Archive for category Elevators
Left Elevator Tip Installed (3/30/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 31, 2010
1.8 Hours -
The left elevator tip was installed in the same manner as the right tip. I thought this tip would go on in about half the time of the right one. However, it ended up only taking about 10 minutes less, but it was easier and looks slightly better. At least I got smart this time and used a shop vac to suck away dust as I cut away the fiberglass flange with my Dremel. Granted, I still wore a respirator and safety goggles while cutting.
A close up of one of the 1/8" ID rivet washers already glued to the tip. Next to it is a CS4-4 blind rivet
The left elevator tip is on, and there is a pile of shanks from the blind rivets to prove it. This one was easier than the right and it looks a tiny bit better.
Right Elevator Tip Installed (3/28/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 28, 2010
2.0 Hours -
With the wing kit on order and the wing stands essentially done, I have nothing that I can do on the airplane except work on the fiberglass empennage tips. I was going to leave these parts off until just before the empennage components are attached to the fuselage, however, I really enjoy working on the plane and do not want to sit idle for another month and a half while waiting for the wing kit to arrive. With this in mind, I decided to start working on the tips.
Some people just rivet the tips on and call it good, others rivet them on and then glass over the seam so that there is a perfectly smooth transition from aluminum to fiberglass. For now, I’m just going to rivet them on. After seeing how they look, I’ll decide if I want to fill them. the nice thing is that I could fill them at anytime in the future…even after flying.
Starting with the right elevator, I quickly saw that the flange on the tips was too long and would need to be trimmed. Also, the flange on the forward end of the tip must be removed to compensate for the location of the counterweight.
After carefully measuring and marking the tip flange, I proceeded to remove the excess material using my Dremel with a cutoff wheel. Cutting the fiberglass generates a lot of dust. After making a small cut, I decided to put my respirator on. Unfortunately, the respirator doesn’t prevent the dust from getting all over me and everything else in the garage. Oh, and that dust can make you itch too!
The flanges on the elevator tips are too long as they come from the factory. Almost 1/4" has to be trimmed off.
A bit of the forward flange also has to be removed in order to allow for the counterweight.
The right elevator tip is cut and ready for an initial fitting.
Once the flange was trimmed, I did a test fit. A little more sanding and the fit looked good. I started to drill the tip to the elevator using a #40 drill. The elevator is pre-punched but the tip isn’t. I would drill one hole, cleco the tip to the elevator, adjust the fit, and drill the next hole. Once all the holes were drilled to #40, I enlarged them to #30 in order to accept the CS4-4 blind rivets.
The initial fit looks good...time to drill.Another view of the initial fit.
Another view of the initial fit.
After drilling and deburring, I dimpled the holes in the elevator using my pneumatic squeezer. The tip, however, must be countersunk. Since fiberglass is abrasive, and I’ve been told it will ruin a countersink bit, I decided to try making the countersinks with a conical grinding tool attached to my Dremel. Surprisingly, this seemed to work well…at least well enough to justify not buying another countersink bit specifically for fiberglass work.
The tips are attached to the empennage using CS4-4 blind rivets. Van’s instructs you to attach the tip directly to the elevator. However, many builders elect to bond a strip of aluminum to the inside of the tip along the rivet line. The aluminum adds strength and gives the rivet something a bit firmer to grip. I elected to use another method…aluminum rivet washers. These washers have a perfect 1/8” inner diameter and serve the same purpose as an aluminum backing strip. However, rather than placing a strip along the entire length of the tip, the rivets are simply bonded to each hole with some E6000 adhesive. This is simple and it should save some weight in the overall aircraft (at least a few ounces).
Some people rivet the tips directly on, others glue on strips of aluminum backing, I chose to use aluminum rivet washer...it might save a few ounces of overall weight.
The rivet washers are glued on and temporarily held with clecos until they are ready to be riveted.
I used E6000 glue for the washers since it was recommended by another builder.
