Speaking of the new tank vent....

[MacPara]

Particularly on steep climb out after take-off. That way you'd be siphoning your fuel over board without even knowing ...

[rvbuilder2002]

Originally Posted by mrt890

The second smaller line is a siphon breaker(preventer)

Originally Posted by Jetguy

To add just a little bit more. Consider you are going on a long x-country and you fill the tank all the way up to the top of your filler neck then your fuel would be higher than the vent hose so a siphon could occur.

Correct.
The ideal design situation would have been to route the vent line above the highest point fuel could ever be in the filler tube. There was other means of dealing with that, but the current design was considered the simplest (particularly in the context of doing a retrofit installation).

[Mark Henderson]

I hadn't thought about a siphon situation. Thanks for the answer.

[dick seiders]

I haven't seen the vent up close yet, but why would it not go all the way to the top tailcone skin with the anti siphon line at that point?
Dick Seiders

[RFSchaller]

I'm not familiar with the new vent configuration, but it seems like the siphon effect would break as soon as the vent penetration point is uncovered so all you would lose is some fill neck volume. What am I missing?

[TomVal]

Wrt the RV-12 fuel tank vent mod, I cannot figure out where the blind rivet referred to below goes into fuel vent air line. Figure 3 does not depict the location of the rivet, and I don?t seem to have the ?Installing Static Air System? instructions in my records for reference.


Ref: Fuel Tank Section 37-08

Step 11: Install the blind rivet into the F-1282-R Skin as shown in Figure 3.
NOTE: Take care not to crush the Air Line in the Plastic Tie Wraps. Do not
install the Air Line through the Adel Clamp.

Step 12: Install the Fuel Vent Air Line as shown in Figure 3. Refer to 'Installing Static Air System' instructions for guidance on connecting the fuel vent air line to the blind rivet.

Appreciate your input.

Regards,

[engineerofsorts]

Originally Posted by TomVal

Wrt the RV-12 fuel tank vent mod, I cannot figure out where the blind rivet referred to below goes into fuel vent air line. Figure 3 does not depict the location of the rivet, and I don?t seem to have the ?Installing Static Air System? instructions in my records for reference.


Ref: Fuel Tank Section 37-08

Step 11: Install the blind rivet into the F-1282-R Skin as shown in Figure 3.
NOTE: Take care not to crush the Air Line in the Plastic Tie Wraps. Do not
install the Air Line through the Adel Clamp.

Step 12: Install the Fuel Vent Air Line as shown in Figure 3. Refer to 'Installing Static Air System' instructions for guidance on connecting the fuel vent air line to the blind rivet.

Appreciate your input.

Regards,

They are referring you to the same large-headed blind rivets used for the two static ports--they include one in the kit that you install in the #30 hole you drill in the bottom skin. Then you drive the mandrel out, attach the 1/8" tubing, and stick it in place with some RTV.

[engineerofsorts]

The location of the hole in the top of the tank for the new vent hole doesn't seem too critical, but, for those of us retrofitting, it would be really swell if some dimensions/template for location of the tank's vent hole, and maybe the rear bulkhead too, were given in the instructions. Any help for this, Scott?

[Terrybrd]

They have the dimensions in drawings 37B-03.
but I don't know if I can copy it to this thread.
I don't know how to post it on here and I tried to copy and paste but that didn't work.
I got it from support but if you want to send me an e-mail I can send you the file. It is about 4 pages with a picture of where to install the fitting on the tank, and the hole in the bulkhead.

mrterrybrd@gmail.com

[Dave12]

I recently bought the vent kit and it came with complete revisions for the build manual.