Pete_SMS

T-28 over BC. By far the best XP aircraft for me. So addictive, that it holds me back from development sometimes. ...even a very simple aircraft (I am not into fancy avionics and autopilot flying anyway), the representation of flight, the sound environment and all the other little things make it awesome and create a believable aircraft simulation.

Good to know. Thanks!

Yip, totally agree. Had strange side effects as well, when changing aircraft multiple times during a session and working on my own. Loading a default aicraft and starting XP over again, always solved the problem.

Yes, that is a really annnoying shortcoming of X-Plane. I kind of have the same problem with another dataref. I am completely overriding the flight control surfaces, which means my plugin is handling all the stuff from reading joystick input and finally deflecting control surfaces. The override flag keeps being set when I change aircraft. That means other aircraft, without my plugin can not be controlled any longer. The only cure I have found so far: Load the default Cessna, close XP and start it up again. Switching aircraft during runtime won't work. ...but I am still working on a solution. Not much priority at the moment, though, because as Arnaud said, it is a shortcoming of XP, I guess. function OnAicraftUnload() --This function needs to accept an index number telling us which aircraft changed, currently it does not. --You know an aircraft was unloaded, but not which one. end ..might work, if there was a way to find out the index number of our own aircraft. Then the dataref could be reset to the default value, when the aircraft gets unloaded.

Looks great Goran! This is a type of aircraft I really like

Yip, agreed 3D Buzz and Blender Cookie have the best Blender training out there. This is why I am a Member Sponsor for 3D Buzz and a Citizen at Blender Cookie. First of, to support these guys, and second I will have access to a lot more training resources on their sites, model source code, exclusive member videos and so on. For me it is well worth the money. Sorry, I can not help you with your animation question, because I haven't looked into Blender/X-Plane animation, yet. Just the modelling part. I will start with animation very soon and also have to check out the new Blender export script for the 2.57 version. Just post your question as a new thread in the 3D shop, if you like. This way we also keep this thread clean for training related stuff. The comment from Zak, over at 3DBuzz So true. The new interface is just amazing and you can basically customize it completely to your needs. Also the modelling workflow is awesome. I don't miss my expensive 3ds Max anymore.

The second drop of 3DBuzz free Blender training videos is available. http://www.3dbuzz.com/vbforum/showthread.php?188994-Blender-Fundamentals-Drop-2-is-now-ready-for-download Since I am a Member Sponsor, I already have drop 3 and you can look forward to it.

Nice article you might find useful: http://www.blendercookie.com/2011/05/11/blender-community-starters-guide/

You are welcome! Great if you find it useful.

OK, here it is. As announced in one of my last posts, 3DBuzz released the first drop of free Blender training videos to the public. The first drop is related to the Blender interface. I can highly recommend these training videos and you can look forward to the whole training series. I did a lot of training via 3D Buzz, mainly 3ds Max and Maya, and it is so cool that they work with Blender now as well. So go and check it out yourself. You won't be disappointed. http://www.3dbuzz.com/vbforum/showthread.php?188849

Hi Kundian, Welcome to the forum and have a good time.

Yes, that movie is a very nice. I also like this one

Another website with useful Blender tutorials, if you are interested. www.blendernerd.com

Ever thought about getting your license? LSA aircraft are very sophisticated these days and you pay less for the hour and also the license is cheaper compared to a PPL-A, but I guess you know that. The air was very calm that day as well. Just smooth flying with a beautiful sight. I also could see the Alps in the distance. These are moments you never forget.

Take the guys for a spin and let them experience this cutie and you don't have to hide anymore. ;D

Yes, a very cute little aircraft. I love flying it and it has great performance too. So I can imagine that you want it.

This is me flying a Remos over southern Germany. Had an awesome flight. I really enjoyed flying on top of the clouds, while having beautiful light. One of the nicest flights I had so far. The quality of the pictures is not the best, because I took them with the cam of my old mobile phone, but I was happy that I could capture this moment.

