fly/flightgear
1
0
Fork 0
Code Activity

Yasim-test: add detailed lift/drag graphing

Browse source 
Patch by Huntley Palmer, to extend range of recorded angles, and
offer a detailed mode with finer resolution over a specific range.

SF-ID: https://sourceforge.net/p/flightgear/codetickets/2629/
This commit is contained in:
James Turner 2022-02-07 11:42:28 +00:00
parent 82863d3f3e
commit f8afde7528
1 changed files with 154 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

164
src/FDM/YASim/yasim-test.cpp
View file

@ -59,6 +59,9 @@ void _calculateAcceleration(Airplane* a, float aoa_rad, float speed_mps, float*
s.localToGlobal(output, output); s.localToGlobal(output, output);
}; };
// Comments are incorrect: Historically this function only produces lift, drag curves
// For lift, drag and LD three column output please use --yasim-graph-detailed
//
// Generate a graph of lift, drag and L/D against AoA at the specified // Generate a graph of lift, drag and L/D against AoA at the specified
// speed and altitude. The result is a tab-separated file of // speed and altitude. The result is a tab-separated file of
// numbers: "aoa lift drag LD" (aoa in degrees, lift and drag in // numbers: "aoa lift drag LD" (aoa in degrees, lift and drag in
@ -77,8 +80,8 @@ void yasim_graph(Airplane* a, const float alt, const float kts, Airplane::Config
float cl_max = 0, cd_min = 1e6, ld_max = 0; float cl_max = 0, cd_min = 1e6, ld_max = 0;
int cl_max_deg = 0, cd_min_deg = 0, ld_max_deg = 0; int cl_max_deg = 0, cd_min_deg = 0, ld_max_deg = 0;
printf("aoa\tLift\tDrag\tLvsD\n"); printf("aoa\tlift\tdrag\n");
for(int deg=-5; deg<=29; deg++) { for(int deg=-15; deg<=90; deg++) {
float aoa = deg * DEG2RAD; float aoa = deg * DEG2RAD;
_calculateAcceleration(a, aoa, speed, acc); _calculateAcceleration(a, aoa, speed, acc);
float drag = acc[0] * (-1/9.8); float drag = acc[0] * (-1/9.8);
@ -97,7 +100,7 @@ void yasim_graph(Airplane* a, const float alt, const float kts, Airplane::Config
ld_max= ld; ld_max= ld;
ld_max_deg = deg; ld_max_deg = deg;
} }
printf("%2d\t%.4f\t%.4f\t%.4f\n", deg, lift, drag, ld); printf("%2d\t%.4f\t%.4f\n", deg, lift, drag);
} }
printf("# cl_max %.4f at %d deg\n", cl_max, cl_max_deg); printf("# cl_max %.4f at %d deg\n", cl_max, cl_max_deg);
printf("# cd_min %.4f at %d deg\n", cd_min, cd_min_deg); printf("# cd_min %.4f at %d deg\n", cd_min, cd_min_deg);
@ -235,6 +238,94 @@ void findMinSpeed(Airplane* a, float alt)
} }
} }
// Additional command functions with 10x detail, smaller AoA range
//
// Generate a graph of lift, drag and L/D against AoA at the specified
// speed and altitude with fine deteil. The result is a tab-separated file of
// numbers: "aoa lift drag LD" (aoa in degrees, lift and drag in
// G's). You can use this in gnuplot like so (assuming the output is
// in a file named "dat":
/*
plot "dat" using 1:2 with lines title 'lift', \
"dat" using 1:3 with lines title 'drag', \
"dat" using 1:4 with lines title 'LD'
*/
void yasim_graph_detailed(Airplane* a, const float alt, const float kts, Airplane::Configuration cfgID)
{
_setup(a, cfgID, alt);
float speed = kts * KTS2MPS;
float acc[3] {0,0,0};
float cl_max = 0, cd_min = 1e6, ld_max = 0;
int cl_max_deg = 0, cd_min_deg = 0, ld_max_deg = 0;
printf("aoa\tlift\tdrag\tLD\n");
for(float deg=-2.0; deg<=25.0 ; deg+= 0.10 ) {
float aoa = deg * DEG2RAD;
_calculateAcceleration(a, aoa, speed, acc);
