Author Topic: I got bored....  (Read 1785 times)

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Offline rossw

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I got bored....
« on: April 22, 2012, 11:13:24 PM »
Was on a flight home the other night.
It was lousy weather. It was a small aircraft (Saab 340).
The hostess tried to pour drinks, but they were going everywhere, she gave up.
The aircraft was being tossed around the sky. I couldn't do any work, couldn't even read a book.
So here I am, looking out the window into the nothingness.
But it was interesting. There were all these horizontal white lines. Like snow on the old TVs.

Rain. Heavy rain. Being illuminated by the wingtip strobes. Quite beautiful.
So I started doing some mental maths....

Q. How long is the flash from the strobe??
I guessed a millisecond or so, based on nothing other than gut feeling.

But now I could actually estimate it moderately accurately!

We were flying at close to 600kmh.
Thats 10,000 metres per minute.  or 10000 / 60 = 1000/6 = 166 metres per second. Near enough.
The white stripes had a very bright leading edge (when the strobe obviously had maximum energy) and faded out and stopped about 250-300mm long.
166 is a horrible number, so if I said 150 metres/second (slightly slower), it would be 300m in 2 seconds, so 300mm in 2 milliseconds.

If we were going faster than 150m/s the strobe must have been slightly under 2ms duration (now that I have a calculator its actually about 1.8 milliseconds).

Given the approximate nature of the input figures (couldn't go measure the light streaks, didn't know for sure the actual aircraft speed) - but I bet they're pretty close.

How did your mental maths go?? :)

Offline shawn

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Re: I got bored....
« Reply #1 on: April 23, 2012, 01:27:14 AM »
That is just sad, I would just throw penuts or somthing at sombody, takes all kinds I guess.

Offline WooferHound

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Re: I got bored....
« Reply #2 on: April 23, 2012, 11:29:56 AM »
according to this PDF about aircraft strobes
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA030855
The duration runs from 175 usec to 410 usec
depending on brand and model
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Offline Rover

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Re: I got bored....
« Reply #3 on: April 24, 2012, 04:18:41 PM »
RossW,

Impressive.

Don't think I've ever been that bored :). If I have I'm sure I didn't tend towards math to alleviate the boredom (maybe not directly anyway)

Rover
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Offline MadScientist267

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Re: I got bored....
« Reply #4 on: April 24, 2012, 05:29:39 PM »
Wow, a 71 (ok technically 72, but the last one is missing...) page report on a blinky blinky light...

The government is fully involved. In everything. Everywhere.  ;D :o

Wonder what the manual for a typical aircraft bolt looks like... :)

Steve
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Offline ksouers

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Re: I got bored....
« Reply #5 on: April 24, 2012, 08:41:02 PM »
Wonder what the manual for a typical aircraft bolt looks like... :)

Steve

You couldn't lift it :)


Kevin
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Offline ghurd

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Re: I got bored....
« Reply #6 on: April 24, 2012, 09:25:30 PM »
Wonder what the manual for a typical aircraft bolt looks like... :)

Steve

You couldn't lift it :)


Kevin

Couldn't lift it at what frequency?
THAT is the real question as I see it.
 :P
G-