What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

RV-10 Fuel Return Line Location – Pre-Drill Verification

C

cobra967

Member
Hello everyone,

I’m looking to future-proof my RV-10 by adding a fuel return line. I’m thinking of using the VA-141 (same part used for the fuel line) and placing it similar to—but not exactly like—the RV-14 setup. Before I drill, I want to make sure the location won’t interfere with anything inside or outside the tank.

From my photos, I’m planning to center-drill about 32 mm from the top skin and 32 mm from the baffle (Orange arrows in picture). Does that sound reasonable, or is that the wrong location?

Thanks a lot for any advice you can share.

1768675756558.png

1768675811262.png
 
The location for the 14 since the return is over the supply feed it might be possible to suck bubbles into the supply when the tank was low. (air bubbles play havoc with the type of fuel pressure regulator I am using) This seems to be working well on the 10. (The 14 also seems to be working ok even when the tank is low but why take a chance)

Screenshot 2026-01-17 181407.pngScreenshot 2026-01-17 181600.png
This is where the 14 per plans is located: (Below)

Screenshot 2026-01-17 185450.png
 
Last edited:
Thank you all for the insight. If I’m understanding this correctly, there are a couple of key reasons why the placement matters:
  1. Avoid mechanical interference with other components.
  2. Placing it too low and too close to the pickup can potentially lead to:
    • Fuel aeration
    • Foaming
    • Inconsistent fuel pressure
If that’s the case, then the best approach would be to first ensure there is no mechanical interference, and then route the return line in a manner similar to—and roughly parallel with—the vent line toward the opposite side of the fuel tank. This would allow any aeration or foaming to settle before the fuel reaches the outlet.

That said, I may be overthinking this—please let me know if my understanding is off.
 
My fuel system as it currently stands does not require a return. However I did install a return line when building just in case I ever needed it. I made it like a -6 version of the vent line and ran -6 two bays into the tank. It sits just forward of the current vent bulkhead fitting.

I feel like we would have known by now if fuel foaming was an issue- and that vans would have the return push further into the tank as well. Seeing as they seem happy with just the bung style fitting it’s prob ok as is.
 
Richard Connell said:
My fuel system as it currently stands does not require a return. However I did install a return line when building just in case I ever needed it. I made it like a -6 version of the vent line and ran -6 two bays into the tank. It sits just forward of the current vent bulkhead fitting.

I feel like we would have known by now if fuel foaming was an issue- and that vans would have the return push further into the tank as well. Seeing as they seem happy with just the bung style fitting it’s prob ok as is.
Click to expand...
For those who are installing the return line fitting on the tank are you running the line to the fuel valve and onto the firewall; capping it; installing a purge valve?
 
danlh said:
For those who are installing the return line fitting on the tank are you running the line to the fuel valve and onto the firewall; capping it; installing a purge valve?
Click to expand...
That would require the use of a duplex fuel valve if that's what you mean? I guess that would make it easy to empty a fuel tank if needed and later easier to plumb a return, but my guess is very few are doing this way.

If you really want to future proof your fuel system, use 1/2-inch supply and 3/8-line returns. Filters and valves most come with -8 flare fittings built in. Never need to worry about pressure drop and vapor pressure issues with new fuels. Andair does make a fuel valve to cover this configuration.
 
Last edited:
Have a look at the video of Austin, he describes the location for a return line. However I don't know if he had any problems in the further build with it.
 
danlh said:
For those who are installing the return line fitting on the tank are you running the line to the fuel valve and onto the firewall; capping it; installing a purge valve?
Click to expand...
Not for now. I had envisaged a full time return for a constant flow rather than a purge valve.
I haven’t installed a duplex valve in the meantime as I don’t want the return half operated dry.
 
TS Flightlines said:
Dwights post #3 is from the plans and what we recommend for both the Rv10 and RV14. Works well.
Tom
Click to expand...
That’s where I located my bung also.
Richard Connell said:
Not for now. I had envisaged a full time return for a constant flow rather than a purge valve.
I haven’t installed a duplex valve in the meantime as I don’t want the return half operated dry.
Click to expand...
so you just capped the return fittings on the tanks?
 
danhl,

What did you use for the cap? I was thinking of a simple stainless, or brass plug from Lowes Aviation....

Thanks,
Mike
 
You must log in or register to reply here.
Back
Top