Propeller Balancing

Is your airplane fitted with pneumatic wheels? The odds are, it is.
That means you probably have tools in your kit that allow you to
remove the wheel, remove the tire & tube from the rim, to re-install
them, inflate the wheel and so forth. Indeed, if you're a serious
airman you give your the same degree of attention you devote to the
engine and air-frame, which means you have the tools and fixtures
needed to maintain your wheels.

All of that also holds true for wooden propellers. Not only do you
pay careful attention to its finish, protecting it with a waterproof
sleeve when it must be parked out in the weather, you have the means
of periodically refinishing and balancing your propeller.

With regard to balancing, go here...

.....http://www.youtube.com/watch?v=uw95sC3keQs

.....and watch the video a time or two. The video shows balancing the
prop by installing a relatively massive amount of weight very near the
center of rotation. That is, he's using a very short radius.
Another common method is to use an additional coat of paint or varnish
near the TIP of the LIGHT blade. That is, using a relatively small
weight having a relatively LARGE radius. Both methods work equally
well but the small-mass/large-radius is better suited for the amateur,
in my opinion, since it calls for fewer tools and parts (ie, drill
bit, drill motor, lead slug of suitable size, wooden plugs and so
forth.).

Right now you don't have a prop to balance but I want to make you
aware of the things you WILL need, not just when making a propeller
but when MAINTAINING your propeller in the years to come.

The most important of those things is the BALANCE STAND and the
BALANCE BAR.

The Balance Stand is literally anything that can hold a pair of knife-
edges at PRECISELY the same height. Here in the States it is common
to use joiner blades as the knife edges and a section of precision-
ground oil-hardening steel for the balance bar.

There is no requirement to spin the propeller round & round on it's
balance bar; you only need to see which blade is heavier, which means
the Balance Stand may be a bench-top device, such as a pair of
accurately cut boards that have been grooved to accept the router
blades. The 'truth' of the jig is determined by placing a straight-
edge across the pair of knife edges and using a precision protractor
or level to ensure the blades are level. Nowadays, if you have the
money, you would probably use a digital protractor, most of which are
accurate to a tenth of a degree. Or you can use the old fashion
method which consists of a carpenter's framing square, a bit of thread
and a plumb-bob.

The point that needs to be made here is that your propeller balancing
tools are something you will use periodically, not just when you carve
a propeller. Just as you keep a set of tools specific to your landing
gear tires and wheels, so too must you keep a kit of tools specific to
balancing your prop.

-R.S.Hoover