Safety issue?

Ray questioned the safety of not attaching the outboard leading edge ribs to the wing spar as a normal leading edge would. I didn't do this to keep the leading edge removable but I didn't take into account the 'shear' forces in this area. My plan at this point is to create a splice plate that ties the outboard wing rib to the outboard leading edge rib. I'm not sure what I could do about the other two ribs since access is severly limited at this point.

Final Thoughts on Long Range Tanks

Early on in the build process, Sandi and I decided that we wanted to do some oversea's flying to Europe to visit some students of ours and as a vacation. That meant I needed to increase the capacity of the fuel system in our RV-9A. The stock fuel tanks hold 18 gal each. Depending on how what your fuel burn rate is, that is 4-5 hours of time minus an hour for reserve.

I did some hunting online to see how other builders expanded capacity. Of the few I found, they elected to add outboard tanks and/or tip tanks. One company was starting to make these little tube tanks that fit in the lightning holes in the outboard portion of the wing. I didn't want multiple tanks to manage, so outboard tanks were out. The tube tanks really didn't add a lot of extra fuel. Van's was selling tip tanks for $2,000, which was way over-priced.

So I came up with the bright idea of expanding fuel capacity by creating a single fuel tank in each wing but just making it larger. I did this by creating a leading edge fuel tank skin that runs the entire length of the wing. The standard RV-9 configuration is a 6-bay fuel tank on the inboard portion of the wing and a 6-bay leading edge portion on the outboard. There is a seam in the middle where the two meet. I expanded the fuel tank to 9-bays in each each, adding 3 additional tank ribs. Since I was going to the trouble of bending a new skin I might as well make it long enough to run the lenght of the wing, giving it a smooth look.

Assembly of the tank was no different than the standard tank. I bought a long piece of aluminum sheet, drilled and bent it the shape of the standard tank skin. From there I continued as if it were a normal tank.

With that all being said.... was it worth it?

Tips for those who try this:

1) Don't drill any of the screw holes in the spar until after the tank is done, then back drill them. The guarantee's proper alignment.

2) One flange of the baffle is bent past 90 degree's. This is important as it allows the skin to sit better on the spar flange.

3) Given the length of the tank, make sure that we you go to install the baffle that there is no twist! I cleco'd the baffle in place, then used a level at various points down the length of the tank to check.

4) The root and outboard ribs of the tank have one rivet hole that is slightly different than the interior ribs. Remember this when match drilling the skins.

5) The spacing I chose for the addtional nutplates wasn't close enough. I have slight puckering between screws. I'd figure out a way to get them closer next time. I used the existing rivet holes for one leg of the nutplate. Make sure the spacing is at least the same as the inboard ones.

6) Do not underestimate the amount of force it takes to bend aluminum. I used a contraption made of wood and it was not adequate. If you can find someone to bend it for you great... I used a 1" pipe for the bend. If not, devise a metal contraption. I have an idea for one if you want to make one.

7) Get help when it comes time to proseal, particularly the baffle.

8) You'll notice that the top side of the stock fuel tank skin has a slight curve to it. If you can do this on the new skin, do. I have a couple of spots on mine where the skin buckled when trying to put it in the cradle. This small curve prevents that from happening. I'm sure Van's uses a roller system to put this curve in, I just didn't think about it or have the setup to do it.

Tank done!

This should be the second to last post in this log. I'm declaring the tank leak free! I left the manometer on the tank for a day and it didn't loose pressure. The downside to a manometer is that is is super-sensitive to temperature and atmospheric pressure. Monday night after work it was higher than when is started. I may test both tanks again before final assembly to make sure they are in fact leak free but I think they are. I need to shoot some primer on the baffle but other than that.. IT's DONE!!!

Leak testing

I hooked up the manometer to leak test. After getting the tube to seal on the fitting, it APPEARS that it's not leaking, however, it did drop a 1/2" after an hour or so, I don't now if that is the temperature or atmospheric pressure. I'll find out Monday night when I get home from work.

If it is leaking, it's slow!

(Time: 30 min)

Access plate

I installed the access plate and fuel float tonight. Want to leak test it on Sunday.





(Time: 45 min)

Tank attach screw holes

Tonight with Sandi's help I back-drilled the tank attach screw holes. I didn't match drill them with the stock tank skin as doing it this way allowed for better alignment. On the first tank, the screw attach holes didn't line up perfectly, this way they will.

View from inside.
View from outside.

(Time: 2 hours)

Baffle On!!

Bill came over tonight and helped me rivet the rear baffle on the tank. It went extremely well and the tank fit perfect on the spar. All the holes lined up dead on. (A testement to Dan C's method of doing the z-brackets.)

Having two people do the tank was almost a must for me. I have twice as many rivet holes as a standard tank. I put a bead of proseal on using a 60cc syringe, slid the baffle in place, cleco'd every hole on one side and every other hole on the other. Bill dabbed proseal in the holes, I stuck rivets in and squeezed them. We finished off by putting the z-brackets in. MAKE SURE YOU CHECK ALIGNMENT. I managed to mismark a couple of brackets. I started to rivet them on and then decided I better set the tank up on the spar just to make sure... yep.. it was on backwards. Caught it early. I can't imagine having to take one off and redo it.




(Time: 3 hours x 2 people)

Few last rib rivets / baffle

Sandi helped me put in the last 6 rivets in the nose portion of the outboard ribs. Was easier with two people. I also trimmed the excess lenght off the baffle. (Realized I need to do some stuff on the wing skeleton before I'm ready to seal up the tank.)

Slightly different angle of the tank.

(Time: 30 min)

Root rib done

I spent about 5 hours this weekend helping Bill put the ribs in his fuel tanks. They came out great and we were in such a groove, it took us under 2 hrs to do one tank Sunday morning.

I managed to put in the outboard rib reinforcement plate and the root rib today. All that's left is the baffle and the tank will sealed!

(Time: 1.5 hours)

Filler flange / fuel float

I finished riveting the outboard ribs. Then I riveted on the fuel filler flange which I didn't do before putting in the ribs. (I'd suggest doing it before as instructed.. it's easier.)

Outboard Ribs
Fuel filler flange

Finished up the evening by bending the float wire and test fitting the fuel float sender. My bends weren't perfect, so the float touches the top of the skin. (If I adjust it so it doesn't touch the top, it touches the bottom.) I put a dab of proseal where it contacts the top skin just to give it something to hit against when the tanks are full.

