Pe,
The provided spreadsheet is an example of how to use the solution method drafted by me for my thesis work.

Let us discuss it in detail a bit more.
BEM method was the integration of Blade Element with Momentum theorems. It was in place for quite sometimes now to predict the behavior of the propeller. Some Aerodynamic Scholars have proposed a close loop solution (refer to Aerodynamics, Aeronautics, and Flight Mechanics by Barnes W. McCormick). The close loop solutions even though easy to accomplish, the results were a bit far from actual by say around 10 to 15%. The reason for this is, the assumptions that they made in order to close the loop.

Due to this, some recent Scholars have suggested iteration technique, the paper can be found as link in my first post. Like i said before, i put the suggestion for practical usage, unfortunately it is very difficult to converge to usable values.

Looking at this, after a few months of working on the derivations the equations, finally i managed to make it converge almost most of the time and the results are useful enough with margin of error less than 10%.

The Concept of Solutions
Each propeller blade will be divided into smaller elements (in the spreadsheet, 20 of them - not limited to this number, any number also can but the more it is slightly more accurate it will be but the time will be longer to iterate). Forces acting on those elements will be evaluated individually based on established aerodynamic theorem and counter checked with conservation of momentum. These processes require the introductions of interlink variables between the two concepts. Finally summations of all those forces from each element will make up for total thrust, torque and power required.

When you asked about the pitch, yes, in the example there are 2 cell (F7, F8) that depict the individual element pitch, one is in radian and another is in degree. The calculation for each element angle based on the position of the element along the spanwise direction from the center. It has been modeled as such that anyone of the element, if being subjected to a rotation will move forward by the same amount. Say the first element which is located closes to the root, the angle will be large in order to arrive forward at the same time as the element that is at the tip which off course will be having smaller pitch angle.

When you say about airfoil chamber, No, it is not in. Like i mentioned before, i just use 'clark y' airfoil data with flat bottom as the initial ref. The technique is to plot the Cl and Cd based on physical testing data of it, add a curve fitting technique and produce a function of Cl = Cl(a) and Cd = Cd(a). the variable 'a' here is the actual angle of attack on each element. Now if we want to use some other airfoil, perhaps with certain degree of chamber, then we search out for the actual data for that airfoil, chances are, some professors somewhere have test it in windtunnel and produced the result. Once we have those data, we plot again to produce Cl and Cd functions based on angle of attack.

When we talk about speed, yes we can model it directly. Say our engine can rotate 23 x 8 prop at 7000 rpm at full throttle statically. Based on the spreadsheet the amount of power required is ~ 5HP. Now we add some forward speed, say 35mph... with the same 7000rpm, we can see a reduction in power required, i.e. it reads only 3.83HP. From first scenario we know our engine can produce 5HP at WOT, this clearly shows that the rpm will climb to match the power avail if we keep the throttle at full open. How much increment? Then we need to feed in the rpm number so that it match the on ground scenario on power required - give a little compensation as the higher you're in the air the less density the air is...(you may add the flying altitude for compensation) Say in this example, i found out that the rpm will climb to 7600, i.e. 600 rpm extra. This effectively increases the pitch speed from 53mph to 57.6mph.

The main thing here is, all other parameter can be changed as required, say your CL, CD, rpm, prop diameter, prop pitch, chord profile and lots more. However the derivation towards the solution is the key here! And you my friend are the lucky one having to look at this even before my University Senate catch hold of it.