Archive for category Vertical Stabilizer
Rudder Stop Installed (5/25/10)
Posted by Ethan Jacoby in Construction, Empennage, Rudder, Vertical Stabilizer on May 26, 2010
0.5 Hours -
With very little left to do on the empennage, I went ahead and installed my internal rudder stop. Nothing complicated…just clamp it in place and use the holes in the rudder stop to drill holes in the hinge bracket for two AN3-7A bolts. Once drilled, I used AN3-7A bolts with two washers and a stop nut on each. Everything was torqued to 25 inch pounds, inspection lacquer applied, and done!
The rudder stop is pre-drilled for AN3 bolts. The hinge must be match-drilled.
The rudder stop is mounted using AN3-7A bolts and stop-nuts. I also used two washers per bolt to adjust the grip.
On another note, my wing kit shipment, originally scheduled for mid-May but delayed to mid-July, has been bumped up the priority list at Van’s. My kit went to crating on Monday and will be shipped as soon as it is all boxed up. In two or three more weeks, I should be back to some serious airplane building!
Internal Rudder Stop
Posted by Ethan Jacoby in Construction, Empennage, Rudder, Vertical Stabilizer on May 20, 2010
Rudder stops are another one of those RV things where you can ask 5 people and get 10 different opinions. After reading as much as I could about the pros and cons of internal vs. external stops, I decided to purchase an internal stop. At $25, it isn’t a big loss if i decide not to use it (and I can probably get $20 back by selling it to another RVer).
If following the plans as Van’s has written them, the rudder stops are pieces of aluminum angle that are riveted to the aft fuselage just forward of the rudder. At full deflection, the rudder horn will hit these stops before the rudder skin smashes into the elevator. By modifying the angle of the stops, you can alter the amount of swing in the rudder. While this works well, I think it is unsightly. Granted, the rudder cables hanging out of the fuselage are a little ugly too, but at least one ugly can be eliminated.
The internal rudder stop is simply a chunk of delrin plastic that is milled to a specific shape and drilled for two AN3 bolts. The plans for this stop are available for free on vansairforce.net, or a pre-cut stop can be purchased from Merlin Enterprises (Stockton, CA) for $25. I chose to buy the finished product since the purchase of raw material, combined with my time to make two of them (because I will screw up the first!), will easily surpass $25.
The infamous internal rudder stop...some love it, some hate it.
The internal stop is bolted to the top half of the lowest rudder hinge on the vertical stabilizer using two AN3-7A bolts (if I measured correctly). When the rudder swings to its limits, the rudder spar will contact the stop, preventing further movement. The down-side of this system is that some people believe the stop, when in contact with the rudder, will stress the aft-most fuselage bulkhead. However, no one has done a complete stress analysis, it is believed that the only stress severe enough to cause damage would occur only in an aggressive maneuver such as a tail slide (I’ve got bigger problems if this happens), and there are over 500 RVs that have implemented the internal stop. In my opinion, concerns some builders have are unfounded. If my rudder jams in-flight, I’ll change my opinion 
The rudder stop will attach to the lower rudder bracket on the vertical stabilizer with two AN3 bolts.
A bigger view of the vertical stabilizer for reference. The rudder stop is on the top half of the bottom hinge bracket.
Vertical Stabilizer Tip Finished (4/24/10)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on April 24, 2010
0.5 Hours -
Good news and bad news today.
The good news is that I sanded down the micro on my VS tip and put on a couple coats of primer. The gap filled in nicely and the tip looks great now.
The VS tip looks great after a couple coats of filler primer.
The gap in the leading edge of the VS tip is nicely filled. I may come back at some point and file in a line to make it look the same all the way around the tip.
The bad news is that I received a letter from Van’s stating that my wing kit shipment will be delayed. A poster on VansAirforce.net told me that there are shortages of raw material in the supply chain and some of the OEMs that Van’s contracts with are probably not able to get enough material to fill all orders. In addition to this, kit orders are way up. Looks like the economy is recovering!
So, my delivery date has been pushed back almost two months! The wing kit is now scheduled to be shipped the week of July 12th.
Still Working On The VS and HS Tips (4/23/10)
Posted by Ethan Jacoby in Construction, Empennage, Horizontal Stabilizer, Vertical Stabilizer on April 23, 2010
0.7 Hours -
Today, I was able to get another 45 minutes of work in on the HS and VS tips. As usual, now they have to set overnight before I can do anything else.
After sanding down the layer of micro on the aft surface of the HS tips, there were a lot of pinholes present. On the VS tip, I decided to layer on some more micro, but, this time, I decided just to put on two coats of straight epoxy and see if that seals the holes.
