I’ve been spending the last few weeks finishing up the tail fairings. Lots of filling and sanding – repeat.
Here is the lower rudder fairing. I sanded off the molding for the tail light and then added some foam, epoxy filler, and a fiberglass layer. This will need some iteration until I’m satisfied.
Also on the bottom of the rudder fairing is a flat spot that needed to be added to allow clearance for the tail wheel. This will also take some additional work to finish off.
The top of the vertical stabilizer also got some filler. This one is close to complete, just another iteration and then I can prime it.
The elevator fairings are done and primed. I’m very pleased with how they turned out. It’s not perfect, but more than good enough until final paint. The horizontal stabilizers also have some final filler added and will be sanded and primed next time.
The whole process involves some West Systems epoxy, cotton flox, 60 grit, 150 grit, and 320 grit sand paper. Lots of sanding.
Tail is almost done done, then I can finish up the remaining fiberglass work on the canopy, and then do the cowl. Things are coming together!
I added some more epoxy and filler to the tail fiberglass tip fairings, and while that was curing I spent some time wrapping up additional finish items.
I started by marking the wing root fairings for a 3/16th” gap. I marked the fairing with some black sharpie, and then used a 3/8″ bolt to score a small line, resulting in a 3/16th” gap from the side of the fuselage. I then removed the fairings from the wings and used my snips to cut back to this line. I then filed this edge to smooth out the cut. After this I installed the rubber seal that will bridge this gap, and reinstalled the fairing to the wings.
After this I spent some time inside the cabin installing support braces for the panel. Originally, the design has two large ribs that extend from the firewall all the way back to the panel through the sub panel, making the entire structure very rigid when riveted all together. With my panel design however, I removed those ribs between the sub panel and the panel so that I can fit all my avionics. As a result, I needed to fabricate some new supports that I can install between the sub panel and panel so as to not lose any rigidity. I fabricated the supports out of some 3/4″ angle stock, and cut to length so I could use my avionics trays as the anchor point on the panel, and then drilled two holes through the sub panel for a screw to hold the supports.
While I was in the cabin, I finished securing all the wiring below the seat floors and in front of the spar. Additionally I also added rubber edging to the fuel line passthrough holes in the sides of the fuselage so the steel braided hoses won’t rub against the fuselage. I will additional silicone tape around the hoses to make an air tight seal (or at least more of a seal).
I also added the four remaining wing spar bolts. They are AN4-13A bolts that are inserted from the aft side of the center-section spar into some nutplates on the wing spar. These bolts are often missed as they are not part of the larger main bolts that go through the entire assembly. (The paint marker got a little runny)
I began wrapping up the interior controls installation by adding all the necessary washers (which are pain to install) to the Aileron Pushrod – to – Control Stick attachments. This included tightening the jam nuts on all the pushrods and ensuring that a sufficient number of threads are available on either end to ensure that if something does come loose, nothing can fully unscrew. I then marked everything with torque paint.
While I had the floor pans out and working on the aileron pushrods, I decided to install the aileron pushrod boots. These are leather covers that attach over the pushrods to prevent air from entering the cabin. They are from Classic Aero Designs and were quite easy to install. The provided instructions are very clear. Another great product to go with my complete interior!
In parallel to all the above items, I began working on some of the fiberglass parts on the plane. Starting with the Horizontal and Vertical Stabilizer tips. They are pop-riveted to the surfaces, and have some foam and fiberglass filling to close gaps around the attachments. I also filled the gaps and glassed over the joint after riveting them to the surfaces. This is an iterative process and the epoxy curing time allows for a lot of work to get done in between. I’m using the West System Epoxy 105A (and 205A hardener). They make it super easy with the pumps – 1 pump from each is exactly the amount for proper mixing. This is going to take a few iterations to complete, but once the surfaces are bonded and glassed, I will paint over them with some primer to seal the whole thing.
February has been a bit of a slower month in making big progress. I’ve spent a few evenings working on several different things. I got some new shelving units from an old storage unit that my mom was getting rid of, and they sat in the hangar for a few weeks before I finally got some time to assemble them and reorganize a lot of the stuff we have.
