Archive for the ‘Elevators’ Category

Empennage is COMPLETE!!!

March 9th, 2012 No comments

Drilling the Horn

I was eager to get home tonight and finish the last couple of items on the elevators. After all, these are the only items left on the entire Empennage as far as construction goes.

I cut and filed the last two HS skin clearances for the counterbalance arms on the top of the skins. The elevators can now swing free top to bottom. It was cool to just stand there and see them move through the travel range. They look like airplane parts for sure. At this point, drilling the horns for the center pivot bolt is the only step that remains.

Last weekend, I placed my order with McMaster-Carr for the requisite 8491A784 drill bushing to assist in tackling the drilling of the horns for the pivot bearing bolt holes. It arrived this last Wednesday. It was not cheap. It appears to come slightly oversize for the 1/4″ bolt hole in the bearing. Actually, I think the bearing is slightly undersized. To fit the bushing inside the bearing, I had to put the busing in my drill press and simply sand it down little by little until it slides into the bearing.

Above you can see the bushing in place in the bearing and my #40 drill bit inserted. This centered the drill bit and kept the bit from wandering. I clamped the right elevator in trail of the HS and committed to the hole. The bit drilled through pretty quick. I then opened the hole up with a #12 bit and then finished with my step bit to a finished size of 1/4″. I repeated the process on the left elevator.

Finished One Hole

Above is the finished result on the left elevator horn. All in all a pretty clean hole. I then installed the elevators back on the HS and to my delight, the two horns and the bearing all lined up and I was able to get the bolt in and some spacer washers in place per the plans. I then replaced all the temporary hinge pins with the bolts that go in each hinge point and tested the travel again. No binding from top to bottom travel. I was also enamored with the smoothness of the travel. Silky.


As far as major construction goes, the Empennage is COMPLETE! Only items that remain are the fiberglass tips on the Empennage parts. These will wait until later as they can tear up tools because of the composite nature. Van’s suggests that you wait, though not required, until you are doing more fiberglass work later on. Now I need to find a way to safely store these assemblies in the shop to get them out of the way and save them from damage. Time to move on to the WINGS!!!!

Categories: Elevators

Every Little Bit Counts

March 5th, 2012 No comments

Horn Clearance Done

After work, and my requisite hug and kiss I give the wife to say hello, I ran out to the shop to tackle another small task on the Horizontal Stabilizer. I was able to get the left HS skin notch for the counterbalance cut out and filed. I then got the call for dinner and had to put the tools down. I love having a dedicated space to build. Only one more step on the underside of the HS to go.

Once dinner and Family Night stuff was over, I headed out to take care of that last task. The lower flange of the HS rear spar interferes with the full deflection of the elevator horns. To solve this problem, you need to notch the flange to clear the horns. I am sure that it would have been possible to do this step earlier during the construction of the HS, but the manual has you wait until the elevators are mounted to do it. While the elevators were mounted on the HS, I made a mark on the spar flange in line with the outboard edge of the horns. I then added 1/8″ to that to give the horns clearance along the sides.

I had to remove the center bearing assembly that I had previously final torqued the bolts, but that was no big deal. I then masked over the spar reinforcement bars as the plans explicitly say, DO NOT REMOVE ANY MATERIAL FROM THE HS-609PP! I looked at the plans and basically notched the flange flush with the reinforcing HS-609PP bars inside the spar. I figure the lower travel stop that will more than likely stop the elevator horns from ever hitting this flange now so I have good clearance and clean lines.

I also noted as I was completing this step the obvious increase in my expected level of perfection. When I had started the HS, I rounded the corners of the spar where they met in the middle. The corners were not even close in shape though just fine. As I looked at the other parts in progression of completion, I noticed my attention to detail has improved. Perhaps Van, in his wisdom, knew this would naturally occur and left these last tasks where they are to create better results through natural progression. The accuracy of this kit keeps shining through no matter the mistakes I have made.

Horns Close

Once the center notch was complete, I remounted both elevators to the HS. To my delight, the horns appear to be very close in orientation to one another. Some other builders, and even the plans, note that these may not be exact as the manufacturing process is not perfect on the horn weldements. Vans has either improved this, or I am lucky, as mine are pretty darn close as you can see in the above picture.

