Retractable Landing Light

[f1rocket]

Anyone designed and installed a retractable landing light in the fuselage? I'm thinking of duplicating the Long-EZ design for this and was wondering if anyone else had already done so?

The Long-EZ design is pretty simple with a throw-over handle which locks the light in both the up and the down position. One of the few people who can compete with Van for simple and elegant designs is Burt Rutan.

Before you respond with the "put it in the wing dummy, like a thousand people before you" post, I have my reasons for wanting it in the fuselage. The Rocket EVO wing is pretty narrow up front, access is limited, and I don't really like them out that far from the centerline (among other reasons).

Any lessons learned from people who have already thought of this but discarded it would be appreciated before I go and design the mechanism. Thanks.

[Randy Walls]

I think that is a great idea, unfortunately I have no info.

[flyboykelly]

I am looking at doing the same thing, though in the wing. I was thinking of installing one under each wing in one of the access panels. That way if they need maintenance all I have to do is undo the panel and I can work on it on a bench instead of on the aircraft. Does the EVO wing have simiar access panels?

[Ironflight]

I've seen a couple of neat HID installations in the engine cooling air inlets Randy - not as "trick" as a retractable mechanism, but they looked to be pretty simple, and keep the lights out of the wings. I shudder to remember how often my Grumman ate the cowl-mounted (and vibration-prone) landing lights, but perhaps the new style bulbs can handle it better.

Paul

[roee]

No personal experience with a retractable light, but I could think of a few ideas. Firstly, I'd consider actuating it with something like a MAC servo, rather than a mechanical handle and catch.

[I should disclose that I am an electrical engineer, so I do have some bias on the subject ;-) ]

Likely advantages to the servo approach:
- The installation will be lighter weight.
- The installation will be mechanically simpler.
- No additional handles cluttering up the cockpit.
- The installation can go just about anywhere, including places where a mechanical handle would be inconvenient or impractical.
- If you're really ambitious, it could have intelligently variable incidence angle. For example, if you design it to pivot down from the bottom of the fuselage, you could set different optimal incidence angles for taxi, takeoff, or landing. If you were even more ambitious, you could have it auto-adjust the light incidence angle based on aircraft attitude from your AHRS. Neato!

Likely disadvantages to the servo approach:
- Cost of the servo.
- Added electrical complexity.
- The actuation will be electrically dependent, but then again, so is the light bulb. The only undesired scenario I can see with this is if you experience an electrical failure while the light is deployed. Then you wouldn't be able to retract it, and will have to put up with the added drag for the remainder of the flight. With a full electrical failure, you'll want to terminate the flight as soon as practical anyway, so I don't think the extra drag from the light fixture is major concern.

Hey, I like it! Having said all that, I think I'll still install my own landing lights in the conventional way in the wings. I've got enough little custom touches like this already...

-Roee

[RV7Guy]

Hi Randy,

I have plans to make mount at least one in the cowl using the MAC servo as the actuator. The light/door will be mounted to a retractable landing gear device from my box of RC goodies. This will give a positive lock in both up and down positions. When down, it will also serve as a cowl flap!!!

The light itself will be the Creative air LED light. (tentatively)

I also plan to flush mount the same light in the LE of the wing tips.

[lancef53]

I would love to see some info on it, I was thinking a cowl mounted light, but retractable sounds even better.

Lets keep this alive!!

[f1rocket]

Thank you for some very creative ideas! I am trying to stay away from a servo-style implementation because it is more complicated and costly than the Long-EZ mechanism, which is dumb-$ss simple. However, it has the disadvantage of requiring the handle directly above the light so placement becomes an issue. A servo-based solution makes it possible to install anywhere so I may come back around to this.

In looking at servos, the MAC servos are too slow. The biggest servo they have takes 17 seconds to fully extend only 1.2 inches. I'm not aware of other servos out there.

Darwin, I like the idea of having locking mechanisms in both the up and down configuration. I will need to check into that. Do you have a link to a source where I could check this out?

If I could get it to fit within the size of the wing inspection plate, I might have something that others might be willing to purchase. Interesting. Stay tuned, I plan to work on some designs to see if I can come up with something that's not too complicated or expensive.

[pierre smith]

....have retractable lights under the wings. www.airtractor.com

Regards,

[Kyleag04]

Originally Posted by flyboykelly

I am looking at doing the same thing, though in the wing. I was thinking of installing one under each wing in one of the access panels. That way if they need maintenance all I have to do is undo the panel and I can work on it on a bench instead of on the aircraft. Does the EVO wing have simiar access panels?

Retractable landing lights are handy, but be sure you think about the failure modes. If you've got one light under each wing and you have an actuator failure, and one light comes up and the other stays down, how much rudder is that gonna take to counteract that drag?

As Pierre says, the Air Tractors have large retractable landing lights under each wing near the tips. There have been a few cases where one light will fail in the extended position and it takes a lot of rudder to keep the airplane controllable.

Just something to think about.