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Speaking of the new tank vent....

txaviator

txaviator

Well Known Member
I searched before posting, and didn't come up with much....

Why is the darn filler hole not in the side of the fuselage, like I think I saw on one of the prototype RV-12's?

Then we can rule out all of this talk of the fuel crazing the rear window, etc.

I'm sure there must be a great reason, but I have yet to figure out why it ended up, way up at the top? Thoughts?
 
Which do you suppose is more prone to splashing fuel on that new tie you got for Christmas...

- A tank with the filler hole oriented laterally and only 6 inches above the full level of the fuel in the tank?

- A tank with the filler hole mostly vertical above the top of the tank?

The yellow prototype was almost impossible to fuel with some fuel trucks because they could not be made to pump slow enough.

Potential window damage was only one of the reasons (and not a primary one) for adding the vent line
 
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Pic of vent kit:

12 Fuel Tank Vent Mod (available now).

Hal_san photo recon:
i-sP9gtJz-M.jpg
 
Dave12 said:
Thanks Tony, good information, what is the cost?
Click to expand...

Hal picked up the kit at Van's and I think he told me it was $54 w/o shipping or sales tax. If you have some of the items, it looks like one could make the kit up for less.
 
Vent Mod

is the fuel tank vent mod a SB? I thought I saw someplace on the forum a picture of the install of the fuel tank vent?.but of course can't find it now. Can someone provide link to the installation picture. Thanks.
 
Any one got a part number for the fuel tank vent mod kit? I can't find it on Vans' web store.
 
redrv6 said:
Any one got a part number for the fuel tank vent mod kit? I can't find it on Vans' web store.
Click to expand...

Shirley,

There is no part number as yet, and it is not yet in the web store. Van's will accept orders for the "12 Fuel Tank Vent Mod" by phone.
 
No holes in fuel cap

My take from the new drawings is that one no longer drill holes in the fuel cap, since you now have sufficient venting, AND having the holes could allow some possibility of water infiltration. Am I correct, oh noted authority on everything? (i.e. Scott)
 
I managed to get some water in my tank due to careless spraying around the vented cap while washing the plane. Good news: it promptly showed up in the gascolator.
 
I have not seen anything in the tank vent modification docs that would indicate the fuel cap hole is plugged or that the drawings to drill the hole have been modified to eliminate that step. The issue addressed with the tank vent mod was filling the tanks with fuel, not normal operations. I would think that sealing the fuel cap hole would be a good idea to keep water out.

John Salak
RV12 120116
 
When I picked my vent kit up at Vans last month, I ask about the fuel cap and was told by Ken Scott to just dab a little sealer in the hole to keep any water out of the tank.
 
T-1010 hexagonal plate part of tank Mod?

Tony_T said:
12 Fuel Tank Vent Mod (available now).

Hal_san photo recon:
i-sP9gtJz-M.jpg
Click to expand...

I've ordered both, the "Fuel Tank Vent Mod" and "Fuel Tank Mod" (Moeller gauge), both now enjoying customs clearance...
I was hoping that the little T-1010 hexagonal plate that prevents the fuel tank return line AN832 fitting to not to turn, would be part of the kit. (As seen in 37-2, bottom rigth)

Anyone that has purchased the Mod kit knows if is part of it?

Thanks in advance!
 
I think I'll pass on the vent. I am tired of putting new holes in my tank which has already suffered enough surgery with the mods. If the vent is only for filling w/o spilling well gee whiz the little fuel I have spilled isn't worth the tank rework. If it becomes an SB then probably OK, but I'll put it on my "next tank mod list" for now.
Dick Seiders 120093
 
Sorry, I thought I had mentioned it in this thread (maybe another one?).

It will prevent fuel venting / dribbling on the outside of the fuselage as the result of fuel expansion.
 
Window crazing

I am just wondering what is actually causing the crazing. I have spilled fuel on my rear window a number of times and no crazing. I have used nothing but non-oxiginated 91 octane. Could it be that nasty corn stuff they put in auto fuel that the rear window doesn't like.
Bad day for flying the 12 zero degrees and 30 to 40 MPH winds.
Sonny
 
Nasty corn stuff and Proseal

Scott, I think I've picked up somewhere that the ethanol in our fuel attacks Pro Seal. Any evidence of that? Hope not.
 
gossend said:
Scott, I think I've picked up somewhere that the ethanol in our fuel attacks Pro Seal. Any evidence of that? Hope not.
Click to expand...

Not that it does, but it can. but is dependent on numerous factors.

It has been discussed here in the forum previously. The most critical factor is time. Do not let ethanol fuel sit in the tank during periods of extended storage.

Van's official position was published in Sevice Bulliten 13-3-21 located HERE
 
rvbuilder2002 said:
Not that it does, but it can. but is dependent on numerous factors.

It has been discussed here in the forum previously. The most critical factor is time. Do not let ethanol fuel sit in the tank during periods of extended storage.

Van's official position was published in Sevice Bulliten 13-3-21 located HERE
Click to expand...

