[copperpen]

I have been considering steam locomotive behaviour with the present code code and come to the conclusion that things are not quite right. Using default data from the eng file the evaporative surface gets set too high and steam generated is low. Generation once moving does increase but not by much thereby forcing the use of low cutoff and throttle settings until the figure gets high enough. It is my feeling that the generated figure should start at a much higher level than at present.

The evaporative surface figure if not set in the eng file is too high by default but if set in the eng file something strange happens. The initial generated figure is higher by approximately 70% but the generated increase is much slower than default.

[cjakeman]

copperpen, on 09 September 2013 - 12:20 PM, said:

It is my feeling that the generated figure should start at a much higher level than at present.

The evaporative surface figure if not set in the eng file is too high by default but if set in the eng file something strange happens. The initial generated figure is higher by approximately 70% but the generated increase is much slower than default.

I'm glad you're looking at this - we need to get it right.

Can you point to any real life data to compare the calculations with?

[captain_bazza]

This is the wrong forum to bring up this vital discussion .....it's not a bug/report, but a desired outcome for a feature not yet implemented.

Cheers Bazza

[Genma Saotome]

This might help:



Baldwin says the amount of steam produced per square foot of tube area varied by the length of the tube... my own interpretation is that portion of the tube closest to the firebox is hotter than the opposite end, with longer tubes having a greater reduction than shorter tubes, all other things equal. Averaging the gradation of temperatures across the whole length would show something like what the data is with shorter tubes evaporating more per square foot and longer tubes less. Of course, that's just my guess and I could be totally wrong... but at least there is some bit of sense to it.

[copperpen]

captain_bazza, on 09 September 2013 - 05:55 PM, said:

This is the wrong forum to bring up this vital discussion .....it's not a bug/report, but a desired outcome for a feature not yet implemented.

Cheers Bazza

Feature is implemented, but not working properly. If the aim is to be MSTS compatible, then the ability to drive a steam engine without having to "nurse" it in the initial stages needs to be corrected.

[copperpen]

Genma Saotome, on 09 September 2013 - 07:30 PM, said:

This might help:

tubes.jpg

Baldwin says the amount of steam produced per square foot of tube area varied by the length of the tube... my own interpretation is that portion of the tube closest to the firebox is hotter than the opposite end, with longer tubes having a greater reduction than shorter tubes, all other things equal. Averaging the gradation of temperatures across the whole length would show something like what the data is with shorter tubes evaporating more per square foot and longer tubes less. Of course, that's just my guess and I could be totally wrong... but at least there is some bit of sense to it.

It would certainly be a step in the right direction, but would need the code to be altered to use the data.

[copperpen]

cjakeman, on 09 September 2013 - 01:12 PM, said:

I'm glad you're looking at this - we need to get it right.

Can you point to any real life data to compare the calculations with?

Waiting on the arrival of a couple more books that might contain the data. Currently ploughing through the Johnson and Phillipson books which contain a load of data and formulae on all aspects of steam locomotives.