Elevators Mounted, Almost There!

At this point, the spar/skin trimming on the underside of the tail is complete. All that remains is the counterbalance skin clearance portions of the upper side, drilling the center bearing/horn interface, and the fiberglass tips. I may wait to drill the horns when the tail is mounted to the fuselage, but the tips are definitely waiting until the tail is on the rest of the plane per the advice of many builders. Time will ultimately tell.

Stay tuned for the official “Tail Complete” announcement to hopefully come later this week.

Categories: Elevators

Countown of Little Tasks

March 3rd, 2012 No comments

Why buy when you can make?

It was time to mount the elevators to the horizontal stabilizer. However, there is a conflict with the skin and the counterbalance arms at the moment, which prevents one from being able to deflect the elevator to open the areas where the bolts are to go. There is simply not enough room to get a bolt in the hinge and have the elevator in line with the horizontal stabilizer. So what is one to do?

I had seen from some of the tool manufactures, tools they called  hinge alignment pins. They were pricey to me. After all, they were simply steel rods the diameter of the bolts bent to look like landing gear struts for an RC airplane. So rather than buy the tools, wait for them to arrive, I went to Lowe’s Aviation Supply and bought a 3/16″ rod from the misc metal bin. Once I got home, I simply smoothed the ends and bent them to a similar shape in my vise. I think it cost me all of about $2.50 or so. I made two, one for each hinge point per elevator.

Homemade Hinge Alignment Pins

Here you see the pin in place in the hinge of the elevator/horizontal stabilizer interface. They slip into the hinge points easily and allowed me to slide the counterbalance arm into the skin at the tips in preparation for the next step. As you can see, with the elevator in trail of the stabilizer, there is not much room for getting fingers in to install the final bolt. With the alignment pins, you do not need to worry about it.

One caution, do not deflect the surface towards the side that the pins are installed. You could sandwich them in the openings and create a nice pucker in the elevator and stabilizer skins/spars. That would ruin your day.

Another Homemade Tool Worth Gold

Once you can fully deflect the surface to open up the hinge locations, it is still difficult to insert the bolts into the hinge areas. I was reading the 27 Years of the RVator articles and came across this little jewel being described. Tool suppliers also sell something similar, but it looked simple enough to replicate as well. I wish I had done it for the rudder when I installed it.

Bolt Retainer Tool

I simply took some .040″ sheet stock from the Empennage Sheet bundle and fabricated a tongue depressor size stick from it. I then took a smaller piece and drilled a 3/16″ hole in the center. I then used my band saw and opened up from the edge to one side of the hole and made a “U” in it. I clamped it to the other piece and match drilled it. I then bent the “Z” bend in the smaller piece in my bench vise and then riveted the parts together with some AN470AD4-5’s. I think it took me all of 15 minutes to make but should easily save that amount of time installing the bolts into the hinge points. Slide in the bolt head in the opening and insert away!

One Notch Done

As hinted to above, one of the final tasks that you have to do on the elevators is notch the HS skin for the longer counter balance arms on the RV-7. I think that the RV-8, which has the same tail except for the counterbalances, shares this skin. Rather than make a die for stamping out a skin for specifically the RV-7, they leave this task to the builder. Here you can see the complete notch for one of the four areas where this trimming has to be done. Basically the skin is about an inch longer and overlaps the counter balance arm when you mount the elevator to the horizontal stab.

Since my wife was out of town this weekend with her girlfriends scrapbooking, I was playing Mr. Mom. I was only able to get this one notch done. It was a good start and turned out pretty nice. The goal was to get an 1/8″ clearance from the forward face of the counterbalance arm. The shadow on the curve in this picture makes it look bigger, but in person, it is spot on. I started with a notch on the bottom of the HS to start so if I messed it up, it would be hard to see when the plane is parked on the ramp. After complete, I hope they all turn out this good. Once this was done, I called it a day. All that is left is the other three corners and the notch in the center where the control horns go. Then I will set these parts aside and begin the wings!!!