float drag = acc[0] * (-1/9.8);
float lift = 1 + acc[2] * (1/9.8);
float ld = lift/drag;
if (cd_min > drag) {
cd_min = drag;
cd_min_deg = deg;
}
if (cl_max < lift) {
cl_max = lift;
cl_max_deg = deg;
}
if (ld_max < ld) {
ld_max= ld;
ld_max_deg = deg;
}
printf("%-2.1f\t%-2.3f\t%-2.3f\t%-2.3f\n", deg, lift, drag, ld);
}
//printf("# cl_max %.4f at %d deg\n", cl_max, cl_max_deg);
//printf("# cd_min %.4f at %d deg\n", cd_min, cd_min_deg);
//printf("# ld_max %.4f at %d deg\n", ld_max, ld_max_deg);
}
void yasim_drag_detailed(Airplane* a, const float aoa, const float alt, Airplane::Configuration cfgID)
{
_setup(a, cfgID, alt);
float cd_min = 1e6;
int cd_min_kts = 0;
float acc[3] {0,0,0};
printf("knots\tdrag\n");
for(float kts=0; kts<=100; kts += 0.1) {
_calculateAcceleration(a, aoa,kts * KTS2MPS, acc);
float drag = acc[0] * (-1/9.8);
if (cd_min > drag) {
cd_min = drag;
cd_min_kts = kts;
}
printf("%-2.3f\t%-2.3f\n", kts, drag);
}
//printf("# cd_min %g at %d kts\n", cd_min, cd_min_kts);
}
void findMinSpeedDetailed(Airplane* a, float alt)
{
a->addControlSetting(Airplane::CRUISE, "/controls/flight/elevator-trim", 0.7f);
_setup(a, Airplane::CRUISE, alt);
float acc[3];
printf("aoa\tknots\tlift\n");
for(float deg=-2; deg<=25.0; deg+=0.10) {
float aoa = deg * DEG2RAD;
for(float kts = 0; kts <= 180.0; kts += 0.1) {
_calculateAcceleration(a, aoa, kts * KTS2MPS, acc);
float lift = acc[2];
if (lift > 0) {
printf("%-2.1f \t %-2.3f \t %-2.3f\n", deg, kts, ( 100 + 100 * lift));
break;
}
}
}
}
void report(Airplane* a) void report(Airplane* a)
{ {
printf("==========================\n"); printf("==========================\n");
@ -270,7 +361,7 @@ void report(Airplane* a)
MACy = wing->getMACy(); MACy = wing->getMACy();
sweepMin = wing->getSweepLEMin() * RAD2DEG; sweepMin = wing->getSweepLEMin() * RAD2DEG;
sweepMax = wing->getSweepLEMax() * RAD2DEG; sweepMax = wing->getSweepLEMax() * RAD2DEG;
printf("Wing MAC : (x:%.2f, y:%.2f), length:%.1f \n", MACx, MACy, MAC); printf("Wing MAC : (x:%.3f, y:%.3f), length:%.3f \n", MACx, MACy, MAC);
printf("hard limit CG-x : %.3f m\n", a->getCGHardLimitXMax()); printf("hard limit CG-x : %.3f m\n", a->getCGHardLimitXMax());
printf("soft limit CG-x : %.3f m\n", a->getCGSoftLimitXMax()); printf("soft limit CG-x : %.3f m\n", a->getCGSoftLimitXMax());
printf("CG-x : %.3f m\n", cg[0]); printf("CG-x : %.3f m\n", cg[0]);
@ -296,10 +387,12 @@ void report(Airplane* a)
printf("\n"); printf("\n");
wing->printSectionInfo(); wing->printSectionInfo();
} }
printf("\nInertia tensor [kg*m^2], origo at CG:\n\n"); printf("\nInertia Tensor [kg*m^2], ( Angular Moments ) Origo at CG:\n\n");
printf(" %7.0f, %7.0f, %7.0f\n", SI_inertia[0], SI_inertia[1], SI_inertia[2]); printf(" Effect on Axis\n");
printf(" %7.0f, %7.0f, %7.0f\n", SI_inertia[3], SI_inertia[4], SI_inertia[5]); printf(" x Roll y Pitch z Yaw\n");
printf(" %7.0f, %7.0f, %7.0f\n", SI_inertia[6], SI_inertia[7], SI_inertia[8]); printf("Impulse x Roll %7.0f %7.0f %7.0f\n", SI_inertia[0], SI_inertia[1], SI_inertia[2]);
printf(" on y Pitch %7.0f %7.0f %7.0f\n", SI_inertia[3], SI_inertia[4], SI_inertia[5]);
printf(" Axis z Yaw %7.0f %7.0f %7.0f\n", SI_inertia[6], SI_inertia[7], SI_inertia[8]);
} }
int usage() int usage()
@ -307,7 +400,7 @@ int usage()
fprintf(stderr, "Usage: \n"); fprintf(stderr, "Usage: \n");
fprintf(stderr, " yasim <aircraft.xml> [-g [-a meters] [-s kts] [-approach | -cruise] ]\n"); fprintf(stderr, " yasim <aircraft.xml> [-g [-a meters] [-s kts] [-approach | -cruise] ]\n");
