Still more doodling, this time it is based on this.
I want to make sure I am doing the math correct. track at the top starts around a 42 inch radius turn (Mountain) climbs 3.5 inches for 330 degrees and crosses it self.
If I have done the math correct the total run of the turn section only is 244.88 inches, and with climbing 3.5 inches the grade should be 1.45% Does the math sound correct?
I know there would be more drag with it going around the turn. Right now I am just checking the math.
Ken
Sounds close to me.
A 1.5% grade is a 1.5 inch rise every 100 inches, so it looks like you are good.
I got 241.9" (84" diameter x pi x330/360). 241.9/3.5 gives 69" per inch of rise or 1.4%.
Yeah it’s actually a little lower grade, so you should be fine. ‘Only’ 263 inches of length - that’s almost 22 feet of track! I barely have that much on my main line on 3 walls of the room.
Length of run is simple - 2 x radius x 3.14. If you want to do it in your head use 6x radius, knowing the number will come out low so any grade will be less than expected.
–Randy
I was pretty sure I was right, thank you all for checking for me.
Ken
Did you account for the thickness of the bridge and track, or do you need to go a little bit higher than the 3.5"?
Have thought about it some what and need to see how tall the beams are. But like I said, this was more of a math test for now.
Ken
Should be plenty to allow for the clearance - a 1.5% grade over that distance is actually 3.9" of rise. A 2% grade is more than 5" - enough to clear benchwork rather than just an HO scale bridge. The 42: radius makes for lots of length to keep the grade % down.
–Randy