Van's  RV-8  Project

Empennage

Building the empennage is the recommended first step for new builders. In fact, before working on the empennage, I started with a practice kit sold by Van's where it has you build a sort of small aluminium airfoil. I strongly recommend doing it first, more than once if needed, as it introduces basic technics that will be used later on the actual kit. It permits also to learn the usage of different tools like the rivet gun, the squeezer or the dimpler.

Furthermore, in the U.S.A. the EAA (Experimental Aircraft Association) have seminars on airplane building that are quite useful. There might be some in other countries as well.

The build instructions are fairly detailed at first, taking you step by step throughout the process. The plans are also nicely detailed. Just make sure that the instructions and plans are completely understood before doing something. Sometimes, I spent long minutes, indeed up to almost an hour reading and re-reading, making sure I got the right picture.

Note: This airplane will be flown in Canada. You will need to inquire your country's aviation regulator for any information about certification issues.

As for the certification of my project, since the kit will be built partially in France then imported to Canada for final assembly and registration, the parts requesting inspection will be temporarily closed with blind rivets (called POP rivets) every 5 or 6 holes on one side for easy removal after transport as the MD-RA (the body responsible for inspecting and certifying amateur and experimental aircrafts in Canada) don't recognise any foreign certification. So I can't have French inspectors certify my work then close it up permanently for canadian use.

For Canada, before the start of the actual build, a constructor needs to send a letter of intent to the MD-RA. Please visit their site for additional information.

As for my project, the actual work on the empennage started on May 29, 2012. After approximately 175 hours of building time, the horizontal and vertical stabilizers, the rudder and elevators are done except for the fiberglass work and electrical wiring for the trim tab and lighting which are planned to do near completion of the whole project. For now, one side of every part is only temporarily blind riveted for future removal to permit the MD-RA inspection. Once that is done, if all is OK, the parts will be permanently closed with solid rivets.

Meanwhile, as it happens to quite a few builders, I grew unhappy of the final result of my trim tab. I recently decided to re-order the needed parts for a second, more satisfying version.

 On this page there's a series of photos detailing the process of building the empennage. For extra photos, this PhotoBucket link  has a few more, less relevant photos not uploaded here. On the PhotoBucket site, just click on a photo to see the comments.


To build an airplane, one needs a dedicated space and transform it as a plane factory. Some have the privilege of having a hangar, a double or triple garage adjacent to their home or some other adequate room. Aircrafts have known to be built in strange places. This is what I managed to find that will be my airplane factory. It's a single garage in a residential building, 10 minutes from home and about half way between where I live and where I work. It's very difficult to find some sort of garage in the area and to get permission to use it as a workshop. It's roughly 2.8 x 5.8 metres (9 x 19 feet), has one electric plug and no heat but a lockable door accessed through 2 other locked passages so it's pretty secured. I will need to be creative as a space manager...
After setting up the tools in their respective chesses, soundproofing both the garage door and the compressor, laying carpet, building the small paint booth and the worktables, here's the first layout. It will evolve with time.

