EAA Technical Counselor Visit

I invited Norm, our EAA chapter's Technical Counselor over to take a look at my project. It's not a requirement but I really wanted to have another set of "educated" eyes look at how I was doing early in the project. I'd hate to get to the end of the build and have someone ask why I put all the rivets in backwards! Norm has built the same aircraft that I'm working on and is finishing his second (an RV-9). He's what you call a repeat offender. Anyway, Norm was nice enough to drive over from Seguin and give me some good pointers and validate that I wasn't putting the rivets in backwards. Thanks, Norm.

I'll let you read what he wrote. No, I didn't bribe him with a beer or anything!

Rudder Ready for Button Up

I finished all the prep work for the Rudder and now it's time to button it up. Here's the view of the inside of the rudder that won't be seen after riveting on the other side skin.

Here's the front of the rudder at the bottom. The hole is where the hinge rod will be screwed. On the right side you can see a couple of manufactured heads of rivets. I'm proud of those as the plans call for optional pop-rivets if you can't get a good structural rivet in there. With the help of my trusty tungsten bucking bar, no problem!

Here are some of the stiffeners that I got help riveting (see the video several posts back). The specs are dust that I'll blow off before sealing it up.

Dimpling the Narrow End of the Rudder Rib

Here's another McGyver tool. I had to dimple the very narrow end of the upper rudder rib. My visegrip dimpler wouldn't fit in the last hole so I had to improvise. I used my pop-rivet dimpler with spacers and came through the opposite side hole.

Turned out just fine:

Dimpling the Rudder Spar

I'm working on dimpling the rudder prior to riveting and got a visit by niece Micaeli. She was here for Shelby's birthday. Happy Birthday Shelby! She helped by dimpling a couple of holes in the lower rudder spar. Thanks! Also got some help dimpling from R who came out to the shop to see what's new.

Change In Direction

Well, after all the work I've put in on the airplane, I've decided it's not for me. I'm going a different direction now and plan on building a Shelby Cobra replica car. I saw a couple dozen of them drive through town last Friday and loved the look. It's all aluminum so the construction is surprisingly similar to aircraft construction so I'll have a head start on the learning curve. I'll keep you updated under the same label below as this post.

Rudder Taking Shape

I got the rudder temporarily clecoed together. This is one of those deceptive stages of building. It looks almost complete but there's really a lot left to finish. From this stage, I will match drill all the holes. That means a lot of cleco moving. Then, I'll disassemble everything and deburr all the holes. Next, all the external holes and the corresponding understructure gets dimpled. Then comes edge finishing, scuffing, cleaning and priming. Oh, and don't forget fitting the lead counterweight and epoxying the trailing edge wedge and rolling the leading edge. All that before riveting. But...it does look like an airplane part for now!

Rudder Riveting Party

Everyone wanted to get in on the rudder riveting party today. First, my Dad and his friend Irene came by for lunch and a look-see at the airplane. They both did a little riveting. I had the camera set up so I got a little stealth video of my Dad riveting. Then Shelby came home to pick up Hadley (named after Hemingway's wife that loved cats) the cat. She tried her hand at a little riveting and did great. Then Paula tried it and did great also. Thanks for all the help finishing up riveting the stiffeners to the rudder skins!

Drilling the Rudder Stiffeners

Here's a little video of me drilling the rudder stiffeners. One of my neighbors told me the pneumatic drill sounds like I'm torturing cats. The other sound is my too small compressor kicking in. If it looks like I'm drilling into the workbench, you're right! The instructions actually recommend that you drill and cleco right to the workbench to keep everything flat.

Trimming the Rudder Stiffeners

Here's one of the rudder stiffeners all trimmed and sanded and smoothed. The rule of thumb for how smooth edges need to be is if there's no chance of getting a cut from the edge, it's good to go. The stationary belt sander and scotchbright wheel make it fast and easy to do.

Here are the scraps left from trimming the stiffeners. I took a picture of the pile because I thought it looked interesting. I once took a picture of a slimy green rock in the headwaters of our local river and framed it and entered it in the county fair. It looked like art to me. I can't help it if no one else can see art like I do, including the county fair judges!

