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RV-3B Dave's in Colorado

With the left tank now all drilled (but not deburred, I'm saving that until both tanks are ready), I'm working on the right tank. As of last night the top surface is drilled and clecoed to the ribs and the bottom surface is marked but not drilled.

It's strapped down to hold it in shape for the drilling. But no clecoes in the photo - l must have taken the photo before drilling the top. Well, just use your imagination. They're in there.

Also you can see those handy square .063 tabs that I'm using to hold the skins fair. The tabs are an inch square, with a #40 hole drilled 1/4" from the edge in the middle of a side. All edges rounded. Someone should make these and sell them....

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Dave
 
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Both Tanks Drilled

Both tanks are drilled, skin to baffle and ribs, and skin to the spar flange. The spar flange holes are pilot holes for now.

Gettin' closer.... Closer to deburring and dimpling and countersinking, anyway. I left all that to do at once and shortly there won't be any excuse and I'll have to do it.

Dave
 
Doing the Gooey

Yes, I ran out of excuses and started assembling the tanks. Here are the inboard and outboard ribs:

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More recently all the parts are riveted on and the -6 rivets too. Those were easy. And the blue tape's gone.

Then I put the stiffeners on using tank sealant. When cured, I started riveting them. This was taken before I got the tape off the first side.

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I'm now riveting up the second tank's stiffeners. My work is outpacing the photos.

Dave
 
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Still Gooey

The tank stiffeners are riveted on, as well as the filler cap rings and the drains. I've been using the more syrupy type A tank sealant to dot the rivet heads and add additional sealing around the perimeter.

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So far, with the end rib assemblies and the stiffeners, I've used 132 grams of the regular type B sealant and 81 grams of the type A sealant. I expect that another 20 or 25 grams of the type A will finish sealing the end ribs. Sealing around the fancy sealed nutplates takes a bit.

I started using hardware store plastic syringes with the ends cut off to open up the applicator end, and found that it wasn't necessary. I get better results and use less type A sealant with the normal narrow stock end.

Dave
 
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With a whole afternoon available, I used the tank sealant to glue five of the six ribs to the skin for one of the tanks. I didn't glue the inboard rib yet because I need to rivet the skin/ribs before I slip in the vent tube, and the inboard rib needs to be off to do that.

Five ribs and a bit under 80 grams of sealant. Previously, I'd abraded the parts, cleaned 'em and taped off the parts I didn't want to get sealant all over. Today I recleaned them, got them all goopy with tank sealant and then clecoed the ribs to the skin.The only really messy part was putting those #4 nuts on the clecos to get more clamping pressure. The clecos push some sealant through the hole and that gets on the small nut. And of course that's working blind, by touch.

Fun day.

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I think I used something like seven or eight pairs of gloves. if it hadn't been for those silly little #4 nuts it would have been one or two pairs.

The photo was taken after I'd pulled the tape out. That's another fun job, reaching in and pulling out tape that's got tank sealant on it. After I took the photo, I clecoed in the baffle just to ensure that the tank would cure while it was held in the right position. Without the baffle it didn't have any shear stiffness.

Dave
 
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Quick update on the tanks.

I've got the left tank riveted but haven't yet dotted the rivet heads with tank sealant. Also the inboard rib is still out pending the vent line installation.

The right tank is assembled and glued and clecoed, all but the inboard rib, and is curing.

I borrowed a #8 nutplate tool to drill the nutplate attachment holes on the spar flanges but haven't actually drilled the #40 holes yet. The screw holes have been drilled but not countersunk.

Dave
 
Lookin' good, Dave! I went QB on the wings, so I'm missing this rite of passage. :eek: I'm sure it will feel great to apply that last dab of sealant and finish them up.
 
Excellent work

I have done the left tank completely and I wouldn't worry about your use of gloves, as I bought a box and have almost used it all. About one half of those went into tank construction.

