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LED Wingtip & Landing Light Output Comparisons

J

Jeff Argersinger

Member
We spoke to many people this year at Oshkosh and one of the hot topics was regarding light output of the LED lighting choices that are now available. Several threads on VAF indicate the same interest as well.

Although there are many well built, attractive alternatives in the marketplace, Whelen's design objective is to provide products designed, and approved to FAA/TSO qualification standards. By doing this, it relieves the homebuilder or OEM from the time consuming task of proving FAR compliance of their lighting system to the FAA on their own, (if the aircraft is to fly at night).

The purpose of the first test was to show the differences in the anti-collision light output between the Whelen Model 90400 series FAA/TSO certified LED anti-collision light, and the Aeroleds Pulsar EXP non-certified LED anti-collision light. This is purely a light output comparison only, NOT a design critique.

http://www.whelen.com/_AVIATION/images/temp/graph-1.htm

The second test was conducted to provide light output data to answer the many LED landing light questions we also received at Oshkosh. This test compares the light output of the Whelen Model 71141 series LED landing/taxi light, 71125 series and the Aeroleds SunSpot, LED landing light. This is purely a light output comparison only, NOT a design critique.

http://www.whelen.com/_AVIATION/images/temp/graph-2.htm


The photometric tests were conducted in house at Whelen using a Hoffman Engineering goniophotometer system in a fully certified chamber, in an accredited lab. This is the same system used to certify our LED products currently in use by multiple OEM's.

Additional product testing is currently in progress.
 
Great Plots and Data!

Good information. I wish all the players would make detailed data like this readily available on all their lights (Whelen included ;))
 
Dan Langhout said:
Good information. I wish all the players would make detailed data like this readily available on all their lights (Whelen included ;))
Click to expand...

Thanks Dan. I saw from some earlier threads that you and others really wanted more detailed information as to how bright the new LEDs lights are with respect to the FAR's. I admire your pro active approach to try to get light output data by developing your own test set ups. This post is to provide accurate, easy to read data to the builders to help determine what lighting suits their particular needs. As time permits I will continue to offer more information.
 
The Whelen data for the Pulsar EXP strobe appears to match well with the data that I have taken on that unit. As is implied by the product name, the EXP is intended solely for the experimental market and is not the design that we are seeking TSO approvals with. Our other newer Pulsar and Suntail designs do meet the TSO light output levels, and we are going to obtain TSO approvals on those newer designs.

Regarding the Sunspot data, it does not match the data that I have collected. I am not sure if Whelen tested a narrow or a wide lens version of that product, since we offer both versions, but if they tested the narrow lens version then I suspect that they made an error in their testing methodology.

Our test data is here:
http://www.aeroleds.com/resources/theledadvantage.aspx (scroll down to see the graphs)

The narrow beam Sunspot hits about 30,000 candela in the beam center while the wide beam hits about 10,000. We will be offering an ultra narrow version as well in the near future, but for typical light singles (non-jets) we feel that the narrow beam is a good balance between range and short final field of view performance.

If Whelen tested the Sunspot in a still air environment with the light running for 30+ minutes before they started collected data, then the light output of the Sunspot will be diminished by the built-in thermal protection circuitry that turns the light down to avoid over-stressing the LEDs when the light is left on in a parked airplane. That could explain the results they obtained.

All of our lights are designed to take into account the actual operating environment in which they are to be used; i.e. an aircraft in flight. As such, they will have substantial airflow over them in normal operation that will keep them at full output, even when mounted behind leading edge windscreens. Wings leak a significant amount of air in flight, so there is reasonable airflow over the lights when they are used in flight.

If Whelen could provide the test conditions used to test the Sunspot (operating time and speed of the airflow over the light) that would help to qualify the data. I would also like to know if it was a narrow or wide lens version that was tested.
 
Dean,

So if I am interpreting your response correctly, the Pulsar NS90 should have been the unit tested and not the Pulsar EXP, correct?

bob
 
Bob,

The Pulsar NS90, and the new Pulsar are the units that we will be doing TSO compliance testing on, including optical testing, for submittal to the FAA.

Dean
 
Jeff,

Out of curiosity, have you tested any of the Aveo units? I would like to see your data on their stuff as well...

Dean Wilkinson
CTO, AeroLEDs LLC
 
Jeff Argersinger said:
We spoke to many people this year at Oshkosh and one of the hot topics was regarding light output of the LED lighting choices that are now available. Several threads on VAF indicate the same interest as well.

Although there are many well built, attractive alternatives in the marketplace, Whelen's design objective is to provide products designed, and approved to FAA/TSO qualification standards. By doing this, it relieves the homebuilder or OEM from the time consuming task of proving FAR compliance of their lighting system to the FAA on their own, (if the aircraft is to fly at night).

