A Practical question about MPH, KPH, and knots

Wow it took three pages to get the correct answer! :)

We nearly got there on page 2.

Wow it took three pages to get the correct answer! :)

 

We nearly got there on page 2.

I think the correct answer was given on first posts :p

What would be the "correct" answer according to you? Just curious

Ugh, the imperial system! Why do they even teach this outdated measurement system in schools anymore? Most of the world has switched to the metric system, engineering and scientific measurement standards have switched to the metric system decades ago and it is so much simpler to keep everything in your head.

With that said I find that I have little trouble going from one system to another, I am able to think in both. I blame DCS. Still the metric system is the future and the imperial system needs to die.

 

So friggin strange!!! Knots per what???????????? Who made up that system anyway??

Etymologically, the term derives from counting the number of knots in the line that unspooled from the reel of a chip log in a specific time.

https://en.wikipedia.org/wiki/Knot_(unit)

Ugh, the imperial system! Why do they even teach this outdated measurement system in schools anymore? Most of the world has switched to the metric system, engineering and scientific measurement standards have switched to the metric system decades ago and it is so much simpler to keep everything in your head.

 

With that said I find that I have little trouble going from one system to another, I am able to think in both. I blame DCS. Still the metric system is the future and the imperial system needs to die.

I +1 this !

I'm workin with datacenter and there is 1 unit that is the most laughable in all :

BTU/hr (British Termal Unit) which is the heat absorbed by a cooling system for example

1 BTU is the amount of work (heat) needed to raise the temperature of one cubic foot of water (eq 1 pound of water) of 1 °F

-> not a sigle metric unit in that so totally not understandable for 99% of the world population :D

There are some great advice and info in that thread! Thanks guys!

A few weeks ago I created a quick conversion reference for my tablet:

It's based on a multi-layered Photoshop/Illustrator file and I'm supposed to edit specific overlays for specific aircraft highlighting some values (like the blades salad for the Ka-50 :music_whistling:).

So it's not supposed to be that black and white boring scales, but use it if you like.

Like some of you said, I also tend to fly with the parameters I need to be comfortable with, depending on the aircraft, regardless of the system.

I just know the more familiar your are with a system, the less you need to compare it to another one. Eventually, it just feels natural. Even if I prefer my altitude in metres :D

Well here's a practical application: When Iranian Tomcats are to escort Russian Sukhois through their territory, at least one side needs to convert altitudes and speeds, or the rendezvous is going to get a little more interesting than pilots normally like. :D

Of course we have the same in DCS, for instance when MiG-21s fly top-cover for A-10Cs and they need to communicate speeds and altitudes.

But most of our day to day business is just sticking to the system of the aircraft we're in, and that, as previously said, is just a matter of practice and getting used to it.

For the most tedious calculations you can make yourself a crude computer like this one:

http://ben.com/flying/e6b/

I used one in the past that I lost but I confirm it's super useful.

One nautical mile = 1 minute of longitude at the equator. Very useful for navigation.

 

Knot is used two different ways. One is as a measure of distance. The other as a measure of speed. Usually the context makes it clear which is being used.

 

1 Knot = 1 nautical mile

1 Knot = 1 nautical mile per hour

Knots and nautical miles are much more "logical" than mph (1 nm is the lenght of 1 minute of arc (1/60 of degree) in longitude - so it is 21600 nm to go all around earth at the equator (360° so 360x60 minutes, so 21600 nm).

Although you two stand more or less correct, wouldn't it be easier to state that one nautical mile equals to one latitude minute - regardless to the equator?

Also I don't see why you should be converting anything as per cockpit either. Memorizing the F-15's corner speed will do you no good in an A-10 - although both using the same units for speed.

I get the idea if your team is flying both eastern and western aircraft - no shortcuts there, rules of thumb come in handy in that case...

Although you two stand more or less correct, wouldn't it be easier to state that one nautical mile equals to one latitude minute - regardless to the equator?

Because it was originally defined as stated, and the earth is an oblate spheroid -- the circumference is longer around the equator than around any meridian. :)

I +1 this !

I'm workin with datacenter and there is 1 unit that is the most laughable in all :

BTU/hr (British Termal Unit) which is the heat absorbed by a cooling system for example

 

1 BTU is the amount of work (heat) needed to raise the temperature of one cubic foot of water (eq 1 pound of water) of 1 °F

-> not a sigle metric unit in that so totally not understandable for 99% of the world population :D

Would have to argue about the BTU. It's pretty well known by all who "need to know".

And in current predicament (ice storm resulting in no electricity) I have a large container of BTU's just outside my house, but no electrical means of transferring it to interior of house.

So there can be times when BTU's are extremely important and not laughable at all. :cry::)

For the most tedious calculations you can make yourself a crude computer like this one:

http://ben.com/flying/e6b/

 

I used one in the past that I lost but I confirm it's super useful.

Excellente! :thumbup:

I made myself a very rough cheat sheet for that purpose (for speeds only though). Especially when you want to know how that units converts to what time you will roughly need to get somewhere.

You can find it in my signature.

But to be honest: For many purposes it is sufficient to just know the numbers for your aircraft, regardless of the unit they are displayed in. :)