Categories: Elevators

Elevator Final Push…Almost Done!

February 25th, 2012 No comments

The "J-Bolt" and Pipe Method

The time came to make the final push on the elevators. This meant rolling the leading edges. This step has been one that I have NOT looked forward to for some time. You can do really nice work the entire time, and one slip up here can ruin the whole assembly. I read many ways of doing this step. I also tried different ways when it came to rolling the rudder leading edge. The saving grace is that this step does not have to be “precise” as the leading edges are hidden inside the trailing edges of the mating parts. The one catch to this is that it should not rub the interior of the trailing edge of the mating parts through the full travel of the surface. That and you still want it to look “good.”

As I did with the Rudder, I took a tip from a builder over on where he used J-Bolts to hold a 3/4″ Electrical conduit to the table. This keeps the pipe close to the table and should make a nice radius. The other part of the setup is that you can drill the end of the pipe and insert a cross rod that can be used as a handle. Since you are not having to worry about holding the work to the table, you can use both hands on the handle. Supposedly you can also do all three sections of the roll at once.

So I taped the skin to the pipe using “Gorilla” brand duct tape. I think this is the same stuff the USAF calls “100mph tape” because it sticks great. I then anchored the pipe to the bench using the J-Bolts. Once I was committed, I threw my 3/8″ steel handle through the holes I drilled in the end of the conduit, and then twisted away. At first I thought…heck, this isn’t all that bad. The bends seemed to be a nice radius and all three sections rolled together nicely. This may look OK!

Left Elevator Leading Edge

Once I removed the tape and conduit, I took a long look at the bend. The one problem I see is that I think the J-Bolt setup makes the conduit TOO effective. The radius seemed almost too tight. I massaged it as much as I could, but I learned on the rudder that too much massaging can make the problem worse in a hurry. I was reluctant to massage more than I could have for fear this may occur on the elevators. Once the bend was done, I simply pulled the skin ends together and clecod the overlap. There was some squeezing by hand to close them, but not a ton. I then match drilled, deburred, and clecod them, and then pop riveted the leading edges together. The above was the result for the left elevator. I may be hard on myself, but I wished they would have been a little more smooth in the radius. I think this again had to do with the conduit being too effective with the J-Bolts. Most that are not using the J-Bolts simply roll the edge by hand while holding the assembly to the bench. The J-Bolt eliminates the need to hold it down while rolling. In the future, if I have to do it again, I may just use a bigger diameter pipe/stick.

Right Elevator Leading Edge

Here you can see the right elevator roll. Here you can see the tighter radius again. I tried to massage it a little more subtle, but I was still afraid of making a bigger mess than solving. As it stands, the joints at the overlap are nice and tight with no noticeable puckering. I am pretty sure they will function just fine.

End of Empennage MAJOR Construction

At the end of the build session, I walked out of the shop with two good looking elevators. This marks the end of the MAJOR portions of the Tail Kit. This is a big milestone. What’s left then?

  1. Mount Elevators to Horizontal Stabilizer and trim the lower flange of the HS-603PP to clear the elevator control horns for full down travel.
  2. Trim the HS-601PP skin to clear the counter balance arms.
  3. Drill the elevator control horns for the center pivot bearing and bolt.
  4. Fiberglass tips for the Horizontal Stabilizer, Vertical Stabilizer, Upper Rudder, Lower Rudder, and Elevators. (Will do these when the tail is mounted to the Fuselage.)

Once items 1-3 are done, I will store these parts away for safe storage and keeping and begin the WINGS! I will also call the empennage/tail complete!

Categories: Elevators

Trim Hinge Done…Again

February 24th, 2012 No comments

NO Edge Distance Issues Now

After waiting a few days for the replacement hinge to arrive, it was time to finish the elevator side of the hinge…again. This time, I left the hinge long and marked it with the skin on the inboard side…like the manual says to…DUH!

Since the new hinge came with a much longer than needed hinge pin, I bent it to the correct dimensions as well. I need to touch up the primer some, but eventually, this will all get painted with the base color when complete.

The trim tab moves silky smooth top to bottom and my worries about strength are no more.

