Otherwise we would have a limit to how much angular momentum you can generate before you have to bleed it off. (Please, no...)

Hmm. If this is in response to my post then maybe I'm still being confusing. This isn't a controllability issue. I'm not asking "hey, can Jeb land this thing for me because it's all wacky and I can't handle it." I'm saying that my computer is old, and my graphics are cranked down. I have a hard time telling things like "How high off the ground am I?" since there are no shadows. Anyway, I was going to write a list of what I use MechJeb for, but the bottom line is I'm asking if MechJeb or Engineer are not allowed at all. I already know I can't use the autopilot, but that's not what I'm asking. If you can't even have MechJeb installed (except for circumnav), please just say that. I'm just trying to understand the rules and not cheat. Thanks! EDIT: Oh, like the post above this one. m1sz has MechJeb on the craft in the video and it isn't circumnavigation.

Torque and angular momentum can be tricky and defy intuition. Reaction wheels make the object rotate about the center of mass. Because you are in space, the Center of Mass acts as the fixed point of your rigid body since nothing else is holding it still. (i.e. it's not attached to a wall) Torque is not a force, so it does not react the same way as a force to distance from the CoM (or point of rotation). Take this beam as an example. Imagine the CoM marker is a fixed point on the beam. In other words, it's held solid and not allowed to rotate around the center. The sum of moments is zero. So the moment acting around the center must be the same magnitude as the torque acting at the end of the beam. Now, if the beam is allowed to rotate, it will rotate with a moment imparted by the torque at the end of the beam. This can be difficult to conceptualize because the torque at the end of the beam is allowed to rotate freely with the beam. Typically you're going to imagine the beam rotating around the torque, but the torque isn't a fixed object and it has no mass. You can try to replicate this with a pencil. Pinch the center between two fingers in one hand. Use two fingers from the other hand to twist one end of the pencil. HOW you twist it is important. You can't push up or down, but twist around the tip. The pencil will spin easily as long as you allow your twisting fingers to rotate with it. This demo can be susceptible to how you twist, and if you're imparting forces and not torque. (If you have mechanical pencils with clips, you can interlock the clips to help provide rotation without imparting force. Try doing this with the clip at one end, then near the center.) Perhaps a better example is the hammer example put forth above. Find the center of mass of your hammer (which won't be at the center of the length of the handle). Lay it on it's side on the floor. -Use your fingers to rotate the hammer at the CoM. -Use your fingers again to twist the hammer handle at the base and allow your hand to rotate with the hammer. You'll find it's easiest to rotate it this way when the hammer rotates around the CoM. If you're not rotating around the CoM, then you're also imparting a force which is going to make it harder to turn. Torque doesn't impart a force like this at the center of rotation. If you manage to do this right, the amount of twisting you have to do at the CoM is the same as the twisting you have to do at the base of the handle. APPLICATION Now we all know in KSP the spacecraft are rarely rigid. So when you apply all that torque to one end of the space station to flip it around, it will rotate around the CoM. However, the poor module at the end where the SAS modules are located will take all of the strain of bending that torque around the CoM. If you distribute the SAS units, or put them near the center, there isn't nearly as much shear force concentrating at any point on the craft. You can try out the fuel tank experiment above by assembling a fuel "tube" in the SPH and launching it. Then hack gravity and give it a try. The runway provides a visual backdrop to watch the center of rotation. This thing is completely symmetric in weight from one end to the other. It flips around the CoM at the same speed whether I use the three SAS units at either end (one end at a time), or the three in the middle. It takes about 10 seconds to do a 360. The big difference is that using the ones on the end causes noticeable bending.

Yes, that was my point. In addition to the point that we all have different ways of saying exactly the same thing. Maybe another way of saying my point is that we haven't asked the OP what he/she is really looking for. We just keep restating the rocket equation over and over with words, numbers, and examples.

It takes rougly 4500 m/s to get into orbit in stock KSP. As posted above, the exact amount will vary based on ascent profile and other factors. If you build with less than 4500 m/s, you will likely (but not always) end up suborbital. Usually I do like posted above. Build a lifter with around 4000-4500 dV. Then during launch, I get my AP where I want it and leave the PE somewhere in the atmosphere so that the lifter will be in a decaying or impact orbit before I cut it loose. A PE below about 22km will cause it to disappear on its own. Above that, you will have to manually delete the object (in the tracking station) or "fly" it so the physics engine will decay the orbit. Otherwise the background simulation will not deorbit the object.

