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Speaking of the new tank vent....

Boy, do I feel stupid now

I found the missing hole template document--Section 37B, hiding behind my workbench. Got lost in the unpacking, I guess. Everyone is innocent but me. Doh! For the record, this information cannot be found in the new Section 37, and cannot be found on Van's website--ya just have to be intelligent enough to unpack the box properly and find the printed Section 37B.
 
Dumber than a box of rocks...

TomVal said:
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,
Click to expand...

I am down to installing the air vent line to complete the fuel tank vent modification. Now that I know how the blind rivet is used, my next question is what affixes the rivet to the bottom of the fuselage besides being attached to the clear air vent line? I feel really stupid on this one.

Thanks,
 
TomVal said:
I am down to installing the air vent line to complete the fuel tank vent modification. Now that I know how the blind rivet is used, my next question is what affixes the rivet to the bottom of the fuselage besides being attached to the clear air vent line? I feel really stupid on this one.

Thanks,
Click to expand...

Once you pull the rivet, it holds itself to the fuselage.
 
Dave12 said:
Once you pull the rivet, it holds itself to the fuselage.
Click to expand...

Thanks Dave. I completed the vent air line installation yesterday. My reluctance to pull the rivet was over my concern that there would not be enough of the shop head of the rivet shaft remaining to affix the air line to.

Now on to the next task...

Regards,
 
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My apologies if this has been covered in another thread, that I can not find at the moment. I'm about to install all the tank mods. Yes, it's condition inspection time again already. I have the "Abby" interior kit installed since long ago.
To those who have installed the vent mod with the interior kit, how have you handled the new pipe that has to get through the interior kit back panel in some way? How is it handled in the SLSA version? Not looking forward to cutting up that nice panel.

OK, sorry, just found the other thread and JetGuys photos. Nice! Anyone else done it differently?
 
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Consider cutting the hole in the material first

John ? I have not installed the tank vent yet because have not built the tank yet. That said, after ordering the finishing kit, I spoke to Abby about that hole and she asked me if I had already drilled it or not. My answer was not yet ... so Abby said she would place the hole for the vent line fitting in the material based on Van?s drawings so I could use her hole as the drilling location.

Perhaps you could do it similarly by using a piece of tubing with one end sharpened to form a sharp cutting edge then use it either as a punch or twist cutter to create the hole in the material at the desired location ? then you can use the center of newly created hole as the drill location as I will be doing using Abby's pre-made hole in the material.
 
Thanks to all who posted on this thread. I am just now doing the vent mod and the information is very helpful.
Dick Seiders
 
I installed an AN fitting on the bulkhead for the new fuel tank vent so that I could easily disconnect the vent and remove the upholstery panel to get access to the baggage bulkhead. On the upholstery panel itself I pulled a few staples and cut the hole in the backing first, then slit the upholstery to fit the hole and re-stapled it on the back side.
P1050281-M.jpg

P1060016-M.jpg


BUT, after doing this I was told by Van's support that the S-LSA upholstery panels have a SLOT instead of a hole and this eliminates the need for the AN fitting to remove the upholstery. The hole is close enough to the edge of the panel so this makes sense. You then pass the vent thru a snap bushing in the bulkhead like the plans show.
 
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Cover needed for vent tube?

Having had one flight with a bug-infested pitot tube (caused by having the pitot tube cover off too long in the hangar), I'm wondering if anyone is concerned with that lovely 3/8" vent tube being plugged up--or will the fuel fumes discourage any insects from entry?
I've contemplated a vent-tube cover, but, on the bottom of the fuselage, gravity is working against me, and there isn't very much exposed tube to grab onto.
 
I have been pondering the same issue and have decided the small vacuum break hose will allow enough relief to the fuel system if the main tube is plugged. However, I do believe both ports should be on the preflight to check for obstructions by inserting a probe in each. But then, how many people ever check the fuel tank vents on their current setup? It would get quite ugly if it was ever plugged and one would not realize the problem until after airborne.
 
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I too have the old-style vented cap in my RV-12 ELSA. Seems to work fine although its performance while on tiedown in a driving rainstorm has yet to be tested. ;) As part of my pre-flight I always take off the cap and blow through the vent hole to ensure that it is fully open and functioning properly.
 
I just finished my installation of the new vent setup today. In principle it looks good, but it is a bit complicated, and as such subject to issues like clogging up, siphoning if air break line is clogged, etc. On the other hand even if a siphon should start on a very steep bank like 90 degrees it will break as soon as you level off anyway. The fuel in the tank will then be below the AN fitting and break the siphon. If the fuel level isn't that low it soon will be and so no more problem at that point. The only real value for the thing is if you are going to fly in the rain (something about VFR that says that shouldn't normally happen) when you might get some water in the system. Regarding the mod I found in the installation the multiple series of gradually reducing plastic tube size to get to where you want to go is weird. Why not buy a tee that had 3/8 tube size on two points and 3/16 on the air break side? It is a bit shoemakerlike don't you think? Besides wait till you try to get that 3/16 soft plastic tube into that fairly rigid 1/4 in tube. You can't do it without boring out the 1/4 tube a bit or you crush the soft 3/16. I suspect a better mod would have been one fuel cap with vent holes for VFR weather, and one without the holes once you get where you are going in case it rains while you are there. Of course if you you really care about your 12 you would tie on a water resistant cover until you were ready to leave. I think that would have been a simpler solution, and we wouldn't have to clutter up our really nice airplane would all that extra plumbing. I know, but you might forget to replace your unvented cap with the vented cap and that wouldn't end well as we all know. A simple flag attached to the non vented cap would solve that problem for those of us who bother to pre flight a perfectly good airplane. For me I have installed the thing ( can't help but follow directions from Vans), but I think I will let the vented cap in as well just in case a mud dauber crawls in the 3/8 tube at the bottom of fuse. I always put a cover on the 12 whenever it will be out in the cold (or rain) overnite anyway. Just wanted to share my thoughts on a really questionable mod to our already over modded tanks. Having a little fun while doing it too.
Dick Seiders
 
