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  #11  
Old 03-04-2014, 05:10 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
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Quote:
numbers for two 50W halogens in series on the taxi light circuit
Did you mean to say, "Parallel"?
Joe Gores
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  #12  
Old 03-04-2014, 01:01 PM
Norman CYYJ Norman CYYJ is offline
 
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Location: Victoria B.C.
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Why not use a solid state four flasher, quite cheap and works very well?
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  #13  
Old 03-06-2014, 12:41 AM
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DrillBit DrillBit is offline
 
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Location: Pleasanton, CA
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Actually, tried it both series and parallel. Drew about the same amps in both configurations, but the numbers quoted were for parallel.
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N748PK, RV-9A
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  #14  
Old 03-06-2014, 12:56 AM
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DrillBit DrillBit is offline
 
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Quote:
Originally Posted by Norman CYYJ View Post
Why not use a solid state four flasher, quite cheap and works very well?
Recreation, education, and finding inexpensive things to do while College Educations soaked up major discretionary Aviation funding (see post #1).

The only advantages this ckt may have over commercial units are negligible currents flowing through the panel switches and the wig-wag action doesn't depend on the loads (one side will still flash if the other is side is burnt out or open circuit for any other reason).
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P-town, CA (10 min from KLVK!)
N748PK, RV-9A
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VAF dues last paid 30 Dec 2020
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  #15  
Old 03-06-2014, 08:21 AM
krw5927 krw5927 is offline
 
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Quote:
Originally Posted by DrillBit View Post
Recreation, education, and finding inexpensive things to do while College Educations soaked up major discretionary Aviation funding (see post #1).

The only advantages this ckt may have over commercial units are negligible currents flowing through the panel switches and the wig-wag action doesn't depend on the loads (one side will still flash if the other is side is burnt out or open circuit for any other reason).
In addition to these reasons, I designed and built my own wigwag controller because the automotive-style flasher I initially purchased didn't have a true 50% duty cycle for the lights. One would always be on for a shorter time than the other. Great for cars, but I didn't like it on the plane.

I also wanted to use LEDs and not burn through a bunch of (wasted) power to heat up resistors in order to make the auto flasher work.

Finally, if you open up the auto flasher you'll find a relay inside and associated moving parts to wear out. A Mosfet-powered wigwag controller suffers no such wear.
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  #16  
Old 03-08-2014, 06:06 AM
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Glas467 Glas467 is offline
 
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Now this is homebuilding at its finest!
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  #17  
Old 03-20-2021, 01:52 AM
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DrillBit DrillBit is offline
 
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Missing pictures restored in the attached pdf (with reworked text to go with the pdf, page by page...). Click on the thumbnail at the bottom and the pdf should open or be downloaded or something....

Page 1 of the pdf shows the external wiring. Switch inputs J1 and J3, when grounded, each turn on a power MOSFET, providing current to the Taxi and Landing lights, respectively. Just one or both lights can be on at the same time. However, grounding the wig-wag input, J2, always causes the lights to flash alternately regardless of the state of J1 and J3.

I lost the drawing of the 4 x 2.3" board I originally posted. Pages 2 and 3 show the top of and bottom of an unpopulated solder-masked and silk-screened board. Page 4 is a (mostly populated) "bare bones" prototype (no mask or silk screen), showing the input and output 0.25" Faston tabs (J1-J8) along the left and right sides and the blue trimpot R1 which sets wig-wag timing. At mid-range, wig alternates with wag over a ~2 second period (i.e, 1 second on-time, each side). I ran out of Faston sockets for the ATC fuses when I stuffed the pretty green board that's in the plane: so I de-soldered the FS2 and FS4 sockets from the proto board.

I mounted the board on the subpanel with aluminum standoffs at the the four large dia vias in the corners of the board. The vias contact the ground planes on both sides of the board, so those ground planes are connected to the airframe through the standoffs. I bent up an Alclad cover to go over the top of the board (also grounded), in case something tried to fall on and short the topside components one day. However, the cover doesn't completely enclose the board; the ends are basically left wide open to give access to the Faston tabs.

Whether not any of the lights are steady on or completely off, the wig-wag oscillator runs when power is applied to the board, and the sharp edges of the CMOS square waveforms could cause EMI. I generally flip on the wig-wag before engine start and turn it off after shutdown. In flight so far, there's been no hint of noise in the radio or intercom as the wig changes to wag and back again. If I listen very carefully, there seems to be something barely audible coming through after the engine stops until I get the Hobbs and Tach time from the Dynon EMS and open the master contactor.
As always, YMMV.

The circuit schematic is shown in the pdf, page 5. Maybe a little easier to read than the 800 pxl wide picture in the original thread.

Click image for larger version

Name:	LandTaxiWigWag.pdf
Views:	52
Size:	3.64 MB
ID:	9503
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Kurt Haller
P-town, CA (10 min from KLVK!)
N748PK, RV-9A
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VAF dues last paid 30 Dec 2020

Last edited by DrillBit : 03-20-2021 at 01:54 AM. Reason: Added reminder to click on the pdf thumbnail
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