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Ovation recog light replacment alternatives


rogerl

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Great looking project!!

Ive always thought if I could figure out the voltage step down the d-cell LED mag light would be bright enough for me with the recognition lights. This solves that issue!!

Those lights are small and cool enough to figure out a way to figure out how to slap them on my set of flat wing tips. Little angle bracket or something. Maybe on the MLG?

Looks great!!  

-Matt

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On 10/21/2018 at 7:49 PM, LANCECASPER said:

My elves got the Maglite parabola reflectors and cut them down and then then paint the backs black. Then they installed the Crazed Pilot Bullet LEDs and they seem to work just fine.

After I'm sure about them I might think about having the elves install new, unmelted lenses to replace the wingtip lenses . .  or maybe I'll just forget about it and move on.

 

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2 minutes ago, Bryan said:

Did you tie off the existing stepped down voltage for those lights?  Does Mooney bring 24v down to the tip and then step it down for the light or does it bring 14v all the way down?

My elves went with the original design. The LED Bullet lights are rated for 14v so the elves left the 14 v that came through the stepdown resistor.

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On 10/23/2018 at 9:45 AM, LANCECASPER said:

My elves went with the original design. The LED Bullet lights are rated for 14v so the elves left the 14 v that came through the stepdown resistor.

I should point out that the stepdown resistor is only going to give 14V if your new LEDs are also drawing 25W. They almost certainly aren't so you're probably seeing more like 26V or so, which most decent LEDs will handle fine. 

And now... math:

E=IR E=Volts I=Amps, R=Resistance in ohms.

P=EI P=Watts

Old Light: 25W at 14V: 25=14*I: let's call it 1.8Amps

Need to drop 14V at 1.8 amps: 14=1.8*R: R= about 8 Ohms

So, the existing resistor is about 8 ohms and is dropping(P=I^2 * R) 25watts, basically the same as the light itself since it's cutting the voltage in half.

Now, we want the voltage seen across the new light, let's assume it draws 5watts, total voltage still 28V, existing resistor 8 ohms.

Mixing the formulas a bit: 28-V=I*8 5=V*I (V here is drop across the LED which depends on current since we assume it's a constant power device)

After an exercise left to the reader(mostly because I broke down and used an algebra calculator for the math) we get 26.5V across the LED, 1.5V across the resistor and 0.1875 Amps. The good thing is the resistor is now wasting only about 0.28watts and so it's really not worth digging it out.

 

 

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On 10/22/2018 at 2:30 PM, LANCECASPER said:

I have a brand new 70303 in the Whelen box that I've kept on the shelf just in case. $100 shipped.

(I'm going to keep my used ones just in case an IA down the road has something against my elves' work)

You need to go just a little further down the road. There's a better IA at 84R.

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2 minutes ago, LANCECASPER said:

Mine comes to my hangar and 25 years ago used to be Mooney's IA at the service center. He's fine with it but if he ever really decides to retire  . . . . 

Well that's true. Nothing better than an IA who makes hangar calls and even better, has a key to my hangar.

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  • 2 weeks later...

Finally dug out the bits and got round to taking some photos:

From left: Bulb with sticker & leads removed, bulb with leads but sticker removed, bulb with sticker and lead removed, new uncut bulb with box behind ($3 from ebay)

20181110_160146.thumb.jpg.636c1037cd2c9f0f3919b406a79f6b37.jpg

Two old bulbs and the new from the front - note that theold are trimmed off asymmetrically

20181110_160221.thumb.jpg.48928f03463eccd38d7f9d91c5b5ebee.jpg

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On 10/16/2018 at 3:57 PM, LANCECASPER said:

Your elves seem very industrious. I really like their idea of the Maglite parabolic reflector. Some mechanics are fearful of what elves have done and this could help them to walk right past the work without paying a lot of attention, plus of course the light is directed as designed.

I wonder what your elves would think about this combination:

The parabolic reflectors with the blue painted black to match the previous light  . . . 

and then the Crazed Pilot bullet LED in the center of the parabola  . . .

 

LANCECASPER, thanks for your post - much appreciated.  My hangar elves read it with great interest ..

Took a bit of sculpting with the Dremel to get it just the right shape.  LED draws 0.1 A compared to 1.8 A on the original.  No heat on the LED at all, whereas the original melts the covers.  Now contemplating whether I should write this up as owner-manufactured part and get IA to sign off - or just say nothing.  Photo shows a new Whelan on the left, compared to LEDs on the right.

IMG_2141.JPG

IMG_2067.JPG

IMG_2087.JPG

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17 minutes ago, pwnel said:

LANCECASPER, thanks for your post - much appreciated.  My hangar elves read it with great interest ..

Took a bit of sculpting with the Dremel to get it just the right shape.  LED draws 0.1 A compared to 1.8 A on the original.  No heat on the LED at all, whereas the original melts the covers.  Now contemplating whether I should write this up as owner-manufactured part and get IA to sign off - or just say nothing.  Photo shows a new Whelan on the left, compared to LEDs on the right.

IMG_2141.JPG

IMG_2067.JPG

IMG_2087.JPG

Elves do not speak IA language so I think it’s best that the elves keep quiet.

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