Only notable changes since this photo was taken are more lights on the right side and the finished empennage parts are hung on the left wall. I use four 21 watts bright white fluorescent bulbs that gives sufficient lighting while cutting down on the electricity drain of my only plug that's rated to 2000 watts. One bulb is equivalent in light to a 100 watts incandescent bulb.
All aluminium parts are received "rough" from the cutting presses. they all need to be "smoothed out".  This will be quite time consuming throughout the project. First job is to "break" (rounding off) the edges of the rear spar reinforcement bars. Then to trim the ends as per the plans. I used a hacksaw to cut the corners and finished with the Scratchbuilt wheel. The wheel is specially designed for aluminium. Do not use a regular grinding wheel for steel as it will clog up and risk failing and causing injury. It makes a lot of very fine dust, so wear a protective breathing mask. This is a picture of the front spar reinforcement bars but it's the same process. Below is the rough stage and above is the finished stage.
Once the bars are ready after trimming and rounding out, they are "clecoed" to the spar and match drilled. Most of the parts are pre-drilled with pilot holes. Almost all of these holes must be drilled to their final size.
(a cleco is a special cylinder shaped clamp to hold parts together through their holes)
After drilling, all holes must be deburred (removal of debris and smoothing of edges) on both sides. The manual tool on right is for large holes and the one on the left is attached to a slow turning electric screwdriver. One or two revolutions is normally enough. Don't over do it on thin material because you might change the hole size.
This is the center hinge with its roller bearing for the elevators. Only one side and the bearing is pre-drilled. Must clamp all 3 parts together and match drill them to correct size holes. Match drilled to rear spar and reinforcement bars.
The center hinge is primed after drilling and deburring is complete. The bearing was taped for obvious reasons. I chose to prime the hinge even if it was powder-coated from Van's since after drilling, nude steel was exposed. Primed from a spray can.
One of my favorite tool is the pneumatic squeezer or "Jaws". Used to set rivets and dimple holes also with the appropriate accessories. Very useful. To use with caution as it delivers 3000 PSI or 200 Bars.
The first 6 rivets are set! Done with the help of Jaws of course...
The top photo shows the manufacture heads (from the rivet manufacturer) and the bottom one shows the shop heads (made in the shop by the builder).
I make sure that each rivet conforms to a measured standard after setting. The shop head has to be straight, and to the correct depth, neither too short or too long. I use a special gage to measure that it's OK.
The front spar and its reinforcement bars must be bent at 6°. The easiest is to draw the angle on a big sheet of paper. I used the back of the full size building plan.
The bar is locked in a vise, between blocks of wood. Must position the wood block on the bend line marked on the bar. Folded by gently tapping with a rubber mallet. Just had to make sure to bend in the right direction...
Perfect bend!!!

On the lower photo, the 2 reinforcement bars bent.
The same 6° needs to be made on the front spar. Here, it is held down on the work table with clamps and the wood block is on the bend line. I used a thick steel ruler perpendicular to the spar under it to raise it to the correct angle.











Both parts done. The left one has a slight droop that was corrected after the photo was made.
These two ribs must be trimmed to allow space for the front reinforcement bars. Here you see the aft flanges, on the left untrimmed, on the right trimmed as per the plans. I used a hacksaw for the rough cuts then the ScotchBrite wheel to finish. It's important to keep rounded corners to prevent possible cracking of the parts.
The process of forming ribs creates a "banana" curve seen here when it's put against the straight edge of a table. They must be straightened. A fluting plier is used to create dents between the holes on the flanges. These dents "pull" the web straight. Go easy on the fluting, a little at a time as it's possible to over-flute and create a reversed curve. I start in the middle, fluting every other hole at first to straighten about half way,  then complete as necessary.














After fluting, the rib is all good now!!!
The left horizontal stabilizer sub frame parts are clecoed together for match drilling. Missing are the inboard main and front ribs. These will be fitted later.













Then the skin is clecoed to the sub frame for drilling also.

Starting to look like an airplane part :-), but it will have to be undone later.
This is the first "tricky" part of the build.
The inboard ribs are not pilot-drilled so they need to be attached to the skin by special clamps.












The approximate position of holes is marked to permit fluting.















A line is drawn in the centre of the flange, for alignment with the skin holes.
The rib is clamped on again with the drawn line centered with the skin holes. This for drilling and clecoing the rib through the rear spar.













This permits the drilling and clecoing of the rib to the skin.















Then, the front flange is clamped to the front spar and the aft flange of the front rib (not shown) for drilling.
Here I used the angle drill to reach the tight area.












The final result.
Time consuming and complex.
Just make shure that everything is in its correct place before drilling and all should be OK.
One area of concern is this hole in the middle of the photo.
It's on the bottom flange of the main inboard rib close to the front spar, and there's the same on the upper flange.

This hole is drilled with the skin as template and as can be seen, it's pretty close to the edge.

The issue is that prior to the drilling, the instructions have you cleco the rib to the rear spar. So it pulls it back, thus the hole ending up so close to the edge.
I couldn't figure a way how to avoid it being drilled there.

If in doubt, have your hole position checked by Van's.
In my case, it was declared OK.
After the inboard front rib is match drilled (seen here top right), the whole skin must be match drilled to the ribs and spars on both sides. I left every other hole unclecoed for drilling then moved them for drilling the remaining holes. Time consuming but no rocket science here...











After the drilling is done, the assembly is undone for deburring all holes.

The HS skins are ready for deburring of the holes and edge smoothing. The blue vinyl protection is removed completely inside but only over the holes on the outside using a hot soldering iron and a ruler.