Once the glue had some time to set, I went ahead and riveted the tip in place on the elevator. Overall, the fit is good, but there is some waviness/gaps in the joint. I think this is probably unavoidable, and, for now, I’m going to plan on leaving it this way since it is very minor. If, further down the road, I decide to paint the plane, I’ll probably glass the joint over at that point.
The right elevator tip is attached with CS4-4 blind rivets.
The control surfaces of the RV are balanced, meaning they have a counterweight attached to them. I believe this is done to reduce flutter and also ease the amount of force needed to move the stick in flight. To my surprise, the right elevator is almost perfectly balanced as it is now. The counterweight is only slightly heavy which is perfect in the event that I decide to paint it (the paint adds significant weight to the control surfaces and the overall airplane).
The right elevator is almost perfectly balanced. I'm only holding the two rod end bearings with my fingertips.
Elevator Horns Drilled to Center Bearing (3/13/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 13, 2010
1.0 Hours -
With so little left to do on the empennage, I haven’t been spending much time in the garage lately. However, today I decided to finish fitting the elevators to the horizontal stabilizer.
This was another step that turned out to be simpler than I expected. Basically, all I had to do was attach an elevator, clamp the elevator to the horizontal stabilizer so that it is “in trail”, insert my drill bushing into the center bearing, and drill a #40 hole in the elevator horn. I started with the left elevator and then did the right.
Clamps held the elevator "in trail" while I drilled the elevator horn.
To drill the elevator horn, a bushing was inserted into the center bearing.
Once both elevator horns were drilled, I had to enlarge the initial hole from a #40 to 1/4”. To do this, I just stepped up drill bit sizes until I was at 1/4”. I could have used my unibit for this, but I’ve found that it chatters too much and it is easy to make the hole uneven or too large. Since this is a crucial attachment point, I didn’t want to risk it.
Once the initial hole was drilled, I enlarged it to 1/4" by gradually increasing the bit size.
After both holes were enlarged, I reattached both elevators to the horizontal stabilizer and checked that the elevators moved freely, at all hinge points, through the entire range of motion. Everything looked great!
Both elevators are attached at all three points and moving freely through their entire range of motion.
With the elevators done, the empennage is complete minus the fiberglass tips. My wings are scheduled to be shipped the week of May 17th, so we’ll see if I last that long or get bored and go buy myself some West System epoxy for attaching the tips.
Fit Elevators to Horizontal Stabilizer (3/7/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 10, 2010
2.3 Hours -
On a project like this, one thing you quickly learn is that you need the right tool for the job. When I get stuck, I look at other people’s build sites to see how they got through it. Generally, I’m stuck in the same place that many others have had trouble, and, generally, someone has figured out an easy way to get it done. Trying to fit the elevators to the horizontal stabilizer demonstrated this.
The elevators attach to the horizontal stabilizer using two bolts that pass through a hinge (attached to the horizontal stabilizer) and a rod end bearing (attached to the elevator). This sounds simple, but there is relatively little space to maneuver the bolt. On my first attempt to attach the elevators, I could not figure out any way to do this. A needle nose pliers was too large, and I even tried to make a special tool out of scrap aluminum that would hold the bolt while I tried to steer it into place. I quickly gave up figuring that there had to be a better way.
Searching builder’s sites, it appeared that the tool of choice was a pair of curved forceps. The cheapest one I could find was from Avery Tools. Of course, while I was on the Avery website, I found other stuff to buy. My forceps order also included a tube of inspection lacquer (torque seal) and a set of temporary assembly pins. The pins are used instead of bolts during the initial fitting…more on this later. I placed my order from Avery’s on Sunday and it arrived on Tuesday…awesome service.
Temporary assembly pins and a pair of curved forceps are a must for fitting control surfaces.
Using a combination of the assembly pins and forceps, it was easy to attach the elevators. Once attached, I could see how much of the horizontal stabilizer’s skin would need to be removed in order to allow the elevators to rotate freely. Not wanting to take too much, I would attach the elevator, mark, remove elevator, cut, reattach, mark, etc., until the fit was perfect. In the end, it took about three cycles of attaching and removing each elevator before I was happy. To make the cuts, I used a Dremel with a cutoff wheel. To finish the edges, I used a combination of a Dremel with a sanding drum and some emery cloth.
