Nigel,
Thanks for the link... Fascinating video.
Kevin
On Oct 29, 2012, at 5:01 AM, "nigel_graham@m-tecque.co.uk" <nigel_graham@m-t
ecque.co.uk> wrote:
>
> On 31/07/2012 22:27, klinefelter.kevin@gmail.com wrote:
>>
>> Snip ....
> .....I was chatting with Rob Seaton ( of Rotech in canada). He said he lea
rned how too small a fuel line and/or tortured routing can cause "cavitation
" at the pumps. So maybe your fuel filter(s), on the suction side of the pum
p,are causing cavitation in the pump(s). Maybe due to the size (restriction o
f flow) of the filter, even if they are clean.
> ........ Snip
>
> Kevin, I think Rob Seaton may be on the money with this one.
> A year or so back, I experienced a dead cut while flying a friend's 914 po
wered Europa on a hot day. Nifty application of fuel pump restored the noise
, but once safely back on the ground, I checked the filters (all clean). Thi
s aircraft was fitted with Europa specified Purolator glass shrouded filters
that allow you to see the fuel flowing. At low RPM, the filter appeared ful
l, but as power was increased, the filter began to fill with what I thought w
as air. My first action was to check the pipework and security of connection
s - but everything seemed fine - it was definitely not drawing in air from a
nywhere. I then concluded that I had experienced vapour lock and left it at t
hat.
>
> Curiosity got the better of me and I started researching cavitation and st
umbled upon this very stilted, but interesting presentation on Youtube. Take
a look at the first minute from 00.20 - in particular, the glass venturi. T
his was exactly what I saw in the Purolator filters.
>
> http://www.youtube.com/watch?v=K_w3gcvA87I
>
> My conclusion is that the Purolator filter has the correct mesh size to tr
ap contaminants, but the filter capacity is too small and creates a pressure
drop in the fuel line.
>
> Nigel
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