Simviation Forums

see real speed,I mean when im fl35 It shows for ex:300 ias but is not the true speed,Im very aware that i can change that option is realism setting,In "true airspeed" but this is not the point,we can't do that in real life,can we?i mean does the GPS can't tell me the real speed?,how do pilots do? to know the real speed?Is there's a way?

It's been FOREVER since i've done it, but converting indicated airspeed to true airspeed involves computing indicating airspeed, temprature, and pressure altitude using the flightcomputer

By knowing our true airspeed, we can compute known winds into our flight computers to get our groundspeed and wind correction angle.

You could also use checkpoints and use time to get speed


As for the GPS, it shows your groundspeed

Easiest way I can think of in a VFR flight is to use the select airport thing and report your position to an uncontrolled airport, wait 1 minute and report it again. and put the numbers into the equation: V=D/t(min) then convert it into knots (nm/hr) 1knot= about 1.05. GPS should display your GS in the top right corner, and if you know how to use VOR fly directly at the VOR you have set as either NAV1 or NAV2 and it should give you your ground speed somewhere in the appropriate VOR gauge.

May I suggest reading Hal Stoen's articles to get a better understanding of airspeed.

The brute answer concerning airline pilots alrot is that, well, they really don't need to know what their true airspeed is going to be.  For them, GS is more important.

I hope I'm not patronizing you here, forgive me if I am, but make sure first that you have a firm understanding of the different types of airpseed and their uses (KIAS, KTAS, GS)

For airline pilots (jet), mach is what they fly by. Aside from staying under 250kias below 10,000 feet it's all about climbing to where indicated airspeed becomes a lessened, less accurate way to gauge speed. Ground speed is important, but only to the point of figuring an ETA. Winds aloft have a more to say about it than the pilot does.

Flying directly to a VOR/DME (or checking the GPS ground speed) can give you your TAS, but ony in zero wind.

Most GA airspeed indicators have a TAS converter built into them. Temporarily set your altimeter to 29.92. This will give you your pressure altitude. With that information and knowing the OAT, you can adjust the claculation ring on the

[quote]The brute answer concerning airline pilots alrot is that, well, they really don't need to know what their true airspeed is going to be.

Midnight, I'm refering to cruise in a large plane.  In cruise flight, GS is the most important because ETA IS the most important to airline pilots.

Of COURSE KIAS is important in low speed situations.  However. at cruise, the FMC will give you the wind.  Jet pilots do not look to their IAS for the winds-they do keep a very, very close eye on GS.

I have more than 10 hours of RL xcountry time in a 172, so you're preaching to the choir here-although I must say in RL we don't really look the the KIAS for the wind speed either, but we could I suppose (we're more concerned with wind direction when in cruise, we get the speed from FSS and at the airport we have ASOS, AWOS and ATIS to give us the speed, no need to figure it out based on KIAS v. GS)

Now why would some flights going to Europe be faster and doesn't use much fuel as the returning flights to the USA?
That's because the jetstream flows from the west to the east!

Now you're really preaching to the choir-I could tell you the general winds aloft situations of every region of the US (600+ hrs logged commops in FS, and believe me I pay attention to winds in the flightplanning)  GS is STILL more important in these situations, KIAS is too unreliable at that altitude-GS gives it to you straight.  For example-

Flight plans will have the speeds from checkpoint-to-checkpoint in GS, not KIAS.  So if you want to get a rough estimate as to your timing, all you need to do is compare your current GS with that of which you planned your ETA with.  If, at 475 kts GS it was going to take me 16 minutes to get somehwere, and I'm doing 450 kts, I know I'm going to be a little late.

A jet pilot does two things when he enters class "A" airspace...

Set the altimeter to 29.92 and fly the plane by MACH ..

He can monitor GS till he's blue in the face. Not much other than requesting a different altitude can be done about it.  No changing the winds aloft  from the left seat.

[quote]Midnight, I'm refering to cruise in a large plane.

Of COURSE wind is important in a small airplane (any airplane for that matter)... however I do not determine wind by referencing my IAS with my GS is all I'm saying.

Of COURSE wind is important in a small airplane (any airplane for that matter)... however I do not determine wind by referencing my IAS with my GS is all I'm saying.

Check out this video!
http://www.linhadafrente.net/bin/Pousos.wmv

And do the same thing with 70 knots crosswind in FS9!

That was a cool video (although Engima was completely the wrong choice for the music in my opinion), but I'm confused as to how it pertains to my post.

it is possible

You can change the setting between indicated and true in FS9.
IAS is important as it is always relevent to stalling and doesn't change... of and PR Spits at altitude are fun to spin