My constant speed propeller
hub before being sent out for an overhaul. Note the balancing weights
circled in black. Also note the marks on the
components
so when reassemble the parts are
re-installed at the same location on the crank shaft.
 |
What is
Dynamic Balancing
and how is it done? |
 |
People ask me about how my propeller was
balanced. I've seen it done but I never have the answer so after my
prop was returned from overhaul I brought my camera so I
could capture some of the process. The audio isn't great but
here is the video I shot.
What do I know about the process? Very little.
I've watched my prop being balanced twice so I like to think I know
more than nothing.
- Why get the propeller balanced?
- An out of balance prop causes the entire
airframe to vibrate and over a long period of time causes damage
to most everything including cracks in the engine case and motor
mount to the surface skin.
- When is a propeller balance needed?
- Anytime changes are made to the
propeller, spinner or engine. My friend told me about a prop
being thrown out of balance by adding prop guard. Some people
just just do it every 2 or 3 years.
- How long does it take to balance a
propeller?
- Can you notice a difference after the
balance?
- Oh yes. Never felt I had a problem
but what a difference afterwards.
- How much does it cost?
- Less than a tank of fuel for my Super
Viking.
Questions to ask the balancer:
- Do you balance the prop ON the
airplane?
- A prop needs to be balanced on
the airplane when all the parts working together.
- What type of balance do you do?
- You'll want to hear the word
Dynamic.
- Do you have the proper weights for my
model propeller?
- If they are going to drill a hole
in the bulkhead and add a bolt with a nut and washers
run! The hole and weight on the bulkhead
will cause it to crack within a few years. On my plane
that's a $700 part plus paint and labor.
I asked a very competent mechanic for a
referral and without hesitation he gave me a phone number
for Jim Fackler Dynamics. Jim is an A&P
and does balancing only, it's not a side job. Jim is based
in SoCal and he comes to you.
Jim Fackler Dynamics
Southern California
626.358.7568 |
