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@ferram4 In your last response to me, you answered one of my questions about strange static analysis results, saying that it would wait until the wing overhaul. However, there were two other questions/concerns in my last post, on May 25th, which I believe are important: 1. The structural panels produce a strange pitching moment, as if they produce lift backwards or at 90 degrees or something. maybe the pitching moment is calculated backwards. (screenshots etc. in aforementioned post.) Note how a rocket with mass in the back and fins in the front is stable using this method, whereas a rocket with mass in the front and fins in the back would be unstable, in violation of everything taught in ksp rocket-school. These effects occur in flight test, and after waiting several minutes before simulating/running (even though really just 1 or 2 seconds would suffice for voxelization). Further testing shows that other objects, such as structural fuselages placed parallel to the rocket, large landing gear with wheels to the side and facing backwards, and modular girder segments pointed outwards from the body also exhibited this effect. I believe any non-wing part, if oriented correctly, has this effect. 2. Is there a way to see/calculate the reference area of the craft?

@ferram4 1. are you sure? I mean, this rocket is incredibly stable (confirmed with flight test): and this one is incredibly unstable, once its slightly off center (confirmed with flight test) : Both pictures were taken inside SPH. Moving the panels farther from the center enhances the effect, so it must be a force on the panels, using the length of the rocket as a lever. But the lift must be positive, and the drag must be positive, so what force could it be? Whatever it is it would have to be stronger than the combined lift and drag forces on the panels, which are pulling the rocket off-center in situation A, and stabilizing it in situation B. This effect is really unintuitive to me. 2. Yeah, you're right. It was the fuselage that had the high lift coefficient, not the panels, and I assume that the high Cl is intended in that case. I stacked 2 panels per wing so they looked like they were the same size as the wing connector type B i was comparing them to, but I guess the reference area was smaller. Is there a way to see/calculate the reference area, or the total lift produced by the plane at various angles of attack, so as to not get tripped up this way? 5. It happens regularly when I attach a wing connector type B to the end of another wing connector type B. I have a screenshot of it happening without stacking wings onto the ends of wings, and i managed to reproduce that once, but I can't find a reliable way to do it. Putting two wings really close together, such as a tail fin and a wing connector type B, also sometimes has a similar effect, but I can't find a reliable way to do that either. Here are photos of two wing connector type B's attached end to end, and the two possible behaviors:

1. I think I found a bug: Placing M-2x2 Structural Panels at the front of a rocket caused a pitch down moment at high angle of attack, making the rocket very difficult to flip when it's traveling at high speed. Placing them in the back (like a lawn dart) caused a pitch up moment at high angle of attack, which made the rocket easily spin out of control. I am using KSP 1.1.2 on Windows with Ferram_Aerospace_Research-v0.15.6.5_Knudsen, and no other mods. I tested this using the ksp.exe and ksp_x64.exe; I assume ksp.exe is 32 bit. 2. The structural panels have higher lift coefficients than wings. Also much, much higher drag. Is the higher lift coefficient normal? 3. Google searches told me that tapered, swept-back wings stall from the tip, causing dangerous pitch-up stalls. I did not observe this in FAR. Is this effect real? If so, is it modeled? 4. The wikipedia page on stalls says that some planes, notably T-Tailed planes, experience "deep stall", where turbulent air from the main wings blankets the rudder, and makes it ineffective. Is this effect modeled in FAR? 5. Sometimes, when I move a wing around, the static analysis graph shows two stalls, like a staircase, one after the other. Usually, throwing out the wing, then grabbing it again from the parts menu fixes this, so there's only 1, clean, stall. Also, when i move a wing, then immediately run a static analysis scan, i get wrong info. waiting a bit before running the scan, and/or running the scan again fixes this. 6. The static analysis graph shows a small spike in the lift coefficient for dihedral and anhedral wings at 75 degrees angle of attack. I have nothing to say about it, i just thought it was weird and interesting. 7. Yeah, making a stable plane is easy, making an unstable plane is easy, but making a plane which tailspins must require advanced aerodynamics knowledge or something.

A rocket made in the SPH, facing fowards, consisting of a mark1 cockpit, a fl-t800 fuel tank, and an lvt-45 engine has a slight positive Xu that increases up to 0.251 at mach 0.6. At mach 0.61, the Xu suddenly changes to -0.05. When I hacked gravity to try to see the effect in-game, the Xu changed to be negative at all speeds. The github page said that a positive Xu means there's a bug. @tetrydsThanks for the response. The video you linked was pretty good. You had to force your plane into it with roll and pitch controls, and you had your engine at full, so I'm still not convinced you can you make your plane spin without those, but that's still farther than I've gotten. Also, I'm confused about why your left wing is red, meaning stall, at 6 seconds into the video. Based on the navball, your nose is a few degrees above the velocity vector, meaning you're not rolling, not slipping sideways, and at a low angle of attack. I would share my craft, but I have nothing to show at the moment since my designs are fairly simple (jet fuel, a few wing connector type B's) and they don't spin. Also, is the pitch down force caused by the back of the wing stalling less than the front, and thus the plane having more lift in the back than in the front? It seems like if I place the entire wing in front of the center of mass, then there is no pitch down force. A few months ago there was a pitch down force even with the entire wing in front, but I can't replicate that now. I'm assuming that was a bug which was fixed.

This is sort of a repeat of a post I made on October 25th 2015. I came back to KSP to see if anything changed. Every plane I make pitches down upon stalling, and all the stock FAR planes pitch down as well. This is seen in the drop in the yellow Cm line corresponding to the drop in blue Cl line at around 30 degrees, and seen in the way my planes are yanked back when they get too far off center. The planes which don't show a sudden pitch down upon stalling, seem to just have their wings farther back so that they already feel a pitch down force. Offsetting the wings forward causes the plane to be pitch-neutral until the stall, where it suddenly pitches down. Is this a real phenomenon? Is this a bug? I'm trying to make my planes do spins and snap rolls with no success, and I feel that this pitch down force is related to my lack of success. The planes lose control, but never in a stable spin like you would see at an air show. I haven't seen anyone else attempt or succeed at this (not counting engine-induced spins). Are spins possible in Ferram Aerospace Research? I am using KSP 1.0.5 Linux 64 bit and FAR Jacobs 0.15.5.6 with no other mods installed aside from the bundled moduleflightintegrator and modulemanager.

So I was trying to make a stuntplane that can tailspin (no success so far), and I found an oddity. Stalled wings seem to strongly pitch my plane down. I made this rocket, with wings in front of the center of mass and at a 45 degree angle. The yellow Cm line looks positive at negative angle of attacks (when the wings aren't stalled), but then dips right when the Cl does. The rocket is a stayputnik, small inline reaction wheel, fl-t800 fuel tank, lv-t30 liquid fuel engine. Two wingconnector type B's are placed in front of the center of mass, and then rotated by 45 degrees. I launch it. The small inline reaction wheel is pitching it up. The body lift of the fuel tank is pitching it up. The drag on the stalled wings is pitching it up. The lift on the stalled wings is pitching it up. And at first, when the rocket isn't going that fast, it pitches up as expected: But immediately after that picture was taken, it reverses direction and pitches down, fighting all those forces. and then it oscillates, rolls a bit, and completely loses control as you'd expect. Are stalled wings supposed to pitch down like that?