Categories: Elevators

Elevators ALMOST Done

February 20th, 2012 No comments

Major Assembly of Elevators (and Empennage) Complete…ish 🙁

Another found and forgotten photo for the log. All done but the curling of the hinge line.

Categories: Elevators

Elevator Balance Mod

February 18th, 2012 No comments

Inboard Side of Balancing Modification

As I have read up on the balancing of the elevators, several good discussions have taken place on VansAirforce. One that I really liked was a suggestion from an RV-6 builder that simply enlarged a tooling hole in the forward section of the counter balance arm for a 1/4″ bolt. He then installed a nutplate to capture the threads. Once done, you can add a number of large AN washers to get the balance just right.

I thought this was a slick method. I did the same, just in case. It is much easier to do it now than later. So I enlarged the tooling holes, used some NAS1097 rivets and installed the nutplate for the bolt.

Outboard Side of Balancing Modification

Some have expressed some concern as the outboard side is covered by a fiberglass tip, so how do you get to the bolt? One suggestion was to make the tip removable by installing it with screws and nutplates. I do not intend on needing access to the outboard side after the tips are on. Another suggestion was to leave the bolt accessible on the inboard side. Then the concern was if the bolt worked its way out if it could jam the elevators.

I decided to install the nutplate on the outboard side and leave the access to the balancing bolt on the inboard side. I also bought drilled head bolts. This way I can install the balancing weights/washers and then safety wire the bolt head which solves the backing bolt head issue. As part of my preflight, I will simply check the safety wire as with all other safety wire on the surfaces.

Heck, if I am lucky, I won’t need it at all and it will balance just fine. Time will tell once it is painted.

Categories: Elevators

Left Elevator Riveted, Trim Tab Completed

February 18th, 2012 No comments

Ready for Final Riveting

Once the new trim spar arrived, I was able to finish the skin prep and prime both the skin and the new trim spar. Once the primer dried, I then clecod the elevator back together. Here you can see it is all ready to be finished riveted. I should be able to reach most, if not all, with my squeezer. I love that tool. It makes fast work of rivets.

Elevator Done, Trim Tab Hinge to Go!

Here is the elevator riveted together. I think it took me all of about 30 minutes to get this far. I also made the bends in the trim tab. I see now why people dread the left elevator. I had some real trouble keeping my bending blocks from slipping when trying to make the bends. Despite that fact, I think it turned out AOK. I scuffed up the skin in the process however. Since I am painting anyway, I figured I would simply scuff the whole tab now.

Once the tab was match drilled and dimpled, I primed the inside and the faying surfaces of the end tabs and set it aside to dry. I then went to work fabricating the hinge for the tab an the elevator. I was excited at the progress I was making and went to town.

I wanted to make sure that a complete barrel of the the elevator side would be located at the most inboard end. This also makes a complete barrel at the outboard end as well. I figured that this would limit any twisting forces that “could” occur, true or not. I marked the inboard edge of the trim tab side with the inboard edge of the trim tab. I did not however, do the same on the inboard side of the elevator half of the hinge. I simply cut it off flush with the last barrel and figured that would be good. I was wrong.

I positioned the trim tab to the elevator and clamped on the hinge and match drilled both halves to the respective parts. The trim tab half went just fine. I clecod it on and went on with the elevator half. After match drilling the hinge and removing it, I saw something that concerned me a little. The most inboard hole was busting the 2Xdia edge distance and really (and I mean really) close to being inside of the 1.5Xdia edge distance rule. I consulted a few smarter folks and they said I would likely be OK to rivet it on as is. So I did.

I finished the trim tab, inserted the hinge pin, stepped back and admired my nearly finished elevator. I typically do an after rivet smash inspection and looked again at the most inboard rivet on the elevator half. I just did not like it. It WAS too close to the edge. I also thought about where the most force would be transferred to the hinge. Since that is soooo close to where the trim servo actually applies the force to the trim tab, I bit the bullet and removed the elevator side hinge. I know, a whole row of rivets for one perceived mess up. I did not want the hinge to possibly tear out over time. After all, it is my plane and I needed it to be right, not close enough here.

