Hi Jon,
If something is loose inside your PV50 you must dismantle it again and
investigate. The initial balancing, I believe, would have been achieved
by fitting appropiate weights into the centre of the blade roots.I doubt
that any of these would be loose but check!
I did find on my first annual service of my PV50 that the centre
triangular block was loose on the activator tube and the grub screw was
loose!
This year I carried out a static balance following the fitting of new
thrust bearings and bushes.I was surprised at the out of balance that I
had to counteract with 8 mm threaded weights fitted onto the six 8mm hub
assembly bolts. This seemed a suitable method of fitting balance weights
to me? How have you fitted any balance weights? My propeller/engine is
running pretty smoothly now but probably would benefit from dynamic
balancing.
I have a spare set of early PV50 Classic (shorter) 80hp narrow blades,
but they would need serious balancing to match a different hub. Each set
of blades is matched to fit each hub and also each blade must be fitted
in the correct position.
My details are on the members list if you want to contact me otherwise I
will look out for you at a fly-in for some intersting PV50 tales!
Ken Atkinson G-CEKV mono no 19
On 11/02/2017 17:56, italianjon wrote:
>
> Hi All,
>
> If you recall I posted about a year ago, relating to PV50 and some vibration
problems. Well, it has been an interesting year, and some stories which I won't
write on a public forum, but I might share over a beer at a fly-in. A lot of
the year has been a learning curve, and I used the time waiting for the PH-Reg
to come through, to experiment and learn more
>
> Today I was coming to the end of a careful adjustments on the propeller, but
still, alas, there is an imbalance. I'm getting about 0.25 IPS on the prop
(attached
is the outcome of the spectrum), this is now the main and seemingly only
contributor to the vibration.
>
> I've managed to get all three blade-pitches to within 0.16 degres across all
three blades, and the tracking is less than 3 mm. The blades are quite firmly
seated now, after I have installed new plastic blocks. All of this has had no
real effect.
>
> Today was a very quiet day at the airfield. There was only myself and my
> "plane
work buddy". On one of the blades I heard a "tick", and on closer inspection
it is evident something is loose on the inside (One of the static balance
weights,
I am assuming)
>
> Does anyone have any experience at all in setting the static weights on a PV50
blade? Is it possible without manufacturer support?
>
> Failing that, is there anyone with a spare blade that I could try in the
> position,
to close off this investigation?
>
> I know the engine is not contributing, as the latest spectrum shows nothing
> significant
at key engine frequencies, and in addition I have spectra from other
measurements with my aircraft and a Warpdrive installed which shows very good
vibration down at 0.08IPS.
>
> Cheers
>
> Jon
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=466013#466013
>
>
> Attachments:
>
> http://forums.matronics.com//files/screenshot_20170211_182509_207.png
>
>
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