5
a) Seriously consider coating the last 1/4” of the trailing edge of the blades
in thin CA. It really helps to make them more durable.
b) Finish the blades with Lacquer Paint, Dope, Polyurethane, whatever you
can use to seal the grain, and make the blade a little more solid. I
prefer the Lacquer paint, it dries quickly, and makes balancing a quicker
easier task.
c) Apply several coats, sanding after each coat.
d) Apply a final coat to leave a glossy finish.
e) Add more paint to the leading or trailing edges of the blades until they
hang straight down when hung from the mounting hole.
f) Weigh each blade on the most accurate scale you can find. If you really
need to you can probably fashion a crude balance scale to at least
compare the weights of the blades to each other. I’ve pre-weighed the
blades, they should all be within a gram of each other to begin with.
g) Balance the heaviest blade on a ruler, or knife edge etc. to see where
along it’s length it balances.
h) When you add weight to the lighter blades, place it so that they balance
at the same points as well as weighing the same.
i) You can add weight by adding more paint to the ends of the lighter
blades as necessary. If you still can’t get all the blades to balance in
the same place, and they weigh the same. Add weigh to the lighter
blades till they balance, and then add extra weight right on the balance
point of the original heavier blade (now lighter) until it weighs the same
as the others.
j) Strongly consider covering the blades in Monokote, Econocote, etc.
This will make them dramatically more durable.
i) If you can cover the complete blade, root to tip, then do it. I can’t
really, so I just covered the middle.
ii) Start the covering on the bottom right near the trailing edge, with
about 1/8” overlap, and work over the edge, across the top, and
around the front. Continue on the bottom to the trailing edge, and
trim off the excess.
iii) Once all the blades are covered the same way, weigh them again.
iv) Add clear tape if necessary at their balance points until they weigh
the same again. (This isn’t as critical as it sounds, but you really
should get the blades in balance as closely as you can, without
driving yourself nuts about it)
k) Using a knife or file, just barely bevel the tops of the tips of the hub
triangle. This will make it easier for the blades to fold up in an
emergency. When the blades are on, test. They should have a little
movement, then be firm. A reasonable push should fold the blade back.
If it seems like too much effort, bevel the plastic some more.
l) Mount the blades to the center hub with the 2mm bolts, and nylon insert
nuts. The hinge lines on the hub must be angled back against the
counter-clockwise direction of spin. Flip over the hub if need be. When
aligned properly, then hinges will force the blades to pitch down when
lifted, and to pitch up when lowered. This greatly increases the
responsiveness and stability of the whole gyro.
6) Landing Gear:
a) Take the two pieces of 4mm carbon tube, and File/sand them till the
ends are smooth, and they’re the same length.
