Shadin Fuel flow

Funny you should mention that,,, Mine does the exact same thing, but
it only happens at low powers settings like heading out to the active
while at taxi speed. Once airborne and making alot of power then the
readings are identical.

Ben
www.haaspowerair.com
Stan Prevost wrote:
I owned a turbo Saratoga with a Shadin, and have flown a lot in another
identical airplane with a Shadin. Work fine. One strange thing in both
airplanes is that turning on the electric boost fuel pump causes a decrease
in the fuel flow indicated on the Shadin, by anywhere from 0.1 to 1.0 gph.
We spent a lot of effort in removing elbows, insulating the transducer and
fuel lines, relocating things, never changed it.

I always thought it was weird.

Stan

Mine did it at all power settings and altitudes.


wrote in message
ups.com...
Funny you should mention that,,, Mine does the exact same thing, but
it only happens at low powers settings like heading out to the active
while at taxi speed. Once airborne and making alot of power then the
readings are identical.

Ben
www.haaspowerair.com
Stan Prevost wrote:
I owned a turbo Saratoga with a Shadin, and have flown a lot in another
identical airplane with a Shadin. Work fine. One strange thing in both
airplanes is that turning on the electric boost fuel pump causes a
decrease
in the fuel flow indicated on the Shadin, by anywhere from 0.1 to 1.0
gph.
We spent a lot of effort in removing elbows, insulating the transducer
and
fuel lines, relocating things, never changed it.

I always thought it was weird.

Stan

On Fri, 1 Sep 2006 14:59:08 -0500, "Jim Burns"
wrote:

Thanks TC,
I've read about the interference issues and will keep that in mind. Looks
like 3 wires from the transducer to the indicator... 1 signal wire, 1 power
wire, 1 ground, wristlocked and sleeved at the transducer.

Running the wires from the firewall through the nacelle and wing won't be a
problem as I became vary familiar with that routing last month when we
installed copper starter/battery cables.

I haven't found any mounting or plumbing instructions for the transducers,
so your info is appreciated.

What dealers/whose STC's are you looking at? Seem to remember that we
bought quite a few of them from EDMO. Not much on their website
(EDMO), need to take a peek at somebody's dealer catalog.

Copper wires in an Aztec-heh. Some days I guess I don't miss working
on them anymore...

TC

I've talked with all the larger avionics houses, I've got an IA already
talking to EDMO and I've talked to a couple guys in sales at Shadin.

The copper wire project really wasn't bad. We had everything opened up
anyway. Wow... what a difference!

Jim

wrote in message
...
On Fri, 1 Sep 2006 14:59:08 -0500, "Jim Burns"
wrote:

Thanks TC,
I've read about the interference issues and will keep that in mind. Looks
like 3 wires from the transducer to the indicator... 1 signal wire, 1
power
wire, 1 ground, wristlocked and sleeved at the transducer.

Running the wires from the firewall through the nacelle and wing won't be
a
problem as I became vary familiar with that routing last month when we
installed copper starter/battery cables.

I haven't found any mounting or plumbing instructions for the transducers,
so your info is appreciated.

What dealers/whose STC's are you looking at? Seem to remember that we
bought quite a few of them from EDMO. Not much on their website
(EDMO), need to take a peek at somebody's dealer catalog.

Copper wires in an Aztec-heh. Some days I guess I don't miss working
on them anymore...

TC

"Jim Burns" writes:

[...] My primary reason for choosing the Shadin over other fuel flow
meters/systems is that the Shadin is STC'd for primary replacement
of our Piper factory original fuel pressure type flow indicators.

You realize that you are sacrificing some redundancy with this, right?
Having both fuel pressure and flow rate is a useful cross-check.
Plugged fuel injectors show up as a drastic mismatch between the
pressure-based vs flow-based numbers. Plus the two of them can
complete a corss-checking triangle against the EGT gauge(s).

The original fuel flow gauges actually have small fuel lines
attached. 40 year old copper fuel lines inside the cockpit do not
make me especially comfortable. [...]

True, though how frequently do such instruments/lines leak near
the cockpit?

- FChE

Sorry Frank, I hit the wrong reply button... anyway, my plan includes a twin
engine analyzer and a couple Aerospace Logic electronic fuel
pressure/ammeter gauges.
Jim

"Frank Ch. Eigler" wrote in message
...

"Jim Burns" writes:

[...] My primary reason for choosing the Shadin over other fuel flow
meters/systems is that the Shadin is STC'd for primary replacement
of our Piper factory original fuel pressure type flow indicators.