Many pinholes in my HS tip micro. Hopefully a layer or two of epoxy seals them nicely.
Once my epoxy was on the HS tips, I turned my attention back to the VS tip. I had piled on some micro to see if I could fill the gap on the forward edge between the fiberglass tip and the metal skin. I did a quick, rough sand on this micro, and it looks like the gap is nicely filled. I still need to do a bit more sanding, follow the sanding with a coat of primer, and the gap should be a distant memory!
After a quick rough sand on the VS tip micro, the gap looks like it will be covered up.
Another angle on the now fixed VS tip gap. A little finish sanding and a coat of primer should make it look good.
More Work On The Horizontal Stabilizer Tips (4/21/10)
Posted by Ethan Jacoby in Construction, Empennage, Horizontal Stabilizer, Vertical Stabilizer on April 21, 2010
0.8 Hours -
Since this is more fiberglass work, as with the last few posts, this entry covers work that occurred over multiple days. I’m combining some of these because I can’t justify writing one post for something that took 15 minutes to do and then had to set overnight before I could do more work.
The other night, I reinforced my wood HS tip ribs by adding a layer of fiberglass to the inside of the joint over the flox filet. Once the epoxy was set, I returned to the tips today and put a layer of micro over the aft face of the wood ribs. This was done in the same manner as with the vertical stabilizer tip. However, I tried to make the micro a bit thicker in order to prevent it from running down the side of the tips (it took a lot of sanding to fix that on the VS tip). This time, my micro was the consistency of thick frosting rather than a runny glaze. This thicker micro had to be spread on instead of poured, and it seems to have fewer air bubbles than my previous, runnier micro.
This time, I used a much thicker mixture of micro. Hopefully, no runs!
Once I coated both HS tip ribs, I still had some micro left over. With the extra, I decided to slather some on the gap that is present on the leading edge of the vertical stabilizer where the aluminum and tip meet. I’m hoping the micro will fill the gap and be easy to sand back to the contour of the vertical stabilizer. If it doesn’t work, I may have to glass the seam on the VS and I’m trying to avoid this.
With luck, the micro will fill the gap on the VS tip.
Vertical Stabilizer Tip Done…For Now (4/16/10)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on April 17, 2010
0.5 Hours -
The vertical stabilizer tip is now complete. Well, it is attached to the vertical stabilizer, but it still needs some work before I’ll be happy with it.
Once the micro/fiberglass was set on my new forward flange, I removed the peel-ply and gave the entire tip another light sanding with fine grit paper. I wanted to seal the micro layer on the aft surface and decided to try a technique I read about on another builders site. I simply mixed a batch of epoxy, used a brush to paint the epoxy onto the micro, then used a squeegee to scrape off as much of the epoxy as possible leaving a very thin layer than, hopefully, will fill any pinholes. Once this layer became tacky (about 45 minutes) I repeated the process and then left the tip to dry overnight.
My rebuilt forward flange. Hopefully it will take care of the gap.
The next day, I had a smooth, hard surface on the micro. I final sanded it to smooth the epoxy and then riveted the tip to the vertical stabilizer. There is still a significant gap on the leading edge between the metal and fiberglass, but I’ve sat the vertical stabilizer aside for now as I decide how to handle the gap. I can either fill it with some micro and sand it smooth, or I can fill it and then tape the entire seam and rivets with glass. If I go the glass route, I’ll do it on all the empennage tips for consistency. However, since the vertical stabilizer tip is the only one I’m really not happy with so far, I’m leaning towards just filling the gap and calling it good. On to the horizontal stabilizer tips.
The VS tip has been riveted on.
The gap on the forward edge is still present. I'll either fill this with some micro or fill it and then tape the seem with some fiberglass.
Vertical Stabilizer Tip Part 3 (4/14/10)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on April 14, 2010
0.7 Hours -
After my first layer of micro set, it had a few large bubbles in it and many small ones too. In an attempt to get rid of them, I started to sand down the micro. However, I sanded as far as I could and the bubbles were still barely visible. While I could have left it as is, I decided to mix another batch of micro and place another layer on the tip.
Unfortunately, I’m still trying to figure out the right consistency for the micro mixture and I made this batch too thin. I spread it on the tip and carefully watched for bubbles to rise to the top so that I could pop them. When I thought it was good to go, I went back inside and left the epoxy/micro mixture to set overnight. When I checked it the next morning, the surface with the micro looked good, with no bubbles, but the micro mixture had also run down the side of the tip in several long, thick drips. Looks like I’m in for some sanding! (I should have taken a photo of this for a before and after, but didn’t think about it at the time.)
