Erick Duran 946537 Posted October 27, 2005 at 03:05 AM Posted October 27, 2005 at 03:05 AM Hi, what's the difference among: * Indicated Speed * True Speed * Ground Speed Thanks, Erick Link to comment Share on other sites More sharing options...
Dustin Robbins 887494 Posted October 27, 2005 at 03:20 AM Posted October 27, 2005 at 03:20 AM Indicated - read off the airspeed indicator True- actual speed the aircraft moves through undisturbed air Ground- aircraft's speed over the ground Link to comment Share on other sites More sharing options...
Steven Perry Posted October 27, 2005 at 03:37 AM Posted October 27, 2005 at 03:37 AM Indicated - read off the airspeed indicator True- actual speed the aircraft moves through undisturbed air Ground- aircraft's speed over the ground Not exactly. True airspeed is the speed over the ground a plane would be moving at in undisturbed air. Down low, this is roughly indicated speed plus 2 knots for every thousand feet MSL. Add your wind component to TAS and you get groundspeed. This is all a simplification. Google for these airspeed types and you can find the exact answers and more than you'll ever want or need to know about airspeeds. As a bonus, since it's getting colder around this time up here in the northern hemisphere, I'll remind you that all airspeeds are more or less useless unless you turn on your pitot heat when operating in visible moisture. I had my first two virtual pilots of the year today speed up to 500+ knots true in the descent who insisted they were doing 250 indicated [thru the clouds in northern ohio, USA]. Steve Perry EDIT: Clarification: Dustin wasn't wrong, I just meant to clarify by specifying speed over the ground vs just speed. Steven Perry VATSIM Supervisor Link to comment Share on other sites More sharing options...
David Klain 874106 Posted October 27, 2005 at 05:37 PM Posted October 27, 2005 at 05:37 PM True airspeed is the speed of an aircraft relative to the airm[Mod - Happy Thoughts] in which it flies, i.e. the magnitude of the vector difference of the velocity of the aircraft and the velocity of the air. Under zero wind conditions this is equal to the speed over the ground. Under wind conditions an estimation of the wind is used to make a windspeed vector calculation that computes an estimated ground speed from the true air speed and a wind correction angle to maintain the desired ground track. Indicated airspeed will differ from true airspeed at air densities other than some reference density. Air density is affected by temperature, moisture content, and altitude. Indicated airspeed is used in aircraft operation as the aircraft will always stall at the same indicated airspeed, regardless of its true airspeed, and below the speed of sound, maximum structural speed is shown by indicated airspeed. Proper navigation via dead reckoning (without constant ground reference) requires the use of true airspeed and wind corrections. As mentioned, Groundspeed is the speed over ground... Link to comment Share on other sites More sharing options...
Rey Lopez 883899 Posted October 28, 2005 at 02:06 AM Posted October 28, 2005 at 02:06 AM True airspeed is the speed of an aircraft relative to the airm[Mod - Happy Thoughts] in which it flies, i.e. the magnitude of the vector difference of the velocity of the aircraft and the velocity of the air. Under zero wind conditions this is equal to the speed over the ground. Under wind conditions an estimation of the wind is used to make a windspeed vector calculation that computes an estimated ground speed from the true air speed and a wind correction angle to maintain the desired ground track. Indicated airspeed will differ from true airspeed at air densities other than some reference density. Air density is affected by temperature, moisture content, and altitude. Indicated airspeed is used in aircraft operation as the aircraft will always stall at the same indicated airspeed, regardless of its true airspeed, and below the speed of sound, maximum structural speed is shown by indicated airspeed. Proper navigation via dead reckoning (without constant ground reference) requires the use of true airspeed and wind corrections. As mentioned, Groundspeed is the speed over ground... thanks to dictionary.com for translation lol... The thoughts and/or words or any general things that are expressed above are not a direct reflection of the views of the actual poster myself, Rey Lopez, and should be disregarded and left unread. Link to comment Share on other sites More sharing options...
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