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I created a feedback report explaining the situation in detail. https://bugs.kerbalspaceprogram.com/issues/24853

I've been playing the aircraft design Using mod installed in KSP (1.8.1 and now 1.12) for years, All of it is good, except for one fact that this mod generates lift in slow speed (taking off speed) obviously weaker than it should be in reality. I built aircraft according to the real-life examples, I always edit the mass and size in part.xml file and change all mods' setting to make sure the aircrft is close to real ones. This Fokker Dr.I in game is made to be 5.77m × 7.19m, Weights 550kg, Wing area is 20m^2. It's really close to the Wiki data, and I make the Mass-Lift-Centers-distance close enough for a fighter aircraft. However, the stall speed is tragically much higher than real-life-data's 72 km/h, I have to fly over 120km/h to make sure it doesn't need too much AOA to keep level flight. When it comes to other larger aircraft like B-29, the taking-off is so unrealistic that it feels like flying a Space Shuttle. I've been testing the different factors that might affect the Lift force, like the thickness of B9-procedural-Wing, or the length of Leading and Trailing edge, or the distance between deckedwings, And the result is, the only factors that determine lift, are Wing area (not matter how the wing is shaped) and Wing AoA in flight. So that means I can never use the real-life aircraft example's WingArea-to-TotalWeight Ratio to take off in the real-life speed, I have to fly much faster in higher AoA I've tried to edit part.xml to increase the "deflectionLiftCoeff " or any factor that looks like being about Lift or wingarea, but nothing works, the flight test data are the same. So, is there a secret setting button I don't know in FAR fuction that can increase the Lift generated in low speed ? Or is there any other ways to violently edit and increase Lift of B9ProcedralWing or other wingparts?

Yes this is urgent as my custom Space Shuttle is in the reentry process while the game is paused, so I built it with a different design as the common one, I got a mastodon engine at the back with 4 thud engines with 2 jet engines at the sides, and with a wing that goes all the way from cockpit to the Mk3 to 3.75m adapter, without front canard, and the problem is when I do the 40 angle pitch up the vehicle slows down but it keeps going up, tho no thrust is being applied, what should I do now in-reenrry?? Remember, it's urgent.

Hey guys , I know there are already a lots of tweets but i watched already a lots of tutorials etc... Well i tried to built a big cargo-SSTO. On ground it is good to turn left right but i have the problem that it cant take off I have built also another one but it has exactly the same problem. I can built planes i constructed the SR1-Blackbird and it worked well but SSTOS ... are not working ^^. One Problem i could imagine, is that the center of lift is not at line with the center of mass but I am still a noob in planes. I started 4 days ago to build planes xD. kind regards PS: i hope the pictures are there https://imgur.com/PG1H2RQ https://imgur.com/GmihCbH