I spent an evening with my wife moving the old shelves and workbenches to opposite sides of the hangar, and moved the new shelves to the back wall (they’re much bigger) and just general organizing of tools and parts and a lot of clean up.
We also made a trip to the Container Store and got more plastic boxes for stuff. Its always satisfying when putting things back on shelves and seeing how organized it is at the end.
I came back a few days later and worked through a short to-do list of things inside the plane. I needed to shorten the elevator pushrods so that the bellcrank would rotate aft a small amount. When I pushed the elevator fully forward, it would get a little “squishy” and if I pushed harder, it would then hit the forward (down) stop. I figured the only thing that could be causing this is that I was over rotating the autopilot servo, which is attached to the bellcrank. After shortening the pushrods, I reinstalled everything and tested the forward (and aft) stop, everything hit their stops with no problem or squishiness felt anymore. I then torqued all the bolts and marked them with torque paint.
As I was working on the larger aft pushrod, I noticed that the aft fuselage skin still needed to be riveted. Its the portion right under the empennage, totaling ~50 rivets. I’m surprised I didnt notice this earlier, but It would have been caught when I started doing the fiberglass work on the empennage fairing. I realized I needed to remove the horizontal stabilizer in order to sufficiently gain access to rivet these holes. I proceeded to remove the tail and then riveted the aft skin with no issues and then reinstalled the vertical and horizontal stabilizers.
Now that I have the elevator and rudder off the plane, I will be working on the fiberglass tips.
Today I spent most of the day working on a bunch miscellaneous items.
I started by fabricating my aileron stops. I am using a small delrin bushings around the aileron pushrod spacer to act as the stops.
Aileron stop bushing
After fabricating and installing I measured the deflection angles – I have 28 degs up and 16 degs down for each aileron. The specifications call for a minimum of 25 deg up and 15 deg down, so I’m within the standard range.
Left aileron neutralLeft aileron upLeft aileron downRight aileron neutralRight aileron upRight aileron down
Next I drilled two holes in the fuel tank mounting bracket in order to attach the safety wire. These bolts are tightened snugly with a large washer in order to allow for separation from the fuselage in the event the wing is hit. The safety wire will prevent the bolts from prematurely backing out.
I also made some slight modifications to the position of my accessory bus fuse block. I needed to modify the position lower in order to allow for the forward top skin to be installed. I’ve modified the top skin with the optional access panel kits. The panel is held in place with nutplates and the bottom of the nutplates interfered with the fuse block. Now that I’ve lowered the position the top skin is ready to be installed.
Last but not least, I also secured the pilot’s stick wiring harness connectors, among other wiring bundles below the seat skins.
Happy New Year! I wrapped up 2023 and kicked off 2024 by completing the wingtip installation. I am using the Aveo Engineering ZipTip Premier wingtips that have integrated lights. These include Landing, Taxi, Nav and Strobe lights with a rear position/strobe light as well. They recently announced a completely new and upgraded version – Vegas. Check them out, I may upgrade in the future.
I started the installation by trimming the inboard edges of the wingtips to 5/8″ width. This is so that they sit flush with the wing skins. I also trimmed back the trailing edge to provide 1/4″ gap to the aileron.
I then used my ratchet strap to hold the wingtip in the right position and snug up against the leading edge.
With the strap holding the wingtip to the wing, I drilled #40 and clecoed all the holes top and bottom. Then I removed the strap. I also used this opportunity to verify the lighting was working as expected. I drilled the left wingtip, then the right followed the same process.
I removed every other Cleco and drilled to #27 for the -6 screws I’ll be using. Once all the holes were drilled I removed the wingtips and began the tedious process of drilling and installing the nutplates.
I made a small nutplate jig using a -6 screw, and use that to drill all the rivet holes for the nut plates.
after drilling everything I countersunk all the rivet holes and the screw holes. The screw holes need to be counter sunk big enough to accept the dimple from the wing skin. After that, I riveted all the nutplates on to the wingtip. I repeated this process with the right wingtip.
Once everything was riveted, I installed the wingtips to the plane and ran the harness through to the lighting module. I powered up the panel and did a test of the lights. It was night time so I used this opportunity to test out the performance of the lights at night. They are very bright. I may need to make some minor adjustments to the taxi light angle somehow, but they are sufficient for now.