I now needed to replace the hinge. I first called around to fellow builders and A&P’s to see if they had any AN257-2 hinge. Turns out, it is not common. Not to mention, after some looking, the only AN257-2 hinge on the plane is right here. Guess it was time to order one. I checked Vans’s and Aircraft Spruce. Turns out for the same money and probably the same shipping, I could get 3 feet of #2 hinge from Aircraft Spruce over 18″ from Van’s. Both would arrive the same day, so order was placed at Aircraft Spruce. You can always use extra at the same cost. All in all, it was a great build day and a good learning experience.


Categories: Elevators

New E-606PP Arrives

February 15th, 2012 No comments

No pictures tonight. The new E-606PP trim spar arrived and I ran it out to the shop. I slid it into position, matched drilled it, and countersunk the upper holes. This time I used the same matched drilled backer and the countersunk holes looked great. I then dimpled the spar, the skin and slid in the assembled skeleton previously done, and clecoed it all together for fun.

Hopefully this weekend I can prime the skin and spar and be able to get the elevator riveted together final. Then I can move on to the trim tab itself.

Categories: Elevators

One Step Closer

February 11th, 2012 No comments

As far as the parts could go

Saturday came and it was a nice day to boot. I got some honey do’s done and then headed to the shop. Since prepping all the parts aside from the trim spar for primer, I knocked out spraying them. While the primer was drying, I took the time to remove the blue vinyl from the rivet lines on the skin, deburr it, and dimple all the holes except where the trim spar goes to be able to match drill it when it arrives.

I then scuffed the skin for primer but the temp fell to far to shoot it. So I looked at the assembly instructions for the skeleton and determined I could start riveting the parts together without causing any trouble to getting the new E-606PP spar taken care of.

The above shot is at the end of the building session. I was able to get the skeleton mostly complete. I love how it all lines up. You can also see my wire exit hole near the hole for the trim servo jack screw.

Everything went straight forward as it could have. I love having the right tools for the job. If you have not purchased a longeron yoke for your squeezer…do it now! As for now, I am as far as the parts can take me on the elevator.

Categories: Elevators

Left Elevator Work Resumes

February 9th, 2012 No comments

Dimpled and Scuffed, Ready for Primer

I decided now that I have heat, I needed to get back to work on the plane. It has been a few months and life has been busy. Since the last build session concluded with the match drilling being mostly complete, and I keep a good list of where I am in the manual, starting up again was a breeze. I got back to work prepping the rear trim spar (E-606PP) for the trim tab. I needed to disassemble the spar from the skin and countersink the upper holes where the hinge for the trim tab will go.

I set up my countersink cage with my piloted countersink to get these done. Here is where I made a small error. Since the spar is .032″ thick material, and the holes have to be a little deeper to accept the dimple of the skin, I forgot that it may open the hole a little more which will allow the pilot to no longer center and cause chattering. That is what happened on the first hole. Once the hole was opened up larger than the pilot, it made a real mess of the hole. The pilot was able to wander all over.

Some may say that the larger hole is a real problem. Traditionally yes it would if the spar being countersunk and the skin were the only parts being riveted together here. However, eventually the trim tab hinge will be added underneath, and this spar will be sandwiched between the hinge and the skin. There will be plenty of support for the shop head and the parts will lock together just fine.

So how do you keep the pilot from wandering? I grabbed a piece of scrap sheet stock and simply matched drilled it to the spar and clecoed it to the spar so that as I cut the material out of the spar hole, it still had a good hole for the pilot to continue to hold the cutter solid. This worked great for the rest of the holes that had to be countersunk.

Once the holes on the top were done, I dimpled the rest. As for the first chattered hole, I decided I would finish the rest of the hole prep and then decide what to do with this one. As I was dimpling the underside of the spar, I missed a hole with my dimple set in my pneumatic squeezer and punched a hole bigger. At this point, I decided it was time for a new rear spar.  As cheap as the parts are for the tail, it was an easy decision.

The rest of the night, I deburred, dimpled, and prepped the rest of the skeleton parts for primer. I did not dimple the skin tonight but will in the next build session.