Hi Steph, Thank you very much for the answer and talking to your colleague would be very nice. I am an aerospace engineer myself and work on professional flight simulators and totally agree, that there is a learning curve in X-Plane, even you have the full academic background and lots of experience with professional simulators in general. This is due to the fact, that you don't have full control of the underlying model X-Plane is using, and lots of things are kind of unclear or not known. You have to find out what effects all the settings in planemaker have and often they don't follow the standard or what you would expect in the first place. (planemaker is the aircraft design program that comes with X-Plane) Once you get it, it does make sense though. For specific problems you end up in a trial and error cycle. Currently, I am trying to break that cycle by doing extensive research in order to understand how X-Plane is ticking internally. I put these results into mathematical models, based on classic engineering and aircraft design equations and refine them until I get close to the results of X-Plane. This way I get a pretty good picture of X-Plane internals and I can approach the whole thing better than by just using trial and error, because I can calculate things already offline. At least I am in the right ballpark before firing up X-Plane. There are still a few topics where I have to do more and deeper investigations, but I think my glide speed issue is on a good way now. Flight Dynamics and handling qualities are not that big of an issue, if you know what you do and here you have the chance to influence most of the stuff yourself by coding plug-ins. Gizmo is great for that. Not sure if your colleague knows about it already, but if not, I let him know I assume he uses X-Plane in his freetime or is he doing professional day job stuff with it? I am looking forward to talk to him. I will send you my email via PM and really appreciate that you came in to help. I could hear my own echo already pretty loud. *just kidding Have fun on the forum, because this is a very cool place and do not hesitate to ask questions, if you have any. Have a great day, Pete

Having a better understanding of X-Plane internals now, I can go to about 90% accuracy by using an engineering approach and the last 10% by trial and error. Well, I guess having a deviation of < 2% in the end should be satisfying, knowing that you could have this spread on a real aircraft as well. Basically, I am very satisfied with my overall aircraft performance, but I still need to get that glide speed and the corresponding L/D correct. After getting a hint, I played with wing incidence and in fact this helped a lot. Is here anybody who would share his strategy for moving the max. L/D to a lower speed and increase the ratio at the same time? I figured that by increasing the wing incidence, the max. L/D is moving to a lower speed. Probably due to the fact, that the fuselage will be at a lower AOA and therefore closer to its minimum drag at 0 AOA. Is the strategy to increase the wing incidence, lift curve slope and/or CL0 correct, or would you use something else. I would assume that a lot of you have done this before and any help would be much appriciated, because this is basically the last nut I have to crack. Thanks!

And yes, I did something stupid during my last test. I based all my calculations on SI units and converted kts to m/s, lbf to N etc. However, I forgot to convert my calculated drag force in unit [N] back to unit [lbf], in order to compare it with the values shown on my data display in X-Plane. Drag and lift is unit [lbf] there and that means I have to devide my calculated values by 4.44822162. Does a "I was a little tired when I did this" count? Well, now I can continue with my research of X-Plane internals...

Thank you for the answer Morten. Much appreciated. At least I know now, that I can not solve the problem analytically by using an engineering approach. When you talk about using a plugin for the drag, do you mean changing the fuselage drag sim/aircraft/bodies/acf_fuse_cd dynamically, or something else?

OK, I tested this thing a little further. This time I used one simple rectangular wing shape and the cycle dump file gave me exactly the wing area and aspect ratio I calculated by hand for this wing. Also the oswald efficiency factor was given to me. Having this info I went flying again and stabilized the aircraft at a certain speed. Using X-Plane's parameter display, I wrote down the lift force and the drag force of the wing alone, the true airspeed, the density and so on. Then I went back caculating, using the following equations: L = 0.5 * rho * Vtas^2 * cl * Swing D = 0.5 * rho * Vtas^2 * cd * Swing Since X-Plane was showing me the lift force for the wing alone, I calculated the CL of the wing for that condition. cl = L / (0.5 * rho * Vtas^2 * Swing) OK, the cl was a little lower than my airfoilmaker value, but that is OK, because I am using an finite wing instead of a 2D airfoil. Then I did the same for the drag, and here something very strange became obvious. Knowing the cl at that condition from my previous calculation, I should have been able to calculate the induced drag of the wing by using cdi = cl^2 / (AR * pi * e) I did this and the calculated induced drag was already about 3 times higher then the drag X-Plane showed me for the wing. I then went to airfoilmaker and wrote down cd0, the drag coefficient of the airfoil at zero lift. Having cdo, I calculated the zero lift drag of the wing alone by using D0 = 0.5 * rho * Vtas^2 * cd0 * Swing Also this value was almost twice the drag force X-Plane was showing me for the wing. If I now add-up zero lift drag and induced drag for the wing, I am about factor 4 higher then the value X-Plane showed me. Either I am doing something stupid, or X-Plane is not following the standard at all. I am getting more and more the impression that tuning the performance of the flight model is a more or less "change-test-change-test" approach until you are close to the real vlaues, since a lot of X-Plane internals are unclear. How do you guys and girls handle this issue? Would be great to have a discussion about this topic.