I offer this as a question though, it would be a concern to me that any tape might have been left behind to cause a clog in your fuel system. I bet you already know this though. :rolleyes:

Nice work!
 
You're right - we've got to be careful to get that tape off while the sealant is still wet. I didn't do that with the first set of stiffeners and spent some happy hours listening to the radio as I worked the tape free of the cured sealant.

Got it all and then went back with the thinner type A sealant and resealed those sealant edges.

Learned that lesson!

To date, the tanks have used 333 grams of the usual type B thicker sealant and 112 grams of the thinner type A. But I've got a way to go. And "used," in this context, included sealant that's still in the mixing containers and syringes.

I haven't even bothered with the SEM gun I bought.

This shows the rivet dotting that I did yesterday on the top ribs of the left tank using the type A sealant in a syringe. I didn't do the bottom rivets because I didn't want the sealant to run. It's like honey and it might not, but I didn't want to risk it.

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I decided to do the top first so that I could get the vent tube in place before proceeding.

You'll note that one rib seems to be reversed compared to the other. The right rib in the photo is the outboard rib. The plans say to have the flange outboard, which would be consistent with the other rib, but that doing it this way is optional for more fuel. It's about half a gallon and hey, I LIKE having more fuel. Beats the alternative.

Dave
 
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Well, a friend came over and helped me rivet the tank skin to ribs on the right hand tank. We'd already done the left tank, and I'd installed the inboard rib on that tank.

Dave
 
So dave, when you do a plans built kit like this. I know you have to drill all the skins with a fan spacer and such is anything drilled for you? Or do you literally get a box of stamped parts and thats it
 
There are probably a dozen parts that come with holes, and that includes the main wing spars, which are drilled and riveted (except for the holes on the spar flange that attach to the skin, those aren't drilled). None of the skins, ribs, bulkheads, etc., come with holes.

Take a peek up to post #99 for a look at the right tank still undrilled. The first photo shows the undrilled ribs and the next, the skin. Here's how I drilled those holes.

1. I carefully located the ribs in the jib and secured them in place. I used a bit of brass tube as a bushing to back-drill through the spar to get the aft flange holes, removed the ribs, and opened them up to #30. Post #51 shows that. Then I clecoed them to the spar and put some threaded rod through their leading edge.

2. Place the skin in position and do any trimming to get the aft top edge in perfect alignment. Use the Howe fittings to strap the skin into place, see post #75. This is kind of an iterative process.

3. When I was happy with the fit, I removed the skin and drilled the top skin for the the spar flange holes using a handy jig I'd made from some scrap 4130. The jig rides on the edge and locates a position 1/4" in from the edge; I still need to mark the spanwise locations. Then I removed the ribs from the wing jig.

4. I located all the holes on the rib flanges top and bottom and drilled just the top rib flange's holes.

5. Replaced the ribs and skin with the Howe fittings and straps and drilled and clecoed the skin to spar flange holes, securing the skin into position.

6. Starting at the aft-most holes, I back-drilled and clecoed every top rib flange hole in the skin. At the leading edge, I had to hold the skin to the ribs, but that wasn't hard, just a bit awkward.

7. With every top hole clecoed, I made a table of measurements locating every single hole in the bottom except the spar flange holes. I measured everything as many ways as I could, paying special attention to external references so that I could transfer the hole positions to the skin.

8. Strap down the skin again with the Howe fittings, and when satisfied (it takes me a couple tries to get it right) measure and mark the hole locations on the bottom of the tank skin.

9. I didn't bother using a center punch. The vinyl holds the drill position well enough. Starting at the most forward, blindly drill through the rib and skin. I could see the mark on the ribs so I knew it was okay. Placing a cleco in each hole as I went along, I drilled about 1/3 to 1/2 of the way to the aft edge. Then I stopped.

