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  #31  
Old 01-09-2018, 03:18 PM
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RVbySDI RVbySDI is offline
 
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Originally Posted by BMW_X6M View Post
OK, but when you report your distance from an airport on the radio, it should be in nautical miles!
Yep, do that, but, now we are talking about distance, not speed.
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  #32  
Old 01-09-2018, 03:58 PM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by BMW_X6M View Post
OK, but when you report your distance from an airport on the radio, it should be in nautical miles!
Because the difference of 3/4 sm between 5 nm and 5 sm is significant and could be the difference between life and death.

Should I make my call before or after the GPS tells me I'm 5 out. What if I'm not using a GPS and I'm guestimatting my distance? Should I include my confidence level in my estimate?

Heck, if the pilot gets his/her direction from the airport and gives the aircraft type and intentions rather than, "N123 over the firestation, inbound", I'm happy.
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Last edited by N941WR : 01-09-2018 at 04:02 PM.
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  #33  
Old 01-09-2018, 04:42 PM
BMW_X6M BMW_X6M is offline
 
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The wind is also reported in Knots.
Knots, or nautical miles per hour have long been the standard units of velocity for both nautical and aeronautical navigation.
Knots are used almost universally for marine and aviation navigation because a nautical mile relates directly to mapping of the earth. A nautical mile is equal to 1 minute of latitude making it very easy to use Knots for speed and nautical miles for distance when already the earth's mapping uses degrees and minutes of latitude. Each degree of latitude is equal to 60 minutes of latitude.
To each his own, even if its ...
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  #34  
Old 01-09-2018, 05:49 PM
Bevan Bevan is offline
 
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Quote:
Originally Posted by RVbySDI View Post
I cannot answer for anyone else but me. As for me, every other speed measurement in all other aspects of my life are measured in MPH. Every non-aviator who I talk with about flying asks me how fast my plane flies. I tell them I cruise around 150 knots. They answer with: "How fast is that?" Telling them in MPH bypasses that drawn out conversation.

Besides, knots are for boats and boy scouts!


Not true. It's all about standards. If it wasn't for standards when you fly into Canada, you would have to think and have your instrumentation converted to metric. Fortunately Canada uses the international standard for aviation units (as should the US).

Beside's there's only 15% difference between knots and MPH so your friend will only be 15% less impressed with knots. In Canada ground based vehicle speed is measured in Km/h (kilometers per hour). If a Canadian friend wants to know how fast 150 kts is, you first have to determine who your audience is. If they're younger than mid 40's , they will likely only understand Km/h (but will be VERY impressed), the older ones will likely know both. This is because we changed from Imperial to metric in the mid 70's (except not in aviation where the international standard prevails). I find it better to teach someone what knots are, and then carry on. It's called education.

1kt = 1.15mile (or 15% more, easy math)
1kt = 1.85Km (or almost double, easy math)

Bevan
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  #35  
Old 01-09-2018, 06:31 PM
rightrudder rightrudder is offline
 
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I like to have both....indicated and true airspeed in knots on the EFIS, and ground speed in mph on the backup GPS.

It's fun to tell passengers how fast we're going over the ground in units they're used to, without having to do the math.
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  #36  
Old 01-09-2018, 08:40 PM
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Once you fly the big stuff Knots is everything. If you want to impress a non aviation person about speed KPH is the way to go, sounds more dramatic:-) As has been mentioned KTS is mostly universal world wide for the measurement of speed & has it's origins dating back to the sailing days where most of early aviation was taken from with ref to maps. Remember when flying machines where invented it was a new form of transport the early pioneers didn't know what to do other than adopt some rules of the sea.

Last edited by Capt : 01-09-2018 at 08:43 PM.
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  #37  
Old 01-09-2018, 09:06 PM
Bevan Bevan is offline
 
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Quote:
Originally Posted by Capt View Post
Once you fly the big stuff Knots is everything. If you want to impress a non aviation person about speed KPH is the way to go, sounds more dramatic:-) As has been mentioned KTS is mostly universal world wide for the measurement of speed & has it's origins dating back to the sailing days where most of early aviation was taken from with ref to maps. Remember when flying machines where invented it was a new form of transport the early pioneers didn't know what to do other than adopt some rules of the sea.
Exactly so how did it go from knots to MPH?

Bevan
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  #38  
Old 01-10-2018, 09:08 AM
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RVbySDI RVbySDI is offline
 
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Quote:
Originally Posted by Bevan View Post
Exactly so how did it go from knots to MPH?

Bevan
Actually it didn't. In fact it was the reverse. Early aviation speed measurements were in MPH. That is why the old planes had air speed in MPH. It wasn't until much later on the switch was made to nautical measurements as a standard.
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