Shot of proseal dab.

(Time: 1.5 hours)

Outboard ribs

I put some rivets in a couple of the outboard ribs.

(Time: 30 min)

I'm back!

I'm back from my week long trip to Philadelphia and Minneapolis. It may take me a while to get back in the swing of things. I need to help Bill put his fuel tanks together and we close on our house next week.

Suffice it to say that updates may be slow in coming.

I'm sure my shop mascot Winnie will keep you post of any progress as he did while I was away..

Cleaning cleco's - Out of Town until 4/22/04

All I did tonight was clean proseal off cleco's. Does that count as build time? Dunno. I have the root rib and baffle to finish and then I'm done with proseal for awhile.

OUT OF TOWN UNTIL 4/21/04. I'll be in Philadelphia until Sunday and then in Minneapolis until Wednesday.

(Time: 1.5 hour)

Vent line fitting / proseal touch-up

We had company, so I spent just a little time in the shop. I installed the vent line fitting in the root rib, touched-up the tank ribs with proseal, installed the vent line and bent it as necessary to match the fitting.

TIP: After finishing prosealing the ribs, wait a day or so and then go back to look for spots you missed. I found two rivets I didn't cover at all and lots of little spots that needed some touch-up. Not sure if they would have leaked or not.. but now is the time to make sure they don't! (I also had Sandi come out and look, that second set of eyes helps.)



(Time: 1 hour)

Marathon riveting of tank ribs

Decided to tackle riveting the tank ribs today, so I called Bill to come over. After 6 hrs of riveting all the tanks ribs are in except the root rib. There are three outboard ribs that need riveted but don't get proseal.

Before riveting.


After riveting with the baffle cleco'd on to hold it in place.

(Time: 8 hours)

Stiffeners on.

I had some extra time I wasn't planning on, so I started prosealing/riveting the stiffeners on and managed to get them finished along with the fuel drain.

Fuel drain / stiffener

(Time: 2 hours)

Finished dimpling skin, ribs and stiffeners... ready to start assembly

Today I finished dimpling the skin, then I dimpled the ribs with the tank dimple dies and also the stiffeners. (I scuffed the rivet lines on the skin before dimpling.) I scuffed up the flanges of the ribs and stiffeners and washed them. I have all my proseal supplies assembled and ready to go. Bill wants to come over and help me before he tackles his tanks.

(Time: 4 hours)

D&D tank skin

I disassembled the tank and deburred all the holes and started dimpling the tank skin.

(Time: 4 hours)

Baffle drilled

I managed to get the z-bracket/baffle holes drilled tonight. Just a bit of a mental challenge to figure out the best way of doing it. It's done! Now on to the d&d part.

(Time: 2 hours)

Finished countersinking

I finished countersinking the skin-to-baffle holes. I cleco'd the wing skins on set the tank up on the spar. Looks good. I need to do some positioning and then I can drill the z-brackets

Tank resting on spar.

(Time: 1.5 hours)

Lots of drilling

I finished drilling all the tank ribs and the 3 outboard ribs. I drilled the T-910 and T-405 reinforcement parts. I drilled the tank baffle holes and started the countersinking the skin-to-baffle holes. I should be able to finish those tonight. Next I need to mount the tank on the spar to drill the z-bracket/baffle holes.

If you don't visit the main page, check it out as I got some transition training in Sam Benjamin's RV-9A this weekend. I also helped Ray rivet the last skin on his plane. All he has left is prep for paint and final assembly!


(Time: 5 hours)

Drilling ribs

I started drilling the tank ribs tonight. I finished about half of them.

(Time: 1.5 hours)

Misc parts

I made the tank reinforcement plates and have them drilled.

(Time: 3 hours)

Working on wing skeleton...

Working on wing skelton before I start assembling he tank

Sucessfully bent the skin

I bit the bullet and bent the skin. It took three of us to do it. I recruited Yuri and Sandi to help out. I won't go into details as I essentially bent it the same as the first skin but let's say it wasn't a walk in the park.

After bending, I cleaned up a bit and put things back in place. I cleco'd the ribs to the bottom and put the skin in the cradle and cleco'd the top side. Holes lined up pretty easily. I need to order a couple of ribs to replace some that I mangled during the last attempt.

(Time: 2 hours)

Skin bender

I have the homemade skin bender set up again. It's ready to test bend a couple of pieces and then on to the tank skin.

(Time: 2 hours)

Finished drilling

I finished match drilling all the holes in the new tank skin. I cut the hole for the fuel filler flange and drilled the drain hole. I also timmed the skin to the correct length.

Now I need to bend it. I pulled out the parts for the bender. I need to stop my Home Depot and grab a new and straighter 2x4 and the wax ring for lubrication! :-)

I'm really dragging my feet on this... I sure hope this skin comes out right as I really don't want to do it again. I was telling Bill this weekend that I'm kinda wishing I hadn't tackled this long range tank setup. It's been a bit of challenge. Hopefully once it's all over with I'll be glad I did it.

(Time: 1.5 hours)

Drilling...

I finished match drilling the holes for the top side of the skin. Next I'll drill the holes for the bottom side and trim the skin the the correct length.

TIP: For anyone that's doing this. The rib holes for the inboard and outboard fuel tank rib are different than the interior ribs, so be carefull when match drilling. Really, it's the one rivet hole next to the baffle holes that is off.

(Time: 1 hours)

Starting right fuel tank

I brought up the new tank skin, did some measuring to see how parrallel the edges were cut. (Within a 1/32").

Unfortunately the vendor didn't do what I asked by puttin vinyl coating on both sides and one side is pretty scratched up. I called to complain but they said tough shit. He didn't recall that I asked for that and it wasn't on the order. I filed a complaint with the KC BBB. For the record, don't do business the Gieske Sheet Metal in Kansas City Missouri. Bad customer service. This all happened about 6 weeks ago. I was so infuriated for about 3 days I couldn't see straight. Sandi will tell you that it takes a LOT to get me mad but when I do.... I'm pure hell to deal with.

Anyway... I positioned the stock tank skin on the new skin for match drilling. I will start that on Thursday.



(Time: 30 min)

Proseal fuel pickup

I had some proseal leftover from the flap trailing edge, I prosealed and riveted the fuel pickup fittings and angle to the access cover plate.

