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Quick Build fuel vent issue at filler cap end?

bluskydreamin

Active Member
While quality checking my QB tanks with the bore scope this was seen on both tanks at the filler cap end. the vent tubing cut off has reduced the ID considerably with no rework to open it up = using deburr tool. Are others seeing this and have you tried to open up - could be a safety of flight at full fuel flow? I thought maybe a #30 drill through the rear baffle and guided through both sides of the tube .25 inch from the end, then seal the baffle with a closed end pop rivet and sealer?

https://live.staticflickr.com/65535/50520126508_7320ddf1f0_m.jpg
https://live.staticflickr.com/65535/50521029002_1798525058_m.jpg

These tanks have also had the following issues:

- #6 plate nuts in all the fuel sender screw locations
- small leak in rear baffle seam R\S bottom
- loose B nut vent line L\S
- rivet heads not sealed over on drain and feed flange both tanks

I've included a pic of the "inspector" who passed these tanks if anyone needs a laugh on a Friday. thanks
 
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So vans doesn't inspect when they arrive there? :eek: Yeah instead of doing a vans website search like I should have its states "When a container of QB kits arrives, each is carefully unloaded and inspected yet again."
So if they truly are inspecting they need to double down on the QC department.
 
So vans doesn't inspect when they arrive there? :eek: Yeah instead of doing a vans website search like I should have its states "When a container of QB kits arrives, each is carefully unloaded and inspected yet again."
So if they truly are inspecting they need to double down on the QC department.

I have no doubt Van's does what they can in balance with the leadtime and flow of parts to customers. it's probably a matter of you have to assume some areas are vetted given inspector stamps, etc. It would be hard to imagine that every area is checked like fuel tank leak testing, etc.
 
I feel the need to remind some (but not most) builders of one thing. YOU ARE THE BUILDER. YOUR NAME WILL BE ON THE DATA PLATE AS MANUFACTURER. The issues mentioned are the responsibility of the manufacturer - YOU. The people you hired to do work for you (in the Philippines) are not responsible for ensuring compliance with your airworthiness certificate.

The issues you mentioned:

. #6 platenuts in the fuel sender. An obvious miss that I’m impressed you caught, hopefully early, but very easy to fix. Drill them out and replace with #8, as specified, and make sure you tell Vans about it so they correct the miss.

. Leak in the baffle seam. An occasional problem in home built tanks, but not common on QB tanks. I hope you caught this when you pressure tested your tanks before installing your wings, which would result in a very easy fix prior to installation.

.loose B-nut on the vent line on the inside of the completed tank. This is very easy to check. We have had four of these on QB tanks at my airport alone. This is something that should always be checked prior to installing that fuel sender baffle piece.

.Not sure what you mean by “rivet heads not sealed” on feed flange, but assuming it’s some fitting going in to the tank. This should also show up on the fuel tank leak test that you did.

The important thing here (and not really worth mentioning) is that you are the builder. You hired people to do work for you, and you need to inspect their work, which you obviously did. Good on you. Don’t expect perfection. If you wanted that, you would have built it yourself. They saved you countless hours of monotonous building, but there are some critical components of that, and you should never expect their work in those areas to substitute for yours. Hence, your detailed inspections and corrections when necessary.

These QB kits and impressively engineered kit parts that we have now make building not much more than an assembly of parts. The important thing we should remember is that “Builder” should hold some distinction, and along with that some responsibility.
 
I forgot to mention the fuel tank vent tube - the real reason I started to respond to this post..... I don’t see anything wrong with that vent tube. Are you saying that the ID on the vent tube should have been opened up after cutting with a tubing cutter? If so, why? This tube equalizes pressure in the tank, so airflow through it is very small. The only reason they specify 1/4” tube is because it is readily available, and easy to work with, including fittings, and It’s a right sized opening for a positive pressure load. The slight reduction in tubing diameter due to using a tubing cutter won’t matter. But it’s something that you could address if you built your own tanks. I’m sure that detail wouldn’t matter though.
 
I forgot to mention the fuel tank vent tube - the real reason I started to respond to this post..... I don’t see anything wrong with that vent tube. Are you saying that the ID on the vent tube should have been opened up after cutting with a tubing cutter? If so, why? This tube equalizes pressure in the tank, so airflow through it is very small. The only reason they specify 1/4” tube is because it is readily available, and easy to work with, including fittings, and It’s a right sized opening for a positive pressure load. The slight reduction in tubing diameter due to using a tubing cutter won’t matter. But it’s something that you could address if you built your own tanks. I’m sure that detail wouldn’t matter though.

