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Speed of light

Postby expat » Thu Sep 13, 2007 4:55 am

I was asked a question the other day and I had no answer to it and now I am rather curious as to the answer.
The question was: Runway approach lights have a central light that "runs" towards the runway. I am talking about the strobe(s) light(s) that are in the last 100 meters or so of lighting. What is the speed of the strobe effect. Or to put it in a simple form, if you could drive your car down the length of travel of these landing lamps, what speed would you have to travel at to get the light to effectively sit at your shoulder, thus giving you a speed read out of the switching on/off of each lamp.

Matt
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1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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Re: Speed of light

Postby Fozzer » Thu Sep 13, 2007 5:02 am

...let's give it a try Matt...!

You in your Volkswagen 1500 Beetle, and me on my Honda Fireblade Super-bike.

See who can keep up with the strobe lights, and register the speed...;)...!

Another first for "Top Gear"... ::)...!

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Re: Speed of light

Postby Brett_Henderson » Thu Sep 13, 2007 6:24 am

That's an interesting question. I wonder if it's a specific speed, or just kinda random... My first instinct is that it's not the same at every runway. If I ever find out, I'll be back with the answer  8-)
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Re: Speed of light

Postby expat » Thu Sep 13, 2007 7:53 am

...let's give it a try Matt...!

You in your Volkswagen 1500 Beetle, and me on my Honda Fireblade Super-bike.

See who can keep up with the strobe lights, and register the speed...;)...!

Another first for "Top Gear"... ::)...!

F....Red....Amber...Green....Go!.... 8-)...!



Whilst I have no doubt that your Fireblade will beat me at the lights, I would like to point out that I am a bit quicker than a 1500 Beetle ;)

Matt




                                             
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"A bit of a pickle" - British translation: A catastrophically bad situation with potentially fatal consequences.

PETA Image People Eating Tasty Animals.

B1 (Cat C) licenced engineer, Boeing 737NG 600/700/800/900 Airbus A318/19/20/21 and Dash8 Q-400
1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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Re: Speed of light

Postby Fozzer » Thu Sep 13, 2007 8:11 am

Nothing can compare the speed of light between the last mouthful of Patak's Chicken Madras Curry, and the nearest Toilet facility.... :-[...!

The speed of flashing Runway ILS lights fades into insignificance

...trust me... ::)...!

F....;)...!
Last edited by Fozzer on Thu Sep 13, 2007 8:16 am, edited 1 time in total.
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Re: Speed of light

Postby expat » Thu Sep 13, 2007 8:30 am

Nothing can compare the speed of light between the last mouthful of Patak's Chicken Madras Curry, and the nearest Toilet facility.... :-[...!

The speed of flashing Runway ILS lights fades into insignificance

...trust me... ::)...!

F....;)...!


Somewhat off topic, but a nothing can beat three or four pints of Weissen Bier and a Gyros Tellar (a sort of Kebab, but on a plate) for a good clear out.

Matt


PS I would still like to know about the lights.
"A bit of a pickle" - British translation: A catastrophically bad situation with potentially fatal consequences.

PETA Image People Eating Tasty Animals.

B1 (Cat C) licenced engineer, Boeing 737NG 600/700/800/900 Airbus A318/19/20/21 and Dash8 Q-400
1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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Re: Speed of light

Postby EGNX » Thu Sep 13, 2007 10:19 am

Well... by guestimating...

If the strip of strobe lights is 150m long, from what I have seen FS it takes roughly 1-2 seconds for the light sequence to repeat (Well it looks pretty quick but i'll use 1 for simplicity). So effectively the light is 'traveling' 150 m/sec or 9000 m/min or 540,000 m/hour. Converted into Km/h is 540 Km/h, which is roughly 330 Mph....

So sadly a Volkswagen 1500 Beetle nor Mr F's Honda Fireblade would quite be able to keep up with the lights in this example....

But who knows... each airport could have a different timing....  ::)
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Re: Speed of light

Postby expat » Thu Sep 13, 2007 10:30 am

Well... by guestimating...

If the strip of strobe lights is 150m long, from what I have seen FS it takes roughly 1-2 seconds for the light sequence to repeat (Well it looks pretty quick but i'll use 1 for simplicity). So effectively the light is 'traveling' 150 m/sec or 9000 m/min or 540,000 m/hour. Converted into Km/h is 540 Km/h, which is roughly 330 Mph....

So sadly a Volkswagen 1500 Beetle nor Mr F's Honda Fireblade would quite be able to keep up with the lights in this example....

But who knows... each airport could have a different timing....  ::)


Thanks for that. I will be in the jump seat of 737-700 tomorrow and a return in a 800 on Sunday 8-), maybe the big man knows the answer.

Matt
"A bit of a pickle" - British translation: A catastrophically bad situation with potentially fatal consequences.

PETA Image People Eating Tasty Animals.

B1 (Cat C) licenced engineer, Boeing 737NG 600/700/800/900 Airbus A318/19/20/21 and Dash8 Q-400
1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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Re: Speed of light

Postby DaveSims » Sat Sep 15, 2007 6:57 am

I dug through all my "Running Airport for Dummies" information I have in my office with no luck.  Monday I will ask the FAA Airways guy next door.  He maintains the approach lighting.
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Re: Speed of light

Postby Felix/FFDS » Sat Sep 15, 2007 9:25 am

[quote]I dug through all my "Running Airport for Dummies" information I have in my office with no luck.
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Re: Speed of light

Postby DaveSims » Mon Sep 17, 2007 8:47 am

Ok, the verdict is in.  ;D  The lights move at 400 feet per second.  And that is the FAA standard for all airports.
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Re: Speed of light

Postby EGNX » Mon Sep 17, 2007 10:17 am

[quote]Ok, the verdict is in.
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Re: Speed of light

Postby expat » Mon Sep 17, 2007 10:51 am

Excellent job Davy. I had my doubts that we could get an answer to this one.
So Fozzer, looks like you would have to strap yourself to a Top Fuels dragster to keep up with it. The Fireblade just won't cut this one ;D

Many thanks.

Matt
Last edited by expat on Mon Sep 17, 2007 10:54 am, edited 1 time in total.
"A bit of a pickle" - British translation: A catastrophically bad situation with potentially fatal consequences.

PETA Image People Eating Tasty Animals.

B1 (Cat C) licenced engineer, Boeing 737NG 600/700/800/900 Airbus A318/19/20/21 and Dash8 Q-400
1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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