nuckollsr(at)cox.net
Guest
|
 Posted: Wed Nov 22, 2006 5:29 am Post subject: Wig-Wag Makes Strange Buzz (the rest of the story) |
 |
|
I didn't finish the thought in the paragraphs below -
so here's the rest of the story:
The principal of a pair alternately illuminated lights is
the same . . . generate a perception of motion.
Years ago when we started installing the incandescent
Aeroflash beacons on Cessnas, there was a lot of objection
to the flashing of panel lights when the SINGLE 12A bulb was
cycled on and off. Since our flasher modules would handle
two lamps, we tried on lamp on top of vertical fin and
the other on the bottom of the fuselage. THE IDEA WAS THAT
HAVING AT LEAST ONE LAMP LIT ALL THE TIME WOULD REDUCE THE
BUS VOLTAGE PERTURBATIONS AND STOP THE IRRITATING 'BEAT'
IN PANEL LIGHTING. THE FIX "WORKED". HOWEVER . . .
Vertical
separation was on the order of 10' so you had to be less
than a mile away before the alternately flashing lights
would be perceived to have vertical motion as opposed to
looking like a single, always lit lamp.
SO, INSTEAD OF TWO LAMPS TO PRESENT A CONSTANT LOAD TO
THE BUS, WE WENT TO ONE LAMP AND A FAT RESISTOR IN PLACE
OF THE SECOND LAMP. THE APPEARANCE OF 'FLASHING' AT
DISTANCE WAS RESTORED AND FLICKERING IN THE PANEL LIGHTS
WAS SURPRESSED.
So it isn't just the flash but a combination of things
most important of which is appearance of motion that makes
the wig-wag system work well. Got to study these issues in
detail back in my accident investigation and courtroom
presentations days.
Bob . . .
--
-- incoming mail is certified Virus Free.
Checked by AVG Anti-Virus.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
