Wanderfound

On the tent that I used to take to bush raves, I had painted on the door in glow in the dark paint "not all those who wander are lost". It's a Tolkien quote, made it easy to find my tent in the dark, and became something of a personal motto (I had a somewhat disreputable youth and I'm an outdoorsy sort, so it fits in several ways). When the internet came along, I started a blog titled "Lostwanderfound". That later got shortened to Wanderfound as my usual online name, although I occasionally go by Doc Rattus instead (yes, I'm a doctor [1], and my thesis research was based around working with rats). [1] No, not a physician, a real doctor: PhD.

There are some things that mess up the CoL indicator, but they're cosmetic; they don't affect flight behaviour. I'm not sure if that's happening here. Why are you angling it tail-first? Remember, the "wind" is coming from the door.

Are you adjusting your wing mass/strength tweakables? If they're still set to default, you're carrying much more weight than necessary; wind them down to about 0.4. Shifting your landing gear a smidgeon further forwards (or lowering the rear gear) will ease rotation. Tailstrike issues can usually be solved by careful piloting, but if you don't want to have to worry about it: The SAS wobble is a consequence of the SAS code being (a) designed for rockets and stock aero, and ( not very good. There are several solutions, but you've already hit the simplest: turn SAS off and use the FAR stability aids instead. What do your analysis screens look like at temp 0 / density 0.5 / speed 0.8? Again, when you lose control after turning the rockets on, exactly what happens? And do you have access to Vernors?

Not to forget the old standby of watching your shadow. Personally, I use Kerbal Flight Data: Which, of course, should already be stock, but isn't due to Squad's bizarre number-phobia.

You're planning a VTOL; drop rover, fly up five metres, hover forwards five metres, land. For a bit of stock-part VTOL and rover-carrying inspiration, see http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1527285&viewfull=1#post1527285 and http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1504987&viewfull=1#post1504987

Sounds like we're better off with two weeks for flight testing, then. As far as I know everything is listed in the OP, but I'm sure that I've overlooked one or two things. Point 'em out to me and I'll update the list. (and if we've got any last-minute entrants, we could use some numbers in the Interplanetary Science Explorer and VTOL categories...) I'll probably do a "best of the rest" category, which will include all of the craft that were submitted for things that didn't get the required 3 entries.

Some slight steering issues with the current Kerbodyne car... I suspect I might need a bit more downforce up front.

Careful weight balancing (RCS Build Aid is very helpful here) is also worth the time. Get it right and you can fly smoothly on either engine:

The wobble I can't help with 'cos I don't use those parts (although: moar struts is the usual solution). As for the wings...well, this is why Ospreys don't have top doors. Any reason not to flip the cargo into a bomb bay instead?

It has adequate yaw stability; flying straight is no problem at speed. If you are having yaw problems, though: bigger tailfins or a Vernor each side of the nose. FAR analysis assumes that you're flying towards the door, AFAIK.

Well, at least it wasn't space vampires or something.

With that many mods and part-hacks involved there are so many potential complicating factors that I wouldn't know where to start. Yes, the difficulty in maintainng level flight is related to lack of lift, but there are ways around that that don't require big wings. To see a successful implementation of a similar concept (for reverse-engineering inspiration), have a play with http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1509571&viewfull=1#post1509571 Your video is set to private, BTW.

Okay: your standard basic FAR/DRE speedster. Self-launching. Good climber. Level off. ...and that's maxed-out for level flight. 1,777m/s over land. Let's try a dive. Nope, no better. Lost too much speed from drag. Try a more gentle slope. Better airspeed, but only a single m/s improvement over land. 1,778m. Can't be bothered landing. Let's see what it can take in heat and pressure... Who needs a tailfin anyway. 430kPa, not bad. Apparently DRE proof as well. Not a good idea to touch the controls at this pressure, however. 1,778m/s over land, no penalties. Craft file at https://www.dropbox.com/s/glgupx19kl0i82b/KSV%20Woomera.craft?dl=0

As is usual in FAR: let reality be your guide. You'll notice that rotating-engine craft like the Osprey tend to have high-mounted wings in order to to deal with this issue. If you want to rotate engines, mount your wings higher on the fuselage. For shifting CoM: place your fuel load so as to keep the CoM/dCoM offset below one metre, and use fuel lines to control the order in which they drain. And place your cargo bay as close as possible to CoM. A decent number of SAS units and a few Vernors are also useful for negating minor imbalances.

Competition closing today! To avoid confusing folks, I'll keep it open until the end of the 14th in California (rather than Sydney time). But, still: if you want to enter, now is the time. How long do folks think we should give for flight testing and posting reviews? The original proposal was for a week, but given the number of entries I'm not sure that this would be long enough.

The reason to refuel the station instead of just leaving the spaceplane tanker in orbit is because the tanker has a cost and part count about 10x that of the station itself, and the presence of fragile aerodynamic surfaces requires a more cautious docking approach then would be allowed otherwise. Obviously, this is a YMMV issue. But there are valid reasons for dedicated orbital fuel stations that don't depend upon ISRU.