You realize that you are sacrificing some redundancy with this, right?
Having both fuel pressure and flow rate is a useful cross-check.
Plugged fuel injectors show up as a drastic mismatch between the
pressure-based vs flow-based numbers. Plus the two of them can
complete a corss-checking triangle against the EGT gauge(s).

The original fuel flow gauges actually have small fuel lines
attached. 40 year old copper fuel lines inside the cockpit do not
make me especially comfortable. [...]

True, though how frequently do such instruments/lines leak near
the cockpit?

- FChE

Stan Prevost wrote:
I owned a turbo Saratoga with a Shadin, and have flown a lot in another
identical airplane with a Shadin. Work fine. One strange thing in both
airplanes is that turning on the electric boost fuel pump causes a decrease
in the fuel flow indicated on the Shadin, by anywhere from 0.1 to 1.0 gph.
We spent a lot of effort in removing elbows, insulating the transducer and
fuel lines, relocating things, never changed it.

I always thought it was weird.

Stan



"Jim Burns" wrote in message
...

I'm currently in the process of obtaining quotes and researching Shadin's
DigiFlo-L fuel flow system. If there are any group members that have had
a
Shadin installed in their airplane, I'd love to hear from you.

My primary reason for choosing the Shadin over other fuel flow
meters/systems is that the Shadin is STC'd for primary replacement of our
Piper factory original fuel pressure type flow indicators. The original
fuel flow gauges actually have small fuel lines attached. 40 year old
copper fuel lines inside the cockpit do not make me especially
comfortable.

Shadin has been impossible to deal with concerning an install manual.
They
do not post them on their website and do not sell them without the unit.
I'd love to get a copy before I spend the money and throw this project
into
an A&P/AI's lap. If anybody can help me locate an install manual, I'd be
grateful.

Thanks,
Jim





Stan,
Actually that makes sense. If you are pumping against the metering
device you will be initially raising the flow until the down stream
plumbing becomes "full". then things will slow down.

Michelle P

"Michelle P" wrote in message
ink.net...
Stan Prevost wrote:
I owned a turbo Saratoga with a Shadin, and have flown a lot in another
identical airplane with a Shadin. Work fine. One strange thing in both
airplanes is that turning on the electric boost fuel pump causes a
decrease in the fuel flow indicated on the Shadin, by anywhere from 0.1
to 1.0 gph. We spent a lot of effort in removing elbows, insulating the
transducer and fuel lines, relocating things, never changed it.

I always thought it was weird.

Stan


Stan,
Actually that makes sense. If you are pumping against the metering device
you will be initially raising the flow until the down stream plumbing
becomes "full". then things will slow down.

Michelle P

No, when I turn on the boost pump, thus increasing the fuel pressure to the
sensor and to the engine-driven pump, the flow indication decreases to a
new steady-state value until I turn it off, then it increases again to its
former steady-state indication. If I turn it on again, it decreases again.
Appears to be something unique to that sensor type since it does it in both
airplanes I fly that are equipped with the Shadin system.

Higher pressure giving lower flow indication is what is wierd. Actually, we
would like it to not change.

"Stan Prevost" wrote:

No, when I turn on the boost pump, thus increasing the fuel pressure to
the sensor and to the engine-driven pump, the flow indication decreases
to a new steady-state value until I turn it off, then it increases again
to its former steady-state indication. If I turn it on again, it
decreases again. Appears to be something unique to that sensor type since
it does it in both airplanes I fly that are equipped with the Shadin
system.

What kind of sensor is it? It's a turbine type, right?

Higher pressure giving lower flow indication is what is wierd. Actually,
we would like it to not change.

Interesting problem. Perhaps the higher static pressure is putting some
kind of friction load on the turbine shaft, maybe by deforming an o-ring
seal or some such.

--
Dan
C172RG at BFM

"Dan Luke" wrote in message
...

What kind of sensor is it? It's a turbine type, right?

It is a rotary sensor, but I'm not sure it is a turbine. Some type of
positive-displacement paddlewheel design.

Higher pressure giving lower flow indication is what is wierd. Actually,
we would like it to not change.

Interesting problem. Perhaps the higher static pressure is putting some
kind of friction load on the turbine shaft, maybe by deforming an o-ring
seal or some such.


Something like that is all I could theorize, also. We suspected for a while
that we had bubbles giving abnormal high readings, and the increaed pressure
from the boost pump prevented the vapor bubble formation and thus lowered
the readings, but we did about everything that we could think of to
eliminate bubble formation, to no avail. I concluded it was the sensor
itself.