(Time: 30 min)

Root rib work (right tank)

I put the nutplates on the tank access cover and riveted the ring to the rib with the nutplates.

(Time: 1 hours)

Tech Counselor visit

I was concerned about the tank fitting on the spar. There is some twist in the tank and I had to really pull it down on the outboard end to get the holes to line up. So I emailed Richard, one of our tech counselors, about it. He rounded up Ken Perkins, our other Chapter tech counselor and they came out for an inspection.

Good news.. they didn't see any problems. Apparently, having the tank screwed to the spar for a week helped. There is about 7/32" twist in the wing however, which is more than the 3/32" that Van's manual says. Ken and Richard didn't see a problem with this and suggested to take out as much twist as possible when riveting the bottoms skins on.

Whew! Now I have no excuse not to build the 2nd tank.

More tank fitting and wiring conduit

Spent just a little time getting the tank on and in position and screwed on. I'm not sure if I'll have to take if off again at some point or not so I didn't cinch every thing down.

Spent 30+ minutes running the conduit through the ribs. Not the easiest to do, as the holes are only as big as the inner rib of the conduit, so I had to tuck it in itself and slowly feed it through each rib.

(Time: 1 hours)

Fitting the fuel tank

Now that the skins are riveted on, Chuck and I started fitting the fuel tank on the spar. Needs a little tweaking and adjustment but we are close to getting it on and fitting well.

(Time: 2 hours)

Fuel tank leak checking

I ordered some EZ-Lube from Aircraft Spruce this past weekend and it showed up on Friday. Seems that getting the fuel caps to seal during leak testing is very difficult. The EZ-Lube goes on the o-ring to help it seal.

Fuel tank checking can be done a couple of ways. Some builders put balloons on the fuel inlet/vent tube and pressurize the tank until they are inflated. Let them set for 24 hours and if they are still inflated.. your good.

The other method I think is a bit more accurate and almost as easy. I made up a manometer with a piece of 1/2" ID clear tubing from Home Depot. I attached it to the fuel fitting and then capped off the vent line. I attached the tubing in a U shape to a piece of plywood and filled it with some colored water. Once the tank was all sealed up, I turned the air compressor very low and blew some air into the tank from the fuel drain valve. I put enough pressure to seperate the two columns of water about 16" or so. (Don't over-pressurize your tank!!)

The first try yielded a very fast drop of pressure... UGGH! Out with Mr. Bubbles to look for leaks. First leak was the capped fuel vent, so I used some fuel lube on it. The next TWO leaks were on the access cover. I didn't have two of the screw tightned all of the way so it was blowing big bubbles. The 4th leak was at the fuel cap, which was expected. I put some more ez-lube on it. Took a couple of trys to get it positioned so it wouldn't leak.

At this point I am declaring a leak free tank. It's only been a couple of hours... but I think things are good and tight.

I've heard about keeping the shop temperature constant while checking as it can make a difference in the water column levels... well, my shop temp is dead on 69 degree's but my columns are fluctuating up and down by 1/2" or so. I marked it then was out of the shop for 5 min and come back to a 3/8" drop. Crap.... I marked where it had dropped to, just to see if it kept dropping. 30min later it was above the original mark.. and 30 min after that it was up 1/2" from the top mark. It is very windy out today and I think there must be some fronts moving through.

Manometer setup
Changing levels/pressure

(Time: 1.5 hours)

Last two nutplates

Before putting the skins on for the final time, I need to finish the two extreme outboard nutplates that I hadn't taken care of yet. Should have done it a long time ago. This required putting the fuel tank on the spar so I could back drill the skin. I'm using a #6 screw for this hole since I am so close to the edge of the spar. (Rest of the tank attach screws are #8 which are larger.)

Outboard nutplate configuration

(Time: 1 hours)

Deleted entry... moved to wing log.

Finished countersinking

Tonight I finished countersinking the tank attach holes in the spar. You'd think it would go quick but it didn't seem to. Of course I have holes the entire length of the spar.

(Time: 1.5 hours)

Access cover and more countersinking

First, a lesson. Bill had asked me earlier this week to come over and check out his riveting job and while over there I was thinking about the little rivet gauges you get with your Avery kit that allow you to check the amount the rivet is mashed. You don't want to under mash it or over mash it. The gauge just has a notch cut out. Then it dawned on me.. what do you do about measuring dimpled holes? That would make the rivet stick up a little more. I had no idea. Well, Bill clued me in. The rivet gauge has a hole on one end that you use when measuring rivets that are in dimpled holes. (I thought it was there just to tie them together if you wanted. DUH!) BTW, rivets should be compressed 1.5 times their diameter.

Rivet gauges

Anyways.. tonight I put on the tank access cover plate. A rubberized cork gasket is used to seal the plate to the rib. Apparently it is common for this to starat leaking after awhile so many builders proseal it on as a preventative measure. Of course, this makes it difficult to remove if necessary. I confirmed with Van's about the leaking and they said that yes, sometimes it is a problem. For now, I prosealed under the screw heads and will leak test the tank. If it passes, then I will proseal around the edges of the cover as preventative maintenance.

Access cover/root end of tank
Baffle in place

I also spent some time countersinking the spar tonight.

(Time: 2 hours)

Test fit of tank on spar

The tank has had time to cure so I put it on the spar to check the fit. The fit is OK. Not perfect and not bad. The right tank will hopefully come out better.

I back drilled the remaining screw holes in the skin with the holes in the spar. Deburred and dimpled the holes. I need to fabricate a couple of stiffeners since the tank baffle doesn't run the lenght of the skin but I have holes clear to the end. This is actually a good thing as the skin would tend to pillow between the ribs I think.

Did a little cleaning and prepped to finish countersinking the spar for the nutplates.

I need to put on the tank access cover now and get it leak tested. Need to find some instructions on how to do it.

(Time: 1.5 hours)

EAA Meeting and project visit

I'm organizaing a weekend seminar with Bob Nuckols in Kansas City, so I attended EAA Chapter 91's meeting tonight to promote it. They have a beautiful chapter hangar and meeting room! They had Dr. Dickmann, the regions flight surgeon give a talk which was informative.. even if I don't have any medical issues. I also got to go over Larry Youngs RV-9A which was in the hangar. Larrry is the chapter president and just received his airworthiness certficate. Good looking plane.

