Friday, December 21, 2012

Left Wing Wiring and AOA Plumbing

One option that was purchased along with the wing kit was a lighting kit which consists of navigation lights, strobe lights and position lights all in one unit for each wing, along with a landing light for the right wing, all manufactured by Aeroleds.

The parts do not look like they will be a piece of cake to install … but the instructions appear to be concise enough to allow for a hopefully smooth install. Van’s includes 18 gauge wires for wiring the navigation light power, strobe light power and strobe sync lines to the Aeroleds lights. One discrepancy I noticed immediately on a schematic in one of the Aeroleds boxes is the use of shielded wire. I know I’ve read about builders mentioning they can hear a little noise in their headsets when the strobes are on. Installing the strobe wiring using shielded wires as opposed to running unshielded wire may really help keep strobe noise out of the electrical system.  A call to Aeroleds confirmed my thoughts and they have 3 conductor shielded cable available so will probably place an order for that today.

Before any wiring begins in earnest inside the left wing, I want to have all the components together to see if there is plenty of room in the grommets that will be placed in the ribs for wire runs …. May have to go to the next size up because of the shielded wires and plumbing I plan on installing.

Pluming in a RV-12 wing you may be asking? Yes, for the AOA indicator of course!! (Similar to a reserve lift indicator). One of the features built into the Dynon SkyView which Van’s elected not to utilize because of the RV-12’s removable wings, is an AOA (angle of attack) display.  A builder in Michigan (Joe) did the research and pioneered a working method where a small piece of tubing is connected to a port strategically placed at a 30 degree point under the leading edge of the wing. When the RV-12 approaches a stall, the tube’s air pressure changes and the SkyView analyzes that pressure change and displays a bar scale with increments in green, yellow, and red (falling out of the sky).  Quite a few builders on the forums have modified their RV12’s to take advantage of this very useful display function (which adds another element of safety) and all have been very very pleased with the results.  Since the RV-12 is being built as E-AB and not E-LSA, I will install the AOA plumbing now.
                              Just a hand full of small inexpensive parts are needed to install the AOA hardware.

The parts consist of: … Center in the photo - 1/16” ID Tygon tubing ( I chose tubing rated at Shore 64 because it is firmer than totally soft but still considered soft), below the tubing is a threaded 1/8” NTP male adapter which will screw into the ADHARS for the SkyView and allows the small Tygon tubing to be attached.  Upper right - a female Luer Lock, Lower left - a male Luer Lock. Luer Lock connectors are a ¼ turn release connector and will be placed at the root of the wing for easy disconnect during wing removal.  On the left side of the photo there are Luer caps: Top – female caps, Bottom – male caps. The caps are for protecting the tubing from contamination when the wings are removed and are really not necessary … I noticed them while placing the parts order and they seem like a good idea so picked them up as well. The 1/8” NTP adapter was the only item available as a single unit all the Luer connectors were in bags of 10 but they are very cheep. All total think the parts were around $20 from McMaster-Carr. (Not including the Locktite 243 which is for installing the stall warning micro switch).

At a strategic location under the leading edge of the wig, in the bay with the inspection plate, the tubing is connected to a drilled hole for a port which can be a rivet similar to the static port rivets (mandrel driven out) or a sports ball inflating needle as the original author of the modification used. Builders have had great success with either method. One good thing about using a ball filling needle is where the threads protrude the wing skin, a cap can be screwed onto the threads (where an air hose would normally go) to protect the tubing from insects and dirt. while the plane is on the ground.