A Practical question about MPH, KPH, and knots

[Zimmerdylan]

I am just a casual DCS user. I do not spend hours every day learning everything there is to know about the inner workings of planes, and I just don't have tons of time to learn a lot of this stuff.

I have most of the modules, and as all of you are well aware, some measure in Metric, some nautical, and some in Imperial.

Honestly (may sound dumb) I find having to go back and forth between all 3 to be confusing and frankly, pretty hard. I have been using the imperial standard for most of my life and the only time I ever use metric is when I'm fixing my car or something.

I was wondering, do most people just learn all of the specs for each plane without converting in their heads? Otherwise, the ME 109 lands (according to the German pilots interview) at 200 KPH. I have a tendency to try and convert that to MPH in order to effectively fly. When I'm trying to dogfight in a Mig, or other plane that uses knots or Kilometers, my brain just seems to try and relate it all back to Imperial.

Is this a common problem? DO Europeans go through this trying to go from a metric plane to an imperial plane or is this just me?

What is the most effective way to deal with the different units of measure.

Altitude is the big one for me. I have no clue what my altitude is in metric planes unless I use the external view in the sim. And the KNots conversion is beyond me.

I do have conversion charts taped up but there must be a better way. I suppose that just learning the 3 would be the most effective thing to do.......:smartass:

 

Oh...and in the MI8. I love to fly it bit I am completely clueless as to my alt, or air speed in it. I know that when it's at 0, I'm hovering (LOL), and I just determine my alt by looking out the window. Although I can fly and land it just fine, I really would like to know how fast and how high I am.

Edited November 24, 2015 by Zimmerdylan

[AussieFX]

Roughly 3.3 feet to a metre.

 

1000m (1km) ~3300 feet or so.

3000m is close to 10,000ft.

 

1.6 km/h is 1 mph.

1.604 to be exact.

 

A rough rule of thumb.

Edited November 24, 2015 by AussieFX
added speeds

[Sporg]

For the single modules: I usually learn the take off, gear, flaps and landing speeds in the unit used for the module.

 

If you want it easy, make a quick list of these on a piece of paper.

Before long you will roughly remember them.

 

My quick calculations are like this:

 

m to feet: divide by three and add a little.

 

Km/h to MPH: Multiply with 1.5 and add a little.

 

Knots to MPH is apparently to multiply with 1.15.

 

But since I'm European, and used to km/h, I use this:

Knots to km/h: multiply with 2 and subtract a little.

 

It's not exact, but easier to calculate on the fly, and will usually do. :)

 

But usually I just use the units for the module.

[Sryan]

I just use the numbers that work for that particular plane. If I need to dial in 150 for takeoff and about 140 for landing then I'll do just that. If I really want to know my altitude or speed in metric. I just hit F2, on the bottom you'll see your readouts in the system you set in options.

[NeilWillis]

I use the rule of thumb, and make a rough calculation in my head to convert one unit of measurement into a known one.

 

I do however also get accustomed to different units in different airframes by remembering key values - for example the 200 kph required to land the Bf-109.

 

A combination of the two will allow you to fly and fight effectively.

[Ironhand]

...I just don't have tons of time to learn a lot of this stuff...and as all of you are well aware, some measure in Metric, some nautical, and some in Imperial...

 

Honestly (may sound dumb) I find having to go back and forth between all 3 to be confusing and frankly, pretty hard...

 

I have a tendency to try and convert that to MPH in order to effectively fly...

 

What is the most effective way to deal with the different units of measure...

 

I do have conversion charts taped up but there must be a better way...

Make it easy on yourself. Just stay in the cockpit using the measurement system the cockpit uses. The only "chart" you'll need is one listing take off, landing, and stall speeds in the measurement system for the aircraft.

 

How high are you? How high are you supposed to be? If you are supposed to be at 5000 meters, that's where you need to fly. It doesn't matter that 5000 meters is 16404 feet.

 

If your stall speed is 270 km/hr, stay above that airspeed. Preferably well above it. If you should land at 145 knots, land at 145 knots. It doesn't matter what it is in MPH (166.86) or KPH (268.54).

 

Just stay in the cockpit. Your brain will thank you for it. :)

[Zimmerdylan]

Why is the F86's speed measured in knots of all things?? I'm not sure that I understand the whole knot measuring system any way.

 

[ame]

[/ame]

 

 

 

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

Edited November 24, 2015 by Zimmerdylan

[cichlidfan]

The key is to play submarine sims for a while. You either get it sorted or you end up dead an awful lot. :D

[Ironhand]

Why is the F86's speed measured in knots of all things?? I'm not sure that I understand the whole knot measuring system any way...

 

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

Sailors. 1 knot equal 1 nautical mile per hour. :)

[flanker0ne]

The key is to play submarine sims for a while. You either get it sorted or you end up dead an awful lot. :D

 

I agree, for some extent the submarine simulators, with theyr slowliness, are the "crawl" part of your geographics Situational Awarness.

[cichlidfan]

I agree, for some extent the submarine simulators, with theyr slowliness, are the "crawl" part of your geographics Situational Awarness.