TLDR I did some tests with various rotors to determine which yields the highest lift/weight ratio for heavy payloads on either Kerbin or Eve. In the static tests I’ve performed on the ground of Kerbin and Eve, I noticed that the large helicopter Type S blades provide the most lift per tonnes rotors+motor . In my flawed tests, 8 rotors per motor work best on Kerbin and 4 rotors per motor work best on Eve. I was also able to roughly determine the maximum mass of a craft at which it would still fly. Long story I’ve been running tests with various sizes of propellers to determine the a correlation between vertical lift and mass. I’m especially looking for optimum mass to lift ratio’s for heavy crafts and trying to find a way to calculate the amount of propellers I need to get something in the air. I’ve been trying to approach it scientifically but eventually just tried some stuff at random. Literature study None.. just felt like messing around with the propellers. There are probably a bunch of better articles describing how to calculate the amount of lift on a given planet at a certain altitude. My initiial guess is that the lift is calculated something like: Lift = Function [ rotating speed, angle of attack, air density, rotor blade type] Experimental setup I performed two experiments: 1. On Kerbin , using a rigid clamped setup with 3 heavy motors in series. I tested 3 types of rotors with 8, 4 or 2 blades per motor 2. On Eve, using a massive s4 fuel tank setup ( 1,200 tonnes) with 4 motors. Testing 2 rotors, with either 8, 6, 4 or 2 blades per motor Results The current measurements have been done under static conditions on kerbin and Eve. Below you find the results. Propeller type Amount of props on motor Total weight of props (ton) Weight Motor (ton) Max RPM optimal Angle of attack Planet Lift (kN/prop) Total lift (kN) Lift/total weight motor + rotors (kN/ton) Heli S-Type 8 1.44 2,2 440 5 Kerbin 270 2160 593 Heli S- type 4 0.72 2.2 445 8 Kerbin 335 1340 459 Heli S- type 2 0.36 2.2 450 8 Kerbin 346 692 270 Propeller S type 8 0.96 2,2 460 82 Kerbin 34 272 86 R-25 fan 8 0.96 2,2 460 84 Kerbin 37 296 94 Heli S-type 8 1.44 2,2 253 5 Eve 403 3224 886 R-25-fan 8 0.96 2,2 450 84 Eve 163 1304 413 Heli S-type 6 1.08 2,2 253 3 Eve 500 3000+ 915 Heli S-type 4 0.72 2,2 418 3 Eve 700 2800 959 Heli S-type 2 0.36 2,2 450 3 Eve 1100 2200 859 I changed the angle of attack to find the optimum angle at which most lift was created. From these short tests, I found that the Heli S-type blades performed the best when you look at lift per weight ratio. I also tested if less rotors would yield in better performance on either Kerbin or Eve. From what I’ve measured I could state that: 1. On kerbin 8 Type S Helicopter blades performed better than less blades 2. On Eve, the optimum lift/ton motor+rotors weight seems to be 4 rotos per large motor Discussion One of the things I wanted to find out If I could calculate the maximum weight a certain setup would be able to lift. From what I’ve conducted. It’s fairly easy to calculate: m = max mass (in tonnes) = F * G F = Lift (kN) G= gravitational force ( 9,81 for kerbin, and 16,5 on Eve). For a two motor helicopter with 4 large helicopter type s blades per motor, this would mean that it could carry: 2800kN / 16,5 m/s^2 * 2 motor with 4 props = ~336 tonnes I tested this and It seems to check out. I also wondered if I could translate tests on kerbin to match the results on Eve. It seems that the there is a correlation between air density, RPM and lift on Kerbin. However, the maximum amount of RPM is different on Eve, compared to kerbin, so I think I need to add torque and drag into the equation for this. I didn’t have time to work this out though. Btw, this was a very flawed study and many additional tests need to be done before any hard conclusion can be made. Several things come to mind: - Does the lift vary with different vertical velocities (anything else than 0 m/s)? - Does the optimum angle of attack vary as the density changes (it does) - What is the effect of the angle of the ship on the optimal angle of attack of the blades - Etc.. Anywho… It was a nice experiment. I’m now able to calculate how many rotors I need to carry a certain payload.

Recently I have had problems with my center of lift always pointing straight down, even though i have my wings set forward, can someone help me with fixing this issue?

From my experience it's difficult to impossible to dock with a surface outpost, because the docking ports have to be the same height above the ground. And they have to be axially aligned, so if there was a way to control the orientation and raise it up it would be easier to dock.

In a plane the Centre of mass is just ahead of the centre of pressure, so it is stable. When elevator movement is given, it does go nose up but it doesnot climb. Instead in it tries to come down. How to make it climb. P.s Rhodes34 airfoil if used inclined at 8deg Basically I want to know what affects the rate of climb and vertical velocity

I am creating a variable wing that can be deployed and retracted. I want to use ModuleAnimateGeneric and ModuleLiftingSurface of parts.cfg file. 1. How to change the lift with deploy and retract? 2. Is there a way to know the current status of deploy and retract? I have just started Addon development, and I do not know much about it. Thanks for any advice.

I am trying to make a model of a Boeing 747, but the "fat 455 aeroplane main win" is too small for what I want. I found a forum that told me how to resize it, and i did, but the problem is that it still has the same amount of lift, and I have not been able to find ANY article of the forum even remotely talking about how to add lift to an object. please help me out.