As said earlier, an 1 or 2 turn of the deburring tool is sufficient.














Seen here are the small shavings from deburring the holes.
The next step is to dimple the ribs, the spars and the skins so flush rivets can be installed. I mainly used Jaws with dimple dies. This set up works like magic to dimple the flanges of all ribs and spars.
With the help of a blind rivet puller, a copper nail and special close quarter dies, it is possible to dimple hard to reach holes like the ones on the end of this flange.












As seen here, the pull capacity of the copper nail is limited and the rivet stands a bit proud. Stainless Steel nails are stronger and give a better result.
I did rework this dimple to get a better rivet seating.

Since, for hard to reach holes, I prefer using this Tight Fit Dimpling Fixture from Cleaveland Tools.

The hole to be dimpled is placed on the Dimpling Fixture with a male dimpler set on top. Then it is tapped with a rubber hammer
I use a shaft removed from the DRDT-2 (seen next picture) to hold the male dimpler
To dimple skins or other parts when I can, I use a DRDT-2 dimpler developped by  ExperimentalAero.

It is derived from a conventional C-Frame.

This tool, set with dimple dies, is a classic C- Dimpler with an improvement. Instead of hitting the die with a hammer, a simple handle is lowered.
When set correctly, this tool dimples skin holes and other holes quickly, silently, effortlessly, and with consistency.

A great investment !!!


Top photo, before dimpling.












This photo, after dimpling.

One word of caution: Make sure that the male die is inserted in the hole prior lowering the handle.
If not, a new hole or a larger one will be created,  more on this a little further...

Once the complete HS sub frame and skins are disassembled and the blue vinyl removed, all holes must be deburred and all edges smoothed.

Then all surfaces are roughened with ScotchBrite pads and the appropriate holes get dimpled.

After, it's time for priming...
As canadian authorities recommend priming all internal parts, I had to choose my primer wisely.
Aluminium requires some preparation as washing and etching before applying primer.
Some use self-etching primer from spray cans or gun spray but that needs adequate ventilation because of strong fumes and smell.

I found out and use Stewart Systems cleaner, etcher and primer.     International distributors
All aviation designed and water based.
No toxic fumes or residues, almost no smell and a breeze to clean up with water only.

Perfect for my small and poorly ventilated shop.




Having no running water in my shop, I transport my parts at home for preparation.

After a wash and rinse with the Stewart System cleaner (diluted 1:30), the parts are etched (diluted 1:3) for 3-4 minutes and then water rinsed and let to air dry.


























The skins get the same treatment for the inside. Because of their size, I used the shower for preparations.

Note that felt markings will disappear with the etching so ensure that there's an alternative way to identify parts (left-right-top-bottom) for later assembly.

After preparation, I avoid touching the parts with bare hands to not contaminate the surface.

Primer should be applied when completely dry but within 6 hours of etching.
Primed spars.

Seen here are also some parts that belong to the vertical stabilizer.

This shade of gray is not what I intended to use. I ordered what is called "Smoke Gray" which is lighter in color.
However, when I received the primer, I didn't realise that I was sent the wrong color despite what was written on the can.
I only found out later that it was an error.
I finished this can of primer on most of the empennage parts except the 2 elevators.
It doesn't bother me as most of the primer won't be seen and any outside surfaces will be painted with top coat anyway.




















The steel parts come normally powder coated but after drilling, some of that protective coating is removed so I spot primed the holes.








Priming with a spray gun was new for me and it took a while to get decent results.
I had a "cheap" spray gun at first and I really struggled to have it work properly. I bought a better one and it was instantly better!!

I now use about 45-50 psi from the compressor and further regulate at the gun as needed. Then I adjust the paint flow to get a very fine mist, and presto.
After priming, it's final assembly time!

The doublers are clecoed to the rear spar parts.
Notice the masking tape covering the holes that are not to be riveted for now as they will serve to rivet the hinges.












After riveting the doublers and the outboard hinges, the centre hinge is installed with bolts and nuts.

One note, I installed the rivets with the manufacture head on the thicker side. As a norm, when two parts have different thicknesses, like here where the doublers are thicker than the spar, the manufacture head should be on the thinner side when practicable. After consulting, my reversed rivets are considered OK for this situation.
Next step is to rivet the front spar assembly.

