fly/flightgear
1
0
Fork 0
Code Activity

Scaling "idle" MP to 6 inches or so is all well and good, but not if

Browse source 
the engine continues to develop 20% power.  Rescale the output power
accordingly, so idling aircraft stay put.
This commit is contained in:
andy 2002-02-20 07:10:58 +00:00
parent 3f35de9507
commit 6b10d8b128
1 changed files with 8 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
src/FDM/YASim/PistonEngine.cpp
View file

@ -141,16 +141,19 @@ void PistonEngine::calc(float pressure, float temp, float speed)
// turbocharging and reduced by the throttle setting. According
// to Dave Luff, minimum throttle at sea level corresponds to 6"
// manifold pressure. Assume that this means that minimum MP is
// always 20% of ambient pressure.
// always 20% of ambient pressure. But we need to produce _zero_
// thrust at that setting, so hold onto the "output" value
// separately. Ick.
_mp = pressure * (1 + _boost*(_turbo-1)); // turbocharger
_mp *= (0.2 + 0.8 * _throttle); // throttle
if(_mp > _maxMP) _mp = _maxMP; // wastegate
float mp = _mp * (0.2 + 0.8 * _throttle); // throttle
_mp *= _throttle;
if(mp > _maxMP) mp = _maxMP; // wastegate
// Air entering the manifold does so rapidly, and thus the
// pressure change can be assumed to be adiabatic. Calculate a
// temperature change, and use that to get the density.
float T = temp * Math::pow(_mp/pressure, 2.0/7.0);
float rho = _mp / (287.1 * T);
float T = temp * Math::pow(mp/pressure, 2.0/7.0);
float rho = mp / (287.1 * T);
// The actual fuel flow is determined only by engine RPM and the
// mixture setting. Not all of this will burn with the same