I also visited Bill Gill's RV-7 project tonight. He's having trouble finding a tech counselor and wanted me to inspect his rivet work on his HS before he closed it up. All I have to say is that his work is superb and was a bit of an inspiration to do better on my own project. My work isn't bad but sometimes it lacks in perfection. I'm not building a show plane by any means but I do want a nice looking plane. :-)

Here's a shot of me and my sweetie in San Francisco in October just before we checked into Alcatraz. I'm the tall one goofy one, she's the shorter pretty one. :-)

Matthew & Sandi at Alcatraz

TANK COMPLETE!

I am happy to say that the fuel tank is now (nearly) complete. Today I riveted on the rear baffle. Man o man what a chore that was. Thank goodness I only have to do it one more time.... have to say it was the worst part of the tank process.

I cleaned up the tank, primed the outside of the baffle, marked the position of the brackets and double-checked it on the spar, then tackled the beast.

TIp #0: Mark the orientation of the z-brackets and double-check it. I'd hate to think what you'd have to go through if one got put on backwards!

TIP #1: GET A PARTNER. This is almost a must.

Planning ahead, I read up on Dan's site to see if there were any gotcha's I should plan for. He basically said the same thing I'm saying.. get help. He also pointed out a couple of things I hadn't thought about. (Using solid rivets on the root rib.)

TIP #2: Get a 60cc syringe to proseal with.

I had seen on Andy Karmy's site that he used some 60cc syringes to apply proseal when sealing the tank. I orderd a half dozen in anticpation of using them but ended up not on the ribs. For the tank baffle, you put a bead of proseal just forward of the rivet holes and then drop the baffle in place, pushing the proseal as it goes, creating a good seal. Van's suggests using a plastic baggie and cutting the corner off. That didn't seem to appealing to me, so I mixed up a big batch of proseal and put it in the syringe. WORKED GREAT! Laid down a near perfect bead.. no fuss, no muss.

TIP #3: It takes a lot of proseal!

My first batch of proseal was 60 grams + hardner. That did about 3/4 of the bead. Had to quickly mix up another batch of proseeal (50 grams). (Remember, I have 3 extra fuel bays, so for you stand tank buildes, the 60 would have been enough.)

Got the proseal down and then slid the baffle in place and proceeded to cleco EVERY hole. This is where the partner comes in. There are a ton of holes (more in my case). Got those in place. Since Sandi had to leave, I had her help me buck the root rib rivets real quick. I then started putting the z-brackets on. Kinda thought I should get those first. I had a very hard time getting the pop rivets to go in. I finished 3 brackets and got too frustrated, so I started the skin-to-baffle rivets. I don't think the instructions call for it, but I did dab some proseal in the holes on the bottom row as none had oozed out. Thank god for the pneumatic squeezer, it made it go quicker. Finished the bottom side and then finished the top side. (Not terribly happy about them.. they stick up just a bit above the skin.. not a smooth surface. I think the proseal was enough to make them sit proud. ) This is also where your partner could help out. They could remove the cleco's, dab some proseal while you squeezed.

TIP #4: Make your countersunk holes just a tad deeper than necessary to account for the proseal.

Now back to those (*@!*$& brackets. This time I took the ends of the rivets on the scotch brite wheel just enough to give them a pointier tip. This made all the difference in getting them to go in the holes. I managed to get them all put in place.

Dan made a smart comment on his site about turning the tank nose up so the proseal will settle onto the baffle. Did this and then started on some cleanup.

From the time I mixed the proseal until I put the last z-bracket on was just under 3 hours! I was beat!

(Time: 5 hours)

Deleted entry.. moved to wings page.

Root rib

Tonight I prosealed in the root rib and associated components. Squeezing the rivets was a breeze with the pneumatic squeezer but the nose reinforcement plates were a bit difficult. For some reason I had a hard time getting the holes to line up. Of course you can't see the holes with all the proseal smeared everywhere.

I primed my z-brackets and scuffed the outside of the baffle getting it ready to prime. Once that is primed and ready, I'll put the baffle on and the tank will be complete!!! Things should progress quickly this weekend.

(Time: 2.5 hours)

More countersinking

I swung by my tech counselor's house tonight and he flared my vent lines. I finished countersinking the tank attach holes on the top side of the spar. I'm waiting to do the bottom side until I match drill the holes in the tank skin. And just for the fun of it, I hooked up my fuel float to the fuel gauge. It works.. big surprise.

I'm ready to put in the root rib and then the baffle.

(Time: 1.5 hours)

Root rib fittings

Tonight I prosealed on the vent tube and fuel pickup fittings. No big deal. I also worked on countersinking the holes in the spar for the dimples in the tank. I think I've already done a good portion of this on the right wing spar.

Fuel pickup (inside)
Fuel pickup (outside)
Vent tube fitting (outside)

I saw a post in the RV-9 Yahoo group about self-etching primer in a aerosol can. Had to get some.. so I ordered two cans from a supplier in California. I then called around locally and found some so I grabbed 3 cans for $8.50/ea. Well today I came home to a package from the California vendor. $12/ea + $12 shipping!!! Ouch! Should have cancelled that order.

SEM Self-Etching Primer #39683

(Time: 1 hours)

Fuel tank float

Kinda piddled around tonight playing with the rear baffle to see how it fit. I also finished bending the float wire. (The float wire is steel and requires a hack saw to cut!)

Fuel sensor float

I can now understand why the gauges are accurate with low fuel but not full tanks. In order to get the float 1/8" from the bottom of the tank like the plans state, the float is about 3/4" from the top. No biggie, would much rather it be accurate down low then up high.

(Time: 1 hours)

Outboard rib

I went ahead and put in the outboard tank rib and generally cleaned things up. The inboard rib and baffle are really all that remain on this tank to proseal. I need to install the tank vent and the few misc. pieces on the inboard rib.

TIP: Drop your gunky cleco's into a container of MEK and they clean up well when your done.

(Time: 1.5 hours)

Interior ribs complete!

KANSAS CITY CHIEFS 9 Wins-0 Loses!!!!

I continued through the afternoon working on the interior ribs. I finished those up and then riveted the three outboard ribs.

Bowl-O-Gunk





(Time: 4 hours)

2 more ribs down... 8 to go.

Ran to Wal-mart for rubber gloves but they didn't have them in bulk. I did pick up some cheap tupperware cups to use as mixing bowls.