Temporary assembly pins from Avery made fitting the elevators much simpler than on my prior attempts.
The left elevator is temporarily attached to the horizontal stabilizer. Some of the horizontal stabilizer has to be trimmed away in order to properly fit the elevator.
Just a bit more needs to be trimmed away for proper fit of the right elevator.
With both elevators attached, I was able to do a preliminary check on their range of travel. Downward travel was severely limited by the horizontal stabilizer’s rear spar flange. Some builders wait to cut this flange until everything is attached to the fuselage, but most builders go ahead and make the cut now. I chose to make the cut now as it was obvious that the elevator travel was nowhere near the required amount. To make the cut, I just marked where the elevator horns contacted the flange and cut away the material almost to the rear spar reinforcement bars. The plans are very clear that you do not want nick these bars. As with the previous cuts, I used a Dremel to make the cut and some emery cloth to fine tune the edges. A bit more material may need to be removed in the end, but I’ll wait until it is attached to the fuselage to cut away any more. If I could do this again, I would make the cut before the horizontal stabilizer is assembled.
Both elevators have been temporarily attached to the horizontal stabilizer.
Some of the horizontal stabilizer rear spar will need to be trimmed away to allow the elevator horns to reach their full down position.
The completed horizontal stabilizer rear spar cut-out for the elevator horns.
Finally, I did a little bit of electrical work on the trim servo. I’m going to wire the servo with a D-sub connector as demonstrated at aeroelectric.com. While i won’t attach the actual connector yet, I went ahead and crimped male d-sub pins to all the wires coming out of the servo. This will make them easier to work with in the future. To crimp the pins, I used a 4-indent crimp tool and closed barrel machined pins. I covered the crimps with a piece of 1/16” heat shrink tubing in order to give them some protection.
A close up of the crimps on a couple of male d-sub pins.
Bottom left: a male d-sub connector. Top right: the pieces of wire resulting from my first attempt with the d-sub pins.
Once crimped, a piece of heat shrink tubing seals the exposed areas and protects the crimps from vibration.
Finished Elevator Leading Edges (3/4/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 5, 2010
1.5 Hours -
Maybe the third time is the charm. Rolling the right elevator’s leading edge seemed to go much easier than both the rudder and the left elevator. However, there’s still got to be a better way to do this…or at least some more tricks!
The left elevator’s leading edge was already rolled, so I started the evening by drilling and riveting it. Pop rivets are used here and setting them was a non-issue. If I ever build an RV-12, which uses mostly pop rivets instead of solid, I would definitely want to get a pneumatic pop rivet puller.
The leading edges of both elevators have been rolled, drilled and riveted. The left elevator is pictured here.
Once the left elevator was done, I repeated everything on the right. This time, I rolled the top skin first and the bottom skin second. Since the second skin always has to be rolled under the first skin to get the correct bend, I figured this would save me the hassle of pulling the top skin back out after the bends were complete. The only area that I had trouble on the right elevator was the short, outer section. This spot is only about 5 inches long and the counterweight assembly blocks your access to one side. Since I could only grip the dowel with one vise-group, I was having trouble getting a nice even bend. Some waviness resulted in the final product, but no big deal in my opinion.
Finally, I was able to pull my homemade rod-end bearing installation tool out of the toolbox for the first time. When installing the rod-end bearings, a nut, called a jam nut, goes on the rod-end bearing first and then the assembly is screwed into a nutplate. Once the desired depth is reached, the jam nut can be screwed down onto the spar. At least this is how I think it is done, but I can’t really figure out the purpose of the jam nut. I guess it is anti-rotational, but won’t the brackets on the horizontal stabilizer also immobilize the bearing and prevent it from turning either direction? I guess a search of vansairforce.net is in order.
I was finally able to use my homemade rod-end bearing installation tool.
An installed rod-end bearing in the right elevator.
All of the empennage structures are now complete. All that is left is some final work to fit the elevators to the horizontal stabilizer and installation of the fiberglass tips (which may wait until the airplane is almost done).
