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Plans and manuals updated

Notice the fuel tank vent? Hopefully will eliminate splash back while filling.
I was already planning one. Will look this over further to determine if I will install mine or theirs.
 
Fuel Tank Vent

It would be helpful if someone would explain the new vent design. It looks like both an aluminum tube and a 1/8" plastic tube are involved. Not clear to me how/why its done this way.
 
My guess - -

The small tube is to stop syphoning in case you fill the tank to the very top of the neck. It would only drain down to the height of the top of the vent tube.
 
First S-LSA Improvement?

The small tube is to stop syphoning in case you fill the tank to the very top of the neck. It would only drain down to the height of the top of the vent tube.
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I agree. Looks like the hole we drilled in the fuel cap for a vent on the early models has be removed. So if you were to fill the tank full and then half way up the filler neck if you wanted max fuel for a long flight this extra tube would prevent this filler neck fuel from syphoning out incase of bumby air on climb out.;) I have to think this maybe one of the first changes due to the S-LSAs. This mod will keep FBO line men from spilling fuel on the rear window. Most turn key S-LSA owners may not be as attentive to this Idiocracy of the plane.:p
Which brings me to my question, What do you do with this new tubing when removing the fuel tank for annual? Maybe it can be turned in the FLF-00006 fitting counter clock wise up and out of the way after you remove the filler neck. How say the!:confused:
 
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Jetguy - -

I'd guess you could bend it a bit toward the front and slide the tank to the side. If this saves a rear window, it is worth it. Also, if you overfill on a hot day, and walk away, the gas won't run down the side of the plane. It would drip on the ground. I like it !
 
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Avgas burps go everywhere but Avgas does not craze Lexan like car gas. The question eventually will be what does the new 100LL do to Lexan
 
Maybe Scott McD will comment. Sure would be nice to know the purpose of the fuel tank vent. With a fast fill, spillage due to the ensuing burp may be a reason. Based on the bevel on the end of the vent line, with the vent being in the airflow, is there a reason Van's engineering sees a reason to pressurize the tank to a slight amount?
 
Adel clamp location

In fig 3 on page 37-07, can you see any reason why the DG06 Adel clamp couldn't just be bolted to the bulkhead instead of to the new clip on the back of the tank. Just trying to avoid any unnecessary alterations to my completed tank.
 
Robert - -

I think the picture is showing the new bracket BEHIND the bulkhead. The tube goes thru into the rear.
 
I just never experienced an issue that would compel me to do this tank vent mod. I sometimes fill to the brim before a long flight, but assumed taxi time would draw it down the filler neck before siphoning became an issue. I've never seen any residue indicating siphoning.

If there is a problem causing this change in tank venting I wish Vans would tell us what it is so we can decide whether to retrofit.
 
Opps!

I see another revision to the MM cause on page 13-5 under tank removal there is no mention of the removal of the new Fuel Vent line!:eek: Although it does mention them on page 13-3 in the Fuel System Schematic. Hate when that happens.:rolleyes:
 
Two reasons...

The vent has been added to prevent outflow of fuel onto the side of the airplane as a result of a very full tank of cool fuel heating up and expanding (this is the primary reason for the change).

The second reason was to reduce the likelihood of splash back while fueling. This is much more likely to happen when fueling from a truck or above ground tank than the slower delivery fueling systems that a lot of RV-12 owners use for mogas.

The extra vent line, on the vent line, is to prevent siphoning. As was mentioned, without it, the vent could siphon out any fuel in the tank above the top of the primary vent line.

The bevel on the bottom of the vent line is for nothing more than to make sure that in any flight attitude it can't ever develop a negative pressure (suction) on the interior of the tank. It was not added because a positive pressure was needed.
 
rvbuilder2002 said:
The vent has been added to prevent outflow of fuel onto the side of the airplane as a result of a very full tank of cool fuel heating up and expanding (this is the primary reason for the change)........
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This is a good change. When my plane was brand new a couple years ago I filled it to the top one fine day with cold fuel out of an underground tank. The subsequent expansion caused seepage out of the vented cap that ran down the side of my beautiful paint job and left a blue dye streak that no amount of buffing can remove. Fortunately my paint scheme is also blue, so the streak is not real noticeable (except to me.) Imagine what it would look like on a different color, or white paint.:eek:

Scott, will this be available as a retrofit kit?
 
Not Yet

I removed my tank top and decided to install the mechanical gauge and so ordered a new tank top and the gauge. Got a tank top with an extra hole. Called and Gus said that it was for new vent. OK. So called today to order vent kit that I'm not sure I wanted but needed something to plug up hole with and stay ELSA as I am not yet registered with FAA. No kit! So, Scott when will kit be available so I can put tank back together?
 
Gloomy Gus said:
I removed my tank top and decided to install the mechanical gauge and so ordered a new tank top and the gauge. Got a tank top with an extra hole. Called and Gus said that it was for new vent. OK. So called today to order vent kit that I'm not sure I wanted but needed something to plug up hole with and stay ELSA as I am not yet registered with FAA. No kit! So, Scott when will kit be available so I can put tank back together?
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Sorry, that is not a question I have an answer to.
I suggest you call back and talk with Gus or e-mail him via [email protected].
 
I have had my tank apart so many times already, another time really sucks. I am wondering if I could not put a vent in the filler tube, quite easy and would do the same thing, without getting the tank opened up again. Comments?
 
Don, that is what I would do. Keep the vent high to minimize the amount of fuel that leaks out due to expansion.
Joe Gores
 
Don,
Fuel burping out while filling at a high rate is a big problem. The fuel can craze the rear window and can run down your nice paint, and can splash on your face or clothes. It could even catch fire. Maybe it is possible to put a vent hole in the top of the tank without taking the tank apart.
Joe Gores
 
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Joe - -

I think that could be done. Drain the tank and blow air in it for several minutes to be sure fumes are out. Turn it upside down and drill up into it for the hole. Get a sticky surface of some kind and reach inside to get all chips out. We installed a fuel outlet on the bottom, maybe the same type could be added to the top ( riveting it on ). Would not have to get nut inside then. Actualy, I think you could put a nut thru the filler hole, but might be maybe tougher. I'm sure it can be done without taking the front off. I plan to do this, but might use a larger vent line to cut down splash-back.
 
DonFromTX said:
I have had my tank apart so many times already, another time really sucks. I am wondering if I could not put a vent in the filler tube, quite easy and would do the same thing, without getting the tank opened up again. Comments?
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Putting the vent line directly in the filler nozzle does not allow seperation of the vents/fuel. You would still have carryover out the top of filler nozzle during higher fueling flow rates if vent line is positioned there. Positioned on the tank top, full seperation is realized until interface has been eliminated, (full tank). Caution is still required if topping off nozzle.
 
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