Hi all, the heli simulation is almost complete for beta testing. Every thing except the vortex-state-detection and the interface to the yasim-engines is working now (the engine is simulated rather simplified, but is working). The feeling is quite different to the "old" simulation (and I hope more realistic). I just have to strip some debug-stuff and to write the documentation. Then I will publish the code.
While debugging the downwash effects on stabs I found a bug in yasim (and therefore the root cause for the non working stabs). The patch I posted some weeks ago was nonsense. The result of this was not a working stab, it was such a high parameter for the drag, that the drag of the gear rises to a value similar to the total drag of the helicopter. The stabs had no effect at all. As a bug in yasim all stabs/wings without control-surface-subelements have no aerodynamical effect (not only in rotor-simulation. It's the same for fixed wing aircrafts). For every stab/wing: the outermost part of the wing up to the first control-surface-subelement as well as the innermost part up to the last control-surface-subelement is ignored. The bug is in the wing::compile() function in wing.cpp. In the boundary collection the tip and the base of the wing/stab are missing. Another problem was, that a stab in stall condition is not producing any force perpendicular to the surface (in yasim). I have looked into some naca publications where I found, that in stall the lift is reduced to about 20..30%, but not to zero. The effect was visible in hover. The stabs in the downwash were producing no force. I have coded patches for both problems and will publish them with the rotor-code. @Melchior: -do you have a sample of the sound, the bo produces when flown through narrow turns (I would call this a "flapping sound")?. If yes: the simulation generates a property "stall" for every rotor. Playing this sample with a volume generated by this parameter and a sampling rate by the rotor-rpm should sound quite realistic. -it seems, that the rpm-meter is limited to 100%. Due to autorotation, the rotor-rpm exceeds this value sometimes. -the speed-indicator seems to indicate not only the fraction in the x-direction. I do not know, how the real thing works, but I assume, that it only shows the x-fraction (and only if it is positive). -I will add an torque-property for the torque-meter (is on my todo-list) Best regards, Maik ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