The main structures of the empennage are done. All that remains is some finishing work and fiberglass.
Left Elevator Leading Edge Rolled (3/2/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 2, 2010
0.8 Hours -
I got home from work today and was planning to start a load of laundry and then relax in front of the TV for a bit. However, when I went into the garage with my laundry, the airplane started calling to me (this is not an uncommon experience). So, I loaded the washer and proceeded to work on rolling the leading edges of the left elevator.
Rolling leading edges has definitely become my least favorite thing to do so far in the RV-7 build. It is physically difficult to do and it is hard to get the right amount of bend in each half so that the holes line up without having to exert a great amount of force. As with the rudder, I used Van’s dowel, duct tape, and vise grip method to bend the skin. In summary, a length of 3/4″ dowel is duct taped to the edge of the skin. Then, using two vise grips, the dowel is rotated, bending the skin along with it. The bottom skin is fairly easy, but the top skin is a pain due to the bottom skin being in the way.
Eventually, I was able to place clecoes in all of the holes and it took less force to line up the skins compared to the rudder. Maybe a few lessons were learned on the rudder, but I figure there are still many ways to make this easier. Lucky for me, I have a second elevator to practice on. However, it is going to have to wait for another day when my patience has returned.
The left elevator's leading edge has been bent and clecoed. This is easily my least favorite thing to do so far in the build!
More Trim Work (3/1/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on March 1, 2010
2.0 Hours -
The first thing I did today was drill a hole in the elevator spar for the trim servo wires to pass through. According to the plans, the wires can share the hole that the servo’s jack screw occupies, but the jack screw is a threaded rod and, like many other builders, I could foresee this chaffing the servo wires eventually leading to a failure. Instead, I drilled a 3/8″ hole through the spar at the location of the lightening hole on the control horn. Once drilled, I smoothed the edges of the hole and inserted a grommet. My eventual plan is to use a d-sub connector to link the servo wires to a five-wire, shielded cable running to the fuselage. The d-sub will stay inside the elevator with the servo and only the cable will pass through the grommet and run to the panel.
Rather than having the servo wires share a hole with the jack screw, I drilled a second hole and inserted a grommet to protect the wires.
With the trim servo in the full down position, the jack screw extends almost an inch out of the elevator spar.
Next, I started fitting the trim push rod. I was a bit stuck on this and had to post a question in the forums on VansAirForce.net. As usual, I was given a quick and thorough explanation of how to measure and cut the rod. First, I attached one clevis to the servo. Then, I inserted the servo into the elevator and screwed the access panel on tight. Using a drill battery, I ran the servo so that it would be fully retracted (trim tab full down). I then screwed the push rod into the clevis on the servo and used it to measure the approximate length it needed to be in order to screw into the clevis on the trim tab while the tab was in the full down position. Finally, I cut the rod with a hack saw. After doing this twice, I finally had the rod to the appropriate length. I’ll need to do some fine tuning later on, but for now we’ll call it good.
With the trim rod in place, I ran the servo both directions to check and see if any of the hardware was binding or rubbing on the elevator. While there was no contact, it was extremely close. To fix this, I did two things. The first was to put a slight bend in the push rod. The second was to file away some of the metal surrounding the opening where the rod/clevis protrudes. Once I filed enough metal away, I had to do some finishing work to smooth the edges and I also gave everything another coat of primer for appearance sake only.
The elevator is upside down, but this is the full down position of the trim tab.
In order to make sure there was enough clearance, I had to put a slight bend in the push rod and file away some of the access opening.
The good news is that this should be the end of my trim tab battle. At least until I’m almost ready fly!
Finishing the Left Elevator (2/27/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 28, 2010
3.0 Hours -
After quickly squeezing the last of the rivets holding the left elevator skin to the skeleton, it was time to attach the forward trim tab hinge. The goal here is to have the trailing edge of the elevator and trim tab in perfect alignment while minimizing the gap between the tab and elevator and also keeping the inside edges aligned. It all sounds relatively simple, but it was a bit frustrating.
