The Inside Loop - 2009/03

Two tables were most active in the
shop this past weekend; one had a
helicopter going together and the
other had an airplane—a project for each kid.
For me, a tiny corner was free for a
“someday” project.
Practice helicopter blades are relatively
inexpensive, at approximately $12 a set. The
last swap meet rendered us a bounty of blade
slap expertise samples, all for the helicopter
neophyte price of free. Better than the $12
deal?
One particular wooden set included a
325mm blade and one 335mm blade. My
“someday” project was that these would be
trimmed and matched. Even beginner-grade
blades are precision weighted and balanced to
an exacting degree (they match in length
even).
Of notable interest to me was the fact that
shortening both a 325mm blade and a 335mm
blade to a 280mm length removes
approximately “way too much” ballast
material. The $12 deal might have been better.
The correct weight location was easy to
find; it’s right next to the metallic stuff
sticking out of the band saw-chomped end of
the free helicopter accessory (soon to be
resurrected as a helicopter blade). A channel
was milled out of the light blade in the
appropriate location, and sledge sculpted lead
strips were inlaid so that each $6 portion of the
free gift came into sync on the blade balancer.
Overnight, epoxy secured the ballast
position, and its cured state was prepared for
careful blending into the precisely molded
factory airfoil shape—which is available for
roughly $12 at the local hobby shop.
With a fanatical eye and selection of
various sanding tools, fashionable tips in the
blade ends were sculpted. Hours went by as
transverse curve scrutiny was used to hone the
critical lifting devices. A final check on the
blade balancer proved that the careful
application of paint on one blade over the
other would yield a set of closely matched
swap-meet masterpieces.
Layers of primer coated the bare wood
areas and epoxy filler. A can of Wal-Martbrand
primer hiding in the cabinet for years
seemed to be the perfect selection for sealing
such silicon and carbide wielding. The can of
paint must have cost me $1 10 years ago; and
it isn’t made anymore. Darn it, it’s good stuff!
After 24 hours of baking over the electric
heater that kept our provisional garage
workshop toasty warm, the would-be $12
blades were wet-sanded in the guest bathroom,
taking special care that gray paint water didn’t
get on the embroidered guest towels. When all
evidence of the tooling was finally removed, a
sealer coat of primer was added after 30
minutes of drying time over the heater.
Blades can be tricky to paint; there’s no
place to hold it while spraying and the entire
surface must be coated. Using dowel scraps
and paint stirring sticks from the hardware
store (free if you ask nicely), handles were
Editor Michael Ramsey
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fashioned that could be screwed through the
blade-grip hole, which would later be hidden
by plastic covers—available with almost every
$12 blade set on the market.
We settled on Rust-Oleum Chrome for the
finish, which would complement the tiny balls
hidden under the black plastic links on the
mechanics most tastefully. The paint was left
over from a Cub Scout award project—again,
a major cost savings (high praise from the
wife is certain).
Careful paint application was completed
under the best of conditions—out on the
porch, 9:30 at night with blowing snow. It was
found that when blades are painted at the same
angle of attack as the driving precipitation,
there’s little chance of the fresh frostbitten
paint to be contaminated. In between paint
coats, I found a sale on wood helicopter blades
at one of my favorite Web sites.
The blades gleamed as the solvents were
baked from the rustproof paint—an important
consideration when painting wood. After 48
hours, enough time had passed that the
masterpieces of sweat, grit, and Maxwell
House were ready for the final check on the
balancer, the verdict which warranted the need
for just a tiny strip of tracking tape—which
also covered up a snowflake-sized blemish.
The blades are now mounted to my son’s
well-earned 400-class electric helicopter
(another swap-meet special). He’s proud that
his machine looks good, and his building
supervisor (daddy) is glad to have played a
part.
What does this story mean? Builders build
because they want to. Whether it’s an airplane,
helicopter, or X-Prize contender, RTF or
scratch-build, stabilizer or wheel pant, have
fun and enjoy the opportunities that this great
hobby brings.