fprintf(stderr, " yasim <aircraft.xml> [-d [-a meters] [-approach | -cruise] ]\n"); fprintf(stderr, " yasim <aircraft.xml> [-d [-a meters] [-approach | -cruise] ]\n");
fprintf(stderr, " yasim <aircraft.xml> [-m]\n"); fprintf(stderr, " yasim <aircraft.xml> [-m] [-h] [--min-speed]\n");
fprintf(stderr, " yasim <aircraft.xml> [-test] [-a meters] [-s kts] [-approach | -cruise] ]\n"); fprintf(stderr, " yasim <aircraft.xml> [-test] [-a meters] [-s kts] [-approach | -cruise] ]\n");
fprintf(stderr, " -g print lift/drag table: aoa, lift, drag, lift/drag \n"); fprintf(stderr, " -g print lift/drag table: aoa, lift, drag, lift/drag \n");
fprintf(stderr, " -d print drag over TAS: kts, drag\n"); fprintf(stderr, " -d print drag over TAS: kts, drag\n");
@ -316,6 +409,10 @@ int usage()
fprintf(stderr, " -a set altitude in meters!\n"); fprintf(stderr, " -a set altitude in meters!\n");
fprintf(stderr, " -s set speed in knots\n"); fprintf(stderr, " -s set speed in knots\n");
fprintf(stderr, " -m print mass distribution table: id, x, y, z, mass \n"); fprintf(stderr, " -m print mass distribution table: id, x, y, z, mass \n");
fprintf(stderr, " Options to generate LD curve and greater deteiled plotting\n");
fprintf(stderr, " yasim <aircraft.xml> [--detailed-graph] [--detailed-drag]\n");
fprintf(stderr, " yasim <aircraft.xml> [--detailed-min-speed -approach]\n");
fprintf(stderr, " yasim <aircraft.xml> [--detailed-min-speed -cruise]\n");
fprintf(stderr, " -test print summary and output like -g -m \n"); fprintf(stderr, " -test print summary and output like -g -m \n");
return 1; return 1;
} }
@ -355,7 +452,54 @@ int main(int argc, char** argv)
Airplane::Configuration cfg = Airplane::NONE; Airplane::Configuration cfg = Airplane::NONE;
float alt = 5000, kts = 100; float alt = 5000, kts = 100;
if((strcmp(argv[2], "-g") == 0) || test) { // command extensions tested first to preserve precedence
if((strcmp(argv[2], "--detailed-graph") == 0) || test) {
for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-s") == 0) {
if(i+1 < argc) kts = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-approach") == 0) cfg = Airplane::APPROACH;
else if(std::strcmp(argv[i], "-cruise") == 0) cfg = Airplane::CRUISE;
else return usage();
}
if (test) {
report(a);
printf("\n#-- lift, drag at altitude %.0f meters, %.0f knots, Config %d --\n", alt, kts, cfg);
}
yasim_graph_detailed(a, alt, kts, cfg);
if (test) {
printf("\n#-- mass distribution --\n");
yasim_masses(a);
}
}
else if(strcmp(argv[2], "--detailed-drag") == 0) {
float alt = 2000, aoa = a->getCruiseAoA();
for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-approach") == 0) cfg = Airplane::APPROACH;
else if(std::strcmp(argv[i], "-cruise") == 0) cfg = Airplane::CRUISE;
else return usage();
}
yasim_drag_detailed(a, aoa, alt, cfg);
}
else if(strcmp(argv[2], "--detailed-min-speed") == 0) {
alt = 10;
for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-approach") == 0) cfg = Airplane::APPROACH;
else if(std::strcmp(argv[i], "-cruise") == 0) cfg = Airplane::CRUISE;
else return usage();
}
findMinSpeedDetailed(a, alt);
}
else if((strcmp(argv[2], "-g") == 0) || test) {
for(int i=3; i<argc; i++) { for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) { if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]); if (i+1 < argc) alt = std::atof(argv[++i]);