10. I removed the bottom skin clecos and Howe fittings and straps and opened up the bottom and checked the holes. This let me assess how I was doing. I didn't do this on both tanks because on one of them I could see the marks on the ribs better through the holes and knew that everything was okay, so I just kept going.

11. When the clecos were in every hole, I drilled through the spar flange on the bottom.

At this point all the ribs and the spar and skin are all drilled. There's been a cleco in every pair of holes.

This was probably more information than you wanted, eh?

Still, this is the major reason I chose the RV-3B kit, so that I'd have a number of fun problems to solve. In that regard, it hasn't been a disappointment. But I can't say that it's going together quickly or that I haven't made plenty of mistakes - my scrap pile is big. Still, all in all, I'm making progress.

Dave
RV-3B -- Some thinking required
 
When The Real Fun Starts!

Wait until trying to jig the fuselage if you want some real fun!

David
 
Wait until trying to jig the fuselage if you want some real fun!

David

Second that! Of course, you can take the easy approach - build the jig precisely, mount the bulkhead on the jig precisely - then close th ebuild manual, put away the plans, and build an airplane around the bulkheads. Many of the measurements don't quite add up anyway, so don't sweat them - just make it all work!

Oh - no pre-drilled holes in anything.
 
You're Getting Ahead Of Me!

I'm looking forward to the fuselage, I've got to admit. The engine is standing by and so is the finish kit. I even picked up something for the cockpit: an ARP carburetor ice detector, like the one in my Cessna 180 that works so well.

But for actually building it, that's in the future. All I have right now is anticipation and, well, this:

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It's a Frye steel jig, folded up so I could haul it in my pickup (yeah, these jigs fold - cool!) and it's not set up for an RV-3B. I don't have instructions for it - but I do have a bundle of small parts that comes with it. If anyone has instructions, give me an email or PM please. As it is, I'm expecting some "real fun" just getting it to work. But since it's already built a couple of airplanes, this one should be easy for it.

Someday.

Dave
 
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Spar Flange Nutplates

Right now, the top skins are off the wing so that I could install the spar flange nutplates and the autopilot roll servo and things like that. Before, I hadn't countersunk the tank nutplate holes (they had been pilot-drilled and on the tank skins, dimpled), and had to at least countersink these to get the tanks back on when they're complete.

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The countersinking of these holes wasn't well-documented in the RV-3B manual. I used the tip given in "27 Years of the RVator," to open them up to .365 to .375 inches outside diameter. It took some fiddling to get there since the one-flute countersink bit was .377 inches diameter. Interestingly, I noticed in the RV-14 wing section on Van's revisions page, that for the RV-14, the max countersink outside diameter is .370 inches. No minimum is listed.

Dave
 
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Playing With the Gooey Stuff - Tips

After riveting up the tank skins and ribs, the edges of the tank sealant looked like this:

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Then I saw this:

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And went back into the tanks with some of that type A sealant in a plastic syringe and a tongue depressor that I rounded off to 1/4 inch radius. In the how-to, a mill is 1/1,000 inch, so 250 mills is 1/4 inch. I've got a little more to do but now they're looking like this:

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Have to admit, this part was fun.

Dave
 
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The outboard leading edges are riveted on to the spars.

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I didn't forget the rivets through the rib flanges to the spar web.

If you look closely you can see at least one of the alignment strings through the holes in the front and rear spar that let me check for twist. And the landing light lens and stall warning vane are visible too, all on the left wing, the one in the background.

Dave
 
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Nice job indeed.....but tell me, what's the benefit of riveting the L.E before mains skins ?
 
With the main skins on, there's no access to rivet the leading edge skin to the spar flange. With the main skins off, I could get in there with a squeezer and these leading edge/spar flange rivets were easy.

In the photo, you can see the right leading edge assembly in place, to the left of the fuel tank ribs. The spar flange extends aft of the leading edge, and if the main skins were on, I couldn't buck those rivets.