The purpose of the first test was to show the differences in the anti-collision light output between the Whelen Model 90400 series FAA/TSO certified LED anti-collision light, and the Aeroleds Pulsar EXP non-certified LED anti-collision light. This is purely a light output comparison only, NOT a design critique.

http://www.whelen.com/_AVIATION/images/temp/graph-1.htm

The second test was conducted to provide light output data to answer the many LED landing light questions we also received at Oshkosh. This test compares the light output of the Whelen Model 71141 series LED landing/taxi light, 71125 series and the Aeroleds SunSpot, LED landing light. This is purely a light output comparison only, NOT a design critique.

http://www.whelen.com/_AVIATION/images/temp/graph-2.htm


The photometric tests were conducted in house at Whelen using a Hoffman Engineering goniophotometer system in a fully certified chamber, in an accredited lab. This is the same system used to certify our LED products currently in use by multiple OEM's.

Additional product testing is currently in progress.
Click to expand...

I was not at Oshkosh this year, however I have just purchased four of the ?MicroSun? units from the ?AeroLED? company.

While I am still a good while from actually using these units on my RV-8, however I have hooked them to power and they sure are nice and bright, and the built in Wig-Wag circuit sure does simplify the wiring.

Also, I am in the process of mounting them to a light bar which I will install on my truck just to get an idea of how they will work while driving. I figure if they work well enough for driving, then they should work well enough for flying.

This rig should be ready to go in another week or two, and if you are interested I can post the results.
 
Dean_aeroleds said:
The Whelen data for the Pulsar EXP strobe appears to match well with the data that I have taken on that unit. As is implied by the product name, the EXP is intended solely for the experimental market and is not the design that we are seeking TSO approvals with. Our other newer Pulsar and Suntail designs do meet the TSO light output levels, and we are going to obtain TSO approvals on those newer designs.

Regarding the Sunspot data, it does not match the data that I have collected. I am not sure if Whelen tested a narrow or a wide lens version of that product, since we offer both versions, but if they tested the narrow lens version then I suspect that they made an error in their testing methodology.

Our test data is here:
http://www.aeroleds.com/resources/theledadvantage.aspx (scroll down to see the graphs)

The narrow beam Sunspot hits about 30,000 candela in the beam center while the wide beam hits about 10,000. We will be offering an ultra narrow version as well in the near future, but for typical light singles (non-jets) we feel that the narrow beam is a good balance between range and short final field of view performance.

If Whelen tested the Sunspot in a still air environment with the light running for 30+ minutes before they started collected data, then the light output of the Sunspot will be diminished by the built-in thermal protection circuitry that turns the light down to avoid over-stressing the LEDs when the light is left on in a parked airplane. That could explain the results they obtained.

All of our lights are designed to take into account the actual operating environment in which they are to be used; i.e. an aircraft in flight. As such, they will have substantial airflow over them in normal operation that will keep them at full output, even when mounted behind leading edge windscreens. Wings leak a significant amount of air in flight, so there is reasonable airflow over the lights when they are used in flight.

If Whelen could provide the test conditions used to test the Sunspot (operating time and speed of the airflow over the light) that would help to qualify the data. I would also like to know if it was a narrow or wide lens version that was tested.
Click to expand...

Hi Dean,
I looked through the literature sent with the Sunspot and it appears there is no identification as to what the beam pattern is. The literature identifies a GE4509 mounting bracket mount. It very well could be the wide version. Spoke with our photometric technician and the light was simply fixtured and the light output readings taken. Therefore the Sunspot was tested at ambient temperature in our lab without external cooling. Operating time was no more than 15 minutes.

Regarding airflow.....during our prior OEM certification efforts with LED lighting, we were not permitted to rely on external airflow to substantiate performance of our product. Actually, in most cases depending on the operating environment, during testing our lights are subjected to higher than normal operating temperatures such as overflow of bleed air from deicing systems, as well as temperatures seen when mounted in engine cowlings. The Whelen landing taxi lights have thermal protection that starts to back off the current at around 120 degrees C (248 degrees F).

As time and resources allow, we will continue to provide light output data of both Whelen and others so builders and OEMs can evaluate.

Regards,
Jeff Argersinger
Whelen
 
Just wanted to say that it's really great to be able to see data like this... I encourage all manufacturers to do this kind of testing and put the results out there for potential buyers to evaluate. The human eye is not a reliable detector of brightness, especially at close range during the daytime. Good discussion!

mcb (still trying to finalize the big lighting decision)
 
Jeff Argersinger said:
Hi Dean,
I looked through the literature sent with the Sunspot and it appears there is no identification as to what the beam pattern is. The literature identifies a GE4509 mounting bracket mount. It very well could be the wide version. Spoke with our photometric technician and the light was simply fixtured and the light output readings taken. Therefore the Sunspot was tested at ambient temperature in our lab without external cooling. Operating time was no more than 15 minutes.

