The Garmin autopilot pitch servo is furnished with a mounting plate and specific instructions for installation in a Vans RV-7. The plate becomes riveted to the center floor rib behind the baggage bulkhead. The servo moves the elevator push-rod via its connection to the bellcrank.
Care is given to adjusting the length of the servo to pitch bellcrank connecting rod so that no over-center lockup can occur.
Wires from the db15 socket connect the servo to both the instrument panel autopilot controller and to the pitch trim servo located in the left elevator. Torque sensors in the pictured servo generate signals fed to the pitch trim servo.
The flap position sensor is a Ray Allen POS-12. The long arm slides in and out of the body changing the electrical resistance of the unit. A linkage to the motor driven flap actuating arm controls its position. The flap position may be displayed on the G3X screens.
The Garmin G3X magnetometer feeds magnetic heading signals to the ADAHRS units, obviating the need for a whisky compass. It can be mounted anywhere distant from aircraft magnetic fields. Many builders place them in a wingtip or tail assembly.
I fabricated a mounting plate and riveted it to the upper fuselage longeron and aft side of the baggage compartment bulkhead. The magnetometer mounting ring is shown clamped to the mounting plate. It is being marked so the front/rear axis of the magnetometer is parallel to that of the aircraft.
Dolly and I built the horizontal and vertical stabilizers & the rudder and elevators (the empennage) during the winter of ’14/’15 in Florida. The parts were wrapped in blankets, hauled to Michigan and have been sitting on a shelf waiting for today.
The entire process of mounting the empennage, adjusting balance weights and travel stops, installing and smoothing fiberglass tips and connecting controls lasted until July 1, 2016. Other non-empennage tasks were also completed during this interval.
We were careful to align the HS with the fuselage, measuring from the tips to the same rivet position on each side. Then, drill and bolt.
It was necessary to trim the rear outboard skins of the HS to allow clearance for the elevator balance arms. The elevators were temporarily attached. Then the elevator control arms were drilled for a center pivot and the push/pull control rod connections.
The vertical stabilizer was mounted with it’s tip to elevator tip distance exactly 62 1/4 inches on both sides.
Elevator travel was measured as 25 deg. up and 27 deg. down. Later, after adding stops and adjustment the final measurement was 28 deg. up and 21 deg. down.
When the rudder was installed with stops, it’s swing was set to exactly 35 deg. right and left.
May 27, 2016
Van’s plans call for trimming of the lead counterbalance weights that are installed in each elevator balance arm. Our band-saw wouldn’t do it so I jury rigged a clamp and hand saw. ~10.6 ounces of lead was removed.
The Right elevator balanced OK per Vans criteria, slightly elevator nose heavy. Addition of the electric pitch trim servo overbalanced the left elevator tail heavy. More weight ~2 oz. was put back into the left balance arm.
The above photo shows the pink slab foam, 0.17 lead shot pellets and a portion of the large lead weight epoxied into the left elevator balance arm.
After an initial layer of epoxy, both arms were leveled to the top of the aluminum with a micro-bead epoxy paste, and then sanded smooth.
As received, the Vans fiberglass tips did not align well. These photos show how much epoxy/micro mix was added to the HS tip. The pen lines outline the rudder area next to receive micro.
While installing the rudder lower fiberglass tip, I also installed an AeroLEDs strobe tail light. The strobe driver is fully contained in the tail light. It will later be wired to synchronize with the wing strobes.
At the 2015 Sun-N-Fun expo in Florida I first saw a Beringer wheel on display. The wheel hubs (split case with Michelin tubeless tires) are machined on all surfaces from aluminum billets and then anodized to a brilliant red. They are as much jeweled works of art as functional devices. I explored their website. The prices turned me away. However, I read on the VAF forum that Beringer was for a while offering a 30% discount on full Vans RV systems to the first buyer from each EAA Chapter. That and the significant weight savings did it.
In addition to the wheels and master cylinders the displayed parts came in the box.
In the Beringer system the right and left brakes each have their own fluid reservoir. I fabricated a tray to hold the reservoirs and hopefully direct any overfilled fluid to a safe collector. I plan on adding a 5″x8″ inspection port to the fuselage top front skin for access to the area behind the instrument sub-panel and for viewing the reservoirs while the system is being filled.
The device to the right and below the reservoirs is the Beringer ALIR Anti-skid Inline Regulator. It is adjustable and sets the maximum differential between the right and left brake line pressures. At this point I was ready to assemble and install the cabin side brake lines.
The eight Teflon lined and stainless steel jacketed lines were wire-tied to the moving rudder pedal assembly. The rudder and brake pedal movement were checked free and clear with no rubbing or binding of parts.
Our first task upon returning to Michigan from the instrument panel building winter in Florida was to fabricate a support plate and install the Andair fuel valve. This was followed by bending and routing the 3/8″ OD soft aluminum fuel lines in from the wing roots to the valve.
A coiled spring type tubing bender was found to be much more useful than a lever type bender. Rubber grommets protect the lines where they pass through the fuselage skin. The free floating grommets will be placed in the spar forward cover plates.
Fuel vent lines were added for each tank. They enter the fuselage sides, travel up to the top longerons, forward to the firewall and down through the fuselage floor. Cut at a forward facing 45deg. angle the vents tubes apply a small positive pressure to the tanks. A cover screen prevents entry of large bugs. The left vent tube fuselage floor exit can be seen below.
On our home computer I set up X-Panel planing software and started designing the instrument and switch layout.
The Garmin G3X system was selected for several reasons:
I had three Garmin instruments in my Globe Swift: a G400W navigator, a G695 moving map and a SL40 communications radio. The Garmin menu system was familiar.
At two airshows I had the opportunity to compare Garmin equipment with Dynon and Grand Rapids. I thought Garmin had better screen colors and pixilation. Also at the time, Garmin had the only system with full IFR capability not requiring components from other vendors.
There appeared to be little cost difference between vendors when pricing similar IFR systems.
Started ordering switches and other electronic components. I have found the DigiKey online catalog the easiest to navigate when hunting for parts by function and feature, rather than part number. I also started downloading and printing over 1100 pages of Garmin installation and operations manuals. Continue reading “RV-7 IFR Panel Build Photos – 2015/16”
This is the picture story of the summer’s work on our RV-7. Something was done every day, and pictures were taken only to supplement the daily handwritten log. This is not an instruction manual as there were many, many steps in between those illustrated here.
As noted in our status report, the RV-7 Quickbuild Wings and Fuselage arrived in Michigan on June 4th. They were delivered to Dalton Airport (3DA) in Flushing, trailered to our shop, and the wings set into cradles with the help of friends from EAA Chapter 77.
Dolly and I had fun uncrating and unpacking.
It was exciting to be introduced to our next airplane.
Some people call them “Idiot Lights”, lights that are on under some condition, and off when that condition is not present. Pilots may have strong opinions on whether or not they are useful. Many state that most annunciator functions can now be implemented through the glass panel displays that many of us are installing, and therefore an annunciator panel is just adding unnecessary complexity.
If forgetting to turn off a fuel boost pump after takeoff, or not remembering to turn on strobe lights before starting the engine makes one an idiot, then count me in. Our RV-7 is going to have an annunciator panel. Exactly what conditions will be monitored is yet to be determined.
Dolly and I started construction of the RV-7 empenage on November 4th after voting. 72 days later (70 shop days) the tail feathers are assembled except for the fiberglas tips that will be attached later.
This post is the story of building the elevators.
The right and left elevators are identical except for a pitch trim tab that sits in an inboard cutout in the left elevator. Construction starts with the spars and is similar to the rudder,