Device: Xiaomi Poco F3
Operating system: Android11
In solo flight, I set head wind 5knt, but AS and GS is same as 136knt
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Yeah, as right now they have fixed the incorrect airspeed in the update 22.5, for short final speed on solo mode. Hopefully, this is fixed next.
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Speaking without testing first (which is almost always a bad thing for me to do), the first thing I wonder is if this is a coincidence. I can’t see what temperature setting you have. And temperature has a direct effect on IAS. It is possible that for the particular wind speed you put in, that a temperature deviation has erased its effect on IAS (taking into account you are quite close to sea level alt). I’ll try this a bit later.
I assume you have the wind direction set to point opposite your flight path(?)
I have tested it myself, and the ground speed doesn’t seem to change. Normally the ground speed should be the indicated airspeed - wind velocity. Since 5 knots of headwind were added.
The ground speed should be your true airspeed - wind speed, as true airspeed and indicated airspeed can differ greatly. Unfortunately I don’t think there’s an option to display your true airspeed in game.
I just tested it several times and it seems ok. I get the ground speed being the proper difference between IAS and wind speed.
Also the thing I said about temperature, I tried that too, moving it all the way right. It causes some of the gap to be closed but not all of it. So the possible effect of temp change seems to be less than what I said.
(edit: ah!, I was using 25knts which is hard to erase the effect with temp; but 5knts is possible I think)
I’m not sure why we are seeing different results. (edit: I agree with @SuperJet115 's and @Mathurin_Garcier 's comments)
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Actually no… It depends also on altitude of the airport and temperature
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Yeah, trying at sea level, temp is the only thing that affects density altitude (in the sim I think). I’m back to thinking the error (between IAS and TAS) that is being noticed is either actual altitude or temp or a combination of both. (edit: sorry this is redundant, already pointed out)
And the error will be less noticeable the stronger the wind. 5knts is a small enough number to get erased by density altitude conditions.
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Ground speed is how fast your moving over the ground… it HAS nothing to do with the wind speed. I’m not super familiar with the formula but I believe ground speed is calculated by airspeed and temperature. But I’m pretty sure I’m wrong.
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Honestly, I just am not bothered enough to care about ground speed as long as my glide slope is fine, although this really does need to be fixed, good catch since I’d never notice lol
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Wind speed plays a part in ground speed. For example, if your true airspeed was 400 and you had a 100 knot headwind then your ground speed would be 300. On the flip, if you had a 100 knot tailwind then your ground speed would be 500. That’s why it’s important to use the winds aloft when doing your flight plan, because wind will change your ground speed which changes the time in route which changes the amount of fuel you will need.
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Just to be clear, it appears there is nothing to be fixed.
There is a clear relationship between GS, wind speed, TAS and IAS which appears to be operating correctly from flight testing under various conditions.
Groundspeed is The speed of an aircraft relative to the surface of the earth. Groundspeed is effective by the surface wind. If winds are 270 @65 at FL340 and you were going west, you’d have a headwind which means your ground speed would be lower… however if you were going East at FL340 with the winds 270@65 you would have a tailwind which means your groundspeed would be higher
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In my response to @Superdogs I failed to explicitly tie the OP’s particular case to the theory.
I was using the wrong standard temperature.
You can ignore altitude because you are basically at sea level altitude (671MSL). But your screen shot doesn’t show temperature.
Temperature is the missing information.
Standard temperature is 15C. In solo mode, at your sea level altitude, if you set your temperature slider to 15C, you should see the proper difference of your headwind between IAS and GS (I verified this).
This is because at sea level altitude and “standard” temperature of 15C, IAS is the same as TAS.
You are apparently flying with a temperature high enough above 15C to make IAS the same as GS (but internal calculations for TAS would still be correct).
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Nice to know, and also yeah this just proves I don’t notice that stuff
Just in case this can help, I have done the following calculator. It helped me understand those speed issues :
Pretty odd, indicated airspeed and ground speed are almost always different, especially with a headwind.
Groundspeed and true airspeed are not the same. Here’s how the whole thing goes.
Indicated airspeed is what you read straight from the airspeed display. When indicated airspeed is corrected for instrument errors, which is a thing for GA airplanes mostly, you get Calibrated airspeed. When you correct calibrated airspeed for nonstandard pressure and temperature you get true airspeed. And when you correct true airspeed for winds, you have your groundspeed. Hope that helps!
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Very interesting, didn’t even cross my mind.
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Yes, you are right, I should have said true airspeed corrected for wind speed rather than TAS minus wind speed.