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Red Cube question

R

rightrudder

Well Known Member
Hi guys,

I'm in the midst of fuel plumbing, and I'm wondering if it's acceptable to plumb the Red Cube with 90-degree AN fittings, and whether this would cause erroneous readings. Most installations I've seen have straight fittings.
 
Here is something that I try to post each time a new thread shows up on these Red Cubes.

Matt works for the people that make the thing:

Mathew Sharp said:
As far as I know Dynon distributes both the FloScan 201B as well as EI's FT-60.

The FloScan unit is much more sensitive to the angles/fittings entering and exiting the unit. EI's unit does not care. You can run 90 degree fittings in and out of ours without problems.

JPI does not sell EI's FT-60:cool:

Maybe you can get Dynon to trade you for a FT-60?

Good luck!

Matt
Click to expand...


Mathew Sharp said:
You do NOT want to rigid mount the transducer to the motor (any part) using just a fitting. It is a huge safety issue. The fitting could theoretically fatigue and break. You absolutely need to have flexible line on both sides of the Floscan 201B or the EI FT-60 (that Dynon now utilizes).

After manufacturing/supporting flow instruments for a good number of years we have seen that flow transducers accuracy is typically better when mounted after both fuel pumps. They simply seem to prefer to have fuel pushed through them, not pulled through. The truth of it though is that many installation drawings still read as though we were still using the older Floscan 201 transducers. I have seen installs that mount the transducer between the pumps with claimed success. The Floscan units were much more sensitive in regards to mounting location, angles of fittings in and out, and attitude. Our new design will tolerate a lot more. Frankly we don't care if the thing flows straight up, or if you put 90-degree fittings in and out (FT-60 only) of the transducer. Just don't mount it upside down or flowing sharply downhill.



Hope this helps,

Matt Sharp
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Mathew Sharp said:
Hello All!

Your friendly neighborhood EI Tech support rep here!

There are really two issues in regards to EI?s specifications on flow transducer placement.

1. Accuracy of the output of the flow transducer.
2. Safety.

Issue one is pretty basic. After manufacturing flow instruments for a good number of years we have seen that flow transducers accuracy is typically better when mounted after the mechanical fuel pumps. They simply seem to prefer to have fuel pushed through them, not pulled through. The truth of it though is that many installation drawings still read as though we were still using the older Floscan 201 and 231 transducers. I have seen installs that mount the transducer between the pumps with claimed success. The Floscan units were much more sensitive in regards to mounting location, angles of fittings in and out, and attitude. Our new design will tolerate a lot more.

The other more serious issue is in regards to safety. We want to make absolutely sure that the fittings on the transducers never are subjected to conflicting vibration planes. The engine will flex in the motor mounts creating conflicting vibration planes between the engine and the airframe. This is why the ?flexible line in? and ?flexible line out? is called out so often. This is also why we don?t want the transducer rigid mounted, via a fitting, to a carburetor or fuel pump. A contradicting vibration plane will focus the energy directly to the fitting. It is our sincere concern that with the two conflicting vibration planes here could cause the fitting to fatigue and crack. This would be bad?and we have seen it happen?.

On the bright side, we don?t care if the thing flows straight up, or if you put 90-degree fittings in and out of the transducer. Just don?t mount it upside down, flowing sharply downhill, or before the pumps. :eek:

Please let me know if you have any questions or if we may be of any assistance.

Matt Sharp
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That's great, Brian...that answers my question perfectly! There was nothing in the instructions warning against 90-degree fittings, but I wanted to check with the experienced pool of builders here. Mine will be mounted inside the console, between the boost pump and engine's mechanical pump.
 
Doug,
It seems you are building very similar to my setup every time I read one of your questions.
I mounted mine after the servo below the #1 & #3 cyl. with a 90 degree fitting on the outlet. Mine is within .1 gallons of usage every time I fill up.
You are in the stage of the build I had the most fun.
 
MarkW said:
Doug,
It seems you are building very similar to my setup every time I read one of your questions.
I mounted mine after the servo below the #1 & #3 cyl. with a 90 degree fitting on the outlet. Mine is within .1 gallons of usage every time I fill up.
You are in the stage of the build I had the most fun.
Click to expand...

That's great....0.1 is remarkable.

Yes, definitely getting into the fun part! Sections are really starting to look complete, and I am so looking forward to doing the panel and custom-tailoring it to my liking. Check out the build logs...I got a big box from Classic Aero today!:)
 
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