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The leading edge assembly is riveted while in a simple jig, after drilling the rivet holes between the skin and the ribs while jigged up on the wing. Then after riveting the ribs to the skin, the whole assembly is riveted to the spar.

Don't forget the spar web to rib flange rivets. They're kind of hidden away in there.

Dave
 
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A Bit of an Issue and Rivet Removal Tips

I was assembling the tanks to the wing before riveting on the tank baffles, just to be sure, and the left tank no longer fit on the outboard leading edge's splice strip. Remember that it was built in place on the wing, with the outboard leading edge attached. This time it didn't fit.

Turns out that the outboard tank rib interfered with the splice strip. Here's the rib and the skin. You can see how close the rib and the reinforcement piece are to the dimpled holes.

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This shows the splice strip and how much it would need to be trimmed to fit - clearly a problem.

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Later, I marked where I'd need to trim the splice strip and it was very close to those holes. I contacted Van's support and they recommended replacing the outboard tank rib and relocating the leading edge reinforcement plate to the inside of the tank. This didn't please me - I'm not that great at drilling out rivets. So I took a break to think about it.

For my break, I had a friend over and we set the -4 rivets that hold the main ribs to the spar web behind the tank. During the process, I got to replace a few of these and it went reasonably well. Then came the aha! moment. Drilling out these rivets, I was using a #40 drill bit as a pilot drill.

When those were all finished, I went back to the tank and tried to drill out the -3 flush rivets using a pilot drill. This worked a lot better.

This photo shows a few of the first rivets drilled out and the tools I used.

The basic approach is:

1. Center punch the center of the rivet head.

2. Pilot drill just a bit deeper than the head. Use a drill bit that’s 10 number sizes smaller than the nominal one. In this case, for the -3 rivets which used a #40 bit, I used a #52 bit to pilot-drill them.

3. Drill just the head with the correct size drill, in this case #40.

4. Using the unfluted end of the #40 drill bit, pop the head off.

5. Use the pin punch and a very small hammer to punch out the rivet body. That hammer, by the way, has earned its scars. This is its fourth homebuilt airplane.

6. If you’re my age, the magnifying glass comes in handy, and if you didn’t get the head exactly, the needle nose pliers are helpful pulling it off.

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That left the rib firmly sealed to the tank. Think glue. Here are the top rivet holes with no more rivets:

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How to get the rib out? I bought a set of plastic picnic knives and they were of little use. The sealant was just too tough. I made a sealant knife by wrapping a piece of music wire around a couple of pieces of 1” dowel. I used several pieces of music wire: .015 was too weak. It cut well but broke easily. The .020 was the compromise that worked. The .032 was sturdy but cut poorly in the sealant at room temperature. Going across the dimples was especially difficult.

Then a friend suggested heat. I’ve got an 1,800 watt hair dryer and a few minutes with that let the .020 wire cut through the rest of the sealant. Using a piece of 1/2" plywood as a sort of wedge helped a lot, too, forcing the joint apart. I've got some serious respect for tank sealant now.

These are the tools I used.

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Now the rib’s out and parts are on order. They should be here on the 29th.

That light at the upper left of the photo is a sweet thing. It’s a 9 watt florescent under-the-counter light and makes a handy shop light.

Merry Christmas, everyone!

Dave
 
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Polygone

The Polygone remover really works on tank sealant. It's a translucent jelly, slightly golden, that seems quite similar to paint remover except that it can be cleaned off with rags and soap and water. I'm using one of the plastic picnic knives to spread it on and encourage it. It dissolves the sealant quickly.

This is after I spread the first bit on.

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After all the sealant was lifted, I wiped the Polygone off with a number of small cut-up rag pieces. Then into the kitchen for a wash and bath in the sink- really. Being of course very careful not to contaminate the kitchen.

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I've still got to go over the areas with Scotchbrite again and lacquer thinner before I install the new rib.

The Polygone instructions suggested that some plastics weren't compatible, including acrylic, but these knives did just fine.

