Moin guys.
Well a lot of times i have got questions on how to convert the descent rate to degrees a virtual pilot when he is already online (means he is flying) and has no time to run my specific xls file to make the conversion.
So i already have a personal maths formula for that, that is very accurate:
a = (D.R. / 100) - 0.2
where "D.R." is the descent rate in FT/NM, and "a" is the converted angle in degrees.

- Example: TACAN approach to RWY 02 of Kasteli airbase has a descent rate of 409 FT/NM from IAF until and KLI R-202/10 DME.
So we have (409/100)-0.2=4.09-0.2=3.89 -> 3.9 degrees. (in perfection 409 FT/NM are equal with 3.86 degrees).
That means that we must execute a descent of 3.9 degrees from IAF to KLI R-202/10 DME.
- An other one example: ILS approach to RWY 29 of Tanagra airbase has a descent rate of 359 FT/NM from IAF until and TGR 9.1 DME (over the TGR 11 DME arc).
We have (359/100)-0.2=3.59-0.2=3.39 -> 3.4 degrees. (in perfection 359 FT/NM are equal with 3.39 degrees).
So we need a descent of 3.4 degrees until TGR 9.1 DME.

You can see how precise is this formula for angles from 0 to 5 degrees.
Also it is very easy to remember it as also to calculate it in real time when you are flying .
I hope to help.

Note: The specific formula can be also used in order to convert climb rates to degrees!
Nikos.