Hey there So I had some trouble with this career games first landing on the Mun. Figured I'd not got the balance of the lander correct. When I went in the VAB, I found that any rocket I designed had a lift vector. I tested with an unmodified game, and I guess it's not supposed to be like that, since it didn't happen then. Has anyone encountered this before? Thought I'd ask here first before I start trimming mods to find the problem. Possibly something that updated recently, as the unmanned lander I sent previous didn't have any difficulty landing. Thanks to anyone who takes a look. KSP.log output_log.txt

It'll be really helpful to know the Lift&Drag characteristics on altitude and speed, to fly a proplane. Anyone knows something about this?

Well, after hours of testing, reading, and testing again, I am still having a really hard time understanding the aerodynamics. Previous post: Even though my previous post was ironically the only ground drag issue that came into the equation with trying to make a stable jet, I'm still trying to build a stable jet. Rather, understanding how to make one that is. I know CoM, CoT, and CoL, but I don't understand their results. There are numerous claims that if the CoL is behind the CoM, then the rocket will be stable. KSP wiki: http://wiki.kerbalspaceprogram.com/wiki/Center_of_lift#Flight_characteristics foamyesque: But my mind is vehemently refusing to accept this. Don't you guys mean the "center of drag"? I feel like this is very similar to the CoL, but is still different. You could have a ship with two wings in the front and then a bunch of random parts on the back, and would fly with the drag-inducing parts in the back like an arrow with feathers. Yet, the CoL would be right between the two wings, because they are the only things providing lift. I've had planes where the CoL is significantly behind the CoM, but it still wants to flip at high speeds, or at least doesn't want to just go straight. And this flows into my second question. You know, let's make a list. Welcome to the buffet of questions for all your answering needs: Is the CoL the same thing as the "Center of Drag"? If not, is there a good way to find how far the CoD (center of drag) is behind the CoM? I've been shooting my crafts way up in the atmosphere and then letting them fall to see if the CoD is behind the CoM. Kinda time-consuming. If all parts create lift (KSP wiki quote below), why don't they change the CoL in-game? KSP wiki: http://wiki.kerbalspaceprogram.com/wiki/Lift#Dynamics The wings are symmetrical. Do they still produce vertical lift in ksp if they are not given any angle of attack? Are there specific wings that do/don't produce vertical lift at 0° angle of attack? I'm really sorry I'm asking the same question that everyone always asks, but this is a little different. Thank you so much for taking the time - Spemble

Hi, i dont see anywhere neither in the VAB nor in the SAB how much lift the ship has. In addition, what is an optimal lift per weight ratio?

So I've been making an F-35 Replica(that looks really horrible) and i wanted to see if it would fly. I checked the COL and COM and the COL was all the way on the floor. (I tried to test fly it but it didn't take off and flipped out) Picture: http://imgur.com/a/eBbtV EDIT: It''s a little hard to see. The COL is below the plane on the floor.

Hi! I have designed a run-of-the-mill SSTO. Nothing special, gets Kerbals to orbit. Unfortunately, I noticed an issue: one of the fuel tanks does not provide lift, and only on one side!! http://imgur.com/a/M5wRF Craft file: https://dl.dropboxusercontent.com/u/1414175/ksp/jinxed-jet/Jinxed.craft I just don't get what is wrong with it. Can anybody help me out here? ps.: This happens both in 1.1.3 and in 1.2.