The micro sands fairly easy. I started with some fairly coarse grit sandpaper and ended with finer grit. In the end, I was very happy with the tip.
Not the best picture, but I added a second layer of micro (due to bubbles) and sanded it back down. Not too bad for my first fiberglass work.
When I initially fit the tip, the forward part of the flange was too wide and would not easily fit inside the VS. To fix this, I did like on the rudder top tip and cut off some of the forward flange. However, when I re-fit the tip, there was a small gap between the VS and the tip. To fix this, I decided to place one, small piece of fiberglass inside the forward end of the VS tip and then fill the outside with some micro. Once this dries, I should be able to sand it down so that the original gap is eliminated.
I originally cut this section of flange because it was too tight in the VS. Now, I'm going to fill it a bit so that there isn't a gap after final assembly.
To reconstruct the flange, I placed one layer of glass on the inside of the tip and then filled the outer part with micro. The visible cloth sticking out is peel-ply.
Maybe this fiberglass stuff isn’t so bad after all. At least you can fix your mistakes!
More Vertical Stabilizer Tip Work (4/11/10)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on April 11, 2010
0.8 Hours -
My order from Aircraft Spruce arrived on Saturday. It contained epoxy, fiberglass, flocked cotton, and glass bubbles, everything I needed to complete the fiberglass work on the vertical stabilizer tip.
I'm using the West System epoxy for my fiberglass work.
The first thing I did was to mix a batch of flox, consisting of epoxy and flocked cotton, and use it to bond my balsa rib to the VS tip. I used a bit of flox along the edge of the rib to glue it into place and then I laid a fillet of flox around the rib/tip junction on the inside of the tip. This mixture took a considerable amount of time to dry, so I had to let it sit until Sunday morning (keep in mind that this is my first time using this stuff…I know my fillet is a bit ugly and I probably used way more flox than I needed to begin with).
My initial fillet of flox is a little too heavy!
Once the flox was dry, I sanded it a bit in preparation for laying a ply of fiberglass cloth to reinforce the rib. I bought 3 yards of Rutan bi-directional fiberglass cloth. I’ve opted for bi-directional because it can be used more universally. The bi-directional weave is good for flat lay-ups and it also allows the fabric to drape over curved surfaces better than a uni-directional fabric. Plus, it was invented by Burt Rutan, so it has got to be good!
I've opted for bi-directional cloth. Rutan invented it, so it's gotta be good!
To wet the cloth, I’m using the plastic sandwich method. I have a sheet on 1 mil plastic which I place on a cutting mat. Next, I place my fiberglass cloth on the plastic. Then, I mix my epoxy, pour it onto the cloth, and place another sheet of plastic on top of it. With a plastic squeegee, I then move the epoxy around until the entire piece of cloth is wet (it is easy to tell when it is ready because the cloth practically becomes invisible). Once wet, I make a few final passes with the squeegee to squeeze out as much of the excess epoxy as possible. Finally, I used a rotary cutter to cut my cloth, inside the plastic, to the appropriate shape. Once cut, I can easily peel off the plastic and place my wetted fiberglass where it is needed.
The only problem I ran into was that it was difficult to get my big hands inside the tip to move the cloth to the exact correct spot and smooth out any air bubbles. Fortunately, this cloth will not be visible on the finished product. Hopefully, I’ll have my fiberglass skills refined by the time I get to the forward canopy skirt!
Another few hours and the fiberglass was dry enough for me to move onto the next step. The forward surface of the tip, where my balsa rib is visible, is a little rough from the flox and the rib is not perfectly lined up with the edge of the tip. To fill in the gaps and smooth it out, I mixed up a batch of epoxy with glass bubbles and placed a layer of this on the forward surface of the rib. I have to admit, the glass bubbles are easy to work with and kind of neat too! Once they dry, it should be easy to sand the tip to the final shape.
I placed a layer of epoxy with glass bubbles on the forward surface of the rib. This should be easy to sand into a smooth finish once it sets.
Started Working On The Vertical Stabilizer Tip (4/9/10)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on April 10, 2010
1.7 Hours -
The vertical stabilizer tip is a little more complicated than the other tips I’ve worked on so far. This is mainly because it is the first tip I’ve worked on that has to be fitted using another tip (the rudder top tip) as your guide for trimming, and the aft end of the VS tip is left open by Van’s which means it requires closing before it is mounted. Van’s gives you two methods for closing the rib: 1) temporary foam and fiberglass, or 2) permanent wood and fiberglass. I’ve opted to make a wood rib out of balsa which will be bonded to the tip and reinforced with a single ply of fiberglass.