The left elevator is completely riveted except for the trim hinge attachment holes.
The frustration arises when you can’t find a good straight edge. It continues when you get everything aligned, but can’t keep it aligned while trying to clamp it. The frustration boils over when you have everything in place, managing to keep it place, but then can’t find a way to clamp it so that you can move your hands.
Finally, I managed a system where I weighed down the elevator so that the trailing edge was flat on my table. I then used long, narrow diameter curtain rod to line up the trailing edges of the elevator and trim tab. Finally, I placed one cleco clamp on the inside edge of the hinge and held the rest of the trim tab in place while I drilled the first hole. Once drilled, a cleco was inserted into the hole and I moved on to the next hole using the same tedious method. After drilling and clamping about four holes in this manner, I was happy with the alignment and started to move a little faster. The end result was a trim tab and elevator in perfect alignment and a relatively small gap between the tab and elevator.
Aligning the trim tab for drilling the huge was a royal pain in the A$$!! I used a curtain rod for a straight edge to align the trailing edges.
With the hinge drilled, the tab moved well with no binding.
I'm satisfied with this small gab between the trim tab and elevator. It is straight and both the trailing and inside edges line up perfectly.
Next, the plans tell you to sight down the trailing edge of the elevator and trim tab one last time to make sure everything is straight. If the tab is at all bowed, you should be able to twist it to take the bowing out. Once everything is straight, you drill and cleco the three holes on the inside edge of the trim tab. Once these are drilled and clamped/riveted, everything should be locked into place.
Apparently, this was supposed to be done before I riveted the aft portion of the hinge to the trim tab. Fortunate for me, everything was perfectly straight and stayed that way after I drilled and riveted the inside three holes.
The inside end of the trim tab has three blind rivets that are the last to go in.
Finally, I prepped and primed the forward portion of the hinge before riveting it to the elevator. The left elevator is now done except for drilling one hole for the trim servo cable and rolling the leading edge. Despite the frustration, I’m happy with the way the trim tab turned out. Some of the bends could be smoother and you can see dents caused by the rivet gun while trying to flatten the bend, but, no one is going to see these unless they are really looking. To continue my mantra, I’m building a “go-plane” not a “show-plane.”
The trim tab is finally finished. The gap looks larger here because the tab is angled down slightly.
Final Assembly Started On Left Elevator (2/25/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 26, 2010
2.0 Hours -
My replacement parts from Van’s arrived yesterday, but I didn’t make it into the garage as I was too busy watching the Olympics…men’s hockey to be specific. Everything is looking good for a USA vs. Canada gold medal game!
When I finally made it into the garage tonight, I started by prepping the new E-606PP rear elevator spar. Since the kits are pre-punched, getting everything to line up on the new part was simple. I just had to drill the holes to size, then dimple or countersink them. This time, I quadruple checked that I was countersinking the top flange instead of the bottom. Of course, I thought I did this last time as well. This time, I also kept the bad part on the table to make sure the new part was opposite. Once everything was countersunk and dimpled, I primed it and moved on to elevator assembly while the primer dried.
My new E-606PP. This time, countersunk on the top side instead of dimpling like I did the first time around.
If the picture were better, you could see that I reversed the dimpling and countersinking from my first try (aka...dumb mistake).
The first thing I had to do was re-drill counterweight. I marked the hole locations using the counterweight skin and then drilled the holes with my drill press. I wasn’t sure how this would work since the counterweight skin was already dimpled. Fortunately, everything lined up fine and I didn’t have to use the new counterweight skin I purchased.
Next, I checked the fit of the trim servo one more time before closing the elevator. Any fixes would be easier to perform now while the inside of the elevator was still accessible. Everything looked good as the servo and access panel easily fit into place.
I then placed some blue RTV at the aft end of the elevator stiffeners, slid the skeleton into place, clecoed the elevator together and started to squeeze rivets. I made it through about 3/4 of the rivets on the top side of the elevator before deciding to call it quits for the night. Before heading inside, I marked the top of the elevator over the rear spar “No Rivets.” The trim hinge must be fitted here before riveting…let’s see if I remember to read this when the time comes or if I end up drilling out a bunch of rivets instead.
