Wing Lights

[S Lathrop]

I have been studying as many light setups, mounted in the wings, as I can find on this site and else where. I want to thank everyone who has shared their setups , starting with Russ Erb and all those who have posted pictures.

My goals are to get the best light coverage I can, on the ground and when maneuvering around hangers at night and in poorly lit areas. I also want to minimize the size of the hole through the wing but get a good light spread when on the ground.

I do plan on a landing light in the nose bowl. I really like this light location for landing but on the ground, it is not very good in a tail dragger. With lights in the wing tips, I don't feel that I will not get the light coverage directly in front that I want because the light is set so far back from the leading edge of the wing.

I have a fair number of hours in a Cessna C180 and it is this light setup that I am trying to improve on for my 4 place Bearhawk.

Here is what I have come up with and I am looking for any suggestions, constructive criticisms, I can get. This is definitely a work in progress.

[rodsmith]

I think you need to enlarge the plexiglas area. Unless the bulb you are using is a spotlight, you will be limiting the angular distribution. I plan to cut the opening back to the bezel the light is mounted flush in to take advantage of the 13 deg horiz and vert spread. The light I am using is rectangular, 2" high 5" wide so I don't have to cut very far into the leading edge. I'm planning on mounting the light angled down 5 deg from the wing cord, which is 3 deg down in level flight. That should help seeing the ground on a low fly over and while flaring and make it a more effective taxi light. I welcome other's opinions on that. Those are great cad drawings!

[S Lathrop]

I think you need to enlarge the plexiglas area. Unless the bulb you are using is a spotlight, you will be limiting the angular distribution. I plan to cut the opening back to the bezel the light is mounted flush in to take advantage of the 13 deg horiz and vert spread. The light I am using is rectangular, 2" high 5" wide so I don't have to cut very far into the leading edge. I'm planning on mounting the light angled down 5 deg from the wing cord, which is 3 deg down in level flight. That should help seeing the ground on a low fly over and while flaring and make it a more effective taxi light. I welcome other's opinions on that. Those are great cad drawings!

I came up with that opening by cutting a cone shape from the mounting bulkhead and projecting that cone out at 10 degrees. The diameter of the cone at the mounting bulkhead is 4" which is the diameter of the light. That is also the maximum width that you can reasonably cut between the ribs and have some wing skin material to seal the lens against. The light actually sits forward from that bulkhead. The further forward I can move the light, the better the width will be. The bulkhead is drawn at a 14 degree angle. This is for a taxi light only. The light is about 2.4 inches behind the jig pin hole in the ribs. If I can move that forward, I get a better lateral spread.

Thanks for the thoughts. I might look at doing an oval cut so that the hole allows 20 degrees vertically and the same 10 degrees laterally.

[S Lathrop]

I made some changes to the drawing. The hole through the wing skin is now elongated slightly. The top is what I had originally and the bottom is 1/32" lower. When I project lines from the light through the opening in the wing, I get a 15 degree spread upwards and a 21 degree spread downwards. Laterally the spread is 15 degrees and this is limited by the nose ribs. As before the lights are angled downwards 14 degrees relative to the wing. The lights are intended to be horizontal with the plane on the ground. Maybe that idea needs to be tweaked a bit.

I believe that this is the maximum light pattern I can get with a PAR 36 size taxi light. I am surprised at how small the hole can be and still project as much of the light.

Thanks again for your input.

[Battson]

Bob advised me that the wing is not designed to have big holes cut into it, particularly on the leading edge. He said an appropriately sized doubler, the same thickness as the wing skin, must be installed to strengthen any holes cutting into the L/E, riveted into place per AC43.13

[S Lathrop]

Bob advised me that the wing is not designed to have big holes cut into it, particularly on the leading edge. He said an appropriately sized doubler, the same thickness as the wing skin, must be installed to strengthen any holes cutting into the L/E, riveted into place per AC43.13

I am concerned about strength. That is why I tried to come up with a design that has the smallest possible hole in the wing skin.

I am also looking at having taxi lights mounted in front of the junction of the lifting struts and the underside of the wing. There is a post of such an installation.