Could not yet see the light at the end of the RV7 build, but knew it was getting closer. The list of accomplishments in the interim included:
Fastening the fuel tank “break away” tabs to the fuselage on each side.
Fabricating and installing the short fuel vent lines and connecting fuel supply lines between the wing and the fuselage
Making up brake lines with Berringer fittings to go from the firewall down to the wheel brakes.
Filling the brake calipers and lines up from the bleader valves to the reservoirs over the master cylinders
Final fastening the PAX baggage floor and PAX seat pan to underlying ribs with machine screws. This and other tasks may sound simple, however I found them to take significant time.
Finished wiring the flap motor and position sensor
Installing a quick drain valve on the left front oil sump drain.
Installing Clasic Aero aileron push-rod boots to seal out cold air.
Installing SCAT tubes from NACA air scoops to the instrument panel outlets
Timing of the PMags
Fitting the cylinder baffles and using the “Paper clip” method to trim the baffles 1/2″ from the cowl
Fitting the oil cooler to the right rear engine baffle; doing the install and connecting oil lines
Cuting and glassing the engine air intake snorkle between the air filter and the fuel servo
Installing the ignition wire protectors that I designed last winter
Closing up the six inspection ports in the wing bottom skins
Installing an alternate air door into the snorkle with control from the instrument panel
Installing all interior cover panels, baggage rear wall and pilot seat pan
Sealing the engine to baffle gaps with Blue RTV
Installing wing to fuselage faring strips
Installing seat belts
Whew, and that’s not all.
The Vans upper and lower cowl halves had to be trimmed to fit each other and the fuselage firewall. For October 30th we had a Halloween Lantern.
The cowl interiors were painted with three coats of white two-part epoxy.
I copied the practice of many Vans builders and cut an inspection port into the upper skin in front of the canopy. This provides access to the break fluid reservoirs, the voltage regulators and the forward sockets of the VPX power box.
Another deviation from the Vans standard is that I fabricated and installed a plenum cover over the top of the engine, rather than the usual flexible baffle strips that seal the baffles to the top cowl.
The potential advantages of a plenum in cooling efficiency and reduced wear on the cowl have been often debated on the Vans Airforce website forums. Casting of the plenum was discussed in an earlier post.
Clay risers were set on the plenum to verify 1/2″ clearance from the cowl.
Aluminum and fiberglass edges were set with platenuts for fastening to the engine baffles.
The Catto three blade wood/carbon fiberglass propeller was installed. Specifications:
Nickle leading edges
Design RPM 2750
Red Line RPM 3300
Prior to first engine start start the fuel tanks were calibrated and a weight and balance prepared. Both of these steps will be repeated as the W&B indicates a heavier spinner ‘crush plate’ will be needed to move the center of gravity further forward.
While we were in Oshkosh, WI for the annual EAA convention, Lycoming announced a manditory service bulletin for about 1300 engines that had been manufactured in 2016, plus all engines that had been overhauled with new piston rods around that time. Our engine serial number was one of those listed. The inspection involved purchasing and using a special tool to find those connecting rods that may have looser than specified bearings in their upper ends.
An FAA Airworthiness Inspector friend who once owned an aircraft engine overhaul shop helped me get the job done.
The photo shows the tool (a big coil spring attached to the #4 cylinder’s rod. If the bearing starts to slide out when the spring is compressed by six turns of its inner bolt, it fails. We were lucky all four rods passed. Note the red cylinder base o-rings that are used to keep the connecting rods from flopping around during the disassembly. The S/B was just a PITA that slowed progress by three days.
Soon after the wings were mounted the FAA approved a Registration Certificate for Vans RV7 N50KB, known to us as “The Dream Weaver”. That didn’t reduce the number of tasks yet to be accomplished. I next
installed gussets connecting the fuselage side skins to the wing main spar. Two of the 1/4″ bolts were too short and were replaced by Vans.
Installed the 22 #8 screws that attach the lower wing skins to the fuselage bottom skin
Bolted the wing rear spars to the center rear spars. This required removing and reinstalling the flaps. Flap push-rod lengths were adjusted to synchronize the two flaps.