As for the rear assembly, some holes are taped for different rivet types.













The 4 centre rivets are flush types as opposed to regular rivets elsewhere.















Seen here is the forward side of the front spar.
Again with reversed rivets.












Then, the 2 inboard ribs are riveted to the front spar.
Here, the left top side of the skin is riveted to the underlying rib. Normally, it would be riveted with flush rivets.
I put 3 blind rivets to clamp down the skin for future removal when the inside inspection will be made by the MD-RA. All the top skins of the HS and elevators and one side of the VS and rudder will be temporarily blind riveted as such.

The scratches on the skin look worst than they really are. They were made when dimpling as I was learning to handle the DRDT-2.












The bottom rivets are installed and they are tough to do because of the limited space and inexperience.I had to drill out 3 rivets and reinstall. The 2nd from the left was done 3 times...



















These blind rivets attach the middle rib to the front spar. Normally, they should be permanent.

Later, I realised that I might have to remove them after the inspection as I won't have access to the front top holes when I install the flush rivets on the skin. Unless I decide to use blind rivets, we'll see...

There will be primer touch-ups made prior to final closing.












One little "smiley" on one of the rivets holding the end ribs.  It's not preoccupying, just cosmetic. Still learning to handle the rivet gun...









After riveting both the right and left side skins, the horizontal stabilizer is done as much as I can. The bottom side is completely flush riveted. The top side is secured with some temporary blind rivets. Next work on this part, apart from putting it in a crate, will be to remove the blind rivets to permit the Canadian inspection.
Following the assembly of the HS, preparation is underway for the vertical stabilizer.

As for the HS, the first task is to smooth the edges of the spar doubler.
The outer edges were done with the ScotchBrite wheel.
































As the inside edges were not accessible with the wheel, they were done with a rough, then smooth hand files and ScotchBrite pads.
Some 22 holes on the VS spar doubler need to be countersunk. I use a microstop holder with the appropriate countersink tool to "dig" the hole to the correct depth for flush rivets. Prior to work on the doubler, I used a piece of scrap aluminium to set correctly the microstop for the required depth.
The same process is used as with the HS. The VS frame parts are clecoed together for match drilling.
The parts are then disassembled for edge and hole deburring. Follows the roughening of the surfaces and the needed dimpling and priming.

The skin is then fitted for match drilling, deburring, roughening and priming also.

This is my first real boo-boo.

While dimpling the VS skin, working too fast or a little absent minded, the male dimpler was not correctly inserted in the hole. As a result, I dimpled just a bit off side and the hole was enlarged slightly. Thinking I could save it by enlarging it more to 1/8" from 3/32", it was not sufficient.

Looking for an answer, I thought of seeking help from a very close friend of mine that works as a flight instructor for a government agency than also has a very talented team of aircraft mechanics.




The two dots with question marks were my idea of putting 2 extra rivets while flattening and smoothing the missed hole.

After analysis, the mechanics proposed a relatively easier fix.
To enlarge the hole to a perfect round and use the appropriate bigger rivet.
They also suggested to use a softer compound of aluminium because of the larger size rivet for ease of squeezing.
The final size shown here is 6/32".



The spar hole also needed to be enlarged to 6/32"















I purchased the needed 6/32" dimple dies for the bigger rivet.

The spar and......















the skin is dimpled to 6/32".
The spar doubler and its hinges are riveted to the spar.
Again, Jaws is a great help here.






























The flush rivets on the VS spar.


















Riveting the VS frame together....
































...and the skin to the frame.
Here are the soft 6/32" rivets and the appropriate dimpler dies for repairing the missed hole on the VS skin.


















The completed VS.
Another small mishap.
While riveting the front and rear ribs to the front spar of the VS, I wasn't happy about the final results of the 3 rivets.

The main reason is my rivet gun/bucking bar handling was not proper and these parts are angled, leaving less space for the bucking bar.
I found out later that holding the rivet gun firmly while holding the bucking bar lightly instead of holding both firmly gave much better control and results.

These rivets were drilled out 2 times and because of this, the 2 lower holes were enlarged to 5/32" from 1/8".




This is why 1 rivet is smaller than the 2 others...
The next part constructed is the rudder.

It's a simple process.