Hi, I keep posting here, because I want to share as much information as possible for new Blender users. There are two very good sites with lots of Blender tutorials and most of them are free. Not all of the tutorials are for complete beginners, but once you find your way around the interface you can give it a go. www.blendercookie.com and www.blenderguru.com Have a look for yourself. Blendercookie is offering a membership as well. I think it is around $80 a year or so and there you have access to all videos, can download them and also have access to the source files. However, you don't have to become a member at all. Since this thread is called "Free Blender Training", I don't really want to mix free and non-free training here, but I also want to make you aware of this training series from blendercookie. http://www.blendercookie.com/2011/04/08/vehicle-series-complete-and-available-for-purchase/ I bought this training and it is very very good. Probably not for the complete beginner, but also here, once you get around the interface and know how to do basic stuff etc. you could start with it. Shows a very good workflow, pays attention to mesh topology and you will learn a lot. And no, I am not related to any of these sites and I am not getting paid, but when I think something is good, I will support it and let everybody know that stuff like this is out there, especially most of this stuff is free.

Hi, Today I am requesting some help with respect to the Flight Model calculation in X-Plane. If this is not the correct place to post this, please move my topic to a more suitable area. OK, here comes my problem. After trying to achieve the best glide speed of my aircraft by a changing-testing-changing approach, I stopped working that way and try to tackle the problem with a mathematical and engineering approach, because the previous didn't work out. OK, just a few basic assumptions I made. The best glide speed occurs when the lift to drag ratio is at its maximum. Also it is a known fact that the parasite drag (cd0) and the induced drag coefficient (cdi) are the same at this point. Therefore I can say cd0 = cdi ==> cd = cd0 + cdi = 2 cd0 I also know, that the L/D ratio at best glide speed is, let's say, 15.0. ==> L/D = cl/cd = 15.0 We also know that induced drag is calculated by cdi = cl^2 / (AR * pi * e) where AR = Aspect Ratio e = Oswald efficiency factor Having these equations, I would be able to set my planemaker and airfoilmaker settings to end up with the required cd0 and cl at the required airspeed. However, classic engineering is using the wing area as a reference for lift and drag calculations L = 0.5 * rho * Vtas^2 * cl * Swing D = 0.5 * rho * Vtas^2 * cd * Swing and it looks like, as if X-Plane is not using this approach. The reason why I make this assumption is that I made a test. I stabilized the aircraft at its current (L/D)max. I displayed all the parameters I am interested in inside X-Plane. I wrote down my total cl and cd, true airspeed, density, total lift, total drag etc. Then I calculated the area X-Plane has to use, in order to come up with the total lift using its total cl. I noticed, that it is not only the wing area. It was the total area of all lifting surfaces. This means wing area plus horizontal tail area. OK. Fair enough. Then I did the same for the drag, but this time the required area, was not equal to the one for the lift. In fact it was lower as the reference area for the lift. So I have the feeling that X-Plane is not using the same reference for lift and drag. Based on this observation, I would like to make a few questions: (1) Is my assumption correct, that X-Plane is using the total area of all lifting surfaces a reference in order to calculate the total lift, based on the total cl? (2) Is my assumption correct, that X-Plane is not using the same reference area as for the calculation of lift ? (3) I can set the drag coefficient for the fuselage and the nacelle in planemaker. Let's assume I have a prop aircraft and the prop and nacelle is directly sitting on the nose. The total frontal area of the fuselage has a certain area and so does the prop spinner / nacelle. Is X-Plane calculating the drag of of the fuselage and spinner by adding them up? I think this would be incorrect, because the spinner would already by covered by the fuselage frontal area calculation and would even help to reduce drag, due to its sreamlined shape. So the total drag of these components should be less then the fuselage alone. (4) What is X-Plane using for calculating the induced drag. Only the wing AR and wing lift or the whole aircraft lift and AR? It would be great if you could help with these questions, because I am trying to solve this glide speed problem for several days now and it looks like as if the more detailed I look into this, the more confusing it gets for me, because the classical approach is not really working. Thanks in advance! Best regards, Pete

Simon, that's a cool page and it brought back some good memories. I also loved F-19 Project Stealth Fighter for the C64. Ace: Air Combat Emulator was on the list too. Not to forget Spitfire 40' with 1 FPS, or was it even one ;D