Regarding airflow.....during our prior OEM certification efforts with LED lighting, we were not permitted to rely on external airflow to substantiate performance of our product. Actually, in most cases depending on the operating environment, during testing our lights are subjected to higher than normal operating temperatures such as overflow of bleed air from deicing systems, as well as temperatures seen when mounted in engine cowlings. The Whelen landing taxi lights have thermal protection that starts to back off the current at around 120 degrees C (248 degrees F).

As time and resources allow, we will continue to provide light output data of both Whelen and others so builders and OEMs can evaluate.

Regards,
Jeff Argersinger
Whelen
Click to expand...

Jeff,

SAE J845 test standards are intended for ground based vehicles that operate their lights when the vehicle is parked.

For aircraft, the lights are operated and used when the vehicle is moving at a high rate of speed. Exterior mounted lights will be at or very close to the ambient air temperature due to the high speed airflow.

Lights mounted inside a wing will still receive swirling air due to small leaks where control surfaces attach, and this provides a substantial amount of cooling.

It isn't a fair test to test the light output of an aircraft light that is designed for an environment in which there is airflow by testing it with zero airflow. Even a small desk fan makes a huge difference in the rate of heat extraction and the resulting heat sink temperature.

Regards,

Dean Wilkinson
CTO, AeroLEDs LLC
 
Hello all!

For what is worth, here goes ?

I am working on an RV-8 and I have purchased four of the ?MicroSun? units from the ?AeroLEDs? company. I plan to have two lights in the left wing (one for landing and one for taxi), and to have two in the right wing (again, one for landing and one for taxi). Note: this configuration may seem a bit redundant to some, but it is the way I want to do my landing and taxi lights.

Since I am unfamiliar with these units, I put together a wooden box that I mounted all four lights in along with a switch box that has a switch for lighting the two inboard lights (as would be done for the landing lights), a switch for the two outboard lights (as would be done for the taxi lights), and a wig-wag switch (which causes the both of the left lights to alternate blinking with both of the lights on the right). Then I mounted the box to my truck and gave it some informal testing. I figured if the lights were good enough to drive with, then they would be good enough to fly with.

Well, I did that over the week-end and I am happy to say that the lights are plenty bright to drive with, so I expect that they will be plenty bright to fly with as well.

One pair of lights is brighter than the driving lights, and when both pairs are on, then they are brighter than the high beams. Also, the built-in wig-wag circuit does simplify the wiring job.

But there are some things that I would like to point out.

One, while the lights themselves do not get hot, the large heat sinks do get a bit warm. So one needs to consider that fact when placing them: I will be installing mine in one of the outboard bays of the leading edge and in the wingtips just to keep them away from the fuel tanks.

Two, the mounting points are designed for #6 machine bolts with round heads, and the tolerances are rather tight. There is just enough room to turn the bolt head on the one side and just enough room to turn the nut on the other side. Therefore, one has to be very careful about just where the mounting holes are on the install plate because there is not too much room for error.

Three, the LED driving circuits do generate some radio interference, but shielding the lights with some thin metal does a good job of blocking that interference. Therefore there should be no problem with the lights mounted in the wings, however it may be necessary to provide some shielding in the wingtip mounted lights (but then again, this issue may not be a factor, so I will just have to wait and see on this point). But I do think that it is fair to say that if one used these lights in the wingtips, then one will probably not be able to make use of wingtip mounted radio antennas. In my case, I was not planning to do that anyway, but it is something to keep in mind all the same when it is time to do radio work.

Aside from these three points, I was very pleased with the lights and I look forward to using them.

Thanks AeroLEDs!
 
How the lights are grounded can make a huge difference with RF emissions. Mounting them to a metal airframe grounds the chassis which makes a big difference. Also, how the wires are routed can also make a big difference. Generally our lights are pretty low on their emissions, but the installation can make them noisier. Near field effects can also affect antennas even though the lights may not have any significant far field RFI, so mounting them right next to an antenna is usually not a good idea.
 
Dean_aeroleds said:
How the lights are grounded can make a huge difference with RF emissions. Mounting them to a metal airframe grounds the chassis which makes a big difference. Also, how the wires are routed can also make a big difference. Generally our lights are pretty low on their emissions, but the installation can make them noisier. Near field effects can also affect antennas even though the lights may not have any significant far field RFI, so mounting them right next to an antenna is usually not a good idea.
Click to expand...

Good information indeed!

I would prefer to not use the airframe as a grounding point due to the ground loop issue.

However, I will reconsider should the RFI be a problem.

Thanks Dean!
 
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