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DA299

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    SSTOs and FAR

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  1. @G'th a question for you: Does the 'truesight' pack mirror what is visible from actual Earth orbit? Because it does look realistic.
  2. You can disagree, but accurate aero is not really hard to simulate. Nobody is asking for a full-fledged CFD simulation. You can play with FAR if you want to know what I'm talking about. It has no performance penalty whatsoever that I can notice, and actually even runs better for large part count crafts, due to its voxel based calculations. And it is actually a reasonably accurate model of real life aero(~85%) and most importantly, is not hacky. I have no issue with KSP aero not being realistic, but it should not be hacky. Rest, you can agree to disagree.
  3. Yes, but you need to download the latest version from the Gitlab repository.
  4. Since anyone else hasn't made any real effort to do so, I'm gonna help you out on this. The reason why it's so easy to break the sound barrier(in KSP) is that both the planes and the aerodynamics are incredibly unrealistic. 1) Parts are unrealistically dense, which increases their ballistic coefficient(A crunched up ball of paper flies further and faster than a sheet.) 2) The Jet Engine mechanics... where do I even start. They have incredibly unrealistic thrust curves, and almost every engine can survive Mach 2 speeds. In real life, You need to build an engine specifically for supersonic flight. A high-bypass turbine such as the Goliath will flame out(compressor stall) at anything over Mach 0.9; and will probably not even survive in supersonic flight(as just dead weight) 3) There is no consideration whatsoever on wing sweep/ geometries. A biplane will break the sound barrier just as easily as a highly swept delta wing, and this is simply not the case IRL. Similarly, phenomenon like Area Ruling, and Wave drag is not considered whatsoever in KSP. 4) Air intakes. Yes, even intakes need to be fine tuned for breaking the sound barriers. If not, they will cause supersonic air to enter the compressor, and cause the engine to die. 5) Shockwaves are actually incredibly violent, if your plane is flimsy it will for sure get destroyed in IRL. KSP takes no account of this issue. There are several more issues with KSP's aero model, but these are the more major ones. If you want to learn more, play with FAR and AJE to actually learn how hard breaking the sound barrier is. ___________________________________________________________________________________________________________________________________________________________________________________________________________________________ As for the question in the OP, I have two man problems with KSP as it stands 1) The aerodynamics are incredibly hacky. Like you can design the most sleek looking plane in existence, and then someone will come along, using cheats or hacks, and have a 10X better L/D ratio and 10X better performance. I can deal with all of the inadequacies listed above, but this is where I draw the line. I believe in the quote, "For a plane to fly well, it must be beautiful." and KSP just doesn't care. Why? Because KSP doesn't actually see the plane, it just sees a list of parts. If you are going to have a simplified aero model, then at least make sure its complete, and doesn't allow for hacking away the game's mechanics. KSP's aero just feels incomplete. I play with FAR almost exclusively now for this very reason. 2) The Wheels. I. Hate. The. Wheels. They literally do nothing that real wheels are supposed to do. IMO, they are by far the worst part of KSP. KSP 2 needs to have better wheel mechanics.
  5. Hey man, really love your work. I have an engine suggestion for you: the XLR-99 used in the X-15 rocket plane. But I completely understand if you're busy in something else.
  6. Yeah currently I'm not at home, and this is the only laptop I have rn. But it runs EVE, Scaterrer pretty well(I get ~25-30 fps) with 8k textures. Anyway Thanks, will check out KS3p.
  7. https://drive.google.com/file/d/1m-fLHE4I58-tCpkXRBYsZwgNjdHKjljt/view?usp=sharing BTW Thanks for the help.
  8. Still has the same issue, it crashes the game completely. I don't have any text in the main-menu now. All this with only TUFX and module manager.
