Looking for this Spreadsheet Engine HP rating
- Thread starter blueodessey
- Start date
norfolksouthern37
what's a normal map?
I made this years ago following some research I was doing. I have put it up so you and others can get it if they wish.
http://jrpcloud.com/files/public/files/HPcalc.xls
To use it just fill in the blue areas (at least I hope they are blue on the file). The yellow/orange areas are general calculations based on what you entered.
http://jrpcloud.com/files/public/files/HPcalc.xls
To use it just fill in the blue areas (at least I hope they are blue on the file). The yellow/orange areas are general calculations based on what you entered.
blueodessey
Well-known member
Thank you for the Spreadsheet
It works perfectly in the manner you described.......Much appreciated Sir.
It works perfectly in the manner you described.......Much appreciated Sir.socalwb909
Photo Creator
-What is 'face area'? And would I ever have to change that number?
-Joe
-Joe
blueodessey
Well-known member
I just downloaded it recently, and have been working on other items, pulled up the Spreadsheet, and I hadn't noticed this part, my instinct tells me it is the Square Feet of Wind Resistance area front part of Locomotive Face, like air drag coefficient, aerodynamics Etc,
I could be totally off base here, but like a square boxy looking Semi Track (old days) will not get a great MPG versus newer rounded, air scooped design you see now a days, where you find the info, ? U got me?.....
Hopefully someone here will know what those answers are......Hope this helps a little.
socalwb909
Photo Creator
-Thanks for that. That sounds accurate. Don't know for sure. Maybe norfolksouthern37 will chime in.
-Joe
-Joe
Norfolk, I took a quick look at your spreadsheet and have a few comments. In general it looks pretty good.
A couple of comments affecting the resistance (drag) calculations and hp input for the locos:
1) "Single loco drag" calculation formula in sheet 2 cell b3 multiplies the number axles per loco by the number of locos and also the face area per loco by the number of locos. The value in this cell is later multiplied by the number of locos to determine total drag of locos (sheet1 cell h9). This effectively squares the number of locos used for some parts of the resistance calculation.
2) I didn't find any calculations to determine the grade and curve resistances for the locos in the train. which should be included to determine the total for the entire train. I assumed that the train tonnage in sheet1 cell b3 is a drawbar figure and does not include the weight of the locos. (If this is not the case then the weight per axle calculation in sheet1 cell b13 and coupler loading calculation in b12 are not correct).
3) HP per loco is a user input and the user should aware this value is the hp available at the rail not some maximum or rated value of the prime mover. So a loco with a rated hp of 4400 might have only 3520 hp available for developing tractive force on the rail. The spreadsheet assumes that the HP value specified remains constant for all speeds - a usual assumption unless you know something different like having TE or hp vs speed curves. You do make a check on wheel slip limit for TE.
If you use this for Trainz you should verify that the loco's espec and config support the hp value you enter here. Also the other resistance coefficients coded in the spreadsheet should be consistent with those used in Trainz and not necessarily just "real world" values. I typically work with 2 sets: a)real world predictions and b)Trainz.
Bob Pearson