Plans for the Rudder

Here is the page from the plans for the rudder. The rudder has a lot of stiffeners instead of a skeleton structure of ribs and spars. There are also parts fabricated from raw stock, leading edge rolling and lead counterweights. Something new.

Stored the Vertical Stabilizer, Rudder Next

With the Vertical Stabilizer finished, it's time to move to the rudder. Here's Austin helping begin the rudder by drawing a robot on the box the rudder skins are in. He's so funny!

Here's the Vertical Stabilizer stored on the ceiling of the garage next to the Horizontal Stabilizer. I like having the parts displayed as an extra motivator and reminder for the next step.

Finished the Vertical Stabilizer

I finished the Vertical Stabilizer today. Another small milestone. There are 4 basic parts to building the empennage. This is the 2nd sub assembly I've completed.

Avery Hand Squeezer

I received the Avery Hand Squeezer today. I also got a standard 3" yoke (it's the one in the squeezer below) and a 4" thin nose, no-hole yoke with it. I've already used it and REALLY like it, much better than the Tatco squeezer. The no-hole yoke makes it very easy to get into those hard to access places.

Finishing the Vertical Stabilizer

I'm almost done with the Vertical Stabilizer but I'm stuck on the rivets that are adjacent to the spar doubler. Everyone on vansairforce.net said you've got to have a narrow head no-hole yoke for your squeezer and this picture shows why. I've ordered one from Avery Tools and it should be in Wednesday.

Vertical Stabilizer Ready to Rivet Skin

Here's the Vertical Stabilizer ready to rivet the skin. It doesn't look much different from a previous post showing the VS skinned but a surprising amount of work goes into getting it ready to rivet on skins. You've got to match drill, deburr, dimple, clean, scuff, re-clean, prime and rivet the skeleton before you get to this stage.



Here's a picture of the inside of the VS that will be closed off after the main spar is riveted. This is another of those places where a lot of care goes into getting it right but no one will ever be able to see it except with pictures like these.

Riveting Vertical Stabilizer Spar

Here's the setup I used to rivet the main spar of the Vertical Stabilizer. The spar has a thick stiffener so it takes a bigger rivet. Part of the fun of building is "McGyvering" a tool to get the job done. It may be hard to see, but I've shimmed and taped spacers to my C-Frame to get the spar at the right height to use the rivet gun on the AN4704-7 rivets.

Primed Vertical Stabilizer Skeleton

I got all the ribs and spars for the Vertical Stabilizer primed. I've been using the shipping box the empennage came in as my paint booth.

Skinned the Vertical Stabilizer

I got the skin on the Vertical Stabilizer. Preparing the skeleton went fast as it is very similar to the Horizontal Stabilizer. Next, I'll match drill the skin to the spars and ribs before removing the skin to deburr, dimple, prime, reinstall and finally rivet.

Rib Flange squaring tool

Here's a nifty little shop made tool for squaring the flanges of ribs. It's cut with a 10 degree undercut to allow for spring back. I can't claim the design as I saw similar ones on several other RV builder's websites. Some used 14 degrees of under cut which was too much when I tested it.

I used an old hinge which is sorta' loose which seems best as it allows for a little flex when needed. I also found I needed to always have some blue painters tape on the parts that touch the rib to prevent scuffing.

Vertical Stabilizer Plans Page

Here's the page from the plans for the Vertical Stabilizer. Not as complicated as the Horizontal Stabilizer.

Stored the Horizontal Stabilizer

I stored the Horizontal Stabilizer on the ceiling of the garage. It's plenty sturdy and I like that it's in plane sight. I know...I know, it's a lame attempt at a pun! The workbench is looking kind of lonely. Must be time for the Vertical Stabilizer (the front part of the tall tail).

Finished the Horizontal Stabilizer!

Sure was nice to read this part of the assembly manual.



Here's the completed Horizontal Stabilizer along with the intrepid builder wearing his Van's Aircraft hat. It's a small milestone but it feels good to see a part that someone would recognize as belonging to an airplane. I haven't decided where I'll store it but I'd like it to be somewhere I can see it while I'm building for a little added motivation.

