Elevators

So now that the rudder is done (less the fiberglass work) I have moved on to the elevators. Not much different than the rudder. The construction seems to be not any more difficult, except for the trim tab, but no worries. The elevator tip ribs have several rivet holes in the trailing edge that are very tight. However, turns out the factory has pre-dimpled these holes. Thank you,... thank you very much. In blogs of builders who have come before me, this had been a problem so this stress I don't have to deal with.
One thing the plans didn't tell is how to deal with the trim plate that holds the trim servo or the trim cable. By looking at other blogs, I figured out the rivets that hold the nut plates need to be countersunk. I chose to do this before assembly. The plate is a little thin, but these rivets are non structural since the screws will hold everything together when assembled, so I am not worried about over countersinking. This turned out to be a non-issue.

I am ready to start assembly of the elevators, but wouldn't you know it, its raining in Los Angeles, go figure. So am on hold until I can spray primer. Maybe I should re-introduce myself to the kids ;-)

So got the elevator skins, ribs and all remaining parts primed today. I found it much easier to deburr and prime the skins and ribs before match drilling. What I did was to deburr the holes as they came from the factory using 300 grit paper, then wiped down the inside of the skin with lacquer thinner, let dry and prime. When I get around to match drilling to final size, I will use a reamer instead of a drill bit and touch up the holes afterward with a counter sink. Using the reamer, it seems the major burrs are from the factory punch, not from match drilling.
In order to prime the skins, I built a jig to hold open the skins.

Rudder Fun

Well I have been working on the rudder. By far the most difficult part to date. This piece requires taking the time to plan and figure things out.

I didn't want to buck all the rivets because my bucked rivets are not as good as those when I use the squeezer. So I had to buy a 4" yoke for the squeezer to reach the rivets.

Also the screws that hold the lead counter weight are #10 with a 100 degree countersink. So had to get a #10 dimple die for this screw. Lastly, I had to relieve the lead weight to clear the forward most rivets of the rib.

I needed what is called a longeron yoke to get the rivets on the control bracket, but didn't have one. I ended up putting a nut under the rivet set on the squeezer and this worked.

When I riveted on the doublers and nut plates to the spar, the 3/8" heim joints would not screw in. So I drilled out the rivets, inserted the heim joints in the nut plates and then riveted the doublers and nut plates to the spar. This was the only way to get everything lined up while riveting and I had to use the  4" yoke and longeron trick.

To make the trailing edge angle tooling that will hold it straight while assembling, I match drill all the trailing edge parts, then double sided taped the AEX strip to the aluminum angle and match drilled the angle to the AEX strip using the drill press.

When countersinking the trailing edge AEX piece I made a simple wood jig and used a allen wrench that was just big enough to hold the trailing edge flat.

No where in the instruction manual did it say when to rivet on the rudder bracket. This should be done just before the first skin is riveted on. I riveted the top of the skin near the balanced weight, and then had to carefully lift it up to get the rivets squeezed holding the bottom bracket; it would have been better to do the bracket before the skin.

As per the instructions, I  bonded the trailing edge together with pro-seal using the aluminum angle tooling on the outside to keep everything straight, waited three days, and then riveted. The trailing edge came out straight, but I seem to have gotten some separation of the trailing edge skins from the AEX wedge, and some pillowing between the rivets. This really bothered me until I read other blogs, and I am not the first. There is pro-seal on all the surfaces, so it is not an adhesion problem. Maybe it was too thick. Next time I will use a scrap pick of angle and squeeze the trailing edge together using seaming pliers immediately after assembly. This should squeeze out the extra pro-seal leaving a very thin layer to bond, hopefully eliminating the pillowing. For the separation, I tried re-riveting the end but it didn't change anything. It is acceptable, just not preferred. Maybe in a year or two, if I haven't come up with anything better, I was thinking of adding some JB weld to the seam to fill in the gap, making for a rigid, impervious, blunt trailing edge; nothing I can do about the pillowing an it is very slight. 

