What is the effect of altitude on true airspeed? Announcing the arrival of Valued Associate...
Hangman Game with C++
How often does castling occur in grandmaster games?
Why weren't discrete x86 CPUs ever used in game hardware?
Should a wizard buy fine inks every time he want to copy spells into his spellbook?
Did Mueller's report provide an evidentiary basis for the claim of Russian govt election interference via social media?
Has negative voting ever been officially implemented in elections, or seriously proposed, or even studied?
Drawing spherical mirrors
What would you call this weird metallic apparatus that allows you to lift people?
Did any compiler fully use 80-bit floating point?
Crossing US/Canada Border for less than 24 hours
Is CEO the "profession" with the most psychopaths?
What order were files/directories output in dir?
How to unroll a parameter pack from right to left
Maximum summed subsequences with non-adjacent items
Why are vacuum tubes still used in amateur radios?
Would it be easier to apply for a UK visa if there is a host family to sponsor for you in going there?
In musical terms, what properties are varied by the human voice to produce different words / syllables?
Why can't I install Tomboy in Ubuntu Mate 19.04?
Random body shuffle every night—can we still function?
A letter with no particular backstory
What do you call the main part of a joke?
The Nth Gryphon Number
preposition before coffee
How does a spellshard spellbook work?
What is the effect of altitude on true airspeed?
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 23, 2019 at 00:00UTC (8:00pm US/Eastern)How is the wind direction and wind speed measured in flight?How do you calculate indicated airspeed on a flight plan?How does headwind influence the results of a pitot tube and therefore the airspeed indicator?How to calculate the real Ground Speed from True Air Speed?Does a sudden drop of the velocity of the headwind affect the airspeed by lowering it?What type of airspeed are wind speeds given in?What is the relation between IAS and TAS at a constant altitude?Why do pilots normally fly by CAS rather than TAS?Temperature sensor are needed to compute True Airspeed for low speed aircrafts?What is the relation between altitude and vertical speed?
$begingroup$
I know that wind is taken into account when we compute the TAS(true airspeed) and GS(ground speed). However what is the relationship between the TAS and altitude?
For example: What is the true airspeed on the level flight if the headwind is 20 mph and ground speed is 100 mph at 30,000 feet altitude?
airspeed measurement
edited yesterday
Bianfable
1,635520
asked yesterday
user38468user38468
434
$endgroup$
add a comment |
$begingroup$
I know that wind is taken into account when we compute the TAS(true airspeed) and GS(ground speed). However what is the relationship between the TAS and altitude?
For example: What is the true airspeed on the level flight if the headwind is 20 mph and ground speed is 100 mph at 30,000 feet altitude?
airspeed measurement
edited yesterday
Bianfable
1,635520
asked yesterday
user38468user38468
434
$endgroup$
2
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday
add a comment |
$begingroup$
I know that wind is taken into account when we compute the TAS(true airspeed) and GS(ground speed). However what is the relationship between the TAS and altitude?
For example: What is the true airspeed on the level flight if the headwind is 20 mph and ground speed is 100 mph at 30,000 feet altitude?
airspeed measurement
edited yesterday
Bianfable
1,635520
asked yesterday
user38468user38468
434
$endgroup$
I know that wind is taken into account when we compute the TAS(true airspeed) and GS(ground speed). However what is the relationship between the TAS and altitude?
For example: What is the true airspeed on the level flight if the headwind is 20 mph and ground speed is 100 mph at 30,000 feet altitude?
airspeed measurement
airspeed measurement
edited yesterday
Bianfable
1,635520
asked yesterday
user38468user38468
434
edited yesterday
Bianfable
1,635520
asked yesterday
user38468user38468
434
edited yesterday
Bianfable
1,635520
edited yesterday
Bianfable
1,635520
edited yesterday
Bianfable
1,635520
1,635520
asked yesterday
user38468user38468
434
asked yesterday
user38468user38468
434
asked yesterday
user38468user38468
434
434
2
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday
add a comment |
2
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday
2
2
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
If you know GS and local wind speed, the TAS always the same, regardless of altitude. The true airspeed is called "true" because it is exactly how fast you are moving relative to the air. Picture it as a person in a weather balloon (which does not move relative to the surrounding air, i.e., TAS=0), pointing a radar gun at your aircraft to measure its speed. The results would be the same regardless of altitude, temperature, pressure, etc. This is what sets TAS apart from pretty much any other speed like IAS, CAS, EAS and Mach.
Only at truly ridiculous altitudes you would have some problems with calculating TAS, due to the increased orbital radius from the center of the Earth. However, at this point, you're well into the near vacuum of space which means that the whole concept of 'air' speed is quite silly.
answered yesterday
SanchisesSanchises
6,50812557
$endgroup$
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
add a comment |
$begingroup$
The true airspeed (TAS) can be calculated from the indicated airspeed (IAS), which is derived from the pitot tubes and static ports, as follows:
$$ mathrm{TAS} = mathrm{IAS} sqrt{frac{rho_0}{rho(a)}} , $$
where $ rho_0 $ is the air density at sea level and $ rho(a) $ the air density at altitude $ a $, which depends on pressure $ P $ and temperature $ T $:
$$ rho(a) = frac{M cdot P(a)}{R cdot T(a)} , $$
where $ M $ is the molar mass of air and $ R $ is the universal gas constant.