Riveting Skin of HS

Here's a little video of me riveting the skin of the Horizontal Stabilizer. First, I have to remove the cleco in the hole I'm going to rivet. Next, I select a 3/32 (really tiny) rivet and put it in the hole. Then, I put a strip of riveting tape over the rivet to hold it in place and keep the rivet set from scuffing the head of the rivet. Finally, I reach inside with my tungsten bucking bar and hold it against the bottom of the rivet while I shoot the rivet from the top. Simple, just lather, rinse and repeat many thousands of times.



Here's the Horizontal Stab almost finished. It's over 8' wide so it hangs over my workbench.

Hidden Workmanship

This is just a couple of pictures of the "inside" of the Horizontal Stab. I'm getting close to buttoning it up and these parts will be permanently inside the structure. It's an odd feeling after having worked so hard getting things right and then realizing after the next steps, you'll never see them again. Really brings home how important workmanship and discipline are. If I wanted to do a fast and sloppy job, nobody would be the wiser but I'd always know and part of the enjoyment of building is doing a good job that you're proud of even if no one can see it.

New Torque Wrench

Arrh, Arrh, Arrh, new tools! This is my CDI 751 LDIN 0-75 in/lb 1/4" torque wrench that I got on ebay at a bargain. Sells for 3x what I paid. Love getting a deal but it's a tool I have to have to get it right. Many of the smaller nuts and bolts are torqued in inch/pounds (instead of foot/pounds) so you need a way to accurately measure them. The elevator hinge bracket on the rear spar right behind the wrench will be the first to get torqued. As an added bonus, the torque wrench also measures in Newton-metres so I can now fly in Europe (there will be a test on pseudovectors after lunch).

Horizontal Stab Rib Re-Do

I had another almost oops on the Horizontal Stab Ribs. I say almost because the goof technically met the requirements of AC43.13 which is the FAA bible on repairs and alterations and also MIL-R-47196A(MIL) which are the Military Specifications for rivets. I just wasn't happy with my work so I ordered replacements. Later in the build, I may just "rivet on" but I really didn't want to start off my build with "just acceptable". I don't want to let perfect get in the way of very good but I also want to be proud of my workmanship even if it's on a part that nobody will see after everything is assembled.



Speaking of oops, these are some oops rivets I ordered from Van's when I ordered the new ribs above. They're used when a hole needs to be drilled out to the next larger size but you want the head of the rivet to match the others around it. Sometimes happens when you replace a rivet and the hole is just beyond limits for the original size rivet. You can go up the the next size rivet but the head ends up being bigger. Using the oops rivets keeps everything looking "purdy".

Riveting the Horizontal Rear Spar

Here's a short video of Dexter riveting the Horizontal Stabilizer Rear Spar. He came over to return my welder and I conned him into doing some work. He's using my new 12" C-Frame back riveter. It's a brand new invention by Cleaveland Tools that makes it really easy to back rivet a universal (round) head rivet using your C-frame so everything is aligned and all you do is put the rivet gun on the top and pull the trigger. This was Dexter's first rivet and it came out near perfect.



I thought the rivets turned out well. No smileys and all the shop heads measured good with my Avery Tools rivet gauge. The new tool made it almost foolproof to get a good set on each rivet. My only experience riveting the larger -4 universal rivets was on the practice kits and this is MUCH easier.

Priming

Started priming the ribs and braces tonight. Weather was perfect for painting; 75 degrees with low humidity. Very happy with the results. Only problem I had was identifying the ribs. I marked them with a vibrating pen but it turned out that the primer is thicker than the marks. I could just barely see all but one pair and I had to remove the primer to see which was left and which was right. I turned the pen up to a higher setting for the next marks.

I'm using Napa's 7220 self etching primer. I first prepped the parts with a maroon scotchbrite pad and followed with a good wipe down with MEK.

Dimpling (Whack-a-Mole)

Finished deburring all the horizontal stabilizer parts and started into dimpling. Below is my C-frame dimpler. It has a 22" throat which is the exact size that allows you to access almost every hole in the skins of an RV. You simply place your correct size dimple dies in the upper and lower holders, align the hole in the skin with the dies, and give it a good whack with the hammer. Kinda like Whack-a-Mole, but Whack-a-Hole (for those not familiar with obscure arcade games, I added a video of Whack-a-Mole below).