First, rudder skin stiffeners (angled aluminium) come uncut and need to be shortened to 8 different sizes. Regular sheet metal snips are used.









Two sets of stiffeners, left and right side, are cut to the correct size.
Small dents in the full lenght angled aluminium are used to determine the proper cutting lines.












Then some trimming is done to form angled stiffeners.














Finally, as for all parts, the stiffeners edges are smoothed once the blue vinyl is removed.













The stiffeners are clecoed to the rudder skin and match drilled.

Then all holes are deburred and the skin edges smoothed.

Parts are then roughened, dimpled and primed.
Back riveting is the technic used for the stiffeners.

Seen here is the difference between a non-squeezed and a squeezed rivet.
















One side of the skin stiffeners done.











All the stiffeners are riveted to the rudder skin.

Back riveting uses a metal plate under the skin to hold the manufacture head in place while the rivet gun bucks the shop head from the top.


Work is done on the rudder spar. Same as before; drill, deburr, scratch, dimple and prime.

The long bar below the spar is stock aluminium that needs to be cut and trimmed according to plans.
The aluminium bar needs to be cut to proper lenght in 3 parts.





















The parts now cut, trimmed and deburred.
All the rudder frame parts are assembled and match drilled.



















Then disassembled, deburred and ready for priming.
The rudder frame parts are primed, ready for assembly.


















Assembly almost finished.
Finally, the rudder skin is riveted to the frame
The elevators come in 2 flavors, one right and one left. The difference is that on the left side there will be a trim tab, that can be tricky to do.

The first job is to cut and trim the stiffeners for both elevators.

















For the left side stiffeners, there's more trimming to do as per the plans.

DO NOT CUT AS I DID AND SEEN ON THE NEXT PICTURE !!

I misread the plans, and marked the cut too far from the edge.
My mistake was that I used the wrong hole as reference.
On the plans, the distance is measured from the "second" hole from the right.
On the stiffeners, the "first" hole from the right is NOT YET DRILLED.
So I measured from the "third" hole in fact.

On the un-drilled stiffeners, MEASURE FROM THE FIRST HOLE!!






The stiffeners are cut too short.
This is when I realised something was wrong.


The too short stiffeners not reaching the trailing edge!!!

New stiffeners were ordered with the wing kit.
Work then continues on the right side elevator frame.
Here the spar and outboard horn being drilled.








































As for all mobile surfaces, the elevator horn receives a lead weight. This is for balance and to eliminate possible flutter of the elevator.










The brace and lead weight need to be drilled considerably.
Lead being a very soft metal, It is best to increase the hole size gradually.
I used 3 different bits and a slow turning drill.
Don't go in all at once, but drill a little, remove the shavings and repeat until the weight is drilled through. If not, the shavings will clog the hole and block your drill.

Use lots of lubricant to ease the operation.

The spar assembly is now drilled to the skin.

Notice that lead weight is removed for easier handling.
















The inboard horn is drilled to the spar.

This part will receive the pilot inputs from the control stick and move the elevators accordingly.
The same operations are done on the left elevator.

Notice the recessed area where the trim tab will be installed.
The right elevator being lighter as it doesn't have a trim tab, the lead weight needs some trimming.

Some of the lead is cut off from the block.

Again, it is best to do slowly, and with lubricant.

I used a normal steel hacksaw and it was a pain to do.

I later learned that by using a saw with wider spaced teeth, it should be easier to cut.











The resulting "lighter" lead weight.

I kept the shavings as the elevator will be balanced only on final assembly when the painting is done. In case I need to add weight, I could use these.
Some elevator parts need countersinking.

Here the spar, where the 2 middle holes were done with the microstop tool but the 2 outside holes had to be countersunk by hand with just the cutting bit as the holes are too close to the flange. A deburring tool can also be used.










The depht of the countersink is checked with a rivet.
















On the left elevator, the trim tab spar gets countersink holes all along to permit the flush installation of the hinge.
After priming, here are most of the parts for the right elevator ready for assembly.

It's relatively simple to do.














First, the stiffeners are back riveted to the skin.
















Then the horn and spar are assembled.













And the control horn is installed.













The lead weight is bolted in its place.
Before riveting the skin to the frame, it needs to be "bent" to about its final angle.

For this, I use two wood beams attached together with a lengthwise piano hinge.

