Posts by ussiowa

    Dear IPACS,


    Would it be possible to have a system equivalent to the airplane livery for landscape?

    Or some system of choosing different versions based on a parameter. That parameter could be whatever, based on time, i.e. today version of let's say Hong Kong, and 1990 version (different airport, different vehicles and building around, different land (lots of reclamation), you get the idea.

    But it could also be used to have like San Diego normal, of San Diego Air Races

    Or place in summer, place in winter, or any other creative variation of a particular scenery, just like airplane livery.

    Or futuristic landscape (which becomes pure creativity from the maker) with maybe futuristic planes that could also be designed. That would be more like a "game" per say then real simulator, but at least it would be an extra option and broaden the target demographic.


    Anyway, just putting it out there. I don't think we have enough access in the SDK to do something like that ourselves, so it is basically whether you like the idea and have the strategy/time/inclination for it, or not.


    I'm thinking it could be simple as just a button or slider in menus/map and folder branching with specific sub names, but that's pure imagination, I don't really know how difficult it would be to implement.

    I think you should really look at the Hawaii scenery we made and to come. As far as I know we have tons of helipads all over.

    Apollo had a few too, but I don't know how many. It was the beginning of helos back then, only the R22.

    If 125.4 is "tail heavy" (whatever that means in a no tail aircraft), move it slowly forward (move both, the hanging point, and the CG of the empty glider).

    I'm still assuming that the hanging point of the control system is at the CG of the empty aircraft. When laid on the ground, the aircrafts always rest on their rear, which may mean that it is forward from the empty aircraft CG (not sure on this one). If and when you have access to a real one, check where the CG is in relation to the hanging point of the control system. It's easy just lift it up by the hanging point and check if it balances or fall forward or backward. then find that equilibrium point. If there is a distance, use that for the model (and let me know what it is).


    If the glider behaves worse, or still has a tendency to pitch up, I will change the Cm (pitching moment) of the airfoil. I used the real data, but for Cmbase I had to improvise (see post 44 above).


    I wouldn't mess with elevators yet, The more parameters and variables you introduce, the harder it will be to tune.

    Also the more we stray from real aircraft, the more trouble we're getting into since the physics engine is real and exact.

    Try increasing the pilot weight to see what happens.

    Hangliders do not strike me as having a fast rolling rate IRL, but I don't really know. If you know it's different, then so it is.


    I don't know anything about servoclassic (when I'll get a minute I'll look at it, ("degree in math" from Steve got my curiosity and interest picked up :P). However I can tell you one thing, the movement of a pilot on the control bar is heavily "dampened" by nature, and has 0 elasticity, so that should probably be taken into account, and if the slide has any elastic property and no or small dampening, then it could be the cause.

    The motion should be only affected by the control (joystick), gravity should not affect that motion at all (to simulate the fact that the pilot will adjust the strength in his arms to compensate for gravity change and so on).


    If somehow the current modelisation moves a moveable "object" along a slide, banking will create an adverse motion just by effect of gravity on that object and slide, that is not what we want, and it may be the source of periodic "instability" (which is what I think you mean by "jiggle", don't hesitate to use the French term if it's easier for you to describe)

    I’m surprised IPACS even allowed the dummy rockets to be displayed on the wings. All those 6 year old FS 2 pilots might be offended. You can “hide” the rockets with a click on the Configuration Panel.

    FYI It's not just a "political" point of view. In Germany there are special rules and regulations for weaponry and video game, different than pretty much the rest of the world AFAIK.

    It's a sensitive issue and it is to their credit.

    OK so MAC (Main Aerodynamic Chord) is at 215.86 cm from center line and is 142.20 cm.

    That means that the Aerodynamic Center (AC) for that wing is at 131.58 cm from the nose of the wing (25%).


    Antoine that should be the starting point for the CG of the empty glider. I would expect that the CG point for all together in flight be around 125.4 cm from the nose and in the horizontal plane (20% of MAC or a 5% static margin).

    These should be good numbers to start and should provide a flyable system. We can fine tune later.


    The vertical position of the CG is whatever it is vertically from that point (125.4 from the nose, center line)

    Yes of course it is :)

    Neat! Sorry for questioning, I guess I'm too used to old sims and low computing power, where everything had to be "simplified" to fit the computing power and time.:)


    So great, that makes things easier for us in a sense, all we have to do is model the reality correctly.


