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The VAF News - 2.14.2025. #6277.

DeltaRomeo

doug reeves: unfluencer
Staff member
Wishing you and yours, a happy, safe and RV filled weekend!
v/r,dr


Daily RV Pic …robber
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RNB …RV-10
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Weefle’s DIY RV-10 Visor
“…I’m cheap so what I did was embedded a wing nut in the cabin top pillar on each side then glassed them in. I then bought the Ram visors, balls and short arms on Amazon. I trimmed them a tad so they would fit better. They sit out of the way and seem to work when needed.
If you drill holes in plain don’t use a normal drill bit. Either buy one for plex’s or grind a regular bit otherwise you risk cracks at the holes.”
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Foam to Part ….DanH collage
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Things that Make Red Cube Perform WeirdFailure Data 
…TS Flightlines reply
. Bill and others. Since we started plumbing solutions for the FT60 flow transducer, we had always heard that there were some 'strange' failures. Thats one of the reasons we undertook 2 different plumbing solutions. What was strange to us, was we could have several installs of the same type and no issues and longevity, and others would have some crazy anomalyies. ( how about only failing around 4000AGL, not 4500 and above, not 3800 and below, 4000) . We were really stumped, since we knew the plumbing was good, and the testing we had done on flying aircraft doing aerobatics didnt have the anomalies. We theorized that it had to be electrical somehow, but couldnt prove it. Thats because all the installs were done by different builders, with different skill levels, tools, procedures, etc. We pretty much proved that pushing fuel through it under pressure was better, and in the case of our mounting at the flow divider, pushed the fuel vertically, and at the same time any potential air bubbles that might have been present. With many of those installs flying with no anomalies, we were convinced it was electrical. I even had a conversation with Dave Arata at EI about this--(Dave if youre out there, Hey!). That conversation was mainly about trandsducer orientation, and the 'wires up' guidelines. (What happens when you are in a 45* or 90* bank, or inverted: the wires arent up, and the unit continues to work just fine).
.
Our friend Dan Hortons wonderful autopsy of a FT60, convinced use that the anomalies HAD to be electrical. The VERY small wires (about .025 with twisted) might be creating the issues, especially if there was not sufficient strain relief in the harness, and actually breaking the wires underneath the heat shrink at the cube body. I DONT KNOW THAT FOR A FACT, but on 2 failures that was the case. So we suspected the wire connections into an airframe harness was the most probable root cause of the anomalies. And not necessarily the location, or the plumbing, (although some obviously better than others). As for plumbing, again, we found that pushing fuel under pressure through the transducer was better that pulling it through on the suction side, where air bubbles or any other disruption in flow could create a signal variance. We knew that the stock RV10 had the unit in the tunnel downstream from the boost pump, and upstream from the mechanical pump. We once the boost pump was deactivated, the flow changed to a suction function for the mechanical pump, and it 'could' have some variances due to age, diaghrams, check valves, loose connections, etc. So we made an optional change to move the transducer out of the tunnel to a location downstream from the mechanical pump, so fuel would be under constant pressure. We had RV10/IO540 builder ask why we didnt put the transducer at the flow divider like our 4 cylinder version. Pretty simple----different flow divider mounts made it difficult to know what each engine builder used, and we didnt want each customer to potentially have to change all the injector plumbing around. So we chose a location near the mechanical pump, that ANY engine or induction system could use. The electrical was still up to the builder to assure of positive connections and sufficent strain relief in the cube harness.


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