Instructions for LED Position Lights

What comes with the kit

Tools you will need

Safety Glasses

Soldering iron with a thin pointy tip (like a pencil)

Damp sponge for cleaning tip of soldering iron

Small diagonal cutters (“dikes”)

Very small needle-nose pliers or a hemostat

Small protractor

A piece of brass hobby tubing that will slip snugly over a 5mm LED

Dremel with cut-off disk (if you are going to cut the square board in half or trim the corners on the long board.)

Supplies you will need

Conformal coating for making the board corrosion resistant.

Eight mounting screws, 6-32

Nylon washers

Four mounting spacers to hold the board at the proper angle

Basic Soldering Technique

It takes a bit of practice to solder well enough to assemble this kit. I made up a small practice kit. If you are a novice at soldering, you should ask for one if I didn’t include one. If you haven’t soldered electronic components before, you would be ill advised to learn the skill building this board. Mistakes could get expensive.

Get someone to show you how to do it. I would suggest that you buy an inexpensive electronics kit at Radio Shack that includes instructions on soldering and practice until you have the technique under control. Once you get the cheapie radio Shack kit assembled and working, and you have fully mastered the technique, then begin building this kit.

How to Assemble the Kit

Before you actually start building

The components go on the side of the board with the pictures of the components. With the exception of the angled LEDs (the ones around the edge) align the components exactly with their pictures on the board.

Polarity matters! There is a flat on one side of the current regulators (IC1.) Align this with the flat on the picture on the board. There is also a flat on one side of the LEDs (the side with the shortest lead.) Align this flat with the picture on the board.

The resistors go in with one end pointing up. Polarity does not matter with resistors. (You can put in the resistor either way and it doesn’t matter.)

Be careful not to mix up the red LEDs with the green LEDs. You can’t tell them apart just by looking at them. If you mix them up, you will have to actually light them up to separate them again. A safe and easy way to dimly light these LEDs is to use the continuity (diode checker) function on a digital multi-meter. If you use a battery or something other than a 20 mA (or less) current source, you will certainly ruin the LED instantly.

Snap the two boards apart

The red and green boards arrive as one board with a score line between them. Place the score line on the edge of your bench top. Using your hands, snap the boards apart along the score line.

Cut and trim the board

You need to trim or cut the board, before installing any components. You can use a Dremel with a cut-off wheel or you can use a band saw. You will ruin the blade on the band saw and make it useless for cutting anything but fiberglass, but it certainly makes a pretty cut.

Square Boards

If you have purchased the square boards, you may wish to cut them in half to save space when you install them. If you don’t need to save space, there is no need to cut them in half and there is no need to install the in-line connector, J1.

Gently clamp a piece of scrap aluminum to the board to act as a guide while cutting. Use a cut-off wheel in a Dremel to carefully slice the board in two. Don’t forget to wear safety glasses!

Long Rectangular Boards

If you have purchased the long boards, you have to trim two of the corners to get them to fit neatly inside the sheared wing tips of your RV 7 or 9. If you look carefully at the boards, you will notice that there is a small area outboard of the top and bottom screw holes that has no components or copper traces. This is the area that you need to trim off.

Also, if you are planning to install wingtip landing lights, You will likely want to trim the board in the center region (near the label “KillaCycle.) You can see that a portion of the board in the center has no components or circuit traces. This is the area that you can trim away to clear the landing light.

Fit the boards into place in the wingtips and get them properly trimmed to shape before installing and components.

Put in resistors

Install and solder the resistors first. The resistors are the easiest to solder and can tolerate overheating more than the other components, so that is why we are starting with them.

Bend one of the leads sharply back against the body of the resistor. Insert the unbent lead in the hole with the picture of the resistor (circle.) Insert the bent lead in the hole right next to the circle. Slide the resistor in until the body touches the board. Reach around back and bend the wires away from each other to temporarily hold the resistor in place. Flip the board over and solder each lead to each pad on the board. Using small flush-cutting diagonal cutters, snip off the excess lead wire.

Repeat with the rest of the resistors

Put in regulators

The regulators are heat sensitive. Only heat the lead with the iron just long enough to flow the solder and make it wet the connection well. If you are having trouble, and it is taking more than a couple of seconds, remove the iron and let the part cool for a minute or two before your resume soldering.

Bend the middle lead slightly away from the flat side of the regulator (towards the round side.) Align the regulator with the picture on the board and gently slide the three leads into the three holes. The regulator should sit about ¼ inch off the board, perhaps a little less, when the leads are properly inserted.

Reach around the back of the board and bend the leads away from each other to temporarily hold the regulator in place. Flip the board over and solder each lead to each pad on the board. Using small flush-cutting diagonal cutters, snip off the excess lead wire.