"Just keep swimming.." Dori

I was able to add some wall art to my shop, namely the completed horizontal and vertical stabilizer!
The vertical stab came out good but not great. I vowed to improve my riveting technique half way through..I had a problem with the rivet gun slipping while using the mushroom set for the flush rivets. This would cause a minor smiley or indentation in the skin. I decided to try some double sided tape to see if it would help. I was worried about it leaving the rivets set high. Turns out it worked great. It was sticky enough to keep the mushroom set from slipping, but not sticky enough to prevent removal. You can see in the picture the first rivet I did with this strip of tape left a circular indentation in the tape, but it came away intact from the rivet/surface. I think this is the new way for me when riveting with the gun solo.

Now onto the rudder and elevator.  I was able to prep, mix the primer, shoot, and clean up the mess in about 4 hours. Not too bad and I think worth the effort.. I love the 2 part primer; so much better then the rattle can stuff. If I add drying time into this analysis, priming with 2 part is less time than rattle can, and cheaper too. My prep was simple, wipe with acetone, then shoot, being careful not to touch the surface with my hands. And I did this before dimpling. I am only priming the inside part of the skins, but both sides of ribs, spars, and everything else.

Priming lessons

So....
Started using the proper primer instead of the rattle can stuff from the local auto parts store. This is the same Sherwin Williams P60G2 primer that Vans Aircraft uses, but in the US it is tinted green.

There is a fellow builder, Sam, using  Dupont Veriprime615s. He seems to have had great success brushing the primer on. This sounded great and easy. So I tried that technique with the SW P60G2 on the rear spar of the horizontal stabilizer. Here are my results:

They have a molted appearance, but all the metal is covered, and it isn't too thick... But man is it fugly (really ugly).

So I bit the bullet and decided to brush up on my painting skills using a spray gun (pun intended). I was 18 the last time I painted aircraft parts with epoxy paint; all I remember is plan and prep, plan and prep.  I was going to build a spray booth, or downdraft table,  but this was a lot of infrastructure, and stressing over this became no fun. So I just decided to keep it simple and spray the stuff with cardboard on an old table. The stuff dries really fast once sprayed. And the over spray is easy to control since it is going on very thin; not much worse than rattle cans.

It worked out well. The primer was hard to get stirred up, until I took it to a paint store and had them shake it. Mixing the catalyst was easy, felt just like old times. My prep is simple: Scotchbrite the dimples and very smooth areas of the skins and spars, wipe down with acetone using gloves, and then spray. I didn't go for this 3 stage process others are using with etch, alodine, and whatever. (Some people don't even prime, and the plane comes out fine; do you believe that? ;-)

Below is my vertical stuff all primed. Maybe I will wait a day before assembling, to give it time to harden.

This has been a yuge learning curve but now time to move on. Not sure if I will prime the wings or not. But probably wont prime the fuse because I will be crawling in there a lot and I want the reflection of the metal to help with lighting during inspection.

Busy Few Weeks

These last few weeks have seen great progress.

The horizontal stabilizer is complete less the rear spar; waiting for the rear spar to be primed before installation. The vertical stabilizer is ready to be primed, then riveted.

 I had a tech counselor visit and reviewed my work to date; all is well. We went for a quick flight in his RV9; it flies really well and seems to yearn to be in the sky.

The tech counselor showed me his tungsten bucking bar, and I now own one too. This is a must have tool in my opinion, especially for the front rivets in the horizontal stab. I would recommend buying the smaller bar, something like the 1/2" x 1/2" x 4" for less than $100. I got a slightly the larger one and it seems a little over kill for the tail feathers, but will probably be good for the beefier fuselage and wing rivets.

In addition to finishing the horizontal stab and making good progress on the vertical stab, I picked up the wing kit from the factory. I also picked up Proseal for the rudder and the locking gas caps. I would like to have the wings started before the New Year.