TIP: Proseal is sticky, gooey, THICK stuff. Trying to mix it in paper or plastic cups is difficult. WalMart has these tuppoerware bowls for .63 cents for 2. They work great!

Had to run to Home Depot for rubber gloves.

Back in the shop I started seating the next rib. It came out well.. went better than my first.

Before proseal
Proseal glopped on. (At this point, just use a plastic putty knife to smooth it out to the right thickness.)
Inserting rivets (I have some hemostats that work perfect.)
Rib complete!

(Time: 2 hours)

One tank rib down....

Watched a DVD after my morning proseal session to let my brain cells regenerate then back to the shop where I put the skin back in the cradles. I cleco'd in the ribs and tackled the first one. (Started in the middle)

Ribs are a couple steps up the challenge ladder over the stiffeners. Having two people would probably make it easier, one to buck and one to run the gun. The row of rivets on the top side of the skin came out good but the row on the bottom stick up a little... not sure why other then just being uncoordinated with gun and bucking bar.

I decided to call it quits after the first rib. I ran out of rubber gloves.

TIP: Use tape to mask the skin!! It doesn't take long to do and leaves you with a very clean tank. Proseal sticks to everything it touches. I put one piece on each side of the rivet holes and just peeled it off when I was done riveting. Leaves a perfect clean looking line

(Time: 1.5 hours)

First session complete

I finished the remaining sitffeners and then did the fuel drain and fuel filler flange. Everything went very well I think. The worst part of the whole thing is the smell of the MEK, it's potent. The proseal itself doesn't smell that bad. It is sticky so it can be a challenge to work with.


Session #1 Complete!



Fuel filler flange

(Time: 2 hours)

First ProSeal session!

First thing I ran to Wal-Mart to get a few more supplies. (Digital scale, kraft paper, cups and an apron).

Mixed up a small batch of proseal and got ready to start my first rivet. Here are the steps I used:

1) Blob proseal on interior rivet line and used puddy knife to spread evenly.
2) Dabbed proseal in dimples on exterior and inserted rivets with tweezers. Covered with rivet tape
3) Wiped ooze from rivets.
4) Smeared proseal on stiffener and placed on rivets.
5) Back-Riveted!
6) Dabbed proseal of heads of rivets and 'filleted' as much as possible.
7) Cleaned up the mess and moved on.

Prepped and ready.
First prosealed stiffener
4 Stiffeners complete

(Time: 1.5 hours)

Prepping for ProSeal!

I countersunk the fuel filler flange. I also put the first bend in the fuel float wire. I then just generally prepped for my first proseal sesstion.

Float wire

(Time: 1 hours)

Tank access

I riveted the reinforcement ring to the inboard rib and the nutplates onto the access cover. For grins I attached the fuel sender just to see how it looks. I marked the float wire where the bend needs to go.

I washed some of the smaller tank parts in preparation for prosealing.

Inboard rib
Cover plate w/ fuel sender
Reinforcement plates

(Time: 1.5 hours)

D&D, Misc

I deburred and dimpled the ribs. Scuffed up the flanges a bit for prosealing. I drilled the holes in the tank filler flange. Fabricated the vent tube clip doohickey. Drilled a 7/16" hole in the inboard rib for the vent line fitting.

I think I"m getting closer to being ready for assembling the fuel tank. Need to countersink the tank filler flange and dimple the holes in the skin for the filler flange. Need to wash the ribs and various components to get the dirt/grease off them. Then I think I'm ready!

(Time: 2.5 hours)

Deburring & Dimpling

Back from Chicago....

Finished deburring the left fuel tank skin. Scuffed the lines of rivet holes and then dimpled them all. Next item will be to deburr and dimple the ribs.

(Time: 2 hours)

T905 & T410 Fabrication, deburring skin

I finished fabricating the T410 nose reinforcement plate and the T-905 reinforcement/attach plate. Rough cut them with bandsaw, filed out the grooves and cleaned up with 3M wheel.

Completed about 3/4 of the hole deburring on the skin.

I'm off to Chicago for 5 days this time.... so no updates until next week! I'll finish deburring the skin and then I need to start deburring and dimpling the ribs.

(Time: 2.5 hours)

Leading edge ribs

I dismantled the tank tonight and match drilled holes for the two outboard ribs. I decided to use tank ribs here instead of the leading edge ribs. Since the tank is obviously removable and runs the lenght of the wing, I can't use the leading edge ribs as they are normally riveted to the spar.

After disassembling the tank, I realized I forgot to fabricate the reinforcement brackets for the inboard and outboard ribs, so I cleoc'd those two ribs back in and started fabricating the brackets. Use the the bandsaw and a brand new 18tpi blade... cuts through the aluminum like butter. Didn't realize how dull my old blade was!

(Time: 3 hours)

Baffle work...

Lots of progress today. Started off by finishing the countersinking of the skin-to-baffle holes on both sides.

Countersunk holes

I also mounted one more z-bracket to the spar. Once that was complete Sandi helped me put the tank on the spar. Using Dan's fuel tank mount instructions, I needed to match drill the baffle to the attach brackets. Problem was that it was a long ways in to reach the rib and the 90 degree drill attachment I have is very wobbly. Not sure what I was going to do, when a solution presented itself.

My tank baffle is about 8" to long on the outboard end. I intend to trim it off but haven't yet. What this allowed me to do is clamp a spare z-bracket to the end and drill up from the bottom through a lightening hole. Then I could cleco the holes to hold the baffle in place.

Tank on spar
Looking in from the outboard end
Look up in to the lightning hole

Once that was accomplished, I removed all the cleco's attaching the skin to the baffle and also the inboard rib. This allows you to pull the skin off, leaving the baffle exactly where it needs to be. I think just match drilled the brackets using the holes in the baffle. Prettly slick. I unbolted the brackets from the spar and then marked each bracket for it's location.

Result

I stopped by Lowe's on the way home from breakfast and picked up some "Proseal Supplies"...

Supplies

(Time: 5 hours)

Tank baffle

Finished drilling the skin-to-baffle holes and started countersinking them.

(Time: 2 hours)

Tank baffle

$80 lighter and I have two new tank baffles. Visual inspection indicated they did a great job, measured inspection after I got home... they bent it within 1/32" on one baffle and 3/64" on the other. I have to admit that I'm impressed and pretty happy about it.

