struct FlightData {
	int rpm;
	int airspeed;
	float verticalSpeed;
	float altitude;
	int pitch;
	float heading;
	int bank;
} gFlightData;

const int gRpmIncrement = 100;
const int gPitchIncrement = 1;
const int gAirspeedIncrement = 2;
const int gVsiIncrement = 100;

struct PowerData {
	int rpm;
	int bhp;
} ;

PowerData gPowerData[ 18 ] = { 
	700, 40, 800, 42, 900, 45, 1000, 50, 
	1100, 55, 1200, 65, 1300, 80, 1400, 90, 
	1500, 95, 1600, 100, 1700, 104, 1800, 110, 
	1900, 115, 2000, 120, 2200, 130, 2400, 140,  
	2600, 150, 2700, 160 
	};

	// Function is CalcPowerCurve().
	for ( j = 0; j < 18; j++ ) {
		if ( gFlightData.rpm <= gPowerData[ j ].rpm )
			break;
	}

	if ( i < 17 && j < 18 )
		retval = gPowerData[ j ].bhp - ( gPowerCurveData[ i ].bhpReqd + ( bank / 2 ) );

	gFlightData.verticalSpeed = ( CalcPowerCurve() * 33000 ) / 2300;

	gFlightData.altitude += ( gFlightData.verticalSpeed / 60 ); // Argh: tied to 1-second update.	

	gFlightData.heading += gHeadingIncrement * CalcTurnRate();		

float CalcTurnRate( void ) {
	float retval = 0;
	
	// Are we banked?
	if ( gFlightData.bank != 0 ) {
		int i = 0;
		int bankAngle = gFlightData.bank;
		
		// Absolute value for array lookup.
		if ( bankAngle < 0 )
			bankAngle = -bankAngle;

		// Find array index closest to our current bank angle.		
		for ( i = 0; i < 4; i++ ) {
			if ( bankAngle >= gBankData[ i ].angle ) {
				break;
			}
		}

		if ( i == 4 ) // No index found, so assume very small bank value.
			retval = 1091 * 0.12 / gFlightData.airspeed;
		else
			retval = 1091 * gBankData[ i ].multiplier / gFlightData.airspeed;

		if ( gFlightData.bank < 0 )
			retval = -retval;
	}

	return retval;
}