Connected aileron push-rods to the center section controls
Installed the outside air temperature probe onto a right wing inspection plate
Confirmed the angle between the wing top skin and the flap top skins are 45 degrees when in the down position
Identified, tested, labeled and prepared the 28 wing light wires for connection to a terminal strip under the PAX seat. The LED landing lights draw 13.3 amps and were assigned a 15 amp breaker in the VPX Pro electronic breaker box.
Worked through the Garmin menu structure to find the VPX control page on the MFD screen.
Then connected the VPX box’s serial port to my laptop computer and configured the breaker ratings for each circuit.
Set the graphical image colors and limits for the Garmin screen’s graphical flap, fuel, and trim position indicators.
Threaded the pitot and AOA tubes up from the left wing root through the armrest support and on to the instrument sub panel where they were connected to the #1 and #2 ADAHRS units.
Control Movement Test
Filmed the ease of flight control movement.
Installed fuel lines between the wing tanks and the fuselage manifold.
Then it became time to do the inspection required by the newly announced Lycoming Service Bulletin #632.
For over a year, the wings have sat in their cradle waiting for this day. Working on the fuselage was easier without the wings attached. The day came when the next step in wiring was to connect the wing mounted taxi, landing, navigation and recognition lights.
I asked several RV friends to help Dolly and I with the job.
Word spread around the airport and a gaggle of help arrived. Knowing I would be in the cockpit driving close fitting bolts connecting the wings to the center section, I told everyone that Dolly was the floor manager for the operation. She had helped when we did the test fit of the wings a year earlier.
Before mounting the wings, we sorted out the coils of lighting wires and fed them into the fuselage. We started with the left wing. Both wings had been laid out on padded sawhorses next to the plane. This was for safety in case we had to halt the process mid-way to completion.
In 2016 the wings were test fit and retained with lubricated drift pins that I had made from hardware store bolts in a mini-lathe. Now for each wing, two drift pins were driven in bolt holes before driving the first close tolerance bolt. The pins provide initial alignment and are then replaced by bolts.
There are a total of eight 7/16″ and eight 1/4″ close tolerance bolts holding the wings to the fuselage center section main spar. They give one confidence in this aerobatic airplane.
When the wings were on we all enjoyed a great lunch of Subway sandwiches and cool drinks that Dolly had laid out.
When we left toward Florida in the fall of ’16 the engine had just been mounted. The weather was getting cold. I was OK with the heated hangar but I would be batching it if I didn’t follow Dolly South. Besides, all I had to do was hookup a few hoses and wires.
Hah!! Little did I know.
May was all firewall forward work. It included:
Installing the oil filler neck
Installing NGK BR8ES 3961 spark plugs gapped to 0.31”
Installing the exhaust pipes lubed with Mouse Milk
Installing the cabin heat muff on the #1 cylinder exhaust pipe
Installing vibration dampers on the exhaust stacks
Mounting the throttle servo body to the engine
Fabricating mounts and installing the throttle, mixture and other controls required drilling the firewall and making up cable fittings and linkages to the engine
Installing fuel lines from the engine pump to the fuel servo, and on to the fuel divider
Installing an overflow line from the engine fuel pump
Installing a multi-pressure manifold on the firewall
Drilling exhaust stacks and installing four Exhaust Gas Temperature sensors
Installing fire sleeve in several places
Installing four Cylinder Head Temperature sensors
Installing a Red Cube fuel flow sensor in the fuel servo to fuel divider line
Installing SCAT tubing from the heat muff to the firewall heater box
Installing fuel, oil and manifold pressure lines and sensors
Installing a voltage regulator for the backup alternator
Forming and installing the crankcase breather tube with “whistle slot”
Threading and lacing the wire bundle going to the Garmin GE24 engine sensor box
Routing the lower spark plug leads from PMags to cylinders.
May was a busy month of 5-8 hour days in the hangar.
I took June 1st off to do EAA Chapter 77 treasury work. After that the month included:
Mounting the primary alternator and wiring the field and ground lines back through the firewall
Fabricating buss bars, mounting ANL fuse blocks on the lower right firewall and connecting shunts to the Garmin GE24 amperage sensor inputs.