Sevice Bulletin: typo or Freudian slip? :D
 
Scott, I am not trying to give you a hard time as I really appreciate all you do for us. Following your comment on expansion I was curious so checked it out. If one filled to a full 19.8 gal AND there was a 15 degree C increase in temp after the tank fuel would expand to 36 oz more and overflow a little at the fill neck. So you are correct when those circumstances occur. I normally shoot for 18 to 19 gal as I don't like overflows, and even with a big bump in temp. after the fill no problem. However I never before appreciated the role played by temp increases in the equation. Food for thought.
Dick Seiders
 
dick seiders said:
Scott, I am not trying to give you a hard time as I really appreciate all you do for us. Following your comment on expansion I was curious so checked it out. If one filled to a full 19.8 gal AND there was a 15 degree C increase in temp after the tank fuel would expand to 36 oz more and overflow a little at the fill neck. So you are correct when those circumstances occur. I normally shoot for 18 to 19 gal as I don't like overflows, and even with a big bump in temp. after the fill no problem. However I never before appreciated the role played by temp increases in the equation. Food for thought.
Dick Seiders
Click to expand...

It is not uncommon for even more temp change than that... cold fuel pumped from an under ground tank in the morning, and then the airplane sits in the sun all day at a fly-in. Couple that with a situation where the tank was 100% topped off (either accidently, or on purpose, for departure on a long cross country leg towards home) and it is very easy to have happen.
 
I was wondering why the fuel vent has an air line as well as the vent line? I will be installing it soon, but was curious why the second line. I don't mean this to sound like a criticism of the engineering. I just like to know as much as I can about my airplane and how and why it works. Anyone have an answer? Thanks.
 
The second smaller line is a siphon breaker(preventer)
Click to expand...
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.;)
 
Particularly on steep climb out after take-off. That way you'd be siphoning your fuel over board without even knowing ...
 
mrt890 said:
The second smaller line is a siphon breaker(preventer)
Click to expand...

Jetguy said:
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.;)
Click to expand...

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).
 
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
 
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?
 
Vent Mod Blind Rivet Question...

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,
 
Use static port type of rivet

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...

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.
 
A few dimensions might be handy

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?
 
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Tank Vent

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.

[email protected]
 
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Vent hole locations

The locations of all the vent holes, i.e., bulkhead, bottom skin, are given in Plans Section 37 available on Van's website under RV12 Support for viewing or download as a PDF file.
https://www.vansaircraft.com/pdf/revisions/RV-12/Section_37.pdf

The location of the hole in the tank top is shown in a new section 37B, which is not on the web site but should be in the vent kit.

The new tank top part must come with the hole already punched since section 37 doesn't show how to locate it.
 
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engineerofsorts said:
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.
Click to expand...

Rob,

Now I see...THANKS!
 
Terrybrd said:
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.

[email protected]
Click to expand...

Hmmm...I couldn't find any 37B pages on Van's website, and the retrofit kit I ordered from Van's did not include any revised instruction pages containing 37B-03. I guess my mother was wrong...I'm not special...
 
Rotate Tee???

Any harm in rotating the tee of this SB 90 degrees? Looks like a better way to do it to me. Opinions sought.
 
I'm not that stupid Marty--I know where the "new" Section 37 is

MartySantic said:
See post #41, above. SECTION 37, in its entirety, is on the website.
Click to expand...

I have known/studied the new Section 37 for about a month now, Marty. IT DOES NOT INCLUDE retrotfit instructions, specifically Page 37B-03 referenced by Terrybrd:

Terrybrd said:
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.

[email protected]
Click to expand...

If you can point out to me in the new Section 37 where they have any dimensions for the new holes, I'll shut up and put my tail between my legs.
 
Diagram

Rob, if you're speaking of the holes on the bottom of the fuselage required by the new fuel tank system, go to the following link. It is page 37-13 of the new download PDF file. I can't remember if that view is looking down or up, but once you're under your plane, just count the rivets and make the measurements as shown. The holes are aft of the rear bulkhead of the baggage compartment.
Steve
http://www.vansaircraft.com/pdf/revisions/RV-12/Section_37.pdf
 
No

Paris12Man said:
Rob, if you're speaking of the holes on the bottom of the fuselage required by the new fuel tank system, go to the following link. It is page 37-13 of the new download PDF file. I can't remember if that view is looking down or up, but once you're under your plane, just count the rivets and make the measurements as shown. The holes are aft of the rear bulkhead of the baggage compartment.
Steve
http://www.vansaircraft.com/pdf/revisions/RV-12/Section_37.pdf
Click to expand...

NO NO NO NO--where to put new hole in an old tank and new hole in an old rear bulkhead is the question--All I see is pictures of tanks with the holes already there for the tank/bulkhead--no coordinates given in the new Section 37...apparently I need Section 37B, which is not on Van's Updates web pages.
 
Sorry sorry sorry Rob.... I no longer have my 37B paperwork, but If I remember correctly, they weren't real helpful in location of the hole in the bulkhead.
I just took measurements off of my aircraft and they are as follows.....
From the outside edge of the seat belt flange, measure down 3 1/2".
From the edge of the bulkhead panel, measure outward perpendicular to the line you just drew 4 3/16"
Now measure up for this 4 3/16" line and the top of the fuselage should be 1 3/4".
If you do all that and it works out. X marks the spot to drill the hole in the bulkhead.
The hole in the top of the fuel tank for the new vent tube is located 1 3/4" from the back edge and 4 3/16" from the outside (copilot) edge.
I hope this helps.
Being an "engineer of sorts" you most likely won't like my opinion, but sometimes you just got to wing it! Remember, you're working with a tube you can bend!

Steve
 
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