Well, that's it for the year. Thanks very much to DR for hosting this site, and best wishes to everyone for a wonderful 2015!

Dave
 
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Wow Dave - that has got to be the Holy Grail of anyone who has dealt with tryign to remove tank sealant - going to have to remember this stuff!

Paul
 
First Inspection

Since I hadn't had any luck getting a tech counselor to stop by, I had a local A&P do it. He's someone I know and respect, and he's worked on my Cessna 180 before. He found a serious issue on a friend's airplane a few years ago, and has lot of riveting and tank experience on certified airplanes. I particularly wanted this inspection before putting the baffles on the tanks.

His major finding were:

1. Use more sealant inside the fuel tanks, especially on the rivet shop heads.

2. When putting safety wire through sheet aluminum (I've got a place where I'll safety the trim tab hinge rod by safety wiring the inboard end to a hole in the elevator), slip some plastic tube, like wire insulation or shrink tube, over the safety wire. Otherwise the aluminum might eventually crack.

3. I've got a place where some wiring needs to exit a connector and immediately make a turn. There's no room for a plastic connector end - this is the roll autopilot servo in the right wing, with the servo close to the top skin. He said to use some blue sealant to protect them there.

Dave
 
Outboard Rib Drilled

With the rib removed, I had to locate and match drill to get the new rib in. I used my Vixen file to get the edges straight on the flanges and marked the inside of the skin to show where I had to stay clear to get the tank to fit the splice strip. Then I marked a line for the minimum edge distance to the edge of the flanges. I could view this line through the existing holes in the skin.

I clamped the rib in place - love those Cleco side clamps! - and starting with the forward-most holes, drilled and dimpled. I had to do the first half dozen on either side one by one, clecoing the rib in place because the dimples were pushing the rib aft a bit until I dimpled the rib flanges. So hole, by hole, I continued.

When I got aft of the first half dozen holes, I could simply match-drill the holes.

Here's the rib.

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I've also made the leading edge reinforcement, see the plans clarifications for a note about that.

Dave
 
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All that wouldn't have been any fun if the tank as revised didn't fit, so I figured I'd better try it. It fits. Here it is, with a number of the screws screwed in.

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Whew!

So after riveting the leading edge reinforcement on the rib, I used tank sealant and clecos to glue the outboard rib into the tank.

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One of the things the inspector wanted me to do was add more tank sealant. I got out the type A thinner sealant and re-dotted all the rivet heads in the tanks. I did that before putting the rib in.

Dave
 
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Riveted LH Outboard Rib

I'd persuaded the tank sealant in the outboard rib to cure rapidly with a very simple trick: I put the LH tank, in its support jig, on one of my living room heater vents. It gets warm enough to accelerate curing.

One by one, I removed the clecos and installed rivets. The rib is now riveted in place.

I re-verified that the right hand tank fits the wing. About 20 of the screws are installed here.

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Dave
 
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Hatch Day!

Here's a picture of the three types of tank sealant I've been using. Left to right,

Type A - honey-like consistency for things like dotting the rivet heads.

Type B - The thick sealant we all know and love.

Access-Hatch Sealant, Type B - The pink stuff, used for removable parts like the fuel tank access hatches. I moved it from the SEM tube to the easier containers.

ZlxNRRD.png


When it's mixed, it's a bit thinner than the normal Type B sealant, but closer to that than the thinner Type A sealant. It's also a distinctive dark pink color, almost purple.

I smeared it on the access hatches and on the inboard rib. I was trying to be generous. I put some on the screws, too, just under the heads. Here's the right tank, the first one I did. The color doesn't show well in this photo:

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And then I mixed a bit more and did the left one:

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The only glitch was late last night, when I started to do this using the standard Type B sealant. I got it all buttered up and then remembered that I'd gotten the access hatch sealant specially for the access hatches. Had to clean it off. Sigh.