I will tack onto this. The stock part you are looking for is the quad coupler. It will allow fuel to pass through without fuel lines and you can run all four engines, assuming you are connecting it to the orange tank first, then affixing the four engines. Realize if you build it the other way, you might experience fuel flow problems. One thing to note (there was a recent thread about this) is that some of the engines in a quad layout will cause the rocket to spin. So you'll have to design around that. http://forum.kerbalspaceprogram.com/threads/68424-Question-about-slow-rotating-craft-%28gyro-reaction-wheel-what-is-gimbal-%29 If you have problems with spinning using a quad design, try reading this thread. Especially page 3 and on.

Wow, so many ways to disagree and yet say the same thing... You CAN calculate the dV for a given unit of fuel, but the dV for a given unit of fuel is not a constant. So maybe we should ask the OP what he/she actually wants to know?

Hmm, I'm not sure if I asked my question right. I know idea behind how to fly a VTOL. It isn't that I just engage MechJeb and let it land (Jeb has only ever landed once for me). It is that MechJeb gives me information (like acceleration rates) that help me land. My graphics are down so that I can actually play, but that means I am missing things like shadows and the terrain is really smooth. That makes it hard for me to tell how far away the land is, or how fast I'm falling. I've sort of overcome some of this by adding lights and using Engineer. Although I don't use Engineer much so I don't even know if it has an autopilot? If using Engineer is acceptable, I will learn how to fly with that. It isn't the autopilot I'm asking for, I need the information so that I can land a bit easier. Also, I'm trying to build a larger VTOL for this so maybe that's part of my problem. The speeds are more critical because it's a bit more heavy/fragile. Maybe I'll just go for a small, stout design to handle that roughness. So is it that I can't use the autopilot? Or that MechJeb isn't allowed on the craft at all?

So I have to ask, because I've been trying to do this challenge. Is MechJeb not allowed to fly? Or can we not have MechJeb on at all? I don't usually let Jeb fly, but I use it for all kinds of useful information and I'm finding it pretty difficult to fly without it. I finally landed on the island using Engineer, but then the Kraken got me as I was unloading my Kerbals. I don't know if it was Engineer, but it was pretty frustrating after so many vehicle crashes.

Edit your original post and click "go advanced." You can change it in there. Ninja'd by Capi!

Yes, Psyper already said that and I assumed that the OP knew how to terminate/recover. It was several weeks before I figured out the debris is masked, so I was trying to clarify that piece in case it wasn't known. It was all moot anyway as the OP is looking for an automatic process, not manual.

Ahh, my bad. I missed the automatic part. Probably because I wouldn't like an automatic removal all the time. But I can see the utility as long as I had to click on something to remove a wide area. (I.e. It doesn't go away on its own.)

Yes, the tracking station is your best bet. And no plugin required. As stated above, move the mouse to the top center of the screen. A set of buttons will pop up. When you select debris (the left most button), the tracking station will only display things marked "debris." You can display more items, but by default the debris will only show with your first click.

Awesome! It made my day to know you were able to save it. For your lawn dart comment, I would give it another shot with a set of canards removed. I remember having pitch problens with the original file when I flew, but it might have been from all that wing flex. For the forward RCS tank, I meant to leave it empty on takeoff but put the monopro in it in space (like you have been). That last post was meant for how to configure your plane for reentry. However, you can also fly it like this from an initial takeoff for testing. (I.e. set up the tanks like you're reentering and then launch it.) If you want to add more vertical tails, then go right ahead. Put some on where you like and give it a try. I don't know if I misled you. I don't mean to say "do not add more tail," just that adding more tail wasn't going to address all your original problems. Adding tail fins can help your stability during several points in your flight, so if you think you need it or want to try then do it! Also, as an alternative to deleting canards, you can add some angled tail fins and play around with the CoL. Adding an angled tail can offset the aero AoA control surface bug (so the CoL won't move as much forward with AoA). Be sure to lock out the pitch and roll portion for the angled fins though. Angled fins bring their own set of funny charachteristics, but they can help. Incidentally, adding control surfaces anywhere to the back of the plane can counteract the AoA bug induced by the canards. But you'll still have to contend with CoL placement. So many options, so little time...

