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Message
The flow meter is a
Signet paddlewheel sensor. They are obsolete at the mill I work in but there was
still one in mill stores :-).
Thanks. We use similar
type sensors in the cooler cabinets for MRI scanners. Next time I
open one of those up, I'll take note of how the sensor if
physically set up. I recall it being rather big and bulky.
Either way, it doesn't sound like something that I'll install on the
plane.
Tonight the
weather was crap so I didn't fly, but changed out the water pump, as today I
gave it a real good going over to ensure it wasn't going to have any
problems.
I'm interested to know if
the problem you fixed with the original pump was something that you think
was a flaw in that particular pump, or something that you think exists in all of
them.
Unfortunately the shaft is
not accessible when in operation as I'd like to clamp it to ensure it doesn't
freewheel when off in an effort to simulate a seized pump to measure flow
restriction.
I was thinking of trying
this experiment in the garage to make sure there was going to be enough
flow in the worst case event that one
seizes.
I think you may find that by running both pumps
all the time that you will have a very cold engine on descent.
This is the main problem I see with running both, or maybe
even one pump all the time. I guess it will be another experiment,
and I can always add a controller later if needed. I'm just worried that
the controller allows the flow to get too low. On the other hand,
there are lots of folks running with no thermostat, and during descent,
they will still be at a reasonable rpm to create a lot of flow with the stock
pump. If they aren't having problems, then I shouldn't
either. Since I'm keeping the stock pump housing, I can also use a
thermostat, with enough bypass holes around the edge to allow sufficient minimum
flow to keep the engine happy when the thermostat is closed.
My plan is to
keep the primary pump on the controller with the ability to bypass the
controller (see attached wiring diagram- option 2) with the secondary pump
controlled by a thermal switch set to 95C. In the event of a pump failure,
rising temps will automatically start the secondary. In the event of a
extended full power climb it will also kick it on, however I don't know that
additional flow will reject more heat. If it doesn't then I know that my coolers
are operating at their capacity. Secondary pump will also likely be used to cool
down heat soak after shutdown.
This all
sounds outstanding. May I suggest that you plug your thermal switch into
the temp sensor location near the oil filter pad? I figure that would
be the first place to show high temps in the combustion chamber if the water
flow stops. I've got a variable temp sensor that's used to turn fans on
and off, and was thinking of using it in that location for the second pump,
rather than leaving it on all the
time.
Take that
bulky, heavy pump housing and throw it into the air, if it comes back down get
rid of it and build a lighter, compact adapter:-)
I weighed a spare
housing from the attic yesterday. It weighs 3 lb 2 oz, minus bolts,
plus grease and dirt. What does your adapter, header tank, and
alternator mount weight? I bet it's not that much less :-) If I
had room to move the alternator to the side, I'd consider that to be another
reason to get rid of the pump housing. The stock housing also allows
me the ability to re-install the mechanical pump if the need
should ever arise, or if I want to do some testing with stock pump, plus one
EWP. The housing also allows me to run a (modified) thermostat.
I think those capabilities are worth an extra pound or so.
Cheers,
Rusty (Turbonetics order being placed
today)
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