 

Using yards/meters for ranging while working with speed and larger distances in nautical miles helps you get used to the translations. Charting helps visualize things as well.

[Corbett1403]

A lot of aviation terms are from sailing and the Navy

[ajax]

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

Edited November 24, 2015 by ajax

[Corrigan]

I've never seen knots used as a measure of distance. In either case, I don't think anyone would advise it.

[Stonehouse]

I think with 1.5 you can turn on the external screen info bar when in the cockpit view?? Seem to recall seeing an option for it anyway so people like the OP will be able to do that and not have to worry anymore.

[Mike5560]

Why is the F86's speed measured in knots of all things?? I'm not sure that I understand the whole knot measuring system any way.

 

Knots are the most common imperial unit of measure for airspeed. I believe all current US military aircraft use knots as well.

[ajax]

I've never seen knots used as a measure of distance. In either case, I don't think anyone would advise it.

 

I don't think it is advised either. However, it is used (albeit incorrectly) as a unit of distance:

 

It goes on to provide the following definition:… 1 knot = 1 nautical mile/hour = 1.852 km/h exactly. This is based on the internationally agreed length of the nautical mile… …Knot is sometimes mistakenly used to refer to the nautical mile itself, but this is incorrect…

 

https://blog.globalair.com/post/Origins-of-Knot-and-Nautical-Mile.aspx

[Yurgon]

+1 for the "measurement of cockpit" faction. :)

 

As a European, I was first confronted with imperial units at the time of my very first flight, erm, games, like F/A-18 Interceptor. Didn't know what it meant, but I developed a gut feeling for knots and feet. It wasn't until years later that I learned how to convert between metric and imperial.

 

Strangely enough, I currently find it easier to think of altitude in feet, rather than in meters, although I'll gladly argue anyone to death as to the superiority of the metric system. :D

 

It's all just a matter of getting used to it, and to a lesser degree a matter of converting units from one system to another.

 

Finally, there are a few rule of thumb measurements I've mostly learned by dying a lot. :)

• 300 kph in the Ka-50 is thiiiiiis close to rotor blade salad
  
• 140 kts is waaay to slow for level flight in the A-10C
  
• 200 kts is my lowest break-off-attack speed in the F-86
  
• 700 kph in the Fw-190 is so fast, it's almost the speed of light (and since nothing can be faster than the speed of light, that's why the aircraft will break apart if you fly any faster)
  
• Mach 1.2 is just getting warmed up in the MiG-21
  
• 120 kts is really too fast for the Huey
  
• 220 to 250 kph is my slowest speed to start a looping in the Black Shark (unless I also fly well above 500 m AGL to compensate for the altitude loss)
  
• 30 m AGL just barely qualifies as NOE in the Ka-50
  
• 100 ft AGL is pretty damn low in the F-16C (back in Falcon 4.0)
  

 

So, as I said, all just a matter of getting used to it. ;)

[PiedDroit]

+1 for the "measurement of cockpit" faction. :)

Same here, it's more immersive IMO. Since all speeds are given in cockpit units, it's better to use them.

Good for the brain too, it stimulates it and improves plasticity :D

[cichlidfan]

Good for the brain too, it stimulates it and improves plasticity :D

 

Very important if you want to keep simming well into your golden years. There are lots of things that we need to remember not to forget! :D

[jweisner]

The device that sailors used to make their speed measurement was called the "chip log." Chip as in chip of wood, and log as in to record in a log. The chip was a wedge of wood about 18" in size; it was tied to one end of a rope on a large spool. The rope had knots tied into it about every 47'3" (more about how that was calibrated below).

 

The wooden chip was thrown overboard at the ship's stern (back end). Because of its wedge shape, it would "grab" the water and start pulling out rope as the ship moved forward at some yet unknown speed. One man would hold the spool of rope as it played out; another man would start a sandglass filled with 30 seconds of sand; and a third man would count the knots as they passed over the stern board. When the 30 seconds of sand expired, the time keeper would call out and the counting of knots would stop.

 

The faster the ship was sailing, more knots and a longer length of rope were played out. The number of knots in the rope that were counted in 30 seconds, then, was equal to the speed of the ship in nautical miles per hour. A "knot", therefore, is not a nautical mile, it is a nautical mile per hour. Thus 1 knot was equivalent to 1 nautical mile per hour; 5 knots were equivalent to 5 nautical miles per hour; etc. The similar sound of "knot" and "naut" is entirely coincidental.

 

If you think this is hilarious, you should look up what the other imperial measurements are based on.

[BRAVO_16]

Fibonacci is your friend.

[Bucic]

If you think this is hilarious, you should look up what the other imperial measurements are based on.

Yeah. I think only the progress of adoption of new IT technologies makes me feel more ashamed :)

 

On the subject, any good flight manual should include unit conversion charts. That is, graphical representation of the relationship between concerned units. Try looking it up.

Edited November 25, 2015 by Bucic

[bzhnono]

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).

[Capn kamikaze]

^ that is why we use it in navigation, which is obviously why it is such a common thing in aviation as the same rules apply as naval navigation.

 

Thanks for posting that bzhnono.