RV7-Factory

Per the RVator...My Version

When I opened the Empennage kit last year, a nice little freebie in the box was a copy of the 27 Years of the RVator. It literally is a treasure trove of knowledge of all the articles that the Mother Land (Van’s Factory) had done over the last number of years. While many of the articles dealt with items that the earlier builders had to deal with, it is good read for the information and practices. It is apparent when reading through the info, that Van’s listens to it’s builders as many of these articles on how to do this, that, etc. are now just incorporated in the newer kits. Thank you to all those prior builders for your work and contribution!

One of the articles I saw really caught my eye. It described this simple tool that builder Bill Gast made. I had heard of a mystical tool that one could build that would make the job of straightening the rib flanges to 90° a chore of joy.  Since one of the more tedious tasks on the wings is this rib flange straightening, I was all for making it less of a task if able. I read this article and set out to make my own version. Before I started, I also searched the forums over at VAF, like you should for most questions, and saw a few other versions with clearer pictures.

The trick here is having the right angle on the part that the flange gets pushed into (the anvil). Upon the advice of both the article and the posts on VAF, 11° seems to be about the consensus. With all the information in hand, It was time to construct a new tool.

Bill of Materials:

6″ x 20″ x 3/4″ MDF Plywood Base Plate

2″ x 4″ x 12″ Anvil with 11° undercut on one face. (Mine was actually a chunk of a 5″ x 5″ post that I cut to shape.)

1 1/2″ x 1 1/2″ x 30″ Oak stick purchased at Lowes Aviation Supply. (Note, my local Home Depot Aviation Supply had the same but it was two 1 1/2″ x 3/4″ x 30″ sticks laminated together.)

Cut a 3″ long piece to accept one bolt for the arms
Cut a 20″ long piece with a 22 1/2° angle cut on one end of the handle/pinch bar
The angle is so that the bottom of the pinch bar clears raised portions of the rib like lightening hole flanges.

3/16″ x 1″ x 36″ flat bar stock from the metal bins at Lowes Aviation Supply

I cut two pieces 12″ long for arms.

Two 1/4″ x 20 x 2 1/2″ Bolts

Two 1/4″ Nylock Nuts

Four 1/4″ washers

2″ and 3″ wood screws

After cutting the bar stock to the 12″ lengths, I match drilled on the drill press, the 1/4″ holes in both ends so that they would match exactly. I then radiused  the ends on the grinder and polished them smooth (No burrs to scratch parts or humans). I had some paint left over from a project years ago, and since the color did not matter, better to use it than toss it. I sprayed the arms for protection.

I then took all the wood, cut to length and with the angles cut into the handle/pinch bar and anvil, I ran all the exposed edges over a 3/8″ router bit on my neighbors router table. This makes the handle very comfortable to use. As for the other edges, I was there and the router table was setup, so why not.

I attached the Anvil to the Base Plate, centered on the the long axis of each, with some 2″ wood screws. I eyeballed the location of the metal arms on the handle (approx 4″ from the bottom) and center drilled a 1/4″ hole through it. I attached the arms with a 2 1/2″ bolt and washers on the outside of each bar and tightened the Nylock nut just shy of tight, allowing the bars to pivot on the pinch bar.

I then center drilled on both the length and height of the smaller 3″ oak piece for the other 1/4″ bolt hole, and attached the bars to it. Lastly, I positioned the small oak piece along the center line of the anvil until I had the pinch bar just proud of the anvil face. Essentially, this allows the pinch bar to fully push the rib into the corner of the anvil and the base plate without pinching the thickness of the flange itself. Once the position looked good, I attached the small oak piece to the anvil with 3″ wood screws.

There you have it, the rib flange straightener. I clamped it to the bench and did a quick test on a few leading edge ribs and it appears to work GREAT! Like all tools, it takes a little to get the feel, but with little effort, the flanges on the ribs turned out pretty close to 90° very quickly. I wish I had this when I was working on the Empennage ribs.

Thanks to Bill and the VAF guys for the ideas.

CAP Pilot Wings

I like aviation flare. What pilot doesn’t. Since the shop has a ton of wall space, it is perfect to use for said aviation flare. It is a Pilot Cave after all.

The above is a cooperative effort between a fellow CAP nerd/computer geek to design a set of CAP wings that could be easily cut on a vinyl cutter. I think we finally got the center emblem where it works just perfect. I added a black outline for contrast. Once I earn my Star and eventual Wreath, these will get added on.

So who's kit is it now?

I found an .eps version of the Van’s logo and had it cut in two colors to match those of the colors of my stripes on the walls. This one is big, nearly 48″ across. Any question where my kit is from now?

Never Forget!

I designed this after making a trip to Ground Zero shortly after 9/11. I once stood on the top of Tower #2. I have also been to the Pentagon with my Dad. The design speaks for itself. Let us NEVER FORGET!

I have more ideas floating in my head…so who knows. The nice thing is, I have all the files saved, so when it comes to accessorizing the eventual hangar, it is a simple matter of cutting some more.

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.

COMPLETE!!!

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!!!!

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.

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!!!