The whole process took me approximately 8 hours for all the trimming, fitting, drilling and riveting. Nothing was difficult, just tedious. I wanted to start the fiberglass work with the wingtips for this reason. Now I can proceed to rest of the fiberglass work!
I spent some time over the weekend beginning the installation of my Classic Aero Designs Sportsman II interior with Aviator seats. There are two things I want to call out about Classic Aero – 1. the customer service and overall experience working with them over the last couple years (ordering, receiving, installation) has been great. And 2. the quality is impeccable. Everything is superb in fit, and finish, and it really makes the plane feel like a premium aircraft.
I received some guidance on the installation process, so I began by laying out the carpet in the plane to mark the locations. I then installed the velcro chips (Velcoins) that are used to hold the carpet down. They are pop-riveted to the floor pans and then the carpet is attached.
I then proceeded to install the seat backs, cushions and stick boot covers to really get a sense of what the interior will look like.
In the next few days I will install the remainder of the interior (for initial fitting) including the side panels, pockets, armrests, forward carpet, baggage carpet and baggage side panels as well as rear cover. It’s really starting to come together!
Now that the wings are installed I spent a couple hours working on some remaining wiring tasks inside the fuselage. I drilled two holes through my center section (with the guidance from this post on vansaircraft.com) in order to route my autopilot and right wingtip lighting harnesses forward of the spar. The left side wingtip lighting harness was routed through an existing hole. I will then connect the wires up to the existing wires that were in place already. I also routed the Fuel Level sensor wires through the sides of the fuselage as well. Once these last few connections are complete, the entire avionics and wiring of the aircraft will be complete.
I also took this opportunity to install my wing-walk grip. I ordered custom skateboard grip tape from www.boardpusher.com, and they turned out amazing! I cut them to final size by laying them on the wing and trimming as necessary.
I came back the next day and began wiring up the lighting harnesses and the roll servo. It was a quick job to splice the wires together and secure the bundle forward of the spar.
I got my wingtips out and propped them up on the wings. I connected the included ZipTip wiring connector and powered up the panel. On first try, the left wingtip taxi and landing light both failed to turn on, while the right side worked nominally. I then began to trace the break in the line, starting with just powering the wingtip with a power supply directly via the wiring harness. I went to disconnect the harness, and one of the ground wires separated from the connector. The ZipTips utilize two grounds – one for landing/taxi lights, and one for nav/strobe. I popped the pin out of the connected, re-stripped the wire and re-crimped a new pin. When I plugged it in, everything worked as expected!
With the panel powered up, I also updated the autopilot servo software to the latest version. When it came back online, I calibrated the servo and verified that everything worked as expected. Its fun to see the autopilot try to maneuver the plane!
After rigging the ailerons and flaps and making sure everything was aligned, I needed to remove the wings one more time in order to finish up some critical items. The to-do list included finishing the Root Fairing seals and drilling two more holes for the Pitot and AOA tubes (for the left wing). The Root Fairing seals have about 20 nut plates that need to be riveted to the wing in order to accept the screws that hold everything together. This required removing the wing so I have access to the inboard rib of the wing to install everything.
A few years back, a fellow builder, Vince, told me about a solo method to remove and install the wings using the wing cradle. If it wasn’t for this guidance It would have been quite annoying to attempt this work by myself. The method involves putting the wing cradle under the wing when its temporarily installed in the plane, and then using some plywood clamped to the cradle to prop the wing up in its final orientation.
I used some scrap plywood my friend Norio gave me, and cut it to size such that when clamped to the cradle, it fit snuggly under the wing. I then clamped everything and tightly as I could. I hopped into the plane and began the painstaking process of removing the bolts that had been temporarily holding the wing on. Its quite a tight and awkward fit, but I managed to remove everything. I then slowly removed the wing while it was held up by the wing cradle. Success!
Once I had the wing off, I began the process of drilling, countersinking, dimpling, and installing the nutplates to the inboard rib of the wing. This was pretty straightforward, nothing too challenging here.
