As explained above, balancing the blades is crucial to the proper
operation of the unit. If the blades are out of balance, it will make the
turbine vibrate badly, which causes the tower and everything that's
attached to it to vibrate badly as well. This will cause undue stress on
There are several ways to balance the blades. First of all, if we have
several pieces of wood to choose from, we will try to get three pieces
that are very close in weight to begin with. Also, make sure that the wood
is not warped. Choosing good pieces of wood to begin with, will save you a
lot of frustration when you come to the balancing later. After removing
most of the wood and getting the blades close to being finished, we weigh
them to make sure that they are very close to being the same weight. Once
they are finished and ready to be painted, we put them together with two
round plywood plates, top and bottom and hang them from a perfectly
centered hook to a level truss in the ceiling. If you know that what you
are hanging them from is perfectly level and that your centre hook is
perfectly centered, then you can tell by the way they hang whether or not
they are balanced. If they are balanced, they will hang perfectly level.
If not, they will be slightly off kilter and you can see which blade needs
a little more weight added to balance it to the others.
At this point, the blades need to have a coat of epoxy applied to the
leading edges to protect them from the elements once they are up and
running. Once you have hung the blades and have identified which one or
one's need a little weight added to them, you can do this with the epoxy.
On the blade or blades that are a little light, just put a little extra
epoxy on them and that should even them out. While we are applying the
epoxy and paint to the blades, we always hang them in this way from the
roof truss while they dry and that way we can see how well balanced they
are. This method has always worked very well for us and we usually recommend
this method to everyone.
Another method that we have heard of is to drill tiny holes in the
blade that is a little light and melt some lead and pour it into the holes
and seal the holes up. Apparently, this works quite well also, but we have
never given it a try.
Once the blades are balanced as close as you can get them to perfect,
the next step is to make sure that they track properly. We have a small
test tower right beside our house where we do all of the final checks.
Once the blades have been attached to the unit, we stand to the side and
spin the blades and watch where they track. If you notice that one of the
points of the blades is a little farther in towards the tower or out
farther from the tower than the others, then it is not tracking perfectly.
You can usually fix this by putting a washer behind the blade that is out
slightly to bring it out a bit.
We have not had much problem with the blades not tracking properly
because we are very careful with checking the blades as we go along to
make sure that everything is perfect. If you take your time, they should