  9. I've done a lot of reading on this, but still don't quite fully understand the mechanics of lift. There are several contradictory sources on the internet saying that Lift is due to Bernoulli's principle, or due to Pressure differentials, or due to Newton's Third Law. The vast majority of airfoil cross-sections also further complicate matters, as well as the myriads of wing geometries available. I'm not an aerospace engineer, but my understanding is that none of these explanations are the whole picture, because fluid dynamics is complex, and lift is itself a phenomenon which is intuitively difficult to understand. The first thing I understood, is that airfoils exist not only to generate lift, but to maximize the Lift-to Drag ratio (L/D). Even a brick will generate lift at a high enough AOA, but the resulting drag penalty makes it all but useless as an airfoil. So you can say that anything can make aerodynamic lift, but airfoils are much more efficient at doing so. Next, you have to understand that Lift is generated through entirely difficult mechanisms at different flight regimes: 1) At low-subsonic regimes(=<0.5 Mach), the airplane is moving slowly enough, that simply deflecting the air downwards wouldn't produce much lift. If you used a flat plate at slow speed flight, you could theoretically generate enough lift to fly, but you'd either need huge wings, or very high angle of attack to generate any appreciable amount. So, while they would generate lift, flat-plates would also generate a lot of drag, which would require a lot of engine to compensate. Thus the 'air deflection model', while being reasonably accurate, isn't actually a good model while designing an aircraft for these flight regimes. The pressure differential model is much more accurate, and it dictates the airfoil cross-sections of low-speed flight, which are usually thick, strongly curved teardrops or under cambered. Incidentally, these cross-sections are also observed in hydrodynamic wings, as both water and air(at low airspeeds) are incompressible. Thus, it can be said that while a flat-plate does generate lift, it does not have a great L/D, and properly designed airfoils are vastly superior at low airspeeds. 2)At Tran-sonic regimes(0.5-1 Mach), a flat plate becomes more and more efficient at generating lift, due to the increased airspeed, it need not have a high angle of attack, and so is actually useable at transonic regimes. However, it is still not the absolute best method, as using thinner, flat-bottomed or symmetrical airfoils will still outperform it in terms of L/D. A properly designed airfoil('supercritical airfoil') will generate a lot more lift than a flat plate, as it actually keeps the airflow subsonic at these airspeeds. Thus, it can be said, that both 'air-deflection' and 'pressure differentials' contribute to generating lift at these airspeeds. 3) At supersonic regimes, and especially at high-supersonic regimes, a flat plate(with sharp edges) becomes the best at generating lift with the highest L/D. The standard airfoil shape isn't as efficient, because at these speed, air is no longer incompressible, and is better approximated as a series of tiny balls hitting the wing(Newtonian theory). At these speeds, the air no longer wants to smoothly follow the contours of an airfoil, and it is best to disturb it as little as possible. Thus, the best way of generating lift at supersonic regimes, is in fact by deflecting air down. A pure supersonic airplane design will have very thin wings, and will fly with a slight positive AoA for the absolute maximum L/D ratio. Case in point are most jet fighters, and the Concorde. However, in principle, even these aircraft have wing cross-sections that resemble very thin airfoils, because they are not pure supersonic aircraft(at the very least, they have to land and take-off at low subsonic speeds!) 4) At very high supersonic and hypersonic regimes(>5 Mach), the effect of compression lift is also present. This basically works by trapping the bow-shock beneath the wing, and using it o compress the air between it and the wing. The high pressure air effectively pushes up on the aircraft, resulting in lift. This method is very efficient at high hypersonic speeds, but to date, very few aircraft have actually utilized it(The only manned one was the the XB-70 Valkyrie, and it didn't even fly fast enough for the compression lift to actually become the primary cause of total lift.). This method of lift/ flight is also called waveriding. One of the prime examples of different lift mechanisms at different flight regimes, is the Concorde. It used a delta-wing planform with high sweep, and had very thin wings. At subsonic speeds it L/D ratio was actually less than at Mach 2, because it needed higher AoA at lower speeds. I should also note, that the airfoil cross-sections are by far the best way of maximizing L/D, generally speaking. The most L/D at supersonic airplane can hope to achieve is less than 20, while a subsonic airplane can easily achieve an L/D ratio of 30 or more(i.e. Gliders, and Sailplanes). So, this is about complete an understanding of lift as I have, if there's anything wrong with it, or anything needed to be added, please do so. I'd love to hear any differing opinions as well.
  10. mk2 stockalike expansion, Airplane plus are two of the mods I'd recommend. However the landing gear in Airplane plus don't work.
  11. I haven't built a lot a spaceplanes in RSS with FAR, but I have built a few so here's my experience: 1) First of all, FAR doesn't really model compression lift. IMO this would be a huge addition for spaceplane guys like you and myself, increasing L/D ratios to well over five at even Mach 7+. As it is, we're stuck with about 2 - 2.5 L/D at higher than Mach 5 speeds. I'd love to build a wave-rider in KSP, but Ferram is unfortunately busy IRL and there are no plans whatsoever to model compression lift in FAR(It was too computationally expensive, the last time I asked.) 2) The thing in FAR that is different from stock aero, is that you need to have a lot of altitude for high L/D. At 30 kms, and Mach 5, it is possible to get >2.5 L/D with a properly designed plane. And by properly designed I mean as close to a Sears-Hack Body as you can get. You also need tiny wings with very high sweep, and this brings along its own set of challenges like very high takeoff speed(my designs lifted off at about 150 m/s with flaps, slats, the whole shebang.). 3) Of course, I don't think you can get to 30 kms with the stock rapiers. I remember that I used scramjets from a mod for this very purpose, and with those, it is possible to reach ~40km(In RSS) and Mach 10 on airbreathers alone, at which point you need to switch to NTRs. No matter what you do, the highest L/D you'll get at above Mach 10 is about 2. But this doesn't really matter, as the drag is very little above 40 kms, and because you have a lot of speed(Mach 10 is still half of orbital velocity, so your ballistic trajectory greatly reduces the amount of TWR you need), it is possible to get to orbit with roughly 0.3-0.4 rocket mode TWR. This will increase your dry mass by a lot though, as you basically need 3 different engines to reach orbital speeds. So while it is possible to reach orbit, the payload fractions are almost non-existent. 4) KSP Interstellar is by far the the best mod for engines if you really want a RSS SSTO. It has a lot of nuclear thermal nozzles, that can use either air or onboard propellant. It's very easy to make an SSTO with those mechanics. Almost a easy as making a stock SSTO on Kerbin.
  12. Ok well that's great. Just to clarify, you have to edit them in-game or the .txt files before loading?
  13. Sorry my bad, I thought this was a separate mod from FARwind.
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