I also used this opportunity to drill two additional holes in the side of the fuselage for the pitot and angle of attack lines. Its all quite a tight fit inside this area, so trying to make sure I had everything lined up appropriately. When I initially installed the lines, I mistakenly cut one of them a couple inches too short. In this pic you can see a short segment that is used to attach everything. After taking this pic I added a longer segment in the wing under one of the access panels (where its easier to work) in order to remove this short segment under the floor pan.
I Also needed to attach the nutplate to the fuel tank bracket. This is an AN4 bolt that will slip away in the event that the wing impacts something, in order to prevent the fuel tank from rupturing to minimize the risk of a fire. The bolt here will be safety wired.
Once I had everything drilled, and all the nutplates installed, I reinstalled the wing. The wing cradle method worked absolutely flawlessly, and makes installing the wings solo completely reasonable. I then installed all of the bolts that hold the wing, as this is the final time the wings will come off!
The next day, I went back to the hangar to repeat the entire process on the right wing. This one took me about 50% less time, which was nice. Now that the wings are permanently installed, I can now wire up the wingtip lights, and autopilot servo, which will close out the two remaining avionics to-do items.
With the wings on the fuselage I got the flaps onto the wings so I could fabricate the flap pushrods. I started by cutting the pushrod stock to length. I then tapped both ends of the rods for 1/4-28 rod-end bearings. The plans call to use a CM-4S bearing.
The problem with this is that because it’s an integrated ball into the bearing, there is no way to prevent this from backing out. The instructions call for locktite to hold it in. I will be changing this out to a CM-4M rod-end bearing with a through bolt that can be safety wired. Its much more secure and safe this way.
But while those parts are on order, I still used the default part to do the initial fitting. I installed it onto the flap and then checked the alignment with the bottom of the fuselage. I then cut the hole in the fuselage that the pushrod passes through
When I installed the bearing into the flap I did not put any spacers, but when I put the update rod end bearing I will be centering the bearing so its not rubbing against the side of the fuselage.
With both flaps on the plane, and aligned I was able to test the deflection of both flaps. Luckily everything was symmetric and the full flap deflection was 45deg. This is above the minimum of 40deg for the RV-7.
With the flaps installed, I then began the aileron aligning. I first began by ensuring the vertical-ness of the control sticks in the plane. When I initially aligned the pilots stick, the copilot stick was inboard by about 6deg. So I adjusted the connecting pushrod so that both sticks were perfectly aligned. It’s hard to see in the pic below, but it says 89.7°, which is close enough for me.
I used a long straight edge to align the aileron with the tooling holes on the outboard rib of the wing (per the instructions) and then ensure that it was aligned with the flaps. I then used the aileron alignment tool to ensure the bellcrank-to-aileron pushrod was the right length, and then, with the control sticks in the vertical position I adjusted the main pushrod. Once the left aileron was adjusted I did the same for the right side. Everything was perfectly aligned to within 0.1deg when comparing everything.
I also got the lower fuselage skins drilled to the wing skins. This has to be done now so that I can remove the wings and install all the nutplates. I also temporarily installed the wing root fairings to drill those as well. They will also be attached with screws through nutplates.
The gap between the fairings and the fuselage will be opened up to 3/16″ and then a rubber seal will be added before permanently reinstalling it.
I also recently saw a modification to the canopy installation that I really liked. Its a modification to the canopy lift struts geometry. I found it through this post (thanks Mike). It had some great guidelines, and only a slight modification was needed for my RV-7 (the post is for an RV-6).
I measured 2″ back from the panel for the forward lift brackets. The canopy brackets were 24″ back from the leading edge of the canopy frame. The struts used are Suspa 23.86″ 20lb struts. I also purchased the brackets from there as well.
The initial fitting took some trial and error, but I got it all aligned and double checked the support capabilities. The entire canopy is very well supported all throughout the closing/opening trajectory. Whats really nice about this geometry is that the canopy is supported by the struts throughout the entire cycle, but with the original geometry there is an over-center position in which the struts begin to pull the canopy down, and it is quite unstable.
Here you can see the original geometry vs the new geometry. One other big benefit to this geometry is the increased entry/exit area.
RV-7 N890GF 