diff --git a/Docs/README.YASim.rotor.ods b/Docs/README.YASim.rotor.ods new file mode 100644 index 000000000..363d585df Binary files /dev/null and b/Docs/README.YASim.rotor.ods differ diff --git a/Docs/README.YASim.rotor.xls b/Docs/README.YASim.rotor.xls new file mode 100644 index 000000000..54e5cb352 Binary files /dev/null and b/Docs/README.YASim.rotor.xls differ diff --git a/Docs/README.yasim b/Docs/README.yasim index 5836c709b..d089cf174 100644 --- a/Docs/README.yasim +++ b/Docs/README.yasim @@ -539,20 +539,19 @@ rotor: A rotor. Used for simulating helicopters. You can have one, two values greater than the stall incidence. You could get strange results. - pitch_a: A collective incidence angle, used for the next token - forceatpitch_a: The force, the rotor is producing when the incident - angle is equal pitch_a. Without ground effect and with - maximum translational lift. I.e. hover-pitch and a force - equivalent to the weight. (in pounds of force) - pitch_b: A collective incidence angle, used for the next token - poweratpitch_b: the power the rotor needs at pitch_b. (i.e. at the - bo105 the main rotor consumes bout 90% of the engine power, - and 9% the tail rotor. In kW. - poweratpitch_0: the power the rotor needs at zero pitch. - In kW. Used for calculation of the airfoil coefficients. - In near future you can define them directly. + pitch_a: + pitch_b: collective incidence angles, If you start flightgear + with --log-level=info, flightgear reports lift and needed + power for theses incidence angles + forceatpitch_a: + poweratpitch_b: + poweratpitch_0: old tokens, not supported any longer, the result are + not exactly the expected lift and power values. Will be + removed in one of the next updates.directly.Use "real" + coefficients instead (see below) and adjust the lift with + rotor_correction_factor. - The second way is to define the lift and drag coefficients directly. + The way is to define the lift and drag coefficients directly. Without stall the c_lift of the profile is assumed to be sin(incidence-airfoil_incidence_no_lift)*liftcoef; And in stall: @@ -566,14 +565,21 @@ rotor: A rotor. Used for simulating helicopters. You can have one, two airfoil_lift_coefficient: liftcoef airfoil_drag_coefficient0: dragcoef0 airfoil_drag_coefficient1: dragcoef1 - I read in a forum, that, if you calculate the lift of an heli rotor, - you will get a value larger than the measured one. This seems to be - valid for this simulation. If you use values for the lift - coefficient from real airfoils you will get unrealistic high lift as - result (approx. a factor of 2). As starting parameters you can use - airfoil_lift_coefficient="1.9" - airfoil_drag_coefficient0="0.0075" - airfoil_drag_coefficient1="0.2" + To find the right values: see README.yasim.rotor.ods + (Open Office file) or README.yasim.rotor.xls (Excel + file). With theses files you can generate graphs of the + airfoil coefficients and adjust the parameters to match + real airfoils. For many airfoils you find data published + in the internet. Parameters for the airfoils NACA 23012 + (main rotor of bo105) and NACA 0012 (tail rotor of bo105?) + are included. + rotor_correction_factor: + If you calculate the lift of a heli rotor or even of a + propeller, you get a value larger than the real measured + one. (Due to vortex effects.) This is considered in the + simulation, but with a old theory by Prantl, which is known + to give still too large. This is corrected by this token, + default: 1 flapmin: Minimum flapping angle. (Should normally never reached) flapmax: Maximum flapping angle. (Should normally never reached) flap0: Flapping angle at no rotation, i.e. -5 @@ -616,13 +622,22 @@ rotor: A rotor. Used for simulating helicopters. You can have one, two torque than in higher altitudes. The ground effect is calculated as factor = 1+diameter/altitude*_ground_effect_constant - number_of_segments: The rotor is simulated in four different - directions (probably this will be extended in future). + number_of_parts: + number_of_segments: The rotor is simulated in number_of_parts + different directions. In every direction the rotor is simulated at number_of_segments points. If the value is to small, the rotor will react unrealistic. If it is to high, cpu-power - will be wasted. I now use a value of 10, but probably a - smaller value for the tail-rotor would be sufficient. + will be wasted. I now use a value of 8 for number_of_parts + and 8 for number_of_segments for the main rotor and 4 for + number_of_parts and 5 for number_of_segments for the tail + rotor. Number of parts must be a multiple of 4 (if not, it + is corrected) + cyclic_factor: The response of a rotor to cyclic input is hard to + calculate (its a damped oscillator in resonance, some + parameters have very large impact to the cyclic response) + With this parameter (default 1) you can adjust the + simulator to the real helo. All rotor can have subelements for the cyclic (CYCLICELE, CYCLICAIL) and collective (COLLECTIVE) input. @@ -644,6 +659,8 @@ rotorgear: If you are using one ore more rotors you have to define a max_power_rotor_brake: the maximum power of the rotor brake, in kW at normal rpm (most? real rotor breaks would be overheated if used at normal rpm, but this is not simulated now) + rotorgear_friction: the power loss due to fritcion in kW at normal + RPM yasimdragfactor: yasimliftfactor: the solver is not working with rotor-aircrafts. Therefore you have to specify the results yourself. @@ -654,7 +671,5 @@ rotorgear: If you are using one ore more rotors you have to define a (ROTORGEARENGINEON) and can have a subelement for the rotor brake (ROTORBRAKE). - The rotor simulation is very "beta" and not finished yet. So don't - spend too much time to adjust a flight behavior to the smallest - details now. + The rotor simulation is still "beta". diff --git a/Docs/README.yasim.rotor.png b/Docs/README.yasim.rotor.png deleted file mode 100644 index 5fae93010..000000000 Binary files a/Docs/README.yasim.rotor.png and /dev/null differ