More steps

This weekend, I was able to complete the right side of the horizontal stabilizer. And the local high school celebrated with fireworks.

This was a major riveting sessions. I wish I would have bought a tungsten bucking bar for the nose ribs; it is really hard getting in there; those rivets aren't pretty but acceptable because I had to make do with the bars I had. I tried using a big chisel and other thin steel objects, but they just didn't have the mass to buck. It can be done with the standard bucking bars, but just takes time and yoga.

This kit is very precisely made; if the holes are off by a few thousandths of an inch, then something is wrong. The skin needed some clearance filing around the front spar brackets. Otherwise the skin would have been right up against the brackets. This could produce a squeak in flight, or worse, be a start for skin cracking. A few swipes of a jeweler file relieved the skin a few hundredths of an inch. 

First Rivets

I managed to rivet my first part, the horizontal stabilizer's front spar. I think it came out pretty well, but we will see what the local EAA

tech counselor thinks about it.

Primer woes

As I complete the horizontal stab dimpling and prepping for assembly, I was hit with the imfamous primer plaque.

My plan was to use rattle can primer on the horizontal stabilizer because there are holes in the rear spar and water can get in when parked. Since primer is not required, I figure simple rattle can would be adequate without the hassle of the two part stuff. Boy was I wrong. The rattle can went on fine and hardened up Ok after a week, but any hint of a chemical nearby and it curled up and was useless.

In addition, when priming the spars, a few drops of sweat got under the primer and got trapped there. Of course this will stay forever since the primer seals out, and seals in, moisture. Come to find out this leads to corrision problems. So I had to go over the spars and remove the primer where moisture got trapped. Then during touch up, the old primer reacted and a mess was made. I was able to get the front spars acceptable, but the rear spars required stripping the primer off completely.

For the priming, I think the only way to go is two part primer. The factory recommended Sherwin Williams s60g2 was out of stock; but I will wait and reprime the rear spars with this two part primer. It is more work, but the rear spar seems to be the most exposed to the elements.
Lesson learned: learn from others, do what others have had success with. In this case two part primer

Better Builder

I dont think I am very good at building yet because I am just starting this journey. But I took a day off from building and went surfing with my daughter. It was fun. Towards the end of our session, the waves started walling up and I got rolled in two waves. It is an interesting feeling, being in a ball underwater, trying to keep from getting dorked in the head, waiting for the board leash to pull tight so you know the board is away from you. When I got out, I noticed what once was a straight leash now had a knot; still cant explain how I tied a knot in a leash while it  was on my foot and attached to the board. So I guess I am a better builder than surfer; not saying much for my building skills.

While last week I was able to get the spars for the horizontal stab countersunk. This was the first real test of my building and machining skills and came out good. I was also able to prime the skins, ribs, and miscellaneous brackets. The forward attach brackets are 6061 aluminum and need to be primed. Since I am using rattle can primer, I went ahead and top coated these in white paint to provide proper corrosion prevention.

The FAA likes to see a few pictures during the build with the builder in the picture, so here you go. I am sure when I am flying, in (cough) years, I will look exactly the same.

Paraphrasing a smart man: slow, steady progress is still progress.

Horizontal Stab #2

Been working on the stab as per plans.

I originally only bought 100 clecos, those silver things in the picture, but seems 150 would make it easier and faster. More are on order.

The kit has the pilot holes in the parts very precisely punched using a computer controlled machine at the factory. Very precise. Much like an Erector set. In the horizontal stab jig, the rear spar holes where a little off, probably 3 thousandths. I lifted up the stab from the fixture and everything came into alignment. It seems if the holes in the mating parts don't match up, something is wrong. In this case, the jig is probably not precisely leveled. No big deal, just gotta take that into account. Others say that on first flight, most planes fly very true; this probably has a lot to do with the precise fabrication of these parts.

Not much else to report as I progress through. This is fun.

