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Ron Jensen: extend atmosphere tables to match environment data

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This commit is contained in:
andy 2007-09-05 02:01:57 +00:00
parent d87d172aae
commit f52165731a
2 changed files with 33 additions and 8 deletions
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22
src/FDM/YASim/Airplane.cpp
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@ -28,6 +28,8 @@ const float STHRESH = 1;
// oscillate.
const float SOLVE_TWEAK = 0.3226;
const float GRAV = 9.8f;
Airplane::Airplane()
{
_emptyWeight = 0;
@ -123,7 +125,7 @@ void Airplane::getPilotAccel(float* out)
// Gravity
Glue::geodUp(s->pos, out);
Math::mul3(-9.8f, out, out);
Math::mul3(GRAV, out, out);
// The regular acceleration
float tmp[3];
@ -593,7 +595,7 @@ void Airplane::compileContactPoints()
// Give it a spring constant such that at full compression it will
// hold up 10 times the planes mass. That's about right. Yeah.
float mass = _model.getBody()->getTotalMass();
float spring = (1/DIST) * 9.8f * 10.0f * mass;
float spring = (1/DIST) * GRAV * 10.0f * mass;
float damp = 2 * Math::sqrt(spring * mass);
int i;
@ -785,6 +787,7 @@ void Airplane::setupWeights(bool isApproach)
void Airplane::runCruise()
{
__builtin_printf("runCruise()\n");
setupState(_cruiseAoA, _cruiseSpeed,_approachGlideAngle, &_cruiseState);
_model.setState(&_cruiseState);
_model.setAir(_cruiseP, _cruiseT,
@ -828,6 +831,7 @@ void Airplane::runCruise()
void Airplane::runApproach()
{
__builtin_printf("runApproach()\n");
setupState(_approachAoA, _approachSpeed,_approachGlideAngle, &_approachState);
_model.setState(&_approachState);
_model.setAir(_approachP, _approachT,
@ -936,7 +940,7 @@ void Airplane::solve()
runCruise();
_model.getThrust(tmp);
float thrust = tmp[0] + _cruiseWeight * Math::sin(_cruiseGlideAngle) * 9.81;
float thrust = tmp[0] + GRAV * _cruiseWeight * Math::sin(_cruiseGlideAngle);
_model.getBody()->getAccel(tmp);
Math::tmul33(_cruiseState.orient, tmp, tmp);
@ -977,7 +981,7 @@ void Airplane::solve()
float pitch1 = tmp[1];
// Now calculate:
float awgt = 9.8f * _approachWeight;
float awgt = GRAV * _approachWeight;
float dragFactor = thrust / (thrust-xforce);
float liftFactor = awgt / (awgt+alift);
@ -985,8 +989,10 @@ void Airplane::solve()
float tailDelta = -pitch0 * (ARCMIN/(pitch1-pitch0));
// Sanity:
if(dragFactor <= 0 || liftFactor <= 0)
if(dragFactor <= 0 || liftFactor <= 0) {
__builtin_printf("NEGATIVE drag %f lift %f\n", dragFactor, liftFactor);
break;
}
// And the elevator control in the approach. This works just
// like the tail incidence computation (it's solving for the
@ -1005,7 +1011,7 @@ void Airplane::solve()
// Now apply the values we just computed. Note that the
// "minor" variables are deferred until we get the lift/drag
// numbers in the right ballpark.
__builtin_printf("Apply drag %f lift %f\n", dragFactor, liftFactor);
applyDragFactor(dragFactor);
applyLiftRatio(liftFactor);
@ -1016,6 +1022,8 @@ void Airplane::solve()
continue;
}
__builtin_printf("Apply aoa %f tail %f\n", SOLVE_TWEAK*aoaDelta, SOLVE_TWEAK*tailDelta);
// OK, now we can adjust the minor variables:
_cruiseAoA += SOLVE_TWEAK*aoaDelta;
_tailIncidence += SOLVE_TWEAK*tailDelta;
@ -1032,6 +1040,8 @@ void Airplane::solve()
if(abs(elevDelta) < STHRESH*0.0001)
break;
__builtin_printf("Apply elev %f\n", SOLVE_TWEAK*elevDelta);
// Otherwise, adjust and do the next iteration
_approachElevator.val += SOLVE_TWEAK * elevDelta;
if(abs(_approachElevator.val) > 1) {

19
src/FDM/YASim/Atmosphere.cpp
View file

@ -7,8 +7,10 @@ namespace yasim {
// McCormick lists 299.16/101325/1.22500, but those don't agree with
// R=287. I chose to correct the temperature to 288.20, since 79F is
// pretty hot for a "standard" atmosphere.
// Numbers above 19000 meters calculated from src/Environment/environment.cxx
// meters kelvin Pa kg/m^3
float Atmosphere::data[][4] = {{ 0.0f, 288.20f, 101325.0f, 1.22500f },
float Atmosphere::data[][4] = {{ -900.0f, 293.91f, 111679.0f, 1.32353f },
{ 0.0f, 288.11f, 101325.0f, 1.22500f },
{ 900.0f, 282.31f, 90971.0f, 1.12260f },
{ 1800.0f, 276.46f, 81494.0f, 1.02690f },
{ 2700.0f, 270.62f, 72835.0f, 0.93765f },
@ -29,7 +31,20 @@ float Atmosphere::data[][4] = {{ 0.0f, 288.20f, 101325.0f, 1.22500f },
{ 16200.0f, 216.66f, 10033.0f, 0.16133f },
{ 17100.0f, 216.66f, 8712.0f, 0.14009f },
{ 18000.0f, 216.66f, 7565.0f, 0.12165f },
{ 18900.0f, 216.66f, 6570.0f, 0.10564f }};
{18900.0f, 216.66f, 6570.0f, 0.10564f },
{19812.0f, 216.66f, 5644.0f, 0.09073f },
{20726.0f, 217.23f, 4884.0f, 0.07831f },
{21641.0f, 218.39f, 4235.0f, 0.06755f },
{22555.0f, 219.25f, 3668.0f, 0.05827f },
{23470.0f, 220.12f, 3182.0f, 0.05035f },
{24384.0f, 220.98f, 2766.0f, 0.04360f },
{25298.0f, 221.84f, 2401.0f, 0.03770f },
{26213.0f, 222.71f, 2087.0f, 0.03265f },
{27127.0f, 223.86f, 1814.0f, 0.02822f },
{28042.0f, 224.73f, 1581.0f, 0.02450f },
{28956.0f, 225.59f, 1368.0f, 0.02112f },
{29870.0f, 226.45f, 1196.0f, 0.01839f },
{30785.0f, 227.32f, 1044.0f, 0.01599f }};
// Universal gas constant for air, in SI units. P = R * rho * T.
// P in pascals (N/m^2), rho is kg/m^3, T in kelvin.