THANK YOU FOR THE CORRECTION DRILL SARGENT!!!!! My God! I didn't realize I was treading on some holy ground by asking a question that I thought pertained to safety of flight with fuel suction being equalized by vent relief pressure. Perhaps you thought the low thread count indicates a lack of experience? Like yourself, I have built 4 RVs and helped with several others and was pinging the brain trust to see if anyone else has noticed this issue. You know, ask here.... in a forum before putting your butt in the seat and flying it (assuming it passed the fuel flow testing beforehand). Tomorrow I will be working on testing to develop empirical data regarding fuel suction vs. needed relief pressures at charted max FF (that whole for "spirit of education thing"). In the meantime, I will be doing pushups and running wind sprints to punish myself for daring to approach the sacred mountain an RV sky-god. WTF was I thinking asking such an obviously dumb *ss question on an experimental aircraft forum?
 
THANK YOU FOR THE CORRECTION DRILL SARGENT!!!!! My God! I didn't realize I was treading on some holy ground by asking a question that I thought pertained to safety of flight with fuel suction being equalized by vent relief pressure. Perhaps you thought the low thread count indicates a lack of experience? Like yourself, I have built 4 RVs and helped with several others and was pinging the brain trust to see if anyone else has noticed this issue. You know, ask here.... in a forum before putting your butt in the seat and flying it (assuming it passed the fuel flow testing beforehand). Tomorrow I will be working on testing to develop empirical data regarding fuel suction vs. needed relief pressures at charted max FF (that whole for "spirit of education thing"). In the meantime, I will be doing pushups and running wind sprints to punish myself for daring to approach the sacred mountain an RV sky-god. WTF was I thinking asking such an obviously dumb *ss question on an experimental aircraft forum?
Seems like Scott provided some good, non-judgmental observations and suggestions. Perhaps you read it a different way?
Agree that the vent tube is a non issue as described/shown.
Further, it's also pretty common knowledge here on VAF that while the QBs are probably a bit better than the average builder's product, they are not perfect and a good builder can meet or exceed their quality. Thus, Scott's advice to check all QB products and fix anything that doesn't meet your standards is, again, appropriate.
 
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Wow!! I’ve never been called a “drill sargent “ before (Bluskydreamin). I’m sorry if what I posted upset you. I was not intending to call you out on anything, in fact I applauded you for inspecting your QB parts (“Good on you” - that’s what that means - nice job). I didn’t check to see how many posts you have made, because it frankly doesn’t matter to me. My post on this thread was meant to reinforce the need for all of us to inspect QB parts, like you did, and I agree that letting Vans Aircraft know about these errors is important. The only thing that I thought that didn’t need any correction by you, or anyone else, was the end of that vent line, and I pointed that out. You might not agree with me, and that’s fine. This is a forum. There are hundreds of opinions here. I’m sure you can come up with a tool that you can reach in to the tank with and open the end of the vent line up a little. I just don’t think it’s necessary. I apologize for setting you off, even though I don’t understand why, and I promise to make every effort to avoid commenting on your threads in the future.
 
Being a good neighbor

All,

When I moved into a new house a few years ago, my new neighbor Bob told me we have two commandments for being a good neighbor on our street.

The first is, “Thou shalt not annoy thy neighbor.”

And the second is, “Thou shalt not be too easily annoyed.”

Always seemed like good advice. However, as always YMMV.

Cheers,

Mark
 
All,

When I moved into a new house a few years ago, my new neighbor Bob told me we have two commandments for being a good neighbor on our street.

The first is, “Thou shalt not annoy thy neighbor.”

And the second is, “Thou shalt not be too easily annoyed.”

Always seemed like good advice. However, as always YMMV.

Cheers,

Mark

Well said!
 
While quality checking my QB tanks with the bore scope this was seen on both tanks at the filler cap end. the vent tubing cut off has reduced the ID considerably with no rework to open it up = using deburr tool. Are others seeing this and have you tried to open up - could be a safety of flight at full fuel flow? I thought maybe a #30 drill through the rear baffle and guided through both sides of the tube .25 inch from the end, then seal the baffle with a closed end pop rivet and sealer?

https://live.staticflickr.com/65535/50520126508_7320ddf1f0_m.jpg
https://live.staticflickr.com/65535/50521029002_1798525058_m.jpg

These tanks have also had the following issues:

- #6 plate nuts in all the fuel sender screw locations
- small leak in rear baffle seam R\S bottom
- loose B nut vent line L\S
- rivet heads not sealed over on drain and feed flange both tanks

I've included a pic of the "inspector" who passed these tanks if anyone needs a laugh on a Friday. thanks

The picture of your fuel vent tip shows the lack of attention to detail with the QB tanks. I found mine the same. I don't know if the opening restriction would have any effect on the fuel transfer flow, but it would have literally taken 30 seconds for the tank builder to knock the tubing cutter roll off, and maybe another minute to bend the tip up so the opening is close to the tank top skin. This would help with the complaints of fuel venting out when the tank is fueled and topped off.
 
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