I should just like to endorse Mark's comments.
My original Warp Drive used to vibrate considerably, but much of that might
have been due to the Classic spinner. I had a go at balancing the spinner
statically in a dustbin (garbage can) full of water and that improved it a
little. I then changed my prop for an Arplast PV50 VP prop and the
vibration was much worse, so I had a go at dynamically balancing it by trial
and error by placing washers under the spinner screws and judging whether
there was an improvement or not. (The cost of dynamically balancing at that
time was over 150) I certainly achieved an improvement, but after a while
it became too difficult to detect any further improvement or if it has
worsened. Mark then made me a vibration detector which registered the
magnitude of vibration on my Multimeter, and that helped tremendously, but
took an awfully long time because it didn't tell me where to place the
weights or how heavy they should be. I did that by trial and error, but I
didn't have to rely on my own sense to detect an improvement. I ended up
with several piles of washers on the spinner backplate plus one small slab
of steel because I couldn't find any washers heavy enough! I also
discovered that it was very important how the device was mounted on the
engine to be the most effective. Mark's device was fine but it could really
have been improved with some form of damping to stop the multimeter numbers
---From changing so rapidly. Since then I have been a "guinea pig" several
times for Mark as he has been developing his PB-1 prop balancer. Each time
there has been a distinct improvement and my prop now runs very smoothly.
I can certainly recommend Mark's PB-1; it is easy and quick to use and it
achieves very good results. Very well done, Mark.
Best wishes,
William
----- Original Message -----
From: "Mark Burton" <markb@ordern.com>
Subject: Re: Europa-List: prop balancing (+ Advert)
>
>
> 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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