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Ah, one more thing - the sealants had been stored in the freezer from when they arrived until I needed them. They all work fine, and the expiration dates aren't valid for that storage condition.

Dave
 
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Right Tank Closed

It finally dawned on me that I'm more than a little bit apprehensive about closing the tanks. A friend has a non-RV with a serious leaking issue in his wing tanks that are a bit similar to this sort of construction and the familiarity with that airplane's problems has affected my progress on my tanks.

Well -- we can't have that.

With that understood, I realized that the right tank is fully ready to be closed out, so I did just that this afternoon. I used tank sealant, the regular type B sealant, to stick the baffle in the tank. All the skin to baffle rivet holes are currently clecoed, and the Z-brackets are riveted on. I laid a strip of wax paper on the wing spar and screwed the tank skin to the spar flange, every hole, both sides. It will stay there till cured

Here's the top of the tank:

ZU41QH5.png


The chain coming out of the tank filler hole is the lanyard for the cap. Can't have stray shop debris getting into the tank, so I'll have to either tape over the hole or install the cap.

Here's the root end of the tank, some details still remaining undone. But you can easily see the odd color of the access hatch sealant.

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That's it for now. Have a good weekend!

Dave
 
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LH Tank Closed

Last weekend, I installed the baffle on the left tank. Like the right tank, it's screwed in place on the wing while it cures.

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Since I had to remove the roll servo in the right wing to install the harness connector, it seemed like an excellent time to start the maintenance manual. This first entry will show the top mounting bolt of the servo from the inaccessible side:

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Moving on to something more fun, I saw this on a different thread here and immediately realized that this is the RV-3 I should be building, not the full-size one:

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Oh, well.... Might as well press on with things, eh?

Dave
 
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The tank sealant on the right tank is cured. I'd installed the baffle and screwed the tank to the wing to let the sealant cure in place. I protected the spar with a piece of wax paper.

With the sealant cured, I removed the tank and riveted the baffle to the skins. I'm sure that I'll need to replace a few rivets and I left a difficult one for the next work session, but here's the tank.

rwV8Sd3.png


I also slipped some plastic-coated fiberglass anti-chafe tube over the autopilot's roll servo wiring and added a couple nutplates to secure the wires so they can't interfere with the controls. There's absolutely no room to install the plastic exit guide on the wiring connector.

m0i7Pck.png


The wiring will eventually be secured across to the nutplate on the left, and then forward to the plastic busing on the left. The wiring from the light will cross from the right to the left bushings - you can see where the nutplate is for the clamp - where they should be clear of the controls.

The black electrical tape in the upper left is simply there to simulate where the pushrod will be, someday.

Dave
 
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Both Tanks Riveted

I finished riveting both baffles on and dabbed some tank sealant on the rivet heads and a few other places. I put the tanks back on the wings so that if there's any sealant close to the spar, there won't be any interference; it'll press out. I've got a piece of waxed paper between the tanks and the wings, so the tanks get to come off again.

That being the case, I only have a few screws installed and am using some Cleco clamps to secure things for now.

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Dave
 
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My tanks will be ready to pressure test as soon as the latest batch of sealant dries. They are in the house, out of the shop, for warmer night time temperatures.

The top skins are ready for riveting (the right one) or almost ready (the left one).

In the meantime, I'm making aileron stiffeners. I drew a full-size drawing of the ailerons per the plans to compare with the as-built wing and the plans seem reasonably accurate. I brought the aileron and flap skins, spars and stiffeners home from the hangar.

For you folks who are building one of the pre-punched kits, the stiffeners on the RV-3B are simply strips of plain angle that come four feet long. It's up to the builder to mark, cut and trim them to fit. I marked one strip and clamped them together and gang-cut on the bandsaw and then edged them on my 12" sanding disk. It went well. But I had to taper them individually and when I separated them, I found that the vinyl had fused the stiffeners together. I had to remove about half the vinyl to get on with the job.