Installing an alternator fail light for the main alternator.
Cutting and fitting nine high amperage cables for the alternators, battery and starter.
Installing IN5407 diode spark suppression jumpers for the Master and Starter solenoid coils.
Installing a starter “kill switch” hidden below the instrument panel
Drilling a 1″ dia. hole in the rear wing spar IAW Van’s instructions to pass the magnetometer plug
Lacing spark plug wires with wire ties to keep the wires separated
Testing electrical system components including a starter switch green light and annunciator panel
Fabricating a small shelf for Mounting a terminal strip under the PAX seat. The lighting control switches were the first connections to these terminals.
Running various wires from the instrument panel to junction strips below the Pilot and PAX seats. The pitch and roll servo cables traverse the right side vertical channel. The Magnetometer cable is in the left side channel. All wires were eventually bundled in corrugated flex tubes; some covered with “snake skin”.
Fabricating Pilot and PAX headset socket brackets and mounting them on the sides below the instrument sub-panel.
Installing the Emergency Locator Transmitter on the tunnel cover in front of the seats. The ELT antenna was mounted on a shelf behind the PAX seat. Lithium batteries having a 10 year life were installed in the ELT and the panel mounted alarm. They should be replaced before July 2027.
The daily work continued and I
Removed the front crankshaft expansion plug and pierced the rear plug. Then, I installed a new front plug per Lycoming Service Bulletin No. 1435, converting the engine to fixed pitch operation.
Fabricated a firewall shelf for mounting the Garmin GPS antenna under the fiberglass cowl.
Installed the Comm Radio antenna under the plane and on the fuselage center line
Installed a blade antenna under the pilot seat for the Garmin GDL-39R ADSB receiver
Installed another blade antenna under the PAX seat for GTX23ES transponder. RG400 coax cable was used for all antennae.
Mounted the flywheel and a 2-1/4″ Saber Engineering crankshaft extension to the engine, torquing the combination to 50 ft-lbs with Locktite 248
Installed the Comm Radio, GPS Nav, PFD & MFD EFIS, and TPX in the aircraft and began testing
Fit the front, side and back baffles to the engine.
Dolly and I attended the week long Oshkosh EAA Airventure 2017. There we learned of Lycoming Service Bulletin No. 632. Our engine serial number was included in the list of ~1300 that left the factory with potentially insecure connecting rod upper bearings.
August 1 through 8, 2017
Arriving back in Michigan I ordered the tool required to do the S/B #632 inspection. It was back-ordered. Continuing with the build, I
Calibrated ADHRS #1 and #2 pitch & roll servo offsets and ran many Garmin G3X post-install tests. The left screen in the photo shows when I stumbled onto the Garmin G3X Touch Engineering Test Screen that is not normally available to the customer.
Installed pitot/AOA tubes and wires.
Then came the day we had long awaited – the plane was ready to receive its wings!
Our 3D printer is a Wanhao Duplicator 6 purchased at a 3D printer store north of Tampa. After the magnetic oil door latch, we turned our attention to other 3D printable parts. As Experimental Aviation Association members we have access to no-charge copies of SolidWorks Design Software.
The upper ignition wires for our Lycoming engine pass through aluminum sheet metal baffles and must be protected from chafing. Aviation supply stores sell nylon plastic wire protectors for $21.95 each, and one set is needed for each side of the engine. Having time to spare before returning to Michigan I designed and printed these.
The two halves are identical and interlock around the ignition wires. They install on a one inch diameter hole in the rear baffle plate.
The wire guides are made with ABS plastic that has a glass transition temperature (softening point) higher than nylon.
It’s a few cents of plastic. Don’t ask me how much the printer cost.
With the -7 build in Michigan while Dolly and I are in Florida, a project for the winter was to fabricate a fiberglass plenum lid, the oil fill door and some HDPE firewall and baffle wire pass through. I brought engine measurements (32″plus by 18″plus) and the top Vans cowl with us.