Hello people. I was trying to build a pretty weird craft, and came upon a behavior i was not expecting concerning the MK2 serie of fuselage parts. So, here is a first shot: I would expect this (line of mk2 fuselage rotated on their side) to show some lift on one side, probably to the right of the image given how i rotated the parts. But as the indicators show, there is no lift produced. Then, i rotated each fuselage to get a ring, and it was now producing lift... Shot: Close-up shot: It might be useful to know that on this shot, the root part is a mk2 cargo bay and it's the part on the right, 90 degree from the lift vector. I was expecting this to be neutral as far as lift is concerned, seeing that i have equal lift all around, and that i was careful rotating them so the face in the same way. Am i wrong in my assumption that this should show no lift? But then, it does other strange thing, Shot: Here, i just rotated the whole ring, going by the previous shot, lift should point down, but It now point to the side, at the root part.So, if i place it "lying down" like the first shots, and then upright, i get different lift vector. Could well be me missing something obvious, but i do not get it. So i decided to try and place back my lift vector where i wanted it with wings inside the ring, got there: Shot: Lift looks pretty straight up. with a backward angle. Fact is, the craft does not fly like the vector is there at all, as soon as it get a bit of speed, it push hard toward the direction opposite the root part, like the lift is now offset to a side it never show in the editor. So, am i wrong in assuming that the ring should produce neutral lift vector? And from there, if i'm wrong, what is it i do not get that shift my vector? Side note: The craft attitude is controlled with reaction wheels that i clipped in the fuselage, 12 of them. And i placed RCS thrusters evenly over the fuselage in the hope of getting enough attitude control to offset the problems, did not worked.Then i attached elevon on the backside, they helped a bit. I get it that this will be a really really draggy thing and that it maybe should not really fly, but it is so close too doing it i'm sure i can get there with a bit of help. I'm good at rocket, very inexperienced at "planes".

KerbalX download We can change rotary motion into linear motion :-) Credit to Erasmusguy again (he has so many good ideas). I borrowed the slider rails w/wheels idea from a transmission or something he was working on. If you lift stuff, or flip stuff over, post a pic. Edit: pure stock

In flight, you can open up a nice aero forces display by opening the ALT F12 debug menu, going to the physics tab, then the aerodynamics sub-tab, then checking the "display aero data gui" checkbox. I've noticed however, that the lift:drag ratio numbers seem very poor compared with real-life airplanes. The best I can get is 8 or 9 to one, at 2 degrees AoA, at low speed and altitude. At 0.82 mach and 10km, similar to how commercial airliners fly, best seems to be 2.8 AoA and maybe 5 to one lift / drag ratio. Real commercial airliners are pushing 20:1 at such a point, in fact i'd bet the newest of them, the 787, is over 20 at an "economy cruise" setting. Supersonic , things get worse. At 1.3 Mach, I try climbing higher to use thinner air to compensate for the extra drag. Best results seem to occur at 3.5 AoA and altitudes of 14km or more, I might get close to 4:1. Concorde did 7.5 to 1 at mach 2 and 60,000ft. As we get deeper into the supersonic regime, numbers ebb steadily lower. Above 20km I'll start my final climb to orbit at something like Mach 4 and shutdown engines (needing only to circularise) at Mach 6.6. During this period optimal AoA seems to shift from 4 degrees to 8 or so. At best, I might see L/D display of 2.8, whilst pitching up to high alpha because my craft is overheating can pull it down to 1.6. Reading a little further on wiki, it appears max lift:drag does taper off with increasing mach no matter how high the altitude and thin the air, especially for conventional supersonic/transonic swept designs. However waveriders that rely on compression lift can do better, with designs like the Hypersoar project making 10:1 at mach 6. I guess this is all to compensate for the overpowered nature of jet engines themselves, compared with real life. I still find it a bit weird however, that if my L/D is so poor, why my spaceplanes are so reluctant to actually land. I've long since given up targeting the runway and am quite happy to settle for anywhere on the KSP peninsula or in the shallow seas nearby, usually after flying back and forth across it several times. I guess as we head below 100 m/s our L/D is getting up that of a Cessna light aircraft and we're usually coming in a tad "hot" , also the drag from landing gear, flaps, and jet intakes (with engines off!) is less than it should be .

I've had this happen a few times and have also seen it happen to others...... Situation: Aircraft is perfectly fine to start with and flies somewhere away from KSC (or on another planet). After flying for a while, it lands safely on the surface with no damage. Problem: When it takes off again for another flight, some wing pieces on one side of the fuselage have lost their ability to create lift, while their symmetrical counterparts still produce lift. This produces a bad rolling tendency in the plane which, at high enough speeds, can be uncontrollable. The pic below shows an example of lift-less wing sections marked in red. NOTE: I've had this happen to planes that I've left on the ground, quit the game, and returned to. I've also had this happen during a session where I landed, EVA'd a Kerbal, and returned him to the plane, but didn't go back to KSC or quit the game. So what causes this and how do I fix it? Thanks.