I matched drilled the z-bracket holes using the stock baffle. As usual, I forgot to take into account the offset rivet hole on the end ribs. Once they were all drilled I started on the long row of baffle-to-skin holes.

Baffles side-by-side
Initial test fit
Match drilling holes
Test fit
Tank

(Time: 3 hours)

Inboard tank rib

Still waiting for my baffle to be bent so I started working on the inboard fuel tank rib. This is where the fuel pickup and fuel sensor go, as well as providing access to the interior of the tank.

Instuctions say to use a flywheel cutter to cut the big hole but I didn't have one big enough, so used my router to rough out the opening and then a file to smooth things out, then a bit of sand paper and the 3M wheel to finish it off.

Pay attention to the plans on this. I had actually cleco'd the wrong rib into the tank. It seems logical to me to have the rib flanges on the inside of the tank, providing a more flush exterior. Problem is that the indentations in the rib get in the way of the access cover ring, so they have it the other way. Good thing I caught that!

Next I matched drilled the ring to the rib. Again, pay attention to the plans. I orginally (back awhile) thought that the nutplates were just riveted to the ring... wrong! The rib gets dimpled, the manufactured head of the rivet goes on the outside of the rib, through the ring and then the nutplate, keeping everything secure. The ring gets countersunk for accept the dimples in the rib.

TIP: Read the manual. I've gotten really bad about just winging it. I need to get in the habit of looking at the book.

Picture 1
Picture 2
Picture 3
Picture 4

(Time: 3.5 hours)

Tank baffle

Just dropped off the aluminum sheet to be bent for the rear baffle. Will cost me $80. Hopefully they'll get it right. Didn't say when it would be done but he did say not today. :-)

Drilling left fuel tank

Back from San Francisco, where I managed to pickup a 24-hour nasty. I started the evening off by cleaning things up a bit and rearranging the wing stand. I dismantled the right wing and reconfigured the stand to hold just the left wing. Having both in the stand is too much trouble... hard to work around.

I matched drilled the ribs and stiffeners to the skin. Match-drilled the fuel-drain flange. Riveted a few platenuts onto the right wing fuel tank attach angles. Dismantled the partially cleco'd right fuel-tank. I'm going to finish the left one then go buy a new skin. I also need to go have my tank baffle bent. Hope to do that tomorrow sometime.


(Time: 3 hours)

Z-Brackets - Countersinking & Nutplates

Riveted on what nutplates I had left to the right tank attach brackets. I ordered more from Van's. I bolted the left tank brackets onto the spar in preparation of drilling the tank baffle holes.

I won't be able to use the stock tank baffle as I was hoping I might. The rivet holes don't line up on the the 3-bay extension. So I'm going to have to bend my own tank baffle (or have someone do it for me.)

I'm off to San Francisco for 5-days so no updates until next week!

(Time: 2 hours)

Z-Brackets - Countersinking & Nutplates

I countersunk and attached nutplates to the left fuel tank attach brackets. I started the countersinking on the right tank brackets.

(Time: 2 hours)

Z-Brackets

Continued working on the fuel tank attach brackets. Place them on the spar with the center bolt, square it up, back drill the other 2 holes. Move on to the next one. I also worked out the placement for the 3 additional brackets. I'm not sure what logic Van's used for the direction of the brackets but the additional 3 pretty much dicated themselves where they needed to be. One of the brackets sits right next to the tie-down and aileron bell crank. After drilling them I drilled the holes for the nut-plates and started counterskinking.

(Time: 2.5 hours)

Left tank on wing!

This morning I finished cleco'ng the ribs in the left tank and cleco'd in the rear baffle. Rearranged the wings in the wing stand and then set the tank onto the spar. BEAUTIFUL!! Sandi and I were both very excited. It looks like a wing! It even fit great!

Wing 1
Wing 2
Wing 3
Shop 1
Shop 2

Ok.. now what about this darn right tank skin. I put it back in the cradles and attempted to get everything to go together. I did get some of the ribs cleco'd in but it was really tough. I've decided to trash this skin and start over with a fresh piece. It actually works out OK because this was the first skin I started on and made a few mistakes. This will allow me to do a better job.

Ok.. so back to the left tank. I pulled it off the wing and put it back in the cradles. Started contemplating how to handle the rear baffle. My thought is to somehow use the stock baffles and 'splice' some extra onto the end of the stock to extend it out as far as I need. I don't think this is going to work because in order to provide some strength, I need to overlap the pieces and I can't do that because the z-bracket sits right there and that would make it stick up too far. I have the material to bend my own, so I'll try that first.

I started working on the z-brackets by drilling the #30 hole using the hole guide Van's provides and then enlarging it to 3/16". I'm going to follow Dan Checkoway's procedure for mounting the tanks.

Drilling the z-brackets

I'm heading out to visist a new RV-7 builder, Bill Gill. He's getting close to starting his first batch of riveting on his tail.

Back from Bill's and I hid out in the garage for an other hour or so. (4 teenage girls running around the house.) I put the z-brackets on the spar and back drilled the other two holes. I need to figure out the placement for the extra z-brackets.

TIP: Don't forget NOT to drill 2 of the z-brackets. The two inboard brackets get slight different spacing. The directions state this clearly but as usual I got into a rythm of drilling the brackets and forgot to hold back two. I"ll have to order 2 replacements.

(Time: 5 hours)

Tank Assembly - Good & Bad

I hot-glued felt to the tank cradles to keep them from scratching the surface any more than it already is.

I cleco'd the bottom row of tank ribs to the skin and popped it into the cradle. Ugggh.. the top row of rivet holes doesn't line up. They are about a whole rivet hole off. Called Ray to ask if he had to mangle the ribs to get them to fit. It didn't sound like he did but he did say he ended trimming the foremost little tabs off to prevent them from scratching the skin.

Crap.. now what.

Yanked that skin out and tried the other skin. Bingo! The holes line up with this one. I did discover that the two end ribs have one rivet hole that is different than the inner ribs. WHY?? That doesn't make sense to me at all.

Here are some shots of the tank.

Tank 1
Tank 2
Tank 3

Not sure what I'm going to do about the other skin. I think the problem is that the bend line isn't where it should be. There is too much gap between the nose of the rib and skin. May have to reassemble my skin bender and see if I can bend it in a little closer.