I also added a 3/8″ hole in the E-702 spar just below the hole for the jack screw for the trim screw. I did not like the idea of the trim servo wire sharing the same hole with a piece of threaded rod. I centered the hole between the existing hole and the flange of the spar. It sits exactly centered with the existing hole as well. I think this will be a better way of routing the wire. I got the idea from another builder and have been told that no strength will be lost with a hole of this size here. Both holes will get snap bushings down the road.

It was now time to close up shop for the night and order the new trim spar.

Categories: Elevators

Riblet Complete

November 23rd, 2011 No comments

Match Drilled and Ready for Dimples

Since today is the day before Thanksgiving, I had some “non RV” tasks on the list, I decided to get at least one thing done. That one thing would be match drilling the riblet to the skin.

The part I stewed over is how many holes and where they should be located. The riblet is just long enough to me that it warranted 3 rivets on each side and one on the small tabs. Others have used only 2 per side, but I kinda felt that it left the ends of the flanges with too much length from the rivet to the edge. I seems that the size is right in the middle of going with 3 or 2 rivets. I ultimately decided that 3 was it for me. I spaced them at 1 1/8th” from each other. This caught both ends of the flanges and tucked in the center. I think it will look just fine.

All clecod in, the riblet is nice and straight from the trim spar to the trailing edge bend. It is ready for dimpling with the rest of the parts and the skin and then on to elevator assembly.

Categories: Elevators

Elevator Riblet Fabricated

November 21st, 2011 No comments

1 Down, 2 Remain

Giving credit to Jason Beaver again, I liked his riblet design on his work. I emailed him and asked for his process. It was simple enough. Basically, you make a paper template of the riblet until you are satisfied with the fit. Then you copy that to some 0.032″ scrap and cut it out and then bend it with a pair of hand seamers. Sounded easy enough. The thing I liked about Jason’s design is that it tied the trim spar in the elevator to the riblet rather than simply closing off the end like other builders have done. The thought is that it will reduce/eliminate more twisting at the corner of the skin and the spar and hopefully keep cracks from forming in the corner of the elevator skin where stresses are focused. Since the original design was simply to fold over some ears, this may be overkill, but heck…why not?

After some careful measurements, I generated a template pattern on my computer and printed it on a file folder. I have the vector file now if other builders want a head start. I then cut it out and then scored the bend lines and what do you know, it fit nicely. I figured I was on the right track. With some minor tweaking, I updated my file on my computer, reprinted, cut out, bent, and fitted. I had a winner.

I then transferred the pattern to some sheet scrap and cut it out on my band saw. I then cleaned it up on my disk sander and dressed up the edges. Now it was time to bend. I placed the sheet stock in the jaws of my hand seamer and started to it. That is where all heck fell apart.

One of the challenges of bending metal is knowing where to bend to get the part to be the right size post bend. Paper and metal are totally different beasts. The other issue was the little flanges to capture the spar. Bending these takes a little finesse over the large flanges. As I was bending the first little flange, it cracked right at the bend line. There goes that attempt. I actually cut off the smaller flanges and web and figured it could work as a riblet just fine. Turns out, it fit quite nicely.

I still wanted to make one that captured the spar. So I repeated the process on try #2. I slowed down some and took my time on the smaller flanges this time. It paid off, however, the web of this riblet was too wide and the rib did not fit very well.

Riblet After Much Tweaking

They say that the third time is a charm. It turned out to be true here. I was able to get another cut, bent just right with no cracking, and fitting nicely. Mine is not as tight to the trim spar as Jason Beaver’s rib, but it fits and works and it really stiffens up this area. I match drilled the smaller flanges to the spar/skin. Next up is match drilling it to the trailing edge.

Straight and Clean

It was time to call it a night. Here you can see the rib in and ready to be drilled to the skin. All in all, it turned out OK. Bending may have been easier to try, but at this point, I like the clean look the riblet creates and the added rigidity it also adds. Time will tell if the extra work to get it to tie into the trim spar was worth it. Thanks for the idea and tips Jason B!

Categories: Elevators