FourGreenFields

Where's the CoM? Should be slightly behind your main gear, but only slightly. If that's still possible, try to reduce the drag of the main gear, and increase that of the tail wheel. And make sure the gear doesn't flex. Also worth a try to pull during takeoff run, to increase pressure on the tail wheel. That being said, are you sure the thing will lift off at 50m/s at the AoA it has when sitting on the runway? I don't consider it impossible, but AoA seems relatively low - might still be sufficient if the craft is light though.

I'm quite sure it resets prior to every launch. You could just angle the control surfaces for a "saved" trim though (allthough it wouldn't change thrust vectoring). Or maybe you could write a macro to set trim at spawn (and the rest of the routine, like lowering flaps to takeoff position, etc.). Maybe it'd even be possible to save the trim settings as part of the plane file (as comment?), and have the macro read it.

Or just trim the plane (iIrc alt + qweasd, and alt + x removes trim).

Am I right to assume it only reaches critical AoA due to thrust vectoring? Either way, my money is on side-slip, and possibly higher speed of the outer wing. Considering you compared it to the 190, I assume that you know it's a bad idea to pull hard when using rudder, and afaIk that's because the side-slip causes asymmetric stalls. And you'll usually end up with a small amount of side-slip in turns, unless you counter with rudder. Also the outer wing has a slightly larger turn-radius (unless banked 90°), while keeping the same turn-time, with other words a higher speed. If your wings stall sooner at higher speed, it may make matters worse. PS: How stable is the dev-version of FAR?

Btw: SpaceDock says that FAR is still outdated. Does the outdated version work with the latest KSP patch? Or are you using some experimental branch?

Was a thing in Germany even before 1945. Wing sweep as early as the thirties. Allies should have known about wingsweep too, considering it wasn't kept a secret. They did, however, ignore any knowledge they may have had about it, until they found German blueprints and a prototype (or several prototypes?).

Dihedral effect isn't limited to dihedral wings(/lifting surfaces). A vertical surface (tail fin!) will also make your plane roll when slipping, as long as it's mounted above or below the CoM. If that wasn't the case, nearly every plane would have some dihedral, because you generally want a little dihedral effect (-> roll stability)

I'd guess that might be due to dihedral effect. If you roll at high AoA without using rudder with ailerons (left ailerons -> left rudder) you'll turn your AoA into slip angle, which then causes roll in the opposite direction. Not entirely sure if it's that, but worth a try I'd say.

The challenge went through a redesign, and the scoring vanished at that point. I posted what it may have been at some point, may want to dig that up.

That might be some weirdness with unusual characters and forum redesign. Pretty sure it's meant to say 12°.

The B-2 there used artificial stability, as blowfish mentioned (I think the setting was called yaw brake). However, it is possible to make a plane yaw stable (aerodynamically, not artificial stability) without dedicated tail fins. The most kerbal way is probably to add drag on the tail (like a chute), but that kind of limits your speed. Wing sweep also increases yaw stability, although not usually to an extend that allows you to remove a tail fin. Probably the easiest way is to add an di-/anhedral angle to your wingtips, when using wing sweep - they'll work similar to a tail fin, but aren't technically tail fins. Usually a good idea to use artificial stability/fly-by-wire on top of that. And keep your CoM close to the nose, as that'll increase stability anyway.

I hope I'm not too late for the flying-wing-party... date-volume limit prevented downloading stuff (playing on another PC now) before Deizel made his bomber himself, so I decided to build a cargo plane based on Mk 3 fuselages (as he said that increasing size was the problem). Testing isn't done yet, and there'll probably be some adjustments. Relies on FAR stability assists for stability (yes, pitch too. And any landing attempts without roll assist failed as well).

Ok, Mk2 fuselage, blended wing-body. High speed, and some payload (judging by X-45 and X-47 a bomber/attacker, so doesn't need to be that manoeuvreable). Pilot-friendly handling. Going to try that later today. o7

Aerodynamically stable (basicly translating to di-/anhedral wingtips or stuff) or artificial stability? Messed with both, mostly for the 5th Generation Fighter Challenge. Size? Payload? Speed? SSTO? Any requirements for takeoff and landing (other than being able to do that at KSC)? Existing design that you want improved?

If the CoL is far behind the CoM that usually means high pitch stability. Not nessecarily bad, but means you need a powerfull elevator to pull high AoAs. Put simply, you'll want CoL and CoM close to each other for agile planes (stuntplanes, fighters) and possibly planes with high wingloading (as they may need high AoAs to fly slow). CoL further behind if the plane is meant to be easy to fly (trainers and stuff). But even "futher behind" shouldn't be overdone, or you risk not being able to pull the AoA to sustain level flight - which is probably what is happening to your plane. You can, ofcourse, build agile planes with CoL far behind CoM - a very big/powerfull elevator can overcome stability, thrust vectoring can help (especially at low speed), and some planes may have lower stability at certain speeds (one kind of layout I used had significantly lower pitch stability at exactly 0.9M for example). But it's a bit like building supersonic planes without area ruling them - possible (as the Bell X-1 proved), but there are easier ways. A better indicator for how pitch-stable a plane is are the "pretty graphs" in the FAR interface. There's a yellow (iIrc) line, and if it's going down as AoA increases, the plane is pitch-stable. Good way to see if the plane is, i.e. getting more or less stable as AoA increases. Also usefull to see if the plane will keep the AoA required for level flight without trimming (if you want that, I'd recommend adding an Angle of Incidence (AoI)), and to get the critical AoA. You can also calculate the graphs with pitch input (only elevator, not RCS/thrust vectoring iIrc) to see the maximum AoA you can pull. I'd recommend you to do that, and compare that to the AoA required for level flight (as can be claculated using the "scary numbers" section). The "scary numbers" can also help determine stability in general, but not all of them (not even all of the coloured ones) are vital, and I found it hard to figure out how stable the plane is - only if it is stable at all, or not.