The carpenter clamps serves as handle to apply pressure on the skin's trailing edge for bending.









The bent skin.

Advice: don't do this prior to priming or riveting the stiffeners but only when ready to rivet the skin to the frame.










The skin riveted to the frame.















The last rivets near the trailing edge can't be reached with the squeezer or a bucking bar.

I modified this bucking bar to get a thin steel surface that could fit in the tight space.

Starting on the left elevator skin, the first job is to draw the bend line for the trim tab. It has to be perpendicular to the rivet line edge and 1/32" towards the outwards to allow for bend radius.

The tabs are bent using some triangular pieces of wood clamped in place.
The tabs are bent using Van's recommended procedure using wood blocks. The bottom tab is bent first so the top tab is outwards to prevent water from coming in.
The left elevator frame primed and riveted.

















For some reason, I missed the instructions about installing the 7 platenuts on the trim tab stiffener before riveting it to the skin. The platenuts go just around the centre "house" shaped hole where there's groups of three holes close together. I managed to install them afterwards but it would definately been easier to do before.










The left stiffeners riveted to skin. There are 6 missing (3 on top, 3 on bottom). Remember the stiffeners I cut too short???
This part, called E-713 gets beveled or thinned on the aft and inboard sides (where there are grinder marks) to permit a better fit with the spar and skin of the elevator. It is then touched up with primer.

It's part of the brace that holds the lead weight to the elevator outboard horn.
Work on the trim tab is started. Here, the trim tab servo horns are match drilled to the skin.

















The top of the trim tab spar holes are countersunk to accept the dimpled skin. Depht is checked with a rivet.













The spar is now countersunk on top and dimpled on bottom.






































The trim hinge needs to be trimmed to fit correctly below the skin and spar of the elevator.













The trim tab parts are primed and ready for assembly.

After the priming of the trim tab parts comes tricky operations.
The bending of 4 tabs.
The trimming, drilling, positioning and riveting of the assembly to the elevator.

I followed Van's recommended method for bending the tabs, but wasn't quite attentive to one detail.
The result is a "bruised" trim tab. Nothing too dramatic and reparable with some putty prior to painting.
The positioning of the trim tab is also not to my liking. Even if it was as much forward as possible, it's still protruding slightly by about 1/16".
Again, probably not too problematic.

Having slept on these and knowing that I could do better, I chose to build the trim tab again and ordered new parts from Van's.

The following photos will show the first attempt in building the trim tab and hints to avoid some mishaps.

The trim tab is one assembly that frequently gets re-built.
I believe that it's not too complicated in itself but small "newbie" errors and inexperience could be the main reasons for unsatisfying results.

The bending of tabs.

With the two triangular blocks of wood, normally it should be a relatively simple thing to do.
The first challenge is to clamp down everything in line. The blocks lined up with the bend lines.
With the two blocks and the two clamps moving around, it is recommended to use double sided tape to help in positioning them.
More on that later...

Once everything finally was clamped down, I didn't notice that the top block was too high on the skin, causing an ugly dent near the trailing edge.







The dent can be seen here, bottom left.
Like I mentioned above, it could be reparable with some sort of putty or filler before painting.

I took more care with the position of the blocks on the other side to prevent the denting of the skin.




















Here, the blocks must of slipped so slightly inwards and the bend was off line towards the centre.

Again, not too critical I believe.

Both sides now have defects that could be avoided.
As for the double sided tape, it worked so well being that its glue was very efficient.

So efficient that it left quite some amount of it with some wood also stuck to the inside of the trim tab.

















With patience and the help of thin tools and a lot of glue remover on rags and cotton swabs, I finally got rid of the glue.


I will use a different method of bending the tabs next time aiming to get better results and no glue residue because no tape is involved.

Expect newer photos in time describing this other method.
The hinge is clamped the trim tab spar for drilling and trimming.
















The line here corresponds to the elevator's inboard edge.
The hinge is cut along this line.














Now the trim tab assembly gets positioned on the elevator.

The trailing edges of both parts must be in-line.

However, the trim tab sticks out by about 1/16".

The hinge that gets riveted to the elevator will need some trimming for the trim tab to align with the elevator.

This will be done on the re-build.





