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Old Oct 02, 2012, 07:59 PM
Blade mSR freak
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Irish Hills - SE Michigan
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Strip LED lighting has chip resistors already on the strip. There's no elegant way to do this.
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Old Oct 02, 2012, 08:43 PM
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Sunnyvale
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Well take a look at how I did it. The strips all come ready to go and all you do is power them with a 12volt battery. I use the main battery wired into a brushed esc connected to the gear switch. I recessed the strips into the wings so that they don't affect airflow over the wings and during the day you can't even see them really. But at night this is what you get....

http://www.rcgroups.com/forums/showp...&postcount=306
http://www.rcgroups.com/forums/showp...&postcount=311

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Old Oct 03, 2012, 06:42 AM
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United States, DC, Washington
Joined Mar 2011
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Originally Posted by gooniac33 View Post
Well take a look at how I did it.
Your implimentation is VERY nice! I know that for maximum light output, you need ~12volts. Have you considered a multiswitch from HK to allow selection of different lights in flight?

http://www.hobbyking.com/hobbyking/s...f_Switch_.html

This switch allows you to control up to 7 different circuits (lights) using only 1 channel of your transmitter. You can pick the power supply for these circuits since it is separate from the connection to the receiver.

I'm using this switch for my Dynam T-28. It allows me to cycle various lights on individually, and then cycle them off. I would use your white landing lights that way to only turn them on when you need them.

I would like to see more details of how you mounted your lights in the plane,

Thanks for this wonderful contribution to the thread!

VJ
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Old Oct 03, 2012, 09:19 AM
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Sunnyvale
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Originally Posted by Virginia Jim View Post
Your implimentation is VERY nice! I know that for maximum light output, you need ~12volts. Have you considered a multiswitch from HK to allow selection of different lights in flight?

http://www.hobbyking.com/hobbyking/s...f_Switch_.html

This switch allows you to control up to 7 different circuits (lights) using only 1 channel of your transmitter. You can pick the power supply for these circuits since it is separate from the connection to the receiver.

I'm using this switch for my Dynam T-28. It allows me to cycle various lights on individually, and then cycle them off. I would use your white landing lights that way to only turn them on when you need them.

I would like to see more details of how you mounted your lights in the plane,

Thanks for this wonderful contribution to the thread!

VJ
I think that I may have posted it but here it goes. Basically I just embedded the LED strips in the wing and ran it down the fuse on the inside. A strip of blenderm was used to cover them up after that. The receiver controlled switches work just the same as the brushed ESC's that I use but you can't control the brightness with the switches. You can with the ESC's. I use a GWS 2amp brushed esc to controll all of them and if I needed to I could put different ones for different functions. But I kept it simple. Take a look...
Before

Embedded in the wing

Blenderm in place. Flush with the wing

you can't see them from the front since they are flush with the wing



I mainly fly the plane during the day so you really don't see the lights.
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Old Oct 03, 2012, 09:16 PM
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Long Island, NY
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Originally Posted by hydro_pyro View Post
Strip LED lighting has chip resistors already on the strip. There's no elegant way to do this.
What I am trying to set up is a simple power distribution to six parallel leds in a clean way.
First I ordered one of these:
http://www.hobbyking.com/hobbyking/s...dProduct=23347
This gives me six male JST plugs in parallel and a set of main feed leads where I can incorporate an 80ohm/2W resistor allowing to feed this lot from the 3S balance plug.
Then I soldered a JST pin to each of the led wires, they will plug into the 6 JST's. A piece of shrink tube will hold them together.
Attached is the resistor calculation.
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Old Oct 04, 2012, 09:23 AM
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Sunnyvale
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Originally Posted by Galand View Post
What I am trying to set up is a simple power distribution to six parallel leds in a clean way.
First I ordered one of these:
http://www.hobbyking.com/hobbyking/s...dProduct=23347
This gives me six male JST plugs in parallel and a set of main feed leads where I can incorporate an 80ohm/2W resistor allowing to feed this lot from the 3S balance plug.
Then I soldered a JST pin to each of the led wires, they will plug into the 6 JST's. A piece of shrink tube will hold them together.
Attached is the resistor calculation.
What I forgot to show is that the LED strips have a JST type connector at the end. They would plug right into that lead from hobbyking...
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Old Oct 04, 2012, 09:27 AM
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Sunnyvale
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Based on the comments in this thread I reinforced the nose wheel mounting with a block of Sintra.
I will be taking mine apart as well. The biggest problem is the way that they designed (or didn't design) the nose gear. What you did is what I have been thinking of doing! The load needs to be spread out instead of in one little small area. Good job!
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Old Oct 04, 2012, 09:31 AM
dbc
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United States, FL, Brooksville
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Based on the comments in this thread I reinforced the nose wheel mounting with a block of Sintra.
Nice work. That reinforcement job should work well. I did a much simpler and quicker job and it has proven more than adequate with over 330 logged flights on my plane.
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Old Oct 04, 2012, 07:52 PM
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Long Island, NY
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Originally Posted by gooniac33 View Post
I will be taking mine apart as well. The biggest problem is the way that they designed (or didn't design) the nose gear. What you did is what I have been thinking of doing! The load needs to be spread out instead of in one little small area. Good job!
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Nice work. That reinforcement job should work well. I did a much simpler and quicker job and it has proven more than adequate with over 330 logged flights on my plane.
Thanks. It may be a bit over-engineered but that sintra is fairly light. The nice thing also is that the nose wheel can be taken off and repaired.
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Old Oct 05, 2012, 01:43 PM
Blade mSR freak
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Irish Hills - SE Michigan
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Originally Posted by Galand View Post
What I am trying to set up is a simple power distribution to six parallel leds in a clean way.
Bad idea... Wiring the LED's in parallel will likely give you inconsistent results. The LED's have a "rated" forward voltage, but they have slight variations from one LED to another. What happens as a result, is one of the LED's will drop the parallel voltage across the others, and thus steal a majority of the current. One may appear brighter than the others, and some of them may not light up at all. The LED with the lowest actual voltage drop will drop the forward voltage below the threshold for the others. It's not a guarantee-- It might work just fine. But, chances are, you will have issues with running them in parallel.