Not necessarily; a good spaceplane tanker can deliver fuel to orbit for less than √1 per unit. I'll use one rocket launch to create the station, but resupply with spaceplanes from then on. http://forum.kerbalspaceprogram.com/threads/90337-Economic-Fuel-to-Oribit/page5?p=1361984#post1361984

PJ was asking for community input on landing gear a month or two ago, so you're likely to get your wish.

It varies a lot based on how fast you're coming down. Overheated level flight can be sustained for quite a while, but an over-hot dive is an express ticket to boomtown, IME.

Stock aero or FAR/NEAR? Orbital refuelling isn't necessary for interplanetary travel, but it is very helpful. And the station does not need to be gigantic; a couple of Rockomax 74's is plenty. You wll need to figure out orbital rendezvous and docking, but there are a large supply of forum threads and Youtube tutorials on the subject.

So, as has been established so far: either more vertical stabiliser, a Vernor (or multiple linear RCS ports) either side of the nose, or shift the CoM forwards in order to get the tailfin more leverage. Removing the dihedral from the tailfins will also give them a bit more force, and you probably have enough roll stability already that you can afford to lose a bit. Keep the FAR analysis window open and re-run the numbers after you move or change any of the aerodynamic surfaces; you're trying to get the red number to flip from negative to positive. Keep any changes that move the number in the right direction, ditch any changes that make it worse. - You may want to shuffle your CoM around for other reasons as well. Because your cargo bay isn't on CoM, adding and removing cargo is going to disrupt the balance of the plane. Whenever you add or drop cargo, you're going to substantially alter the CoM/CoL relationship. You may want to try this: swap the positions of the cargo bay and the rear-centre fuel tank. This will increase your CoM/dCoM offset a bit, but you can balance that out by shifting the lateral tanks backwards. As well as putting the cargo bay onto CoM, this should also allow you to increase the distance between CoM and the vertical stabilisers, providing them with more leverage. It may also be helpful to add a passenger cabin or somesuch behind the docking port, as a way of pulling both CoMs forwards without altering their relationship. The plane can certainly handle some extra weight; you've got a lot of wing on there.

Nicely built; those analysis screens are almost flawless. The AoA sweep suggests that the plane should tolerate fairly extreme (25°, maybe more) AoA while maintaining stability. The touch of red in the numbers is not too big a deal; if you hover your mouse over it, you'll get a popup explaining what it's about (I don't have my PC on right now or I'd look it up for you; f you post it here, I'll try to give a FAR-to-English translation). The tooltip will reference assorted variables that relate to this image: The lack of obvious flaws in your aerodynamic design suggest that the issue may be more piloting related. Just how sharply are you trying to lift the nose, and exactly what happens when you lose control? Does the plane pitch end over end, or yaw sideways, or roll upside down, or something else? Also: what have you got the control surface tweakables (maximum deflection, pitch/yaw/roll, etc) set to?

You've got some non-neutral trim set. Alt-X to clear it, then turn the SAS off for ten seconds to complete the contract.

There are a few points to address here. * The only reason to pull the nose up once you light the rockets is in order to climb to an altitude where there is less drag. It's not compulsory; so long as you maintain any climb rate at all, an increase in speed will eventually lift your apoapsis into space. Particularly with low-thrust high-efficiency rocketry (e.g. Poodles or nukes, rather than RAPIERs or Aerospikes), a shallow ascent is often best; let your wings do the lifting while the thrust is concentrated on increasing speed. * Increasing your AoA by too much is going to cause your plane to want to go out of control. If you're getting stall warnings, you're increasing AoA too much and too fast. You need to lead the plane rather than force it; increase AoA by a bit, then wait for your prograde vector to catch up, then increase a bit more, etc. * In the upper atmosphere, the thin air limits the grip available to your aerodynamic surfaces, reducing their ability to maintain stability. For a sufficiently well-built plane this isn't a problem, but for when it is: Vernors. Stick a few around the plane in relevant places (e.g. above, below and to either side of the nose and/or tail) and keep them turned off until you need them. Vectored thrust can compensate for a lot of aerodynamic flaws. * Sorting out these issues is what the FAR analysis screens are for. It would help us help you if you could post some screenshots of the analyses. What would be relevant is an AoA sweep at the speed at which you tend to lose control (that will tell us how much AoA your plane can take while retaining stability) and a stability derivatives analysis at the same speed with the atmospheric density set to match the altitude at which it happens. If you're not sure how to do these, have a look at post #3 in the Kerbodyne thread linked below. That'll also tell you how to translate altitude into atmospheric density. The AoA sweep should look something like this: And the stability analysis should look like this:

...and in both cases, the use of the word "unobtainium" was a suspension-of-disbelief shattering joke. "Unobtainium" has been common motorcyclist slang for flashy alloy parts (usually but not always made of titanium) for at least thirty years.