wardialer
Topic Author
Posts: 1141
Joined: Fri Sep 14, 2001 1:08 pm

Calculation Issues

Sun Jun 24, 2012 7:35 am

How can I convert distance in miles to speed in knots and then getting the total time to destination?
So for instance suppose my distance is 2000 miles and my ground speed will be 400 knots then how can I get my total time to destination?

The flight planning tool that I use does not have mph.
But the distance has both miles or nautical miles but I dont want to use nautical miles.

So how can I get the total time to destination by converting 2000 miles with my ground speed being in knots instead of in mph?



Please help. Thx
 
imiakhtar
Posts: 611
Joined: Sun Apr 02, 2006 3:35 am

RE: Calculation Issues

Sun Jun 24, 2012 7:56 am

1 knot = 1.15mph therefore 400 knots = 400 x 1.15 = 460mph
Time = Distance/Speed = 2000/460 = 4.35 hours (4 hours 21 minutes) to destination

http://en.wikipedia.org/wiki/Knot_(unit)
http://en.wikipedia.org/wiki/Speed
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Stealthz
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RE: Calculation Issues

Sun Jun 24, 2012 8:06 am

Quoting wardialer (Thread starter):
But the distance has both miles or nautical miles but I dont want to use nautical miles.

Why not, then your trip time would be a single calculation, rather than 2 if you convert to miles/hr first.
If your camera sends text messages, that could explain why your photos are rubbish!
 
wardialer
Topic Author
Posts: 1141
Joined: Fri Sep 14, 2001 1:08 pm

RE: Calculation Issues

Sun Jun 24, 2012 9:15 am

On these inflight navigation monitors like the airshow 4200 on each seats in modern aircraft the calculaions are in miles and mph but these are actually from the cockpit avionics which are in nautical miles and knots. So I wonder hoe do those get converted.
 
Stealthz
Posts: 5546
Joined: Wed Feb 02, 2005 11:43 am

RE: Calculation Issues

Sun Jun 24, 2012 9:23 am

The Airshow system makes this simple calculation...

Quoting imiakhtar (Reply 1):
1 knot = 1.15mph therefore 400 knots = 400 x 1.15 = 460mph
If your camera sends text messages, that could explain why your photos are rubbish!
 
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zeke
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RE: Calculation Issues

Sun Jun 24, 2012 10:56 am

Quoting stealthz (Reply 4):
The Airshow system makes this simple calculation...

I think it does the calculation for the distance, however I think the time to run is taken directly from the FMC as that takes into account the enroute winds. I have noticed when I change the runway and STAR, the airshow gets updated on the time to run.
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mandala499
Posts: 6458
Joined: Wed Aug 29, 2001 8:47 pm

RE: Calculation Issues

Mon Jun 25, 2012 4:13 am

Quoting wardialer (Thread starter):
The flight planning tool that I use does not have mph.
But the distance has both miles or nautical miles but I dont want to use nautical miles.

Live with it !   

Quoting wardialer (Thread starter):
So how can I get the total time to destination by converting 2000 miles with my ground speed being in knots instead of in mph?

Make it easier... convert 2000 miles to nautical miles, then you get the time to destination as the speed is in knots.
2000mi = 1739nm
1739/400 = 4.347 = 4H21mins. (same answer as the previous reply)...

Quoting wardialer (Reply 3):
On these inflight navigation monitors like the airshow 4200 on each seats in modern aircraft the calculations are in miles and mph but these are actually from the cockpit avionics which are in nautical miles and knots. So I wonder how do those get converted.

Simple, the processing computers for the inflight monitor system does the calculations from the nautical mikes, knots and feet to miles/mph/feet, and/or to kilometers/kph/meters... simple calculations really...
And most of these systems nowadays takes the position and time from the FMC... I think through the ARINC429 bus?

Mandala499
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