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-   -   Red Cube mouting possible issue (https://vansairforce.net/community/showthread.php?t=91343)

JakeLewis22 09-25-2012 08:08 AM

Quote:

Originally Posted by Ironflight (Post 702125)
This was correct in years back Rob, but I talked directly with the engineering folks that make the red cube when we were mounting ours on Tsam last year, and the design has changed - vibration due to engine mounting is no longer an issue according to them.

Paul

Paul beat me to it but I had the same conversation and I was told it was no longer an issue. I was told that some builders simply allow the cube to be supported by the fuel lines but I didn't feel comfortable with that. It doesn't show in the pictures but in addition to the fire sleeve between the bracket and the top of the cube, I also put rubber washers between the bolt heads and the bottom of the cube. I know engine vibrations are coming through the bolts but my attempts were to isolate it as mush as possible but yet firmly support the sensor.

HSANTIBANEZ 09-25-2012 08:54 AM

an fitting
 
I read in some part that the sensor could not have an elbow attached, and you can hold the hose at no more tha 6 inch from the red cube with a adel clamp leaving the red cube "in the air".

Flyguytki 09-25-2012 09:10 AM

Quote:

Originally Posted by HSANTIBANEZ (Post 702149)
I read in some part that the sensor could not have an elbow attached, and you can hold the hose at no more tha 6 inch from the red cube with a adel clamp leaving the red cube "in the air".

Talked with EI yesterday, as long as you are using flex line you can have a minimum of 3 inches with no angled fittings before the cube and as long as your using flex line again you can connect an angle fitting going out of the cube.

It seems there is no real science to this, I think I hve read on mounting the cube just about anywhere in the system and you will get a fairly accurate reading. Once a decision has been made there are no complaints, now all I have to do is pick a new location. Thanks for all the help

-David

Lars 09-25-2012 09:39 AM

Adding to the chorus, I had the same vibration discussion with EI, and was told the same thing regarding the use of elbows, etc. Mine is mounted on a home made 4130 bracket, oriented vertically up, where the left mag would be (electronic ignition in my case). Straight AN4 going in, 90 degree AN4 going out. I have 50 hours of data now. The red cube is dead accurate. Mounted between servo and flow divider, the reading is unaffected by use of the boost pump. I made a point of ensuring that the only fuel line that spanned from moving engine to fixed motor mount or firewall was the line from firewall to mechanical pump.

To the OP, when running anything (hoses, wires, cables) from the fixed firewall or engine mount to the engine, it's important to understand that when the engine moves on it's mounts, it's mostly rotating. On an axis more or less concentric with the crankshaft. Try to visualize how the engine motion will tug (or not) on the item in question before committing to making the connection.

Flying Scotsman 09-25-2012 11:15 AM

Quote:

Originally Posted by Ironflight (Post 702125)
This was correct in years back Rob, but I talked directly with the engineering folks that make the red cube when we were mounting ours on Tsam last year, and the design has changed - vibration due to engine mounting is no longer an issue according to them.

Paul

I got the same info from them when I installed mine last year. Thus, it's between the FI servo and the spider, mounted via steel bracket to the sump bolts, and wrapped in a hunk o' firesleeve much as seen here.

Flyguytki 09-25-2012 09:35 PM

Thanks so Much for all the help, I have taken everyone's advice and moved the transducer. It can sometimes be hard to hear how wrong you were however I am very glad I asked, my Life's a little more important than my ego.

Thanks again!

-david

Flyguytki 09-26-2012 12:11 AM

Thanks so Much for all the help, I have taken everyone's advice and moved the transducer. It can sometimes be hard to hear how wrong you were however I am very glad I asked, my Life's a little more important than my ego.

Thanks again!

-david

Snowflake 09-26-2012 07:18 AM

Quote:

Originally Posted by Ironflight (Post 702125)
This was correct in years back Rob, but I talked directly with the engineering folks that make the red cube when we were mounting ours on Tsam last year, and the design has changed - vibration due to engine mounting is no longer an issue according to them.

I wish I knew that two weeks ago before I started mounting mine... :). Oh well. It's in now, I'm not going to move it.

There seems to be a lot of "misinformation" about these cubes that is based on the old Flowscan sender:

1. Need straight 6" section at inlet/outlet - no longer true, in fact the red cube will work with 90degree fittings on both ends.
2. Mount to non-vibrating structure - no longer true, apparently it can now take the vibration.
3. Mount between engine driven pump and carb - nope, works fine between the boost pump and the engine drive pump. Others have mounted one in each wing to get the flow out of each tank separately, upstream of both pumps.

TS Flightlines 09-26-2012 08:08 AM

Just my .02 worth-
 
I've had many customers mount their cubes in all sorts of locations. From tunnels to next to the spider. Between the mechanical pump and the servo. Servo to spider. On the firewall before the mech. pump. All with various plumbing. I havent heard of anyone having a real issue.
Some made changes due to other accessories, but as far as I know of, not because of an errratic flow issue with the red cube. The older flow scan was a different issue.
Tom

dhmoose 09-27-2012 08:48 AM

The "misinformation" seems to come from EI themselves. I have an installation document of theirs that clearly specifies how it should be installed. Their recommendations are non-vibrating surface, no heat, between servo and spider, etc. If they changed their recommendations, they should put out a new install manual (and maybe they have as mine is probably dated).

Pet peeve ventimg time: :( MANY companies serving the experimental aviation market seem to answer an endless line of questions via phone/email from customers asking about their products. This costs them time and frustration. Wouldn't it be cheaper, simpler, and less frustrating for them if they invested some time in drafting a new manual from time to time? Vans is notorious for this. They must receive thousands of phone calls per year asking the same questions time and time again about errors or omissions from their manual. Most companies provide a few page manual that can easily be revised and re-printed, saving them hours of customer service calls. Venting done. :D



Quote:

Originally Posted by Snowflake (Post 702443)
I wish I knew that two weeks ago before I started mounting mine... :). Oh well. It's in now, I'm not going to move it.

There seems to be a lot of "misinformation" about these cubes that is based on the old Flowscan sender:

1. Need straight 6" section at inlet/outlet - no longer true, in fact the red cube will work with 90degree fittings on both ends.
2. Mount to non-vibrating structure - no longer true, apparently it can now take the vibration.
3. Mount between engine driven pump and carb - nope, works fine between the boost pump and the engine drive pump. Others have mounted one in each wing to get the flow out of each tank separately, upstream of both pumps.



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