Pitot/AOA – RV-14 Build

Assembly Tasks

Posted on November 21, 2025 by Neal

This week I made multiple trips to the hangar to work on various tasks.

Wing attach bolts

I finally torqued the wing attach bolts. The night before, I tested out my torque wrenches to ensure they were reading correctly, and they were both very close. I used a vice to hold the wrench, and then secured a weight over the arm and measured the distance from the fulcrum. For weight I used a 1 Gallon plastic jug filled with carefully measured amounts of water. The nuts were easy to torque, I only found one where it took a second to figure out how to torque it. I ended up using a socket extension that allowed some movement, so I could torque the nut without fear of bending small bits of aluminum that were close by.

Pitot tube:

I finalized the wiring and install of the pitot tube. I used butt splices to connect the pitot heat wiring, replacing the original molex connector. In the process I included a service loop to help with any future maintenance.

I also trimmed the pitot and AOA pneumatic lines at the wing root, inserting them both into the connectors under the seat. I still need to test the system for leaks, and to verify I didn’t switch Pitot and AOA at any point in the system.

Strobe lights:

I did some troubleshooting on an issue with the wing tip strobe lighting. Both sets of strobes are flashing, but weakly. There is only 6.6V at the wingtip, so I’m losing half the voltage somewhere in the system. I tried the easy tasks such as unplugging and reconnecting connectors, but no luck.

VOR Antenna

I completed the VOR antenna wiring, and was happy to tune in a nearby VOR and see a positive ID and a needle on the CDI. The reception seemed good, even though the antenna isn’t well grounded (I don’t have all the screws in the wingtip, and they provide the ground path). The job was quite simple, I just needed to cut the cable to length and install a BNC connector, then plug it into the fitting I had previously installed under the passenger seat. I added a service loop, for ease of maintenance. At the right wingtip I connected the ring terminals to the antenna and torqued them up. I also tidied up the wing tip wiring and then secured the wingtip fairing. I then fired up the instrument panel, turned in the Julian VOR and was happy to see the reception, even on the ground in a metal hangar at 20 miles, and without a properly grounded antenna.

The main spar wing attach bolts, final torqued

Signs of life from the VOR antenna. The Nav radio is tuned to 113.75, and the green line on the left hand screen (PFD) is pointing to the VOR station

The VOR antenna connection under the passenger seat

Right wingtip wiring. With the wingtip off, I found I could rotate it and set it on its aft edge, balanced against the wing. This made working on the wiring much easier.

Service loop for the pitot heater wiring. Insulated butt splices are visible here and would be the recommended place to disconnect the pitot wiring for any maintenance

Another angle of the pitot tube install. Note, the pushrod is disconnected to allow more room to access the pitot tube wiring.

Pitot Static Check

Posted on July 2, 2025July 3, 2025 by Neal

Tonight I checked another item off the to-do list by testing the pitot and static lines for leaks. Good news – both the pitot and static lines were leak-free. I wasn’t able to test the AOA lines, but will have to do that sometime down the road.

I started with the pitot line. By removing the pilot seat floor panel, I could access the ports where the pitot and AOA lines will connect once the wings are attached. I used a piece of flexible tube, and attached one end to the Pitot connector. I gently blew into the other end until the airspeed registered, and then folded over the tube and held it for a minute. The airspeed indications on the G3X and the G5 held steady for a minute, which met the standard.

Flexible tube plugged into the Pitot connector under the pilot’s seat

Airspeed indication holding steady at 146 knots

For the static line test, I ended up taping over the static ports, then disconnecting the G3X static line where it joins a t-connector. Using the flexible tube again, except this time gently sucking air, I was able to demonstrate steady altitude on the G5 for over a minute. I guess there’s a small chance of a leak between the t-connector and the G3X, but at least I know the G5 has no leaks.

Squeezing the tube sealed the end well enough to conduct the test

Pitot Static

Posted on August 3, 2024 by Neal

Tonight I installed t-connectors on the Pitot and Static pneumatic lines, and routed all lines to their respective ports on the G5 and ADAHRS unit.

With that done, the panel wiring is complete!

Well almost complete, I still need to:

– safety wire some more connectors

– throughly inspect all wiring and fix all potential chafe points

– route the firewall-forward wires up to and through the firewall

– upgrade the battery-vertical power wire from #8 to #6 AWG

The Pitot (Blue tubing), Static (Red and clear tubing), and AOA (white tubing) plumbed into the G5 (left) and ADAHRS (right).

Thinks looking much tidier under the panel now

Pitot Static

Posted on August 2, 2024 by Neal

Tonight I installed a couple of adel clamps to hold the pitot static lines, keeping them clear of the sharp edges they pass near under the panel. The routing is a little weird because I don’t want to put too sharp of a bend in the tubes. The tubes come up out of the wiring channel, pass over the wiring frame I built, come out the bottom of the forward side of the sub panel, then up through a gap between the panel and sub panel. I plan to install t-connectors on the top of the shelf behind the PFD, sending air to both the G5 and the ADAHRS unit mounted on the back of the PFD..

I then mixed up some epoxy resin and glued some zip tie holders onto the shelf.

Two adel clamps holding the pneumatic pitot, static, and AOA tubes where they pass under the sub panel and back up to the shelf behind the top of the panel.

The pitot static lines emerging onto the shelf. Note the black zip tie holders glued to the shelf to support the t-connectors

OAT Wiring

Posted on July 14, 2024 by Neal

Quick job tonight, shortening up the wiring for the outside air temperature probe. Because I installed the probe in the air vent instead of the wing, I was able to shorten up the wiring considerably.

The wiring is a 3-conductor braided cable, and the braided portion of the cable needs to be grounded. I used a solder sleeve with attached wire to quickly solder a ground wire into position. I had plenty of spare pins and connectors, so I was able to install pins on the wires and wrap it up quickly.

The OAT wiring with heat shrink removed, before shortening up the wires

Pitot lines

Posted on April 30, 2024May 16, 2024 by Neal

Tonight I made a fitting to hold two cushion clamps, which will support the pitot and AOA pneumatic lines as they enter the fuselage from the wing.

I also made a corresponding fitting to help guide the Nav antenna on the right side of the fuselage.

I considered installing a bulkhead fitting for the pitot and AOA lines, and eventually decided against that option. I needed some way to prevent the lines chaffing on the aft gear brace assembly, and since the tail dragged doesn’t use part U-01402, I used the two AN5 holes to mount a fitting with two cushion clamps.

I made one of these for each side, the left side for pitot lines and the right side for the Nav antenna.

For the Nav antenna fitting, I epoxied a plastic zip tie holder to the aluminum fitting.