Horizontal Stab

This weeks progress has been the first half of the first page of the instructions. I have decided not to count hours; I don't really want to know. So if anybody asks, the answer is 1/2 a page :-)  And I will be done on Tuesday. I figure counting hours would be like these credit card mileage plans; they are a scam to get one to buy more stuff one didn't know one needed.

So all ribs and spars for Horizontal stab will be done tomorrow. I am looking forward to the first flight rivet in two weeks, I figure.

I originally tried the butterfly deburring tool on the ribs, but this didn't work. I tried a scotch bright wheel, and this seemed similar to using a die grinder to trim fingernails.

What I settled on was 1/4" strips of 320 grit sandpaper with the part clamped loosely into a plastic hobby vise. It might take a little longer than the scotch-brite wheel, but I think it will feel a whole lot better when I am 3 miles up.

The spars were a challenge not so much because they were hard, but because they take careful work. Here precision seemed to pay off.

I still haven't decide to prime or not, but am leaning towards priming and painting rear spar white to match the elevator hinge brackets, and then priming all faying surfaces with rattle can.

Steady progress is my goal.

Officially started

So I have officially started the tail feathers. Not a lot to write about but inventory is complete. I have finished the tool box and am very pleased with the results. I have brought some parts to the hotel to deburr during a soccer tournament weekend. I figure hours on the project are hours towards completion, no reason to let a little soccer interfere with progress. Besides teenagers don't really want to hang around with dad all day anyways when there are teammates to bond with.

Progress

So I have completed the sample wing section practice kit from Vans. This practice kit uses all the tools so is very helpful in getting to know my way around cleco pliers and such.

A word about reamers and drill bits; the holes in the parts are prepunched on a very precise CNC machine so everything lines up. If things don't line up, something is wrong. I found the clecos from Brown Tools are professional grade and line up the holes precisely. The prepunched holes are slightly undersized and need to be enlarged to final size. This can be done with a standard drill bit or a reamer bit. The reamer looks like a drill bit but the flutes are straight up and down. I use the reamer just like a drill bit and enlarge the holes to final size. The reamer produces a nice clean hole that is perfectly round and others say less prone to cracking; reamers also tend to leave smaller burrs so deburring seems to be minimal.

Deburring was a challenge. Most of the tools I tried for deburring the holes were too aggressive. I found what works best was a 120 degree counter sink on the end of a tapped rod. And for the skin edges, the old tried and true butterfly deburring tool works great (red handle on bench). For drilling out bad rivets, the drill press was invaluable. I can lock the piece down to the table and use an end mill to knock off the head. It turns out the heads of a squeezed rivet are pretty hard and it is easy to bugger the flight piece if not careful. All the more reason to make the rivets right the first time, quality is never having to say rework. I also made a holder for the clecos. This was suggested by a mechanic friend and was a great idea.

I thought I would get away without having a belt sander, then I realize the reinforcing strips of the practice kit didn't fit without heavy mods. I tried to trim with snips and files, but was not  happy with the results, so I broke down and bought a belt sander and added it to my lazy Susan in the background. What a difference. I also tried to rivet with the DRDT2 in the foreground and that was hopeless; there was no way to secure the part and operate the handle while keeping everything aligned. My best rivets were with the Cleveland Main Squeeze shown in the corner of the bench; what a nice tool. I used the close edge dimpling tool attached to the bench in the corner with the rivet gun to dimple the ribs; this was noisy and brutal. The results were good, but it is still too out of control for my liking. So next time I will either use the Main Squeeze or I will make a top guide for the rivet tool to keep everything lined up. The less I rely on my holding things straight, the better the results seem to be. Jigs are our friends. Also, having the work well secured seems to make it much easier to add a little English to the tools to keep everything lined up as the rivets are formed.

The practice kit came out fine with errors that are easily corrected. I feel confident that the skills I have tested are good enough for real parts.

So I am making progress. Who needs sleep, there is plenty of time to sleep when I am not building.

