First, I was looking at a rotor design spreadsheet and noticed that the rotor thrust is approx. 60lbs in 24mph wind. What happens to this thrust load as the system begins to furl and the rotor moves parallel to the wind, does it remain constant for instance?
I usually design the tail so that it will furl if the thrust force along the rotor axis exceeds a certain amount. I try to arrange it so that the furling works at a pretty constant force through the 90 degrees or so of movement. In reality it reaches a peak at about half way where the tail is rising most steeply and falls off at the start and finish. Here we are talking about axial thrust component on the rotor blades, not downwind drag on the rotor.
Also, does the rotor rpm remain the same as the system furls and what is it when fully furled?
Rotor rpm will depend on how it is loaded. If it runs free it will be very fast. If it is short circuited and the torque is high then the rotor may stall. In this case the thrust is low and it will not furl. In reality we load it so that it produces the most power if we can. This will mean the rpm will be pretty constant if the power is pretty constant as it furls around out of the wind.
Second, I was drawing lines on some wood stock today and noticed that the drop at station 1 is 1" and the thickness at station 1 is 15/16". Does this mean that the blade narrows at the trailing edge in this section near the root?
Yes the trailing edge will be tapered to a fine edge. The thickest part of the blade should be nearer to the leading edge. The idea when carviing thickness is to make a flat face on the back parallel to the front face and extending as far across the wood as it can, but near the root it cannot extend all the way across. This does not matter because the next stage is to sharpen the trailing edge and curve it all off sweetly.
Getting the right thickness is not critically important near the root so long as all the blades are the same. It is generally most important to follow the dimensions accurately (especially the right drop) in the outer part near to the tip of the blades.