The new E-606PP rear spar in place on the left elevator.
I squeezed about 3/4 of the rivets on the top side of the elevator before calling it quits for the night.
The blue vinyl is a good place for temporary reminders. Hopefully, I'll read this at the appropriate time.
Finished Trim Tab and Ordered Parts From “The List” (2/21/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 21, 2010
3.2 Hours -
Unfortunately, the majority of the time I spent on the plane today was used discovering and fixing mistakes in the left elevator. More on that later, but at least finishing the trim tab went well.
I started off the day by finishing up the trim tab prep. First off, I aligned the aft portion of the trim tab hinge according to the plans. To do this, you draw a line on the hinge. Then, line this line up with the holes in the trim tab’s spar. Once everything was clamped into place, I match drilled the hinge to the spar and skin.
The aft portion of the trim tab hinge is marked per the plans.
The mark on the hinge is centered in the holes on the trim tab spar.
Once the hinge was drilled, I disassembled the trim tab and completed all the finishing work. Once deburred, dimpled, and countersunk, I gave everything a coat of primer and let it dry while I headed in to work for a couple hours.
After I returned from work, I started final assembly of the trim tab. The control horns were riveted first, followed by the bottom side of the spar, and finishing with the top side of the spar and hinge. It was a bit challenging to reach all of these rivets, but i was able to get to everything with my squeezer and avoid using any blind rivets in the trim tab.
The trim tab looks good from the top.
I was happy that I didn't have to use any blind rivets on the trim tab.
Amongst all of my trim tab work, I also managed to test my trim servo. To do this, i simple touched the positive and negative wires on the servo to the appropriate terminals on my electric drill’s battery. Once the servo ran all the way in one direction, I reversed the wires and ran it the opposite direction. It functioned perfectly with no binding. Plus, it was fun to play with my first bit of electronics for the plane.
Once the trim tab was done, I decided to finish assembling the left elevator since I knew all the trim components fit and were working. The first thing I did was locate E-606PP, the trim cut-out spar, so that I could see how the forward portion of the trim tab hinge would attach to it. I’m really glad I did this before I riveted the elevator because it turns out that I countersunk the wrong side of this spar. I was supposed to countersink the top, where the trim hinge attaches, but I countersunk the bottom and dimpled the top. I’m not sure how I made this mistake since I remember carefully trying to figure out which side to countersink. Looks like I’ll be ordering my first replacement part. Unfortunately, this wasn’t the only error I discovered today.
Even though I would have to replace E-606PP, I could still start riveting the elevator since E-606PP is the last piece to go in. The first step in assembling the elevator is to loosely attach the counterweight to the counterweight skin by placing two bolts part way through the weight. As soon as I did this, I could tell something was wrong as the weight was not seating properly in the counterbalance skin. After looking at the situation for a couple minutes, it became obvious that I had the weight oriented in the wrong direction when I initially drilled it.
Since the correct location of the holes in weight would be very close to my wrong holes, i decided to try to fill the holes rather than buy a new weight. At least I was smart enough to keep all the lead that had been removed from the weights previously. Feeling like a heroin addict, I used a torch to melt some lead in a spoon. Once melted, I poured the lead into the drilled holes. A little more heat to the surface of the weight and I was able to smooth out the large globs of lead that had formed on top of the holes. After the weight cooled, I used a coarse file to return the weight to its original shape. Since the counterweight skin is already dimpled, I’m not sure how difficult it will be to re-drill the weight correctly. I’m going to order a new counterweight skin just in case.
At least with metal, some mistakes can be fixed. I'll fill the holes with scrap lead and try again.
I gave the rest of the elevator a quick inspection to see if there were any other errors made. Not finding any, I went inside and placed my first order from “The List” on Van’s website. The trim spar cost $10 and the counterweight skin was almost $7. Surprised that the parts weren’t more expensive, I ordered a T-shirt as well! However, I’m sure these won’t be the last replacement parts I have to order.
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