(Time: 2 hours)

Skin, rearrange shop, tank holder

Sandi and I bent the 2nd fuel tank skin tonight. Wow what a relief to finish those. I was in a complete rut about it. I have a 2nd wind and am ready to tackle the tanks.

Taking skin out of bender.

After bending the skin I needed to rearrange the shop a little. After that I cleaned off the 'wax' from the skins.

Ended the night building the tank cradles. Since my skin is long, I made eight of them.

Next stop... installing the ribs and final drilling.

(Time: 3.5 hours)

Success!

I've been rackin' my brain on how to get these skins bent without investing major amounts of $$. So I called Dad. You gotta love Dad! Told him what I was trying to do and what my problem was. He confirmed my problem but came up with something I hadn't thought about. "Son.. your problem is lubrication! Go down to the hardware store and get yourself a wax toilet bowl ring...rub that on your skin and 2x4's. That will keep the skin from binding against the 2x4." (Taking great liberty here.) Ok.. that made sense to me. He had a couple of other suggestions as well.

Off to the hardware store I went (after doing some flying first.. gotta do that more often, I'm getting sloppy.) Bought a wax toilet ring thing and another piece of angle iron.

Long story short, I got the skin bent. The wax definatly helped. I still had the problem of the center portion of the press bowing up but I used a 2-ton bottle jack and some 2x4's run up to the ceiling joists to push it down.

Here's the result. Now I just have to get the other one bent.

Success!!

(Time: 2 hours)

Still struggling

Uggh.. the bending saga continues. I thought I had it licked last night but nope... the skin is just so long that whatever I use flex's in the middle. I get good bends on the ends but he middle flex's. I even bolted a 3/8" think hunk of flat iron to my 2x8 to keep in from flexing. Didn't work, even it flexed!. (My 1 foot test piece bent beautifully.)

Not sure where to go from here. I'm trying to figure out a way to apply pressure on the center of the jig.

(Time: 3 hours)

Struggling with fuel tank skins

My first attempt at bending this skins didn't work.... and neither did my second. The first attempt put a nice bend on the ends but the middle portion of the skin didn't bend well due to flexing of my wood jig. Second attempt failed for same reason.. to much flex in the wood.

I'll try again for the 3rd time tomorrow. This time I'll do it exactly as was suggested, which I probably should have done in the first place. If it doesn't work I don't know what I'll do then!

First Try - Image 1
First Try - Image 2
Result of First Try

2nd Jig - Image 1
2nd Jig - Image 2
2nd Jig - Image 3

After looking at the pics, this may require some 'splaining. Basically you bolt two 2x4's to the floor about 2" apart or so. Then you drill holes in the floor and put some thread anchors in and install the threaded rod. Get yourself a straight 2x8 and attach a 1" pipe along the edge. Drills holes in each end for the threaded rod to go into.

The theory is that you place your skin in the middle and start tightning the nuts on each end. The vertical 2x8 forces the skin down into the slot created by the 2x4's on the floor. Actually this works REALLY well on small pieces.

(Time: 4 hours)

Skin bender & tank parts

I constructed the "skin bender" today. Basically I needed a way of bending the new skin to shape. The RV-9A wing is asymetrical... the bottom is flat and the top curves up.

It a nutshell, I screwed plywood to the shop floor to act as a base (later will become the holders for fuel tanks. I then screwed a 1" diamter piece of electrical conduit to the edge of a 2x8x12. Since the conduit only comes in 10' lengths, I had to add 2 feet. For the long piece, I put 3 screws, one on each end and one in the middle. I countersunk the holes a bit and then filed the heads till they were flush with the conduit. Then I drilled a 3/8" hole on each end of the 2x8 to screw into the floor, thus clamping the skin between the plywood and 2x8.

Skin Bender #1
Skin Bender #2

(Moved on.. can't bend it myself.)

I constructed the anti-rotation bracket for the fuel tank. Plans call for a 9/16" hole in a 1x1 bracket. I discovered during a test fit that the bracket wouldn't sit flush on the access plate, so I turned the holes in to U's. (I've seen builders do this anyway to make it easy to remove the fuel pickup.

Anti-rotation bracket #1
Anti-rotation bracket #2

(Time: 4 hours)

More fun with skins

I drilled the left wing screw holes tonight and then cleaned up the shop a bit. Next step is to bend the skins but that probably won’t happen until next week. We are headed out for a couples retreat this weekend.

I did get my camera back today so here is a shot of how I setup the skin to back drill. That’s me laying on my back on the floor drilling up from the bottom. And Winnie the shop mascot checking out the insides of my wing.

Self-portrait
Shop Mascot 1
Shop Mascot 2

(Time: 2 hours)

I bought a 12" # 19 drill bit on the way home. I drilled out the right fuel tank skin screw attach holes by drilling up from the bottom trough the bottom flange then through the top flange and finally the skin. I'd drill 3 or 4 holes then put a cleco in. After drilling the top row of holes, I started setting up to drill the bottom side holes and then decided to hold off until after I had assembled the fuel tanks. This way I can be sure the holes line up laterally (length of the wing). If I drill both sides now, I run the risk of them not lining up perfectly once the tank is assembled.

I hung the right wing in the wing stand and setup the left wing for drilling. Junkyard MegaWars was on so I didn't get a lot done.

(Time: 2 hours)

Tonight I started planning how to drill the extended fuel tank attach screw holes. The inboard ones were match drilled from the stock skin. My plan is to back drill from the spar through the skin. So I cleco’d on the wing ribs to the right wing and then cleco’d on the top skins. I pulled the wing out of the stand and placed it on some tables. I’ve laid the new skin onto the top of the spar and pushed it up against the top skins. I need to get a long drill bit to drill up from underneath. (I was planning on a right angle drill attachment but I think I can drill straight up from the bottom by putting the bit through the holes in the bottom flange. I just need a long #19 drill bit.


Once I get them drilled I’ll be ready to bend the skins at which point I get to start actually working on assmbling the fuel tanks. So far I’ve added 21.5 extra hours to the process prepping the new skins.

Time: 2 hours

Skin drilling

Tonight I finished drilling the left fuel tank skin holes. No mistakes on this one! I also drilled the fuel filler holes in both skins. I used the existing skin to draw the circle where the hole goes then used my router to rough cut the hole and then a file to final size and sand paper to clean it up. Wish I had pictures but don’t have my camera back yet.