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I orientate the fuel cap so that the vent hole is above the center of the cap. If the plane will be exposed to rain, I cover the upper half of the fuel cap with tape which will act like a shingle.
Joe Gores
 
The canopy cover sold by Vans also covers the fuel cap. The only water so far has been from washing, and I was surprised to see it works it way all the way to the gascolator without running either fuel pump.
 
New vent lines.

Tony, For what it's worth, My RV12 SLSA has a grey painted rear bulkhead with no upholstery. Just finished the new tank install and vent lines and like the AN fitting better but as an SLSA must adhere to the manufacturers specs. Robin
 
I have the tank mod kit sitting on my shelf. Not sure yet whether I want to install it this winter or not. My problem with the vented cap is fuel expansion in the hot sun. I've learned to not fill it up inside the neck unless I am going to depart right away. I like the idea of the non-vented cap but......
 
Tony, I liked your AN fitting idea even tho I don't have the upholstery. The AN installation immobilizes the vent line instead of allowing it to float to and fro in the thru bulkhead fitting. Also makes it a neater task if you have to pull the tank for whatever reason. Good idea! One caution tho for others thinking about it that haven't yet done the vent. . You need to move the thru bulkhead opening a tad or you may run into the fill pipe with your line from the tank depending exactly where you plumbed the fill pipe.
Dick Seiders
 
Can't take credit...

Actually, one of the other guys did the bulkhead AN fitting before I did. If you search around you will find a post with pictures.

If you use the AN fitting then the bend templates no longer work real well and I had to make several tries at the bends to get things neat and proper in case someone peeks into my tailcone.

Here's the back side:
P1050286-M.jpg

P1050291-M.jpg

P1050290-M.jpg

Please, no comments about the high-temp blue zip ties, I know it doesn't get very hot in the tailcone, but they were the only ones I had handy.
 
RFSchaller said:
The canopy cover sold by Vans also covers the fuel cap. The only water so far has been from washing, and I was surprised to see it works it way all the way to the gascolator without running either fuel pump.
Click to expand...

If you are careful the VANs canopy cover will cover both the fuel cap and the gap between the avionics shelf skin and the upper cowl, a known source of water leaking inside the avionics compartment after heavy rain.
 
Since I have committed to the new vent installation I went ahead with it to be in compliance. (see earlier post). I am in the process of building a welded aluminum tank. The welding is being done by an aluminum welding expert, not by me. I am currently fitting the vent AN fitting to tank top and believe an AN fitting with a pipe thread would be more suitable than the AN 837 6D called for on the plans. Looking at substituting a AN 823 6D. I have added a 1/4" block of aluminum welded on the underside of the top skin to have sufficient material to cut threads for the fitting and in that way can seal the joint with an appropriate thread compound. The question I am pondering is the AN 837 protrudes well below the top skin whereas an AN 823 would not. I don't see an issue here regarding that fact , but would appreciate what others have to say about it. Thanks.
Dick Seiders
 
It would seem that less protrusion into the tank is better for venting. Will the threads be cut before the tank is sealed up? Aluminum cuttings are not desired in the tank. Is 1/4" enough to hold the fitting without stripping the threads. I do not know, just asking. What about clocking? Will the fitting be pointed in the right direction without over or under tightening?
Joe Gores
 
This may be a dumb thought, since I haven't seen your project tank, but what about adding the block to the top of the tank, or use a standard floor plate, like we do on the bottom for the fuel supply line.

Tom
 
Thanks for the comments. I agree the further protrusion of the AN fitting into the tank is not necessary. The 1/4 block (already welded to underside of top skin) is more than ample to cut a thread for the fitting as the tank skin is .090". I have also dropped the idea of using an AN fitting at that location as a friend handed me a slip fit (similar to the tee supplied by VAN's) for the tubing that is threaded at bottom as well so that is going on the tank. It is also a straight fitting as I couldn't really see the need for the 45 degree angle on the AN fitting that was supplied with the kit. I will simply bend the tubing to direct it upward to the bulkhead AN fitting.
Dick Seiders
 
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Dick Seiders,
Make sure the welder does not forget to install the internal tank baffles that are needed to prevent the fuel outlet from uncovering during climb with minimum fuel. Most pilots will not take off with less than 5 gallons. But a pilot might arrive with minimum fuel at the destination after a long cross country, but then be forced to go around after a low approach. That is a bad time for the engine to quit from fuel starvation.
Joe Gores
 
Joe, thanks for the input, and I agree that the baffle feature is necessary. I have had the tank builder include that feature. In fact the basic design of the welded tank is identical to Vans except for the fact it is welded construction using 5032 aluminum. I don't have an issue with the tank design just the required extensive use of sealant which I believe to be a problem for reasons that I have already mentioned in earlier posts. I expect the tank to be completed next week and when testing has been satisfactorily concluded I will follow up with posting results reporting as well as photos for anyone interested in this effort.
Dick Seiders
 
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