Training: Speed

[Hornet]

As you all know, aircraft fly through the air at different speeds.  These speeds are read off the ASI (Air Speed Indicator).  It is usually read in Km/h, mph or Kts (Knots).  In WarThunder, unless you're in cockpit view, this is just a number at the top left of the screen.  Do you know what this number actually means? Did you know that there are two different types of readings for the speeds?

What this post is going to talk about is the meanings and usefulness it can be.  I'm sure some of you already know, and for those that ever read a FTGU (From the Ground Up) you know all there is to know.  Well for those who don't, read on.  This information is pretty important, it may also explain some effects that happens to your aircraft when flying.

This first thing we need to know is the speeds.  Simple enough, Km/h is Kilometers per hour.  As all of us are Canadian we probably already know this, and those of us with a drivers licence, well if you don't know, then please let me know so that we may apply to CWD on Discovery.  Now, mph is Miles per Hour.  The older generation of us, or those who have been in the States should be familiar with this measurement.  1 mph is equal to 1.61 Km/h.  Essentially Km/h is more accurate because there are higher numbers for the same speed that it would be in mph.  Kts is Knots or Nautical Miles, this was first used in ships to determine speeds.  Aviation in Canada uses Kts as its default speed.  Believe it or not Canada uses the imperial system (Kts for speed, ft for altitude, NM [Nautical Mile] for distance, ft/min for rate of climb, but Celsius for temperature, ...go figure) for aviation.  1 Kts is equal to 1.85 Km/h.  Ultimately which unit of measurement you choose to use is up to you.  If you're a diehard Canadian aviator, then Kts is probably your choice.

Now the second option for speed you can choose is IAS (Indicated Air Speed) or TAS (True Air Speed).  Now it's hard to explain these without going into mathematics, so I will simplify it.  IAS is the speed which is read off the ASI, it pretty much is the pressure the aircraft is experiencing.  TAS is the speed in which the aircraft is flying through the air.  So now you have a rough definition of the two, which one should be used?  Well, it depends what you are doing.  For WarThunder, IAS is my recommendation, here's why:

IAS speeds will always be the same for critical V (Velocity) speeds.  What I mean by this is, if you know your plane stalls out (stops flying and drops) at 150 km/h IAS near the ground, then up high it will stall at 150 km/h IAS, the exact same speed.  If the aircraft will experience 10 Gs at 650 km/h IAS when making a tight turn near the ground,  then the same will be for up high.  With TAS the number changes with multiple values.  Altitude, temperature, pressure, etc. Multiple variables effect the TAS.  So let's say your plane stalls out at 150 Km/h TAS, 50 ft over the ocean on the Hokkaido map.  Well it may be 200 Km/h on the same map at 20,000 ft (high up).  Or better yet, your plane may stall out at 150 km/h at 200 ft in Berlin Summer, but in Berlin Winter at the exact same spot it may stall out at 140 km/h.  TAS critical speeds will always change, but IAS speeds will never change.  If your planes wing rip off at 650 km/h IAS making a tight turn, it will always rip off at that speed in a tight turn no matter where you are.  With TAS it might be 700 Km/h one time, or it may be 630 Km/h another, you would have to constantly do math as you played different maps, changed altitude, etc.

So what's the point is TAS then if it's unreliable?  Well, in real life it's used for calculating time.  If you are travelling 800 Km, and your TAS is 400 Km/H, it will take 2 hours to reach your destination.  With 400 Km/h IAS it may take 1 hour, 45 minutes, or it may take 2 hours, 15 minutes.  Depends on many different factors.  So in simple terms IAS is best for aerobatics (fighting) and TAS is good for travelling (passenger planes or fuel burn calculations).  Seeing as WarThunder only really allows 25%, 50% 75% or 100% fuel load, you can't even properly load the correct amount of fuel even if you wanted to.  With such sort distances needing to travel in game, you don't even need to worry about fuel, unless you start leaking, at which point you are probably already heading back to the airfield.

To sum this all up.  Pick a unit a measurement you like, most of you will pick Km/h as it's what you're used to.  Some may use Kts, because it's what Canada uses for aviation, or have flown in real life.  Use IAS, because it is simply better, no math needed, just have to remember a few speed numbers for your plane.

Obviously, it is best if we all as a Squadron use the same measurements, so it's one less thing you have to worry about calculating when playing together.   Ultimately, it is up to the individual pilot.  Hopefully you have learned something off this post and will use the knowledge in your game.  I plan on releasing more information  on other topics at a later time.

Until then...

[Wolfram_42]

I like it ... good info everyone should have