LettersFromFlyoverCountry

LettersFromFlyoverCountry

Well Known Member
Yesterday I installed the left fuel vent line and this morning I'm working on the right one. I'm doing it two different ways, however, because I...well... because I can. :D

From what I can see of the plans, the vent line should take a hard inboard and then outboard turn to fit around the lower longeron and then outboard of the rudder cable.

As near as I can tell, the only way to do that -- comfortably in my case -- is for both spacers to be on the inside of the skin in order to allow the fitting to be inboard enough to make those turns.

But I'm reluctant to place just a nut on the outboard skin, rather than sandwich the skin between washers. I realize just a nut holds the forward vent exit bulkhead on the skin side, but that skin is also thicker in that location, as I recall.

So on the left side, I went inboard around the rudder cable rather than outboard.

ventlineentrance.jpg


I don't really know if I like this or not. I like the route. I like the fact it clears the cable. It doesn't appear to interfere with the pedals. I thought maybe there was a chance I'd whack the line with my foot when I got in the plane, but I tested that out too and that doesn't seem to be a problem.

Now the right side today, for the heck of it, I'm doing the way the plans suggest but with the spacers on the inside. I'm not entirely comfortable with the nut on the outside; I really don't like how it scratches the skin when I tighten the bulkhead fitting, for one thing. I'm just not real happy with it, even if it is structurally sound. But I also am not that impressed with the severe turns required here, even with the fitting (although I've been able to make them with a combination of the pipe bender and the springs, I'm still not thrilled.)

Am I missing something here?
 
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Washers

Bob,

I used 7/16 AN aluminum washers that are 1/16 thick along with the Van's 1/8 slugs. Lets you jockey penetration, grip, protrusion, yada, yada. More to choose from.

John Siebold
 
Speaking of that hole in the side skin.. where exactly is it located? Is there a drawing that shows where to drill that hole?
 
The location of it is shown on "DWG 23 (I think it's 23), the one that shows you all the rivetcallouts for the skins. It has an arrow that says "enlarge hole to 7/16". That's it. That's all they tell you.

Best thing to do here is fit the reinforcement angle on the OUTSIDE (you'll want to use the opposite side's). And then take the spacer that you would use for the bulkhead fitting here and place it in front of that angle and just slighly below a line perpendicular from the third rivet from the bottom.

Add a little bit of a fudge factor if you want (I think I moved the spacer just slighly forward --maybe 1/8 to 1/4" -- because ). Trace the hole and drill. No big deal.
 
RV7ator said:
Bob,

I used 7/16 AN aluminum washers that are 1/16 thick along with the Van's 1/8 slugs. Lets you jockey penetration, grip, protrusion, yada, yada. More to choose from.

John Siebold
Click to expand...
Cool. I finished the right side while watching the Vikings game (I haven't sat for a full football game since I started building 4 or 5 years ago). I ended up putting the slugs on the inside. I'm going to push a washer on the outside and call it done.

I don't think I'm going to adjust the left side at all. Unless there's interference issues with going inboard of the rudder cable (and I sure don't see them), I kind of like the more relaxed bends.

Next stop: brake lines.
 
It is just a vent line

I put the right angle part of the fitting outside between the wing and the fuselage then made a smooth looping curve inside the main landing gear mounting cage to the underside of the longeron, forward to the firewall, up into the upper skin enclosed area then looped back down to the modified straight AN fitting in the floor. Same routing both sides and the brake lines are routed the same way as well. Low visibility and good protection.

Bob Axsom RV-6A
 
I played with this thing tonight.. didn't like how it was coming out.. Now I was thinking about using a 45 degree bulkhead fitting instead of the supplied 90 deg... It'd just help with that very first bend around the angle..

anyone can think of any drawbacks to that?
 
To throw a new twist to this, when you install the wing fairings, you'll be faced with the issue of the washer and nut interfering with the rubber seal that goes between the fairing and the fuselage. I ened up leaving the washer on the outside off.
-Jeff

WINGS%20276.jpg
 
hm.. that's interesting.. I was wondering about that too.

anyways, 45 deg. fitting didn't look right..

