LED wing tip lights - suggestions

[richard cohen]

Hi all. i am looking to put red/green nav lights into a model i am putting together but have a limited knowledge of electronics. I have seen Hobbyking do various pre wired led sets but there is nothing in the specs to indicate a working voltage or if any resistors etc are required. see this link  -  Hobbyking LED

has anyone used them, know the voltage and how bright they are ?   also how hot do they get .. i dont want to melt the plastic wing tip lenses

any guidance appreciated 

Rich

[Chris Walby]

Hi RC, Limited and disappointing experience experience with LED's, but that's not to say you can't get them to work, just don't expect much more that a "sometimes visible" light. Look nice on the ground, but no real benefit in the sky.

 

Wingtip ones tend to be very directional because you need very high intensity light and a wide angle lens and you get what you pay for

 

Strip LED's work ok for foamy flying at night, but again are very directional so as your eyes adjust to the dark they are very bright face on, but dark edge on so better to cover the model. Not tried it, but if I was to do it again would put the LED's inside the wing so you get a lower level of defused light.

 

Good thread and lets see what the others have to say/show.

  

[Shaun Walsh]

Take a look at the Strobon range available from Flytron 

[Denis Watkins]

8 hours ago, richard cohen said:

but there is nothing in the specs to indicate a working voltage or if any resistors etc are required. also how hot do they get .. i dont want to melt the plastic wing tip lenses

any guidance appreciated 

Rich

LEDS don't get hot Rich.

And operate, depending on colour, between 1.5v - 2 volts.

Whatever power you supply you use, e.g. 9v PP3 Battery, then protect the LEDS at 75ohms per volt, e.g. 675ohms resistor

And that resistor will protect all the LEDS in that line

As the lads have said, you won't see them easily, the lens is at an acute angle and you need superbrights.

You can buy LEDS which have a resistor already inside, so buy the same v rating as your supply volts.

 

Edited July 25, 2021 by Denis Watkins
Mis-spelling

[Ace]

Like CW I have coloured strip lights on my Bixler. To prevent glare I faced the lights into the foam which makes the foam glow.

I did channel the foam with a soldering iron then cover with 50mm clear tape. Doing it again I wouldn't use the waterproof ones as the silicon is bulky and dead weight. Power wise they are 12v cut to any length (groups of 3) terminated in a deans plug. As the Bixler is 3s I just use a parallel battery connecter when they are required. 

[Allan Bennett]

33 minutes ago, Denis Watkins said:

LEDS don't get hot Rich.

And operate, depending on colour, between 1.5v - 2 volts.

Whatever power you supply you use, e.g. 9v PP3 Battery, then protect the LEDS at 75ohms per volt, e.g. 675ohms resistor

And that resistor will protect all the LEDS in that line

As the lads have said, you won't see them easily, the lens is at an acute angle and you need superbrights.

You can buy LEDS which have a resistor already inside, so buy the same v rating as your supply volts.

 

Some LEDs do get hot!  I use some Cree high power LEDs as strobes, and as such they can operate without a heat-sink.  But if used continuously on, they need to be mounted on a 2cm diameter heat-sink.

 

I've not come across any 1.5v LEDs; the ones I use in model aircraft and railways always seem to be in the range of 2.0 to 2.7v, depending on colour.  The value of resistor needed depends on the supply voltage, the LED voltage and operating current, and how many LEDs in the string.  It can be easily calculated using this online app. 

[RottenRow]

Different colour LEDs have different voltage drops (as Denis says) and require different series resistor values to achieve the same current at a specific voltage. In addition, the same current through different coloured LEDs (of the same type) produces different levels of apparent light to the eye.

The HobbyKing LEDs that Richard specifically refers to in his original question are made to operate at the voltage of a normal receiver pack or BEC circuit, ie in the region of 5V. You will notice that the connection is via a normal 3 way servo type plug (only two pins used, positive and negative), this is so that the LEDs can be plugged directly into (say) a spare receiver outlet or a Y-lead. They will then come on whenever the receiver is powered. Some HK (and probably other) ARTFs come with these fitted as standard.

The LEDs on the board already have resistors included, it appears in a combination of series and parallel circuits. I suspect that the actual values of these resistors varies dependng on the LED colour (and the number of LEDs).

If you read the reviews for these LEDs and for the various different coloured versions available you can see that as others have pointed out they are fairly directional and not particularly bright. On the plus side they are cheap, and if you are ordering anything from HK it would be worthwhile adding a couple of these to the order just to try them. As a trial they could be taped to a model's wing tip and the wires run back along the undersurface.

They make various versions, with larger numbers of LEDs and different colours, though not all are stocked in the UK warehouse.

Finally, it's always best to use LEDs of the colours required (red and green in this case) and use white ones fitted behind coloured lenses, as you lose too much light that way.

Brian.

[Nik Harrison]

My vote is for Flytron.  Very bright LEDs that are very easy to setup.  As for LED not getting hot - try a 3W LED without a heatsink and see how long it lasts!

Cheers.

[Denis Watkins]

Don't get confused Rich with disco lights mains LEDS, and high power applications LEDS

our piddling little LEDS on our toys with piddling little supplies provide no heat.

if you build 10 foot wingspan foamies with high power industrial bits and pieces then consider heat.

I love this site for discouraging experimenters with simple questions.

let's split hairs and actively discourage innovation

[richard cohen]

Thanks to everyone who has replied. i have had a look at the flytron kit and it looks just the thing. i definitely need 'plug n play' type lighting because while my building and engine tuning skill are good, my knowledge of electronics suck !  

[Allan Bennett]

3 hours ago, Denis Watkins said:

Don't get confused Rich with disco lights mains LEDS, and high power applications LEDS

our piddling little LEDS on our toys with piddling little supplies provide no heat.

if you build 10 foot wingspan foamies with high power industrial bits and pieces then consider heat.

I love this site for discouraging experimenters with simple questions.

let's split hairs and actively discourage innovation

 

I don't think that telling the fact that some LEDs -- even 'plddling little' ones running off 5v supplies -- can get too hot for their own good is splitting hairs or discouraging innovation.  If you want visible brightness you need high power, then heat management can be an issue.  The heat from the 1A Crees that I use (3.45mm square) is mitigated by using them as strobes with a very short 'on' duration compared to the 'off' duration.  This is the same technique that's used with the ones in Nick Harrison's Flytron link to avoid overheating without the need for heat-sink.