Thanks. Yes, it happens I've been reading a manual, and you're right. This is not a design task for the feint of heart.
That said, my heart is not feint. ;-)
Okay, I got the 12 gpm by filling a bucket at a hose bib.
The city's water meter is a 1". I have seen, but will need to verify, that the city maintains 60 psi to the meter.
I am now seeing that, supposing I understand this correctly, I will have to use 1" trunks which will supply 3/4" laterals with no more than 2 of the Rainbird 5000's on each 3/4" line. It looks also like max spacing, assuming a 40' throw, will be 48', which allows throw overlap for the last 40% of throw distance.
The RB 5000 is showing that at 55 psi, with nozzle 3, I will get a 40' throw with a flow of 3.47 gpm. Since my whole supply is 12 gpm, it seems 2 heads is the max I'd want to run at a time, right? (I assume I don't want to use my max available, or a clothes washer or dishwasher or shower will be starved).
I also saw, where if I set up these heads in a square pattern, I will have some drier spots - even if the heads were laid at head-to-head distance. It was suggested the triangular pattern will allow for greater spacing, and the math was shown to prove this, which I completely understand.
So, the dimensions of the back yard approximate 150 x 240, and the front yard dimensions are about the same. My calculations tell me that I will have, for the back yard, 5 heads wide by 3 heads deep, for a total of 15 heads to serve the back yard. Same for the front.
Now, if I'm getting only 2 RB 5000's per zone (max), that leaves me 15 zones. That's a lot of zones!
Do you guys agree with my math?