The oil door was fun, really. First try was two layers of 6 oz cloth cast onto the cowl over clear packing tape and Mother’s Brazilian canauba auto wax. Two layers was too thin both in flexure and contour with the surrounding cowl surface. The second try at seven layers was stiff, but too thick. Like ‘Goldilocks and the Three Bears’ the third try at four layers was just right but will need some anti-flex reinforcing.
I purchased yards of cloth and West Systems epoxy at the new West Marine store located about a mile from here. It seems that from now on the WM stores will only carry smaller packages of cloth, not large rolls.
The outer surface of the RV-7 cowl received from Vans had pits reflecting the shape of the hexagonal cells in the sandwiched layer. After three thin screed layers of epoxy/microlite and two layers of rolled on clear epoxy the surface is ready for spray primer. Of course each layer was preceded by block sanding, but we don’t like to think about that.
After all that I felt ready to tackle casting the plenum lid on the inside of the upper cowl. Clear packing tape and auto wax were again used for mold release. Six pieces of 6oz cloth were cut oversize (I only used five), along with a layer of 2mm Soric core material.
Blue sharpie lines on the cowl marked where the composite layers were to be placed. A single large piece of nylon sail cloth peel ply was laid over the waxed release tape and the blue lines traced. Epoxy was poured over the first layer of glass, and a bit on the second glass layer. Air was worked out with a plastic spatula. The third glass layer also required some epoxy. Then the Soric was placed and a 3″ paint roller used to force contact and squeez excess epoxy to the edges. Corners of the Soric were lifted to verify epoxy was covering the bottom of this layer. The next two layers of glass and peel ply were applied in a similar manner.
The plenum lid easily popped from the mold after twelve hours. It was left for a day before our Tug-of-War and trimming loose cloth from the edges. The finish is beautiful. Weight at this point is 34.4oz. This is undoubtedly heavier than if the assembly had been vacuum bagged and resin infused. However, we can tolerate forward weight to offset the relatively light weight lithium battery and Catto prop.
Our engine was ordered after returning from Airventure ’16. It was delivered to the Dalton Airport on the 18th.
I had expected a wooden crate. Instead it was in a foam filled cardboard box strapped to a pallet. The box was opened that day to check for any damage. The engine was in a large plastic bag that also held four silica desiccant pouches and a color changing humidity indicator card. We did not open the big bag. Apparently Lycoming squirts some foam into the cardboard box and lets it harden before setting the engine. Then, the space around the big bag is filled with liquid foam and the box closed. It was well protected.
October 20, 2016
The engine was picked by Dan Willoughby’s Engine hoist for unpacking.
It arrived with two Slick magnetos, a prop governor oil pump, and a horizontal oil filter mount. Before mounting the engine to the airframe, these appliances were replaced with two electronic pMags and a 90deg. B&C oil filter mount. The prop governor oil pump was removed to save weight as we will install our Catto fixed pitch prop. I also installed a 40 amp backup alternator on the vacuum pump pad in the rear accessory case. Dessicator plugs were installed in the top of each cylinder. All changes were detail documented in the engine logbook.
Dan Willoughby and Mike Goulet helped with installing the bottom two engine mount bolts.
November 7, 2016
Weather was getting colder. The project area was cleaned up, tools put away, and we prepared for our relocation to Florida for the winter.
The big day! Dolly and I have been building this RV-7 for almost two years. Each has had a significant milepost. In 2015 it was the test fitting of the wings to the fuselage. This year it’s the airport move.
Dalton Airport (3DA) is a small private/public airport located on one of the main streets in Flushing, Michigan. Pole barn hangars with electric doors line the sides of both the sod and the 3500′ hard surface runway. EAA Chapter 77 owns a cavernous main hangar and one of the smaller hangars where I rent space. That’s where we are going.
The move was blissfully uneventful. I had arranged for a tilt-bed automobile hauler from Norm’s Towing in Montrose. Norm showed up on time; the plane was winched up the ramp and strapped down. It was threatening rain, but we were prepared with a tarp. Twelve miles and $100 later we were ensconced in our new home.