Chapter 22 - Section 6

Lighting System

 

Nav/Strobe Lights

There are many types of Nav/Strobe lights available in the general aviation market. LED Nav/Strobe lights were gaining its popularity when I was getting close to Chapter 22 (Electrical). You can find a lot of discussions in the Cozy forum on the pros and cons of each. I decided to go with LED Nav/Strobe lights because they are quiet electrically (i.e. minimum noise interference to other electrical devices such as radio communication) and less heat - at least that's what I was told. After pondering a long time, I finally decided on AeroLED Pulsar NS Series P/N 11-1080C Nav/Strobe lights. The wirings for the lights are simple and they do not require a controller. I tested them out on the bench and the strobes lights are bright. If I am not done with wiring these light by Christmas, I am tempted to hook them out outside my house and see if I can drown out my neighbor's Christmas lights. If they do, then, my LED lights pass the brightness test.

 

Installing the Nav/Strobe Lights

My Nav/Strobe lights come with a mounting bracket which allows the attachment/removal of the light component as necessary. The challenge is to attach the mounting bracket to the wing tips. I searched through the Cozy archives and inquired on methodologies in the Cozy forum. Surprisingly, many builders just RTV their lights to the wing tip with no mechanical means. With 200 mph wind blowing against the lights, I am just a bit concerned about it - probably overly conservative. Nut plates are not a good option because there's hardly any room to get to the inside of the wing tip to squeeze the rivets in place. A blind rivet will leave a raised head, thus preventing the mounting bracket to sit flush to the surface of the wing tip.

 

 

 

 

I found a rivet nut insert from McMaster-Carr (98560A172) that can be used on most materials 0.030" or thicker. When inserts are installed, the threaded portion is drawn into the sleeve, creating pressure against the hole sides and securing the insert. The unique design of this insert requires hardly any protrusion above the surface. For a trial run, I took 80 grit sand paper over the top of the installed insert and sanded it flush. The rivet stayed secured.

 

You can see the insert before (right) and after (left) it is installed. Since I do not expect much of a push of pull force against the Nav/Strobe lights, I believe this is a good application for this type of inserts.

 

 

 

My next step is to position the mounting bracket onto the wing tips. Instead of using the wire pass-thru hole as a reference, it is more logical to use their respective wing tips as a reference. For my own record, the tip of my Nav lights is 1.75" from the forward edge of the wing tips. This distance provides the best coverage over the wire pass-thru holes while maintaining identical Nav/Strobe positions relative to the wing tips.

 

The pencil mark shows the outline of the Nav/Strobe light foot print. I only use the two forward holes for securing the mounting bracket because I did not want to drill any hole close to the plies the holds the winglets. Besides, I plan to use RTV as a backup as well.

 

 

 

Grounding the Nav/Strobe

The grounding instructions are more for the metal airframes than for the Cozy. So I have to improvise a bit. I was surprised to learned from the VansAirforce forum that these lights are not internally grounded. The instruction requires the 'black' wire from the light to be attached to the mounting structure/frame (i.e. to ground). In our case, the mounting structure is attached to our wing tip of composite materials - no ground. In addition, the way I attach my mounting frame provides no room to attach a wire lug. I have to make some modification to the original mounting 'Y" frame.

 

Here's what I did, I drilled and tap a 4-40 threaded hole to the bottom tip of 'Y' arm as shown. If you look close, you can see I split the ground wire (black) from the light - one to the mounting bracket and the other to the Molex connector pin. From there, I bring the ground via the shield of the shielded wire cable to the mounting frame.

 

Here's a picture of the Nav/Strobe lights after it is mounted.

 

 

 

 

 

 

 

 

 

Some Learning with Wire Connections

Aside from the grounding modifications I had to make for the Nav/Strobe lights, there are other aesthetic considerations. I have 4 wires coming from each wing tip (Nav, Strobe, Ground and Sync) plus 2 wires coming from each of the fuel sight gauge - a total of 10 wires. If I just tie them all together with traditional butt splice, I'll have a rather sizable lump of wires.

 

As a side note, I decided to tie the fuel gauge LED lights to the Nav lights because I do not see the need for a separate on/off switch for the fuel gauge lights. Chances are I'll need the fuel gauge lights when I need the Nav lights.

 

I learned this wiring techniques from Aeroelectric - Shield Termination Techniques. Instead of joining the selective wires using butt splicing or direct soldering, I terminated all the wires (using D-sub pins) to a male D-sub connector. Then I made the joining via the female D-sub connector. Here's a picture with all the power, ground and sync wires going into the male D-sub connector.

 

The 2 white wires are 3 conductor shield wires - one from the left wing tip and one from the right wing tip. All 6 conductor wires (2 Nav, 2 strobe, 2 Sync) plus 2 shielding (ground) are terminated to the D-sub conncetor - using up 8 of the 15 pin connector. Note the 2 black wire are the shielding-to-D-sub pins techniques from Aeroelectric as well.

 

 

 

 

A female D-sub connector is used to join the corresponding wires as shown. I used a 18 gauge solid wire to join all the appropriate connections and soldered them in place. The female plug is, in a way, the networking plug.

 

 

 

 

 

 

 

 

 

Here's a picture showing the connection assembly when completed. All the incoming and out-going wires came through the male D-sub connector. There's no wire coming out of the female (network) plug. If I un-plug the female plug, all connections will be disabled.

 

 

 

 

 

 

 

 

 

Landing Lights

I installed my landing light in Chapter 13 Section 5. It was a low cost halogen light for pick up trucks. As time passed throughout my building process, LED landing lights were coming into light, so to speak. While I was getting the AeroLED Nav/Strobe, I decided to change out my initial halogen landing light with their AeroSun Landing/Taxi/Recognition lights P/N 01-2120.