Hi Folks,
> It shouldnt be necessary as they are supposed to be factory balanced.
The propeller may be well balanced when brand spanking new but by the
time it has been attached to the aircraft and a spinner popped on the
front it is very likely to need balancing.
In the unlikely event that the prop/spinner combo are perfectly
balanced to start with, they won't stay that way for ever due to dings
on the blades. Apparently, if you take a propeller off and replace it
1/1000" out of centre then that will produce a noticeable amount of
vibration.
I believe from my communications with an experienced prop balancing
guy in the USA that around 80% of all propellers would benefit from
being balanced but most people don't bother because they believe their
installation is smooth enough. Most people are wrong!
> If you must do your own, Lyndhurst in UK does one (inported from USA). Cost
> is about 1000. I believe it can also be loaned/ hired (presumably though
> only in the UK).
>
> http://www.avnet.co.uk/lts/pages/pb1.htm
Actually, it's manufactured in the UK by my company (Smart Avionics),
it costs 850 GBP + VAT (no VAT for non-EU exports!) and as far as I
know, cannot be loaned or hired yet.
<start sales blurb>
Traditionally, the equipment required to dynamically balance
propellers has been very expensive and complicated to use. Since the
PB-1 has become available, I believe that is no longer true.
A large amount of effort has gone into the design of the PB-1 to make
it easy to use by your average homebuilder/pilot. Once familiar with
the operation of the PB-1, someone who isn't a technical wizzard can
balance a propeller in just a few minutes (obviously this depends on
the state of the propeller/engine being basically ok).
For development purposes, I have balanced the PV-50 propeller on
G-NEAT many times now and as the balancing equipment matured, the
results I achieved got better and better. Every time I went flying
afterwards, I could feel the improvement. But now the prop vibration
level is so low (less than 0.05 IPS) that it is completely masked by
engine/airframe vibration.
When propeller balancing is easy to achieve and the equipment to do
the job is (relatively) cheap, there aren't many good reasons for not
having your prop balanced on a fairly regular basis. You know it makes
sense.
www.smartavionics.com has more information on the PB-1 including the
operating manual that explains how the thing is used.
<end sales blurb>
Cheers,
Mark
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