Time: 4 hours

Tank stiffeners and skin drilling

I finished drilling the other half of the right wing fuel tank skin. Got drill happy and drilled a row of stiffener holes that I didn’t need and drilled 2 tank attach holes that will be in the wrong place. (I match drilled the inboard tank attach screw holes but the outboard section I will have to match drill with the holes in the spar. Fortunately they are on the bottom side of the skin. As for the extra stiffener holes… well, guess I’ll put a stiffener in. J)

I also finished deburring the tank stiffeners themselves. Easy job using the 3M wheel. Realized I didn’t quite cut the inboard stiffeners correctly and had to trim a little more off. (I had the top part right, just didn’t trim the bottom edge like I was supposed too.)

(Time: 3.5 hours)

I broke the procrastination spell tonight and started drilling the holes in the new skins. I loaned my digital camera out so I don’t have pictures but I basically laid Van’s tank skin on top of my blank, clamped it along the edges and started drilling. Once I started drilling I used clecos every 4 or 5 holes to keep things in position. I started at the inboard end then moved the skin over and drilled the outboard end. The ribs are 10” on center. I’m keeping to that except for the 2 outboard ribs where I’ll space them a little farther apart. The outboard rib will obviously be clear at the end. The next rib will be 17” from 3rd rib primarily to clear the lightning holes in the spar. I plan on using the z-brackets the entire length of the spar. I finished one side of one skin so I’m 25% done! Woohoo. The rest should go quicker now that I’m comfortable with everything.

(Time: 3 hours)

Tank access covers, tank stiffeners and skins

Started off the morning with the intent to cut my new skins to length. I tried using my jig saw with a metal cutting blade but that wasn’t going to do it. The blade is too flexible and you can’t cut a straight line with it. I put that aside and played with the fuel tank access cover and reinforcement ring. Deburred them on the 3M wheel, countersunk the holes in them. Then I read the directions and discovered that the reinforcement ring gets riveted to the rib, so I’ll have to countersink the holes a little deeper to accept the dimple in the rib. (I really haven’t been reading the manual much... just kinda going with things.)

Made a run to Home Depot to grab a router bit, some 1” conduit and a 1x6x12’. Dropped the stuff off at home and then headed over to Ray’s house for a visit. I needed to return his edge roller and borrow his angle drill attachment do-hickey. I also wanted to see how he was progressing. He’s finishing up the firewall stuff and prepping to paint the interior. The next time he bolts the engine on should be the last. Came home, ate and watched the tube for a bit and then headed out to the garage.

The router bit worked FANTASTIC! I cleaned up the edge I cut with the jig-saw, then cut the other end so it was the proper length. I clamped my long level to the skin to act as a guide for the router. In the process of moving the first skin around, I managed to knock off a metal clamp which landed right on the skin I just cut putting a nice ding in it. &(**@#(!!! Can’t

(Time: 5 hours)

Rib fluting and planning

BTW, after nearly 2 months without rain, it rained 10”+ over the last 4 days!! We needed it!!

Today was a pretty lazy day and was hard to get motivated to do anything. I finished fluting the remaining fuel tank ribs as best I could. I wish I could tell you I figured out how to do it but I really didn’t. Some ribs were easier than others. I usually had to aggressively flute the third and fourth hole from the leading edge and the rest as much as required. The two end ribs that seal off the ends of the tank were the hardest and I never did get them fluted well. We’ll see what happens when I try and assemble things.

I have to tackle this new fuel tank before I can go much farther, so I spent most of the evening just kinda of goofing around with things. I had some scrap .032” that I cut with the jig-saw as a test to see how straight I could cut it. Didn’t come out too bad but wasn’t perfectly straight either. Debating on whether or not I should just cut it this way or take it to have it cut. I don’t know what I didn’t have the sheet metal place cut it to length… didn’t want the additional cost I guess, figuring I could just do it myself. Still may. Anyway, after cutting the test piece to the width of the fuel tank skin, I matched drilled it using the existing fuel tank skin as a template. After that I dimpled the screw holes to #8 to see how things fit on the spar. It fit well. Next I attempted to put the leading edge bend in it. This was just a test to play with ideas I had and to see how close I could get. I used a piece of 1 ½” PVC pipe screwed to a board. My test piece was sandwiched between the pipe and board. This .032” is stiff and requires some ummpff to get it to bend. The bend came out looking good but was way off from where it needed to be. (This is why you play with scrap pieces first!) Also, I think the 1 ½” bend radius might be too big. Will try a 1” piece tomorrow. I’m still thinking how best to bend my 10’ 7” long piece. I have some plans from Bill VonDonne who had to bend his Sonex leading edge.

(Time: 4 hours)

Yet more countersinking, rib fluting.

I finished drilling the last row of nutplate holes and then worked on countersinking the rivet holes. The only holes remaining that require CS are the larger hole for the #8 screw/dimple. I’ve held off on doing those so I can use them pilot hole as a guide for back-drilling the new skin.

I also started fluting the fuel tank ribs. This task has become my new ‘most hated task’. The wing ribs are easy to flute since they are straight. The fuel tank ribs are curved and severely out of shape due to the stamping process making them very difficult to flute. I posted a message to the RV-9A Yahoo Group to see if I can get any tips on this.

(Time: 6 hours)

Shop Visit

Tonight Bill and Patty, a local Kansas City couple, came over for a shop visit. Bill is finalizing his decision to build an RV-7 and wanted to make sure he knew what he was getting into before committing. He brought his wife along so she could see the process and to talk to my wife. We had a great time! I’d recommend sharing the RV story with other potential builders and their spouses.

My order from Van’s arrived as well. I ordered additional tank ribs, stiffeners, tubing and some UMHW tape.

(Time: 0 hours)

Countersinking

Worked on countersinking the holes for the nuplate rivets. I’m almost done with this.

(Time: 1 hour)

Drilling nutplates

Since my new skin will run the entire length of the leading edge on the wing, I first needed to extend the nutplates the entire length. I used the existing holes for one end of the nutplate. I wanted all the screws to line up the entire length, so the nutplates have to sit at a slight angle then the stock ones. I essentially drew a line where the center of the screw hole needed to be, clamped on a nutplate and drilled out the center hole and the other rivet hole. Maybe a few pictures will help.