The best way is to have a separate series resistor for each LED as I suggested above.
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Old Oct 05, 2012, 02:34 PM
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Sunnyvale
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Originally Posted by hydro_pyro View Post
Bad idea... Wiring the LED's in parallel will likely give you inconsistent results. The LED's have a "rated" forward voltage, but they have slight variations from one LED to another. What happens as a result, is one of the LED's will drop the parallel voltage across the others, and thus steal a majority of the current. One may appear brighter than the others, and some of them may not light up at all. The LED with the lowest actual voltage drop will drop the forward voltage below the threshold for the others. It's not a guarantee-- It might work just fine. But, chances are, you will have issues with running them in parallel.

The best way is to have a separate series resistor for each LED as I suggested above.
In my case....all of the resistors are wired in the strips so no worries there. But you are correct. Path of least resistance...
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Old Oct 05, 2012, 07:05 PM
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Long Island, NY
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Originally Posted by hydro_pyro View Post
Bad idea... Wiring the LED's in parallel will likely give you inconsistent results. The LED's have a "rated" forward voltage, but they have slight variations from one LED to another. What happens as a result, is one of the LED's will drop the parallel voltage across the others, and thus steal a majority of the current. One may appear brighter than the others, and some of them may not light up at all. The LED with the lowest actual voltage drop will drop the forward voltage below the threshold for the others. It's not a guarantee-- It might work just fine. But, chances are, you will have issues with running them in parallel.

The best way is to have a separate series resistor for each LED as I suggested above.
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Originally Posted by gooniac33 View Post
In my case....all of the resistors are wired in the strips so no worries there. But you are correct. Path of least resistance...
Hydro, I see what you mean, but if all six leds were the same it should not be an issue and the wiring that way is a lot simpler( I am lazy). Now the difference between red and green is small IIRC both are around 2.2V drop, so I guess it will work. I can plug them in one after the other until I have exhausted the 12.60V starting power and they stop working. If they were blue or white leds, it would be a different story.
@Gooniac, I imagine that within a your strips all the leds are identical. Are they wired in parallel?
If it does not work, having learned something, it's then back to soldering individual resitors. Anyway it's an interesting issue for a handful of stupid leds.
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Old Oct 06, 2012, 11:46 AM
Blade mSR freak
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Irish Hills - SE Michigan
Joined Jan 2010
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A few hundredths of voltage drop difference will cause major differences in brightness between LED's, and it's typical for them to vary by a tenth or two. Try it on the bech first if you don't believe me. some of them will barely light up, even amongst identical colors.
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Old Oct 06, 2012, 12:41 PM
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Originally Posted by hydro_pyro View Post
A few hundredths of voltage drop difference will cause major differences in brightness between LED's, and it's typical for them to vary by a tenth or two. Try it on the bech first if you don't believe me. some of them will barely light up, even amongst identical colors.
With the connector I have on order from HK that will be easy to test. I'm curious.
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