I'm gonna try both thick washers on the inside, along with another 7/16 bolt washer also on the inside, and just a nut on the outside.. that'll definitely help clearing that first angle..
 
I did a QB, so the wingtank fitting was already done per the plans. Plan sheet 28 points to an area instructing to drill out an implied hole to 7/16". I don't recall if the hole was there or a Rivet to be drilled out. I know I follwed the plans and had no fit issues regarding this part of building. Attached is a photo of my fitting exiting the fuselage. Apparently I took the plans as having the two spacers in the inside, as I did not put one on the outside. Hope it helps. No, I won't remove my fairing and measure it. Sorry.

Roberta


tankmount7mo.jpg
 
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The plans leave a little to be desired here on showing where the washers actually go. All of our instincts say put a washer on the inside and outside. After working with the fairing and realizing you can not use one on the outside, I would have to agree with Roberta here. If you use 2 on the inside it helps solve 2 issues. 1. It gives more clearance to make the bend on the vent tubing inside the aircraft and 2. It Physically moves the nipple outside inboard another 1/8" which will also help with the bend needed outside that goes to the tank.

-Jeff
 
Spent some time this morning playing with it.. it took a while, and I'm not finished with one side completely, but both washers on the inside + one 7/16 bolt washer helped a lot..

pic below

s_0044.jpg
 
I ended up ripping out the vent line shown at the beginning of the thread this morning becuase I realized there's a reason for those two bends at the top instead of one 90-degree bend (access to the rivets in the bulkhead), so at that point I also rerouted the new tubing inside of the rudder cable. I also moved the two spacer/washers to the inside. It occrred to me that the key bend to make it work isn't thte first bend, however. It's the second bend.

BTW, after I reinstalled things, I put the rudder/brake pedal unit back in to check for clearance. No problem, but can someone who is installed and flying estimate the amount of forward travel of the rudder pedals. The inboard pedal on each side doesn't have to travel much to hit the angle on the firewall.
 
I know this has been around for a while and was wondering what people thought about the Rocket style vent that stays in the wing and is made of several circles of tubing then vented down through the botton wing skin.I am considering doing this if it works well and some swear it is fine.
rocketfuelvent8eo.jpg
 
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Subpanel rivet and flange clearance

Bob Collins said:
I ended up ripping out the vent line shown at the beginning of the thread this morning becuase I realized there's a reason for those two bends at the top instead of one 90-degree bend (access to the rivets in the bulkhead), so at that point I also rerouted the new tubing inside of the rudder cable....
Click to expand...

Bob,

Not sure the 6 is the same as the 9, but I had to redo one of the vent lines where you are talking about here because I did not allow enough space for the outboard subpanel bottom flange which would have interferred. Just wanted to mention it, because I ended up clecoing the subpanel into place to make sure I cleared it. Here is a picture.
DSC_0050.JPG
 
rv9aviator said:
I know this has been around for a while and was wondering what people thought about the Rocket style vent that stays in the wing and is made of several circles of tubing then vented down through the botton wing skin.I am considering doing this if it works well and some swear it is fine.
rocketfuelvent8eo.jpg
Click to expand...
Yeah, I know, I would like to see some more info as well, I wonder where F1Rocet is nowadays, that is his photo?
 
mikehoover said:
Bob,

Not sure the 6 is the same as the 9, but I had to redo one of the vent lines where you are talking about here because I did not allow enough space for the outboard subpanel bottom flange which would have interferred. Just wanted to mention it, because I ended up clecoing the subpanel into place to make sure I cleared it. Here is a picture.
Click to expand...
Yes, thanks Mike, that's exactly why I ended up ripping the original out of there, becuase I hadn't noticed those rivets before and clearly that was going to present a problem with the original installation. I must've been able to get around it but I figured I might as well do it right.
 
Support that coil!

If you do go with the coiled-up vent tubing method, my 2 cents is that it would be a good idea to support the coil of tubing -- and I don't mean just at the ends. Otherwise you have a system that might vibrate/resonate at some frequency that may ultimately cause the tubing or one of the connectors to fail. Not that a leak in that system would be the end of the world, but I'd still immobilize the coil somehow, keep it from having any flex, keep it from chafing against itself, etc.

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
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