There had been some issues with the flap and aileron skins, the way the factory bent them, I learned. David Howe sent me a sample of his flap skin and mine are bent much better. Van's has taken a lot of heat over the quality of the RV-3B kit and it was heartening to see that they've apparently put some effort into correcting at least these issues. My kit was shipped April 2012, best I can recall.

Dave
 
Top Skins Riveted

Both top skins are riveted to the wing frames.

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I made a Vee frame to hold the ailerons in position during assembly. It's like the fixtures used for the empennage control surfaces. This photo shows it being checked for straightness. I'm using a laser level and you might be able to see the beam on the fixture.

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Much earlier I'd trimmed the narrower of the aileron hinges per the plans, except that I'd misread the fractional part of the dimension and used 32s instead of 16ths. Oops. I sent to Van's for a new pair. I also needed some aileron ribs which had somehow not been included in my kit. These all arrived and are on hand now.

Dave
 
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This is my busy season and progress has suffered as a result. I've started the ailerons and made a jig to match-drill the stiffeners. I thought it would be easier than trying to keep track of them individually. Here's the simple jig. It's a piece of .093 steel with a short aluminum flange riveted to it above the bend in the stiffener, so I could reference the flange for location.

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Here it is in use.

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I made the lightening holes in the aileron spar with a brand new hole saw. I was a bit worried that the hole saw would wobble as it got close to cutting through the spar, so I replaced the pilot with a steel bar and pre-drilled pilot holes in the spars. I also pre-drilled a pilot hole in a piece of plywood, the backing piece, and lubed it:

PIrAv6L.png


This worked well and it only took a few minutes to make all the holes. My drill press has a minimum speed of 500 rpm and the hole saw preferred 295 or so, according to what I could find on-line, but 500 rpm was okay. I used a sanding drum to smooth the holes.

Next, I massaged the end ribs to fit. As delivered, the taper wasn't quite right. At first I thought the ribs were too long but after adjusting the taper, they seem to fit okay. What I had to do was reduce the distance between the two flanges at the aft end.

I first used a soft hammer and a round mandrel, a round bar, to put a bend in the web at the very back, then my Matco flanging pliers to gently squeeze the flanges together. That left the flanges having curved top and bottom surfaces, which won't do, so I used a tapered, rounded wedge of maple in a vice and formed the flanges a bit. Not hard and it seems to have done the trick.

That's as far as I've gotten.

Still have to drill the skin for the stiffeners, that's going to be awkward since the RV-3B aileron skins are one-piece and wrap around. Anyone have any thoughts?

Dave
 
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Drilling Aileron Skins and Stiffeners

The top surface of the ailerons was the tightest.


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I bought a 90 degree angle drill for the job. It's still tight. I had to use a shorter bit, which I'd also gotten, for the aft holes.

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The bottom side was a little easier. Not much, but a little.

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Dave
 
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This is my busy season and progress has suffered as a result. I've started the ailerons and made a jig to match-drill the stiffeners. I thought it would be easier than trying to keep track of them individually. Here's the simple jig. It's a piece of .093 steel with a short aluminum flange riveted to it above the bend in the stiffener, so I could reference the flange for location.

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Here it is in use.

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Anyone have any thoughts?

Dave

Nice drilling jig Dave. Why didn't you use it to help you drill (locate) those hard to reach holes in the skin?
 
Hah!

I thought about and it was worth doing it this way for the certainty of knowing I had the stiffeners in the correct locations.

With double-flush rivets, the tool could have been used externally and that would have been the alternative. No point using the tool inside the skins since I had stiffeners already drilled - they were good for this match-drilling.

Dave
 
With all but the last two drilled in the stiffeners and the skin, cleco the stiffener in place with the drill jig on the outer surface of the skin. Drill the skin and stiffener at the same time undersize and then ream for no burs.
 
Yeah, that would do it. I'd have still needed to double-flush the rivets.