This is what a dimpled hole looks like. Dimpling allows the rivet to sit flush with the skin. Making the outside of the airplane smooth makes it faster and much more fuel efficient. You wouldn't think that a small bump from a rivet would make that much difference, but at higher speeds, they add a lot of drag.

Here's the horizontal stab all dimpled.

Clecos

Here's a close-up of a cleco. It's a temporary fastener used to hold things in alignment when you temporarily assemble parts for drilling or fitting. The yellow "bootie" is optional and used to avoid scratches on shiny parts

Pop-Rivet Dimple Die

Here's one of the specialized tools I have to dimple in tight spots. It's basically a dimple die set with holes drilled through the centers. You feed a nail through one die and then through the inside hole needing dimpling. Then slip the other die over the nail on the outside of the hole and use a pop-rivet tool to pull them together.

Birthday Presents

Yeah, more tools! Shelby & Austin gave me these clamps for my birthday. Thanks a million, kid-links. Clamps are kind of like clecos, you can never have too many. Those are Shelby's hands in the picture. Luckily, I'm the one with the password to this blog so they can't post that I'm now 50.

Drilling the Skins

I peeled the blue plastic off the right horizontal stabilizer skin so I could match drill it to the ribs. To match drill the holes, you first put temporary fasteners (clecos) in the every other computer punched hole, and then final drill the holes to size (they're slightly undersized on purpose) and then swap the clecos to finish the rest of the holes. This makes the alignment very accurate.

You can see the reflection of the raised garage door on the skin. Some builders leave their aircraft unpainted and polish them to a very high gloss but they say it's a lot of work to keep them looking good. I plan on painting but the bare metal look is tempting. Reminds me of a World War II fighter.

First Oops

Had my first oops today on a rib in the horizontal stabilizer (the hole should be round, not oval). It was the first time I had used my angle drill and I hadn't practiced with it which was a mistake. One piece of advice I got at the beginning of my flying was that "if there's any doubt, there's NO doubt!" In other words, if you're not sure, err on the side of caution. I probably could have made an acceptable repair but I had doubts so there was no doubt that I was ordering replacement parts. Luckily, Van's sells replacement parts at cost if you've already purchased a kit so it's not a big deal. Try that at the local car dealer.

First Skin On

Finally got a skin on the horizontal stabilizer. Here's a shot of the left half of the stab showing some of the ribs before the clecos go in. This isn't the final assembly but an intermediate step to align and match drill the holes where the rivets go. The skin will come off to be deburred and dimpled before being reassembled for final riveting. The protective blue plastic will be removed before final assembly.

Here's the skin buttoned up with clecos. Clecos are temporary fasteners that hold things together in alignment during assembly. Paula got me the yellow boots for the clecos to protect the skins. It was encouraging to see something starting to look like an airplane part and not just some aluminum scraps.

Countersinking and Dimpling

Did my first countersinking and dimpling yesterday on the braces for the horizontal stabilizer spar. I practiced several times on some scraps as I was nervous about doing it for the first time on the real deal. It came out great.

Here's my Tatco squeezer with Avery dimple dies on the left and my countersink cage on the right. I got an ebay deal on 7 countersink cages and bits so I'll be able to adjust them individually and not spend time changing bits and readjusting for the correct depth for every job which you have to do if you only have one. When you adjust the countersink cage for depth, you loosen the retaining nut and rotate it one "sawtooth" to raise or lower it 1/1000th of an inch. You can see the interlocking sawteeth in the picture below.

Sanding Spar Braces

Here's one of the braces for the front spar of the horizontal stabilizer. Had to taper the ends per the plans and smooth and polish to prevent stress risers. The part will get a 6 degree bend to match the bend on the spar. Got a new tool today that really makes the job much easier, faster and safer.

Here's the new tool in the crib. It's a Craftsman stationary sander with a 6in disc and a 42in belt. Very reasonably priced and sure to get lots of use. You can already see a pile of aluminum grindings below the upright belt.