Hello all, after a long period of absence on business and family I now want to fix some of the "missings" in the helicopter simulation. But first I have to say thank you to all of you, because of the great development of flightgear in the last three years. And a very big thank you to Melchior for the great Bo105.
The first thing I started to work is the co-work with yasim. I was not able to set up yasim correctly. Therefore the fuselage and the stabs were not producing any aerodynamic forces. (Therefore it was necessary, that the rotor itself produces extremely large drag to avoid to high maximum speed of the helicopter. This was the cause for the unrealistic low descent rate.) Now I found how to setup yasim correctly. This is the base for calculation of downwash effects on stabs and fuselage. With this change the bo105 feels significantly different (and I hope more realistic; but all my knowledge is based on model helicopters and theoretical consideration.) Furthermore I have included the air-pressure to the calculations. The bo now does not any longer climb to unlimited heights. Now I want to add/fix - ground effect - more realistic calculation on power-consumption. Autorotation and co-operation with the yasim engines is my aim (Is there any rotation-speed-controller in yasim?) - translational lift - comments to the source - downwash effects on fuselage and stabs - vortex state With these points the helicopter simulation should obtain much more realism. Is there any other helicopter (3D-model) in preparation? @Melchior: is it possible to add an instrument, which shows the lateral movement of the helicopter or the direction of the translation? With this it is much easier to find the correct setting for the pedals. On real helicopters I saw such a instrument realized in two different ways: one was measuring the diefference of the air-pressure on the right and the left side of the heli, but I do not remember how the instrument self looked like. The other was a simple piece of string on the outside of the cockpit. (There is a small bug in the movement of the blades. Due to gyro effects the rotor reacts (about) 90° delayed. If you put the stick forward, the left blade will decrease incidence). Best regards, Maik Maik Justus schrieb: > Hi > > Maik Justus wrote: > >> The helicopter simulation is not finished yet. I will describe later, >> which functions/ effects are totally missing or simplified. > > > Here it is: > > Missing: > -Downwash > -Effect on stabs > -Effect on rotor itself > -Effect on ground (ground effect) > -Engine (The needed power is calculated, but very simplified (i.e. a > autorotation is not possible now) , but the rotor now accelerates in 5 > sec and hold than the revolution for every circumstances) > -Fuel consumption > -Garbage collection to the source > -Comments in the source > > Unrealistic: > -Translational lift > -Teetering (I am not sure, which effect the teetering has. If I try to > calculate it, I get some discrepancies) > -Lift and drag from the Rotor blades is very simplified. To use > realistic values of a realistic airfoil should be not very complicate > (and then the needed power would be realistic and autorotation should > be possible) > -The rotor is simulated at only 4 points. To use many points along the > rotor blades is much better. > > And maybe much more, which I forgot to mention here ;-) > > > The bo105.xml contain only more or less realistic rotors. The fuselage > and the stabs are still missing. (the same for bell206like.xml, > ch47like.xml and as350like.xml). (I am not sure if the stabs are > working correct without the solver. I tried to use fixed values if you > specify no wing and hstab, but maybe there is a bug. In the > ch47like.xml the vstab seems to have no effect at all) > > > All the best, > Maik > > P.S.: I would be very thankful if someone would correct my english in > the README.yasim.... > > > > > > > _______________________________________________ > Flightgear-devel mailing list > Flightgear-devel@flightgear.org > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > 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