First, I did my initial fitting of the tip to the VS. Unlike the other tips, the flange of the VS tip did not need to be trimmed. However, the aft end of the tip extended into the area of the VS where the rudder fits and would require trimming in order to let the rudder swing. I temporarily mounted the tip and then marked the area that I wanted to trim off. Using my Dremel, I purposely trimmed off less than was required since I can always trim more off, while adding some back is more difficult.
Unlike the other tips, the vertical stabilizer tip's flanges did not need to be shortened. However, I will need to remove about 1/4" from the aft edges.
Once the initial trimming was complete, I attached the rudder to the VS for the first time. This was an awkward assembly. First, I tried to assemble them laying flat on my workbench. However, I could not get the upper most hinge assembled this way. So, I had to stand them on the corner of the workbench and insert the temporary assembly pins while balancing both pieces (they are big). Once I managed to assemble all three hinges, I could balance the VS/rudder assembly on the bench by simple swinging the rudder one direction or the other.
This is the first time I assembled the rudder to the vertical stabilizer.
To my surprise, the VS required no trimming in order to allow the rudder to swing. In addition, the amount I trimmed off the VS tip was almost perfect. It just needed to be sanded a bit to even both sides out and remove any jagged edges.
The gap between the aft end of the vertical stabilizer and the forward end of the rudder is perfect. Once the VS tip was trimmed, no further modification to the metal portion of the VS was needed.
The fiberglass portion of the VS tip was ready, so I moved on to the wood portion. With the tip clecoed to the VS, I measured the width and length of the tip and used these dimensions to cut a rectangular piece of 1/4” balsa. I then traced the outside of the tip on the balsa and trimmed the wood to the shape of the tip. Finally, I sanded the rib until it fit snuggly inside the tip.
The aft end of the vertical stabilizer tip needs to be closed. I've opted for the balsa wood rib method. Eventually, this rib will be bonded to the tip and a layer of fiberglass will give it added strength.
I have a fiberglass supply order in with Aircraft Spruce which should arrive tomorrow. Once that arrives, I’ll have everything I need to bond the balsa rib to the tip and reinforce it. My plan is to bond the rib to the tip and reinforce it with one layer of fiberglass cloth. I then make a slurry of epoxy and glass bubbles and use that to fill the end of the tip. Once dried, I should be able to sand the slurry, leaving a nice, flat aft end of the tip. At least that is the plan!
Vertical Stabilizer Completed (11/14/09)
Posted by Ethan Jacoby in Construction, Empennage, Vertical Stabilizer on November 14, 2009
1.0 Hours -
The vertical stabilizer is done. Of course, the last bit of work on it was not as easy as I expected it to be.
All I had to do was rivet on the rear spar. I assumed this would be as simple as squeezing a few dozen rivets, followed by putting in a couple pop rivets. Well, about one quarter of the rivets could not be squeezed and had to be bucked. In many locations, the rivets attaching the skin to the rear spar were right above rivets attaching the doubler to the spar. Because of this, I could not reach them with my squeezer. I tried, but the squeezer could only reach half of the rivet. A shop head that is two levels (half squeezed, half unsqueezed) won’t do me any good, and the rivet has to be removed.
Fortunately, there was enough room to squeeze in a bucking bar, so I just bucked these rivets. No big deal, and they all turned out well, but kind of a pain to do. To me, it would make more sense if these holes alternated, but maybe there is a structural reason for this that I don’t know about. Either way, the vertical stabilizer is done…on to the rudder.
Some of the rear spar doubler and skin rivets line up, making the skin rivets difficult to set.
The vertical stabilizer is done!
Leading edge view of the completed vertical stabilizer.
Because I have an EAA Chapter 35 meeting this afternoon, I didn’t have time to start the rudder. All I did was locate the 8 pieces of angle that are used to make the rudder stiffeners. Each pieces of angle is used to make two stiffeners. They have to be cut apart and the aft end has to be tapered. The length is determined by placing them on the rudder skins and marking the correct length before cutting. Van’s makes all this very simple by putting notches in the stiffeners. Connect the notches with a line, cut along that line, and you’ll have perfect stiffeners.
The rudder has 16 stiffeners that have to be cut from these 8 pieces.
The rudder stiffeners have notches that show you where to cut...like an expensive game of connect the dots.
I’m off to do some hanger flying with the EAA guys!
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