Except now that I've got that 90 degree angle drill, and one aileron is drilled, I know that it'll take less than an hour to do the other, with much less handling on the .016 skin.

One thing that a builder has to be aware of is that there are often several ways to do something. I aim for a way that I know will do the job. As you can see from this blog, I'm not adverse to building and using jigs or tooling or for that matter, buying tools.

I'll get there - might not be soon of cheaply, but I'll get this done.

Dimpling and riveting are going to be fun, aren't they? Any suggestions about those?

Dave
 
Fear

That and generally being kinda busy are why I haven't bothered testing my fuel tanks (RV-3B slow-build) until now. So I decided to get going on this today.

The right tank was already set up. I put in some colored water and pressurized the tank. Or tried to - it leaked out almost quicker than I could put it in. I stopped before a vacuum developed in the tank, the air was so eager to escape. I could hear the leak at the fuel cap. A couple pieces of duct tape later, the cap was more or less kind of tight.

In egregious disregard for all wisdom, I used my air hose to fill the tank. My bike pump didn't seem to be up to the job and I didn't feel like buying another. I've got two lines, a 90 psi and a 20 psi line. They are color coded. I used the 20 psi line to fill the tank and before I duct-taped the cap, it wouldn't even hold one psi. Afterwards, it took about four or five seconds to reach one psi. There was plenty of time to pull the hose off the tank and I could easily control it to a couple inches of water or closer, just no problem at all. But you do want to keep an eye on it.

Anyone know how to adjust the Deluxe Locking Caps? Don't be bashful. If you have any thoughts, please chime in here.

Back to the air. In it went and it seemed to settle happily in the tank. A big improvement there. When I looked at it more closely I could see that it was still leaking, though. I measured a loss of 22 inches or water pressure in 40 minutes. Since I'd only put about 27 inches in the tank, that meant that the new air was almost as unhappy in its new home as the old air was. And worse, since I couldn't hear it, I'll have to do a soap test to see where my problems lie.

There aren't any new photos for this -- fleeing air is so darn hard to catch.

That was the right tank. I'll get to the left one of these days.

I've done a bit of vacuum-bagging of composites, and generally duct-tape the perimeter of the bag. It's usually reliable to about 9 psi. At my elevation we have about 12.5 psi available. This is with the vacuum pump running continuously. Therefore, duct tape is good but might not be good enough here. On the other hand, the duct tape might be absolutely perfect. During vacuum bagging there are other materials in play which could potentially leak too.

I'm using real cheap duct tape.... FYI.

Dave
 
Okay, the Deluxe Locking Caps use a nut that takes a 10 mm wrench. A socket is best but there's room for an open-end wrench. It doesn't take much to tighten the cap. Now that right tank is holding air.

Whew!

I'd tried to use duct tape to stop the leak. That only worked in a relative sense. It wasn't worth much for tiny leaks, which is what I seemed to have once I'd put on enough duct tape. So I ripped it off, nice and satisfying that was, and found that simply tightening that darn nut was sufficient.

I'd gone over the joints with soapy water and the only bubbles had been at the duct tape....

Looking ahead to when the plane is flying, I've been keeping a maintenance manual. In it are the things like the 10 mm wrench being useful for tightening the fuel caps, how to remove the landing light assembly, the correct sequence for pulling the landing light assembly out of the wing, what sealant the landing light lens uses, and that sort of thing. The manual is a single reference source for these things, so that I won't need to browse through my build notes - which might not be available when I'm out flying somewhere.

Dave
 
...

There aren't any new photos for this -- fleeing air is so darn hard to catch.

...

That's what the soapy water is for, Dave.:D
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As far as I'm concerned, the manometer is just for telling you when you've reached the test pressure, and to serve as a relief valve if you get carried away. There are too many variables to account for to use it as a definitive leak indicator. Even if it does indicate a leak, you still have to find it...
 
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