    Jan, any input on this CG location. I'm thinking the CG of the glider is at 25% MAC and then the addition of the pilot moves it forward enough to create the static margin in essence. Or could it be that the glider itself has the static margin (CG forward from AC) in that it would fly "empty" correctly, and then the pilot is loaded at that particular CG (except lower of course) and then its motion laterally and longitudinally from the neutral point is what steers the glider?

    Okay guys, some updates, since I had time to test the new airfoils that ussiowa gave me.


    First, I had to tweak the CG so that the flying is stable (like in your story, I have experimented, and I didn't rely on theory ;) ). After some tweaking, I was able to observe some stable flying behavior. However, I couldn't experiment much, since I somehow wasn't able to steer the glider.


    Antoine

    Remember that the positions of the CG with the pilot and without are fundamental to the behavior. I'm thinking that the CG without should be at 25% MAC (I will tell you what that is in a few minutes, I have to calculate), and that the CG of the pilot itself should be located like a normal human being.

    Provided that the suspension of the control bar is at the right point, then it should work somewhat.

    I don't know yet about "joints" but I'd think that a rotating joint at the point of control bar suspension would be more accurate (to the reality) than a linear one. But linear may work too.

    Well the question could be as to whether the CG of the group of rigidbodies is dynamically calculated or not?

    If it is, then at least we know the physics dynamics of the masses could be correct, yet somehow the "plane" is not reacting properly. We can continue investigating that way.

    If the CG is calculated once only (at load up or something similar, which could be very possible with a regular aircraft since it is not expected to change during flight (except Concorde and other limited exceptions)), then we'd have to find another way to simulate that part. We can introduce "virtual" control surfaces that would move from the dynamic standpoint (ailerons, rudder and elevator), but that would not exit graphically. That way the "plane" would react properly, and the graphics would be proper as well (only pilot moving).

    Well it's not "unforeseen difficulties", more like it's a whole lot of work, and we all have a life outside of FS2 that includes full time work or other more prioritized obligations for some members of the team. So it takes time and longer than first anticipated sometimes. We're stuck on time and volunteering availability.


    It's 95%+ complete and in terms of "difficulties", no we didn't bite more than we could chew, actually quite the opposite, we could bite much more if we'd be given the food to be chewed to continue with that metaphor.

    As a matter of fact, we did chew much more than we bit as the original idea/project didn't include many animations and features that ultimately ended up in the final product (including tech optimization required because of complexity and size of scenery)

    It deserves and requires a certain standard of excellence, thus we want to do what is needed, and that takes times, more time as affected by conditions as Zosochile explained.


    More importantly, we also wanted to pace ourselves so as not to get more praises and mark of confidence than we could reasonably handle.;)


    Bottom line, it's coming for sure, hopefully by 2021, but no firm date at this stage. Stay tuned!

    OK Thanks.

    So attached range is indeed the value in the positive region, and same in the negative region, thus 1/2 of the maximum span 1/2(max -min) [0.5(14-(-7)) or 1/2*21 or 10.5]

    The attached center is the offset of the real center, compared to the mathematical center.

    Here the math center is at -10.5 from max or +10.5 from min

    But the real center is with 14 to max and -7 to min, so I have to move the center by the distance between my max and min

    or 1/2 (|max|-|min|). So here 1/2 (|14| -|-7|) or 0.5 (14-7) or 3.5

    And I give it a negative sign to move the center below the math center, so -3.5

    Which indeed gives me an upper of 3.5 + 10.5 = 14

    and a lower range of -10.5 - (-3.5) or -7


    Here with more exact values:

    Jan,


    Airfoil TMD data. I assume everything is in radians.

    "Attached Center" is that the AOA of the middle of the Cl/Alpha curve, or is it the AOA at which Cl = 0?


    For exemple I have an airfoil -7 +14 thus a range of 21deg (to put in radian) so "attached range" is 21deg

    The "center" of that curve is at 4deg AoA with Cl of 0.5, is that my "attached center" value, or is it the AOA where Cl =0 (-1deg in this case)?


    Also in your graphs on the wiki, for the attached range, the upper graph (alpha) shows that it goes between - and + (thus the number is the full range) on the graph below (with airfoil pict) it is represented as half (once between 0 and minus, and one between 0 and plus). I assumed it's the former.

    Stall range is also represented twice, but I believe that is probably correct.