Learn by Doing

So tools are at critical mass and I have started the practice kits. First impression are the tools from Cleveland Tools and Brown Tools are first rate; they are high quality and reasonably priced. I bought the professional  surplus tools whenever I could and that worked out well. Sorry to say, but most of the hand tools I bought at Harbor Freight I ended up returning and reinvesting on similar items from Cleveland and Brown.

First discovery is that those machinists scales are hard to read; the 1/32 of an inch graduations must have gotten smaller over the years because when I was 18, I could read them no problem. So it IS true the world is getting smaller.

I found using the dial calipers as a measuring tool works much better than the machinist's scale. Also, the 10 year old Craftsman drill press was a score. Small, precise and nice to work with. What I did not expect is the trouble with deburring. I Invested in several different kinds of debuting tools for the small rivet holes, but still not happy with any of them. The best I found is a countersink threaded into a handle. But the alclad is soooo soft I am still way over deburring. The so called " deburring" bits left too many chatter marks in the soft aluminum. The best was the 100 degree countersink in the handle. Interesting that this produces a flat spot the rivet will sit on when dimpled to accept a 100 degree rivet. But this flat spot exists in the first place because the hole was over deburred. My last attempt is to try a 120 degree counter sink for deburring since the hole burrs are mostly normal to the surface and not inside the diameter. For the prepunched kit parts, I plan to enlarge the holes using  reamers, rather than drills, which should minimize the amount of deburring.

The best tool is the Main Squeeze rivet squeezer from Cleveland. Very precise, light and accurate. I bought a used DRDT2 and it need a but of filing to get aligned, but once set works well too. The slow dimpling speed makes for precise work, as opposed to using a hammer and c frame, and the Wack-A-Mole technique. The aluminum skin is soft and thin, so a fast dimpling force doesn't seem to be needed. But alignment is critical.

Tools and Tools

After the great big learning curve on airplane tools, I think it is time to begin. The tools were not really more expensive than I anticipated, but just mind numbing with all the options. I think this is where a weekend course or the guidance of an experience builder would come in handy; before buying having tried the tools on a sample project, or helping another builder and learning the tools, would probably have saved some grief. But I do want to thank my friends who have stepped up and helped me out with tools they no longer use.

I started looking at the practice kit, and realized one of the first tools I need, is not one I had anticipated buying right away; that is a close quarters dimple die set. But the practice kit needs this for the ribs. So that is on the way. These tools are not really expensive in terms of dollars, but are in terms of time waiting to get started.

Next stop on this journey is completion of the practice kit, to see if I feel good enough to start on things that will leave this earth (and I don't mean being flung across the yard in a desperate rage)

I made the standard EAA workbench... except I used 3/4 melamine, made a 2 inch lip all around for clamping, and added inserts to hold the DRDT2. I also made a lazy susan for the drill press, grinder and belt sander (not shown) so that I can put this up against the wall and minimize wall space for these tools. Notice the tail feathers on the shelf with the earthquake safety straps around the boxes ;-)  Next to the band saw is the real estate for the compressor. Hopefully I can wire it for 220V to minimize the light flicker when it turns on. Besides the compressor, the only thing left to do is add the retractable power cord and retractable air hose, both mounted on the ceiling.

The Gathering of Stuff

As I continue to look at the tail feathers still packed neatly in the box, I realize the beginning of the journey is difficult.

I have been spending a lot of time organizing the shop and acquiring the tools. I still have not reached critical mass on the tools to start the practice kits. But reviewing the plans brings back memories of helping others build their planes so many years ago. I remember learning how to rivet from Bill Statler, both father and son, on the Wildfire Reno Air Racer pictured below. I guess I wont know how good I still am (or ever was) until I start the practice kits.

It seems the road to starting is challenging. Lots to do to get a shop functioning at the minimum level needed. I wonder when I actually start the project itself, if it will somehow be anti-climatic; like planning a long vacation in a foreign land and then finally arriving.



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