For all I know, lift from wings (and probably some drag stuff regarding the wings) isn't strictly shape-based. It takes the relative position of the wing parts into calculation, but, as you already found out, clipping can lead to issues. B9 Procedural Wings (or some variant of it) is probably the way to go (unless you find a mod with non-procedural wings which suit your needs).

Just looking at this thing, it seems very crude. Leading edges not aligned properly, spoilers slightly sticking out of the wings (your wings need to be slightly thicker than the spoilers), ailerons not aligned either. (Are you sure you're using angle snap when placing control surfaces/spoilers on the wings?) Also, the leading edges of the elevators and canards seem a tad small. Usually good for hypersonic drag if you cut down on "normal" wing width, and add longer leading edges instead. (On normal wings that reduces your fuel capacity though)

(Didn't download, just looked at the design) If you want to keep the slip angle low, add proportional gain to the yaw assist. How much depends on the plane (too much and it can cause wobbling/overcompensation; may also need to mess with derivate gain to keep it from wobbling). Just guessing here, but instability might be caused by the relatively blunt nose. Probably not a good idea to place those wings like that. You also seem to have narrowed the fuselage in the middle - and area ruling won't help too much when too far beyond Mach 1. For hypersonic speeds, use simple shapes (avoid any kind of parts sticking out), pointy leading edges, small face surface (? Not sure if that's the right word; cross section when looking at it from the front), and small wings (big surface area will also cause too much drag). B9 procedural wings will come in handy for that. Also helps to keep the entire plane as small and light as possible.

Some B9 Procedural Wings mod. Original isn't being developed anymore, but you should find it (= similar stuff, propably using the same code) if you search for it on this forum (not following it on Space Dock (iIrc not downloadable there) so would have to search it myself as well). Pretty usefull for thin wings. Yes, and yes. And screw not being able to post on the WT forum if you haven't played for a while.

Mach 3 using "Panther" engines on a "proper"™ plane: So close, and yet so far... Sucks how these jets rapidly lose power past a guesstimated 2.8M.

Bad about it? This: https://upload.wikimedia.org/wikipedia/commons/e/eb/English_length_units_graph.svg Yes, it works. So does a pontoon bridge. Doesn't mean it's a good solution. Side note: You may have accidentally swapped the speed with and without afterburner at low alt for your "Viper" there. Ok, point taken.

I don't get why people use the imperial measurement chaos. Seriously, just why? On topic, there is/was also "The 5th Generation Fighter challenge [FAR]". Doesn't really seem to be alive anymore, but still fun to mess around with imo.

https://www.dropbox.com/s/ra2vyxmx67quhci/P1.craft?dl=0 Brakes are still kind of weak, and she likes to steer off course when you brake, but that can be controlled (or just use the landing chute). As said landing and takeoff at about 50m/s, may want to land at slightly higher speed to avoid tail strikes. Lower flaps on action group 1, raise flaps on action group 2. With deployed flaps and full elevator she may stall, so a JS is recommended unless you tweak the controls a little. Assuming a nose-gear setup, the main gear should be placed slightly behind CoM. How "slightly" depends (i.e. the AoA during touch down (too close to CoM and the wheels will be in front of the CoM at high AoA, causing tail strikes when touching down hard), and elevator authority). If you set it up so you can pull the nose up with the elevator (or for more crazy designs with elevator + RCS/flaps/a chute/black magic), it doesn't matter much whether the nose points down or up. TLDR: The sweetspot(s) for gear placement depend on the plane.

Ok, built it. Had to mess with the settings for the gears to make her stay on course, but she takes off, flies, and lands fine. Takeoff, and landing speed about 45-55m/s with the main fuel tank half empty. Reached 150m/s on about 1/3 throttle. Takes off by itself if you extend the flaps. EDIT: May need to upload somewhere else to make the screenshots show here... or I don't have a clue atm. EDIT2: Ok, uploaded it on imgur.

Pretty much what Van Disaster said (only looked at screenshots though). Shape matters way more in FAR. Build a proper tail, make sure the wings touch the fuselage. Also, considering that you're using those cute little jets (forgot their name), delta wings might be a bad idea - they add alot of drag at subsonic speeds (especially at high AoAs). Build long(ish) relatively thin wings (high aspect ratio) without wing sweep, and as you'll change the tail anyway, you can add a horizontal stabiliser too. Side note for the screenshots: Even though "CoM in front of CoL" doesn't matter as much as in stock, a screenshot with those two would help (among others to see the position of the CoM relative to the gear). Going to design a plane with 2 of those jets now. Uploading screenshot soon™.