Hello everyone, I hope you are well, I have a question. I am fond of aviation but I don’t understand something in the simulator.
When I take trips I see that the limited cruising speed is 290kts but in real life it is higher, my question is: isn’t there some way to go faster?
The limited speed is airspeed (which at higher altitudes is less because the air is less dense), and IRL you’re mostly seeing ground speed. If you look at the thing that says “GS” on the HUD you’ll notice it matches up a lot better with the speeds you’re used to aircraft flying.
Hi there! The limited cruising speeds are also aircraft and altitude dependent. What you are seeing as a 290kt limit is the indicated airspeed (ias). As you go higher this IAS on the left bar goes down due to lower air density as @AndrewWu mentioned above. However, ground speed would be much higher given you are not facing 100+ headwinds. Hope this helps!
long story short:
3 types of speeds regarding airplanes in infinite flight:
IAS (indicated airspeed)
TAS (true airspeed–only in airplanes with live cockpits will this be displayed)
GS (ground speed)
----all speed units are knots (kts: nautical mile per hour)
IAS is dependent on air pressure (plane gets IAS from pitot tube ↔ static port measurement comparison. thus, the less dense (or thinner) the surrounding air pressure, the lower the IAS. air is thin at 30,000 ft +
TAS is the speed you’re actually moving through the surrounding air, literally. If you’re moving at 100 kts through the air, your TAS is 100kts, whether at ground level or 30,000 ft. Logically, this is not related to air pressure as it’s your real rate of movement.
GS: the speed at which you’re covering the ground beneath you. aka, the TAS with consideration of any wind component. So if your TAS is 100kts, but there’s a 50kts direct headwind component, your ground speed would end up being 50 kts. But lets say the wind is blowing 50 kts in your direction of travel, your GS is 150 kts as you’re getting a 50 kt “push”.
this should help explain why it looks like the limit is 290 kts as you approach cruising altitude. 290 is the IAS, but take a look at your GS. that should make you feel better about your overall flight’s speed. Peep the ‘mach’ number as well (ratio compared to speed of sound → mach .78 means 78% the speed of sound), that’s your IAS but at high altitudes it’s more sensible than kts IAS. for air compression reasons. no need to worry about that concept too much tho.
Hey @David_Queliz - Welcome to the Community!
Have a read of this community tutorial:
Have a great day - merry Christmas and a Happy New Year!
Hello, thanks for the explanation :-),
Hello, thanks for the explanation :-),
Hello, thanks for the explanation. I ask this because I have seen aircraft twice that go faster and are not fighter jets. If I see it again I will send proof.
Merry Christmas and New Year :-)
Hello, sorry for the inconvenience, look what I was telling you about my speed and that of other aircraft. How come they go faster and I can’t go that fast?
Well couple things I notice here, but I get where you’re coming from. First, 320 IAS @ FL300 is pretty standard, which is fine. May I ask what aircraft this was? Second, you may have been flying into a headwind while the aircraft you pointed out was flying with a tailwind. I can’t tell from the images.
Try this: fly from Haneda/Narita heading to Honolulu. There are strong tailwinds there. Maybe use a 777 or some other long-hauler. Climb to FL350 and attain the highest IAS as possible without the violation buzzer going off. Then check your groundspeed. Maybe this will help you out with the gist of the speed differences. Hope this helps!
Oh, and in the second image, the speed indicated for the user “Hamedo21” is their groundspeed, not airspeed (which is indicated in your flight data config bar).
oooh thanks I didn’t know that about the wind issue in the game thank you very much, you already answered my question
Hi David_Queliz, and Welcome to the community!
You originally wrote:
And your most recent upload was:
IAS (indicated airspeed) is the 290kts. That is the “pressure speed”. It’s the speed your wings, flaps and fuselage “feel” from the air being thinner as you go higher (air molecules can be going past you much faster, but there are less of them, so the speed feels lower: there’s less impact force on the aircraft so it behaves like it’s actually travelling at that lower speed).
IAS is on your vertical speed strip on the left of the screen.
Your actual speed through the air gets much higher than IAS as you move increasingly into thinner air, and that’s what the 457kts comes from.
TAS (true airspeed) is your actual speed through the air. So, this is almost always a higher speed (often much higher), and is not affected by a steady wind speed (even if the wind could be 1000mph, TAS would be unaffected).
TAS is how fast the air molecules are actually moving past your aircraft (or how fast you are moving past the air molecules).
GS (ground speed) is TAS after adjusting for wind speed. So, both GS and TAS will often be much higher than IAS simply because you are flying high up in thin air (a 150 kts tail wind makes your ground speed that much higher).
From your other screen print:
That big difference is almost all due to the thin air effect up at 26,900ft.
Notice we can’t tell directly from this how much the wind speed is making GS different from TAS.
Elsewhere, of course, you can check the windspeed that your own aircraft encounters (4kt tail wind here with GS 0 on the ground, of course):
(btw: mach speed as in 0.87 in your image, is TAS as a decimal fraction of the speed of sound. So that aircraft was travelling at 87% of the speed of sound in terms of how fast the air molecules are actually moving past your aircraft, even though the pressure speed, or IAS, is much lower than the speed of sound.
Since mach is a measure of TAS, it also does not change with wind speed.)
They are also going at basically the max speed possible - which is considerably above the recommended climb/cruise speed.
I’m guessing max speed might be 15% different from best economical cruise speed.
But TAS (GS with no wind) might be 100% more than IAS at high cruise altitude.
In one you look at Airspeed, in the other you look at Ground Speed
Which airspeed though is the main issue.
IAS vs TAS is the main cause of the substantial difference and those are both airspeeds.
For example, if you don’t specify it’s not TAS when talking about Airspeed, TAS will be mostly the same as GS if winds are not too much (independent of altitude).
thank you bro :-)