Using the international standard atmosphere for $ P(a) $ and $ T(a) $, one can plot the TAS as a function of altitude:
The ground speed (GS) is then given by the vector addition of the TAS and the wind speed:
$$ mathrm{GS} = mathrm{TAS} + v_mathrm{wind} cos(alpha) , $$
where $ alpha $ is the angle between the wind direction and the track of the aircraft ($ alpha = 0^circ $ for tailwind, $ alpha = 180^circ $ for headwind). This step is independent of pressure or temperature and as such independent of altitude. This means for a given TAS and headwind component, the ground speed is the same at all altitudes (for your example: 100 mph GS with 20 mph headwind implies 120 mph TAS at all altitudes).
answered yesterday
BianfableBianfable
1,635520
$endgroup$
add a comment |
Your Answer
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "528"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faviation.stackexchange.com%2fquestions%2f62465%2fwhat-is-the-effect-of-altitude-on-true-airspeed%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
If you know GS and local wind speed, the TAS always the same, regardless of altitude. The true airspeed is called "true" because it is exactly how fast you are moving relative to the air. Picture it as a person in a weather balloon (which does not move relative to the surrounding air, i.e., TAS=0), pointing a radar gun at your aircraft to measure its speed. The results would be the same regardless of altitude, temperature, pressure, etc. This is what sets TAS apart from pretty much any other speed like IAS, CAS, EAS and Mach.
Only at truly ridiculous altitudes you would have some problems with calculating TAS, due to the increased orbital radius from the center of the Earth. However, at this point, you're well into the near vacuum of space which means that the whole concept of 'air' speed is quite silly.
answered yesterday
SanchisesSanchises
6,50812557
$endgroup$
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
add a comment |
$begingroup$
If you know GS and local wind speed, the TAS always the same, regardless of altitude. The true airspeed is called "true" because it is exactly how fast you are moving relative to the air. Picture it as a person in a weather balloon (which does not move relative to the surrounding air, i.e., TAS=0), pointing a radar gun at your aircraft to measure its speed. The results would be the same regardless of altitude, temperature, pressure, etc. This is what sets TAS apart from pretty much any other speed like IAS, CAS, EAS and Mach.
Only at truly ridiculous altitudes you would have some problems with calculating TAS, due to the increased orbital radius from the center of the Earth. However, at this point, you're well into the near vacuum of space which means that the whole concept of 'air' speed is quite silly.
answered yesterday
SanchisesSanchises
6,50812557
$endgroup$
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
add a comment |
$begingroup$
If you know GS and local wind speed, the TAS always the same, regardless of altitude. The true airspeed is called "true" because it is exactly how fast you are moving relative to the air. Picture it as a person in a weather balloon (which does not move relative to the surrounding air, i.e., TAS=0), pointing a radar gun at your aircraft to measure its speed. The results would be the same regardless of altitude, temperature, pressure, etc. This is what sets TAS apart from pretty much any other speed like IAS, CAS, EAS and Mach.
Only at truly ridiculous altitudes you would have some problems with calculating TAS, due to the increased orbital radius from the center of the Earth. However, at this point, you're well into the near vacuum of space which means that the whole concept of 'air' speed is quite silly.
answered yesterday
SanchisesSanchises
6,50812557
$endgroup$
If you know GS and local wind speed, the TAS always the same, regardless of altitude. The true airspeed is called "true" because it is exactly how fast you are moving relative to the air. Picture it as a person in a weather balloon (which does not move relative to the surrounding air, i.e., TAS=0), pointing a radar gun at your aircraft to measure its speed. The results would be the same regardless of altitude, temperature, pressure, etc. This is what sets TAS apart from pretty much any other speed like IAS, CAS, EAS and Mach.
Only at truly ridiculous altitudes you would have some problems with calculating TAS, due to the increased orbital radius from the center of the Earth. However, at this point, you're well into the near vacuum of space which means that the whole concept of 'air' speed is quite silly.
answered yesterday
SanchisesSanchises
6,50812557
answered yesterday
SanchisesSanchises
6,50812557
answered yesterday
SanchisesSanchises
6,50812557
answered yesterday
SanchisesSanchises
6,50812557
6,50812557
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
add a comment |
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Thanks for valuable answer..
$endgroup$
– user38468
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
$begingroup$
Not to mention, in re your last paragraph, that you are dealing as much in plasma dynamics as fluid dynamics at those altitudes.
$endgroup$
– KorvinStarmast
yesterday
add a comment |
$begingroup$
The true airspeed (TAS) can be calculated from the indicated airspeed (IAS), which is derived from the pitot tubes and static ports, as follows:
$$ mathrm{TAS} = mathrm{IAS} sqrt{frac{rho_0}{rho(a)}} , $$
where $ rho_0 $ is the air density at sea level and $ rho(a) $ the air density at altitude $ a $, which depends on pressure $ P $ and temperature $ T $:
$$ rho(a) = frac{M cdot P(a)}{R cdot T(a)} , $$
where $ M $ is the molar mass of air and $ R $ is the universal gas constant.
Using the international standard atmosphere for $ P(a) $ and $ T(a) $, one can plot the TAS as a function of altitude:
The ground speed (GS) is then given by the vector addition of the TAS and the wind speed:
$$ mathrm{GS} = mathrm{TAS} + v_mathrm{wind} cos(alpha) , $$
where $ alpha $ is the angle between the wind direction and the track of the aircraft ($ alpha = 0^circ $ for tailwind, $ alpha = 180^circ $ for headwind). This step is independent of pressure or temperature and as such independent of altitude. This means for a given TAS and headwind component, the ground speed is the same at all altitudes (for your example: 100 mph GS with 20 mph headwind implies 120 mph TAS at all altitudes).
answered yesterday
BianfableBianfable
1,635520
$endgroup$
add a comment |
$begingroup$
The true airspeed (TAS) can be calculated from the indicated airspeed (IAS), which is derived from the pitot tubes and static ports, as follows:
$$ mathrm{