Put in LEDs

Before you start putting in the LEDs

You MUST put the green LEDs in the board marked “green” and the red LEDs in the board marked “red.” The green LEDs won’t work in the red board.

The LEDs are VERY heat sensitive. Only heat the lead with the iron just long enough to flow the solder and make it wet the connection well. This should take about one second. If you are having trouble, and it is taking more than a couple of seconds, remove the iron and let the part cool for a minute or two before your resume soldering.

This section assumes that you are going to mount the board facing at a ten-degree angle away from straight. This is very similar to the angle of the back surface of an RV-7 (or RV-9) sheared tip. The sheared tip angle is about 18 degrees, so it is wise to put spacers on two of the mounting screws to get the board to point in the optimal direction. (See More Rectangular Board Tips below)

If you are compelled to mount the board in some other orientation or angle, you will have to modify the angles of the LED. This is not terribly difficult to do, but you need to read that section before installing any LEDs.

The fifteen center LEDS, (3 rows of 5 on the square board, 5 rows of 3 on the long board) point straight out of the board. The leads are not bent and are perpendicular to the board surface. There is no number written on the board next to these LEDs.

The base of these LEDs will sit a little less than ¼ inch above the board surface. A scrap of Teflon-insulated 20 gauge wire makes a nice spacer while soldering. Be sure to remove this spacer wire after you are finished soldering.

The remaining LEDs will each be pointed at a specific angle. This specific angle is the number written on the board next to them. The angle is measured from the perpendicular. Thus, an 85-degree angle LED has the leads bent 85 degrees. Both leads are bent at the same angle and are bent towards the direction of the number written on the board. When properly installed, the LED will be bent in a manner that will tend to cover the number on the board.

Here we go….

Begin with the 15 “straight” LEDs. Align the LED with its picture on the board. The flat side (shorter wire) MUST be aligned with the picture. Slip the leads in the holes and, using the spacer wire, set the height of the LED.

Reach around the back of the board and bend the leads away from each other to temporarily hold the LED in place. Flip the board over and solder ONE lead to its pad on the board. Flip the board back over and align the LED to be perpendicular with the board. Flip the board over once again and solder the remaining lead. Using small flush-cutting diagonal cutters, snip off the excess lead wire as close as you can to the board.

If you solder both leads at first, it can be almost impossible to correctly align the LED. By soldering only one lead, the alignment is much easier.

Repeat with all the rest of the 15 “straight” LEDs.

Select a specific LED position on the board and note the direction and amount of the angle written next to it. Figure out which way you need to bend the leads of the LED. (Both leads are bent at exactly the same angle.)

The angle written on the board is measured perpendicular to the board. For example, the 85-degree LEDs are almost lying flat against the board.

DO NOT bend the leads where they enter the case! Gently grip the leads as they exit the case with a small pair of needle-nose pliers (or hemostat). Then, using your finger, bend the protruding leads to the angle written on the board.

Just like before, align the LED with its picture on the board. The flat side (shorter wire) MUST be aligned with the picture. Slip the leads in the holes. Hold the LED at close to its proper angle.

Reach around the back of the board and bend the leads away from each other to temporarily hold the LED in place. Flip the board over and solder ONE lead to its pad on the board. Flip the board back over. Slip the brass hobby tubing over the LED. Using a small protractor, adjust the LED to the angle written on the board. If you have set the angle correctly, both leads should be the same length and at the same angle. Flip the board over once again and solder the remaining lead. Using small flush-cutting diagonal cutters, snip off the excess lead wire.

Rectangular Board Notes:

The 80 degree LEDs closest to the trimmed corner and the screw hole need to be mounted a little differently than the rest. This is so that the finished assembly will fit properly within the clear cover on the wingtip. You need to leave a bit more “slack” in the leads when you solder it in. Once you have soldered one leg, push the LED down and back, still keeping it at 80 degrees. Its legs will look like it is doing the “Limbo”. This moves the LED away from the edge of the board. The tip of the LED should be just inside the edge of the board if you have done this correctly.

More Rectangular Board Tips:

It has been reported to me that some RV wingtips are a bit more narrow than others. You can gain a little more space on the top and bottom of the rectangular board by mounting it flush with the back surface of the wingtip than by using spacers to tilt the board. See the next section if you decide to do this. Since the back surface is 18 degrees (instead of the ideal 10 degrees) you will need to tilt the “straight ahead” LEDs 8 degrees inboard. This is not difficult to do. Set the 85 degree LEDs to 77 degrees. Set the 50 degree LEDs to 42 degrees. Do not change the angle of the 70 degree LEDs and the 80 degree LEDs.

