Fuel Vent Line Question/Advice

First Post to Forum - Go easy on me!

Purchased 1992 RV6A, Dream Realized!
Working on some upgrades in the cabin and found fuel vents need some care to alleviate any chance of rubbing, kinks, kicking etc. The existing lines have standard Tank—>Cabin(Looped up from Wing Root level to top of inner firewall area then down to bottom fuselage outside vent tube (both sides).

My observation is that there is a cross-tube section that is connection the highest point of the loop on both sides together. If both sides are vented separately and I don’t have any cross-tank gravity flow (fuel selector has only L/R/OFF) Why would the tank vents need to be connected to each other? It’s extra fittings, takes up space I’d like to have for new wiring and instruments, and seems unnecessary.

I’d like to simplify the vent lines by removing fittings and cross-vent connection providing a simple vent for each tank.

Please advise, and my deepest respect for you builders as I’m a lowly modifier!

The plans have each tank vented separately. If your plane cross links the vent tubing, the builder added it.
Probably doesn’t hurt, but I don’t think it adds anything either, other than added complexity.

Only good if one vent gets plugged. I would remove it. I would also re-locate the battery to the firewall as per RV7 plans.... very easy to do.

Vents do plug

I have had a vent plug. On a 60 minute BFR flight. Not the tank used for T/O but switched to it during the latter part of the flight. On landing noticed skins of tank noticeably indented. Loosened the cap, the tank breathed a sigh and the skins returned to normal. Thank goodness it was a short flight.

I cleared a mud-dauber nest from a short distance into the vent with a piece of safety wire and blew it clear with lung power using an upside down water bottle with the bottom cut off inserted into fuel filler. As needs must in the field - and remember not to breath in!

A difficult item to check effectively on preflight so ever since I have filled the vents when parked with pipe cleaners that have a length of orange surveyor's tape attached to their ends. Not the prettiest but effective, cheap and easy to replace.

Jim Sharkey
RV6

Great advice, and thank you!

Gentlemen,

Thank you for your insights, advice, and experiences as well! I’ll go the route of simplicity, while leveraging the advice of experience and add a pre-flight check and clean-out/check during condition inspection. Lucky me I’m hangered well and fly quite often so little chance of vent infestation, but still is great input! This aircraft has small screens just inboard each vent so I’ll assume a previous owner had the plane on a ramp outside or experienced a bee or two at some point. Also researching the battery relocation suggestion! Thanks again AirForce!

Tank vents should be protected from critters either by screens, covers or some other method. Mud doubers loves the size of the pitot and vent tubes.
I still have an RV8 tank out back that was so badly crushed from a clogged vent it had to be replaced, person was lucky he survived.

My solution posted (#5) in this thread.
https://vansairforce.net/community/showthread.php?t=194795&highlight=Vent

Carl

Fuel tank vents

Hi Phil. I hate to be that guy but I see you have floor mounted rudder pedals that need reinforcements. There were two bulletins listed for floor pedals, one for cable connect link reinforcements and the other for pedal to crossbar reinforcements. Best of luck with your plane!