So I played with your plane some more to help the design itself (separate from recovering your existing flight). The simplest recommendation I have is to modify the canards in one of two ways: (I would recommend this if you have plenty of pitch authority with the changes, which I think you will.) 1) Remove two sets of canards. Either the top and bottom set, or the bottom two sets. 2) Keep your 675-700 units of monopro in the forward tank, and fill your NERVAs as required. Transfer the liquid fuel from NERVAs to forward MK-1s when needed. 3) You should be able to fly just about any AoA, but I would stick with 45 deg or less due to limited yaw stabilizers. -OR- (Do this if you find you need more pitch authority.) 1) Remove one set of canards and move the other two back as close to the solar panel as you dare. The bottom set is the best candidate for removal. 2) Keep your 675-700 units of monopro in the forward tank, and fill your NERVAs as required. Don't take excess oxy if you don't have to, but take extra liquid fuel. Transfer the liquid fuel from NERVAs to forward MK-1s when needed. 3) Fly your return profile to maintain below 15 AoA. This config is still susceptible to the control surface bug.

I would say that it seems pretty tough to recover your plane without taking on some fuel to balance the CoM a little more. My recommendation for recovery, if you want to keep as much fuel in space as possible... 1) Put only as much fuel/oxidizer as you need in the NERVA tanks for reentry. Any excess in there isn't helping much. 2) Put about 580 fuel and 700 oxidizer in the main orange tank. 3) Fill the forward RCS tank. 4) Put 75+ units of liquid fuel in the forward Mk-1 nacelle tanks (that feed your tricouplers). That should give you some gas to control it, and helps the CoM. 5) All the other tanks should be empty. If you have monopro in the cylindrical side tanks it will help but isn't necessary. 6) Maintain below 10 AoA during reentry. You might have enough control authority once you get down below 10km to help keep it under control if you exceed 10 AoA. Running your engines at a low throttle setting as you pass 18k down to 12k might help control with thrust vectoring. Up to you. I didn't fly this config (that's what you're getting paid for), but I think that should give you enough control to recover it for design modifications. Good luck!

So I started out going for a fancy looking jet, but ended up with this little bottle rocket. I removed all monopro from the capsule so it wasn't possible to use in any way. No staging or jettison of any parts. Maximum speed 2364.1 m/s before I ran out of gas. Edit: Oh I forgot. I was going to name it Streak, but that name doesn't seem to fit this one. So I think I just go with the Bottle Rocket!

It is probably in reference to KAS.

My bad. I looked where they used to be, then zoomed in to mess with the CoM/CoL. They are indeed still there. Having them that far out has it's own set of challenges, but might be okay if it turns out to be a CoL/CoM/Canard problem.

Okay, I had a chance to look at your plane in the VAB. Before I delve into that, I have to ask. When you say "it flips," are you referring to it flipping over in pitch or yaw? (When I think of flip, I think pitch. When I think about it turning in yaw, I think of sliding.) I ask just so I have an understanding of what you're seeing in flight. (Yaw or pitch departures.) That being said, I see three things: 1) The new craft file I downloaded has no vertical tail fins at all. As discussed previously, they are not strictly needed but can help. more importantly you are being bitten by... 2) Your CoM is ending up directly above your CoL with the current weight distribution you described (forward RCS and NERVA tanks full) even with the gear removed. This will make it neutrally stable. Which means (with such a large craft), that your limited yaw authority will have a hard time compensating (which might explain the yaw oscillations). And finally, the one that snuck up on you... 3) KSP aero has a (one of many) bug. When AoA increases, lift produced by control surfaces increases faster than lift produced by wings. (To the point that control surfaces produce maximum lift at 90 AoA.) You have a lot of canards that are way forward from your CoM. At the config described above, and given my #2 comment, your neutrally stable craft becomes unstable a soon as you put AoA on it (which is pretty much required for flight). Go to the SPH and check this out. Turn on your CoM and CoL markers and set up your fuel config you described. Select your entire craft (shift click wherever) and rotate it with Shift+S (5 degrees, then 10 degrees). Watch the CoL bubble and see where it goes. Bam, out of control... So, to answer my own question at the top of this post. I suspect you are going out of control in pitch and seeing yaw oscillations separately. Lots of ways to fix this. I can ramble on some more in this post, but you can play with it and see what you prefer. If you want help with fixing it, let me know. Good luck! EDIT: I forgot. I can't actually see where your CoM is with the gear on because I have edited my landing gear file. I gave the landing gear zero mass because I grew tired of the SPH lying about the CoM. So I'm guessing that given the location of the gear in relation to the CoM, it looks more forward to you. Make sure you remove the gear when you play around with the CoM.