Setting the LED angles for flush mounting

You may wish to mount the board flush with the surface of the sheared tip instead of using spacers to set the board at 10 degrees. In this section, I’ll give instruction on how to make this modification, assuming you have an RV with the back surface at 18 degrees. If the back surface is at some other angle, adjust all the LED angles accordingly. The change in the LED angles is the difference between the angle of the mounting surface and the ideal 10 degrees.

Since the back surface of an RV sheared tip is 18 degrees (instead of the ideal 10 degrees) you will need to alter the angle of most of the LEDs by the difference, 8 degrees. First, tilt the “straight ahead” LEDs 8 degrees inboard. This is not difficult to do. Just tip each one with the brass hobby tubing and the protractor. Set the 85 degree LEDs to 77 degrees. Set the 50 degree LEDs to 42 degrees. Do not change the angle of the 70 degree LEDs or the 80 degree LEDs. That is all there is to it.

Solder on pigtail

Using aircraft-quality Teflon-insulated wire, solder on “pig tail” leads to the power pads on the board. Carefully mark the positive lead!

If you cut the square board

If you cut the square board, you will need to install the J1 in-line headers. Using diagonal cutters cut the 36-pin header supplied into a 15-pin header and a 9-pin header. Use the 15-pin header for the green board and the 9-pin header for the red board.

The idea is to “fold” the boards so they are back-to-back and take up less space. When you are done, you should see the LEDs sticking out of the board on one side (front,) and the regulators sticking out on the board on the other side (back.) The side of the boards that you soldered the leads should be hidden as they are facing each other and close together.

Start with the RED board. Insert the in-line header into the back of the LED board. Slip the free (opposite) end of the header pins into the back side of the regulator board. Solder all the pins in place.

Repeat for the green board.

Test

Being VERY careful not to reverse the polarity, connect the board to a DC supply (like a car battery) that is greater than 10 volts but less than 30 volts. Double-check your connections before you make the last connection. If you connect it backwards you can damage the components on the board. Again, double-check the polarity before you hook it up.

Don’t point it at your eyes when you test the unit. The brightness can be quite startling and you will see spots for quite awhile. You would be wise to put on sunglasses before you power up the unit for testing. No joke.

Conformal Coat

After you are sure they are working perfectly, you need to clean, then conformal coat the boards.

I clean the flux off the board with lighter fluid (or bug and tar remover) before I apply the conformal coat. It doesn’t take a lot. I use a small brush to apply it and then blow off the board with compressed air.

To protect the board from moisture, it’s important to coat it with some sort of “conformal coating.” There are plenty of choices here. I like clear epoxy from the hardware store (NOT five minute epoxy.) Clear lacquer, like Krylon, is OK. There are some very nice silicone (RTV) type coatings also, but they are pricey.

Whatever you choose, be careful not to coat the lenses of the LEDs. Dipping the board seems to work much better than spraying the board. Painting it with a small artist’s brush works quite well. That is what I do.

Final Test

The unit was designed to put out light in the pattern shown on the attached sheet.

The numbers across the first (top) row are the candlepower required along the centerline starting at the nose of the airplane (zero degrees) and progressing towards the rear of the airplane. In the next row down lists the angle from front to rear (straight off the nose is zero degrees.) The numbers in the second left-hand column list degrees upward and downward.

Put a one-foot string on a photographic light meter and measure the candlepower (CP, foot-candles) in all the listed directions. The meter should be set to measure “incident light.”

The meter reading should be greater than or equal to the each of the numbers listed in the above sheet. If it is not, be sure that the LEDs are correctly aligned and then recheck.

You can use a longer string if you have a very sensitive light meter. If you use a 2-foot string, multiply the reading on the light meter by 4. If you use a 3-foot string, multiply the reading by 9. One end of the string should touch the LED board and the other should touch the tip of the light meter. Be sure to turn out the room lights before you do this test.

Over-current Protection

The red light draws a touch over 0.2 amps and the green light draws a touch over 0.3 amps. You should put these on a circuit protected by a breaker or fuse rated at 1 amp.

Legal stuff

These lights will only work as well as you put them together and install them. They can be damaged (or even made inoperative) by mis-wiring, careless assembly, or misuse. If subjected to voltage above 30 volts or reverse polarity, these lights will likely be damaged or perhaps ruined completely. I will sell you replacement components if you damage them in these ways, express my sympathy, and offer advice on how to make repairs, but nothing beyond that.

During the first 90 days, I will replace parts that were defective from the factory. You ship me the defective part at your expense and I will ship you a replacement at my expense.

I offer no warranty, express or implied, as to the usefulness or suitability of these lights for any purpose. If you were to install them on, say, an experimental aircraft, you would need to verify for yourself that they meet FAA requirements and make a detailed record of that verification. In a nutshell; use these at your own risk.