[rdamurphy]

copperpen, on 05 September 2013 - 03:57 AM, said:

In the SteamLocomotive.cs there is a line dealing with steam usage

SteamUsageFactor = 2 * NumCylinders * 3.281f * CylinderDiameterM / 2 * 3.281f * CylinderDiameterM / 2 * 3.281f * CylinderStrokeM / (2 * DriverWheelRadiusM)

There's a rather obvious error in this formula: Every value is converted from metric to feet except for DriversWheelRadiusM - which is in meters (hence the "m".

In addition, each cylinder fills twice and makes 2 power strokes for every revolution of the wheel. Is that why there's a 2 * before DriverWheelRadiusM?

I think that this could be much better written, much more clearly:

And the formula for the volume of a cylinder is PI * Radius^2 * Height.

SteamUsageFactor = 4 * (NumCylinders * ( Math.Pi * ( 3.281f * CylinderDiameterM /2 ) * ( 3.281f * CylinderDiameterM / 2 ) ) * ( 3.281f * CylinderStrokeM )) / DriverWheelRadiusM * 3.281f;

And, yes, I know this code won't compile, Math.Pi must be cast...

Robert

[rdamurphy]

Just for grins, I changed this equation in OR, and the results were amazing! I could start the Berkshire with about 50% cutoff and 50% throttle with nothing on the drawbar, and drop the throttle almost immediately back to 30% and steam usage dropped quickly below generation.

I believe someone's working on this, I'll send them a message and see if they want to try this...

Robert

[Lindsayts]

rdamurphy, on 23 September 2013 - 11:51 PM, said:

There's a rather obvious error in this formula: Every value is converted from metric to feet except for DriversWheelRadiusM - which is in meters (hence the "m".

In addition, each cylinder fills twice and makes 2 power strokes for every revolution of the wheel. Is that why there's a 2 * before DriverWheelRadiusM?

I think that this could be much better written, much more clearly:

And the formula for the volume of a cylinder is PI * Radius^2 * Height.

SteamUsageFactor = 4 * (NumCylinders * ( Math.Pi * ( 3.281f * CylinderDiameterM /2 ) * ( 3.281f * CylinderDiameterM / 2 ) ) * ( 3.281f * CylinderStrokeM )) / DriverWheelRadiusM * 3.281f;

And, yes, I know this code won't compile, Math.Pi must be cast...

Robert

Thats not an error (I think) SteamUsageFactor is the volume of the cylinder in cubic feet used per __metre__ of the travel of the machine see line 582 and 545. The variable "speed" is in metres/sec.

Lindsay