I may have missed the instructions to dimple the servo motor stiffener prior riveting it to the skin. It was a pain to do. So an advice here is to dimple and install the platenuts before.
The servo motor bracket is drilled to the acess door.

Then all holes are dimpled.













The servo motor bracket and acess door primed.
















And riveted.
The trim tab servo motor is in place.


Still to do: shorten the push/pull rod to the correct lenght, then attach it to the tab horns. Once that is done, full travel must be checked and adjusted so maybe some trimming of the acess door might be needed but only well later as I'll be rebuilding the trim tab assembly and hinge.










Remember the too short stiffeners?? Here are the new ones, cut to the correct lenght, deburred, dimpled, primed and ready to go!!












All stiffeners riveted in. I had to use some blind rivets near the trailing edge because I couldn't reach the rivets.

The cause? I bent the trailing edge before installing the stiffeners.

Lesson learned: Some steps can't be jumped ahead of others...




All 5 empennage parts are now hung in storage.

Next work on them will be rebuilding the trim tab.

When I have some time, I will construct custom crates for protection and transportation.

The parts will be permanently riveted and closed after the MDRA inspection. Then the fiberglass parts will be installed.

PLEASE NOTE THAT STORING PARTS WITH THE BLUE VINYL CAN INDUCE SOME SURFACE CORROSION AS CAN BE SEEN ON THE NEXT PHOTOS.
This surface corrosion was found under the blue protective vinyl.

Van's recommends to remove the vinyl for such reason and it's also known to be harder to remove as it gets older.

These parts were just over one year old when the vinyl was removed.









I used 400 grit paper and a sanding block to gently remove the corrosion.














After the surface was rid of the corrosion, a light spray of primer was applied on the affected area.













Surface corrosion was found on all empennage parts except the horizontal stabilizer.

All was removed and spot treated with primer.

Now all my parts are vinyl free for storage.


Early 2014, Van's Aircraft issued a Service Bulletin (SB 14-01-31) concerning possible cracks on the Horizontal Stabilizer of RV-6, 7, and 8 models tail or nose wheel.

About 10% of flying aircraft are affected.

I chose to install the doublers as a preventive measure.

The garage being busy with the fuselage, I brought the HS home and worked on the kitchen table.
A few rivets are removed as per the SB.

I would suggest to remove 5 or 6 more of these AN426 3-3.5 rivets on each side of the spar as they are easy to remove and to make the work easier.

My HS has only one side riveted permanently and having one side completely open really helped make this simpler.
The main and nose ribs are removed as are the 2 spar angles.

Care must be taken on removing the bigger AN470 4-X rivets.

I used a wrong technique and ended up with 3 oversize holes.

Please refer to the NEW chapter 5 of Van's manual for rivet removal.

When I found this new version and applied the correct method, all was perfect.
Fortunately, as accepted by Van's, my holes can be saved by enlarging for larger (5) rivets.
Using a round file, 4 notches are added to the main spar.
A small cutting wheel on a Dremel is used to trim the flanges of the spar.

A stainless steel protection plate is put between the flange and skin.
The rough cut.
The cut cleaned up.

It was challenging to do as I didn't remove extra rivets.
Both main ribs need to have their front flanges removed.
And pilot holes are drilled for the new flanges.
The doublers are marked and edges are smoothed out.
After lining up with the spars, the doublers are clamped and drilled.

Clecos are used not only to hold them down but to ensure drilling square using the 90° adaptor.
One more hole to drill, lower middle.

This will be one of the larger holes.

Holes for size 5 rivets are number 21 drill bit.

Number 20 bit is the maximum hole size permissible by Van's and can still be filled with a size 5 rivet.
Back to the garage, after priming, the doublers are riveted to the spars.

Only size 4 rivets were used here.

The size 5 rivets will be in the holes used to hold the ribs.
To drill the new flange, it is held to the rib with the 2 small C-clamps while a wood block and a carpenter clamp holds it firmly against the doubler.
After priming the new flanges and touching up the bruised rib, they are riveted to the ribs and the assemblies are cleco'ed to the skins and spars.
Note the larger lower hole.

At this point, The ribs are normally riveted the spars and skins.

I will leave the HS in this state until inspection by the MD-RA before closing up for good.

Expect about 20 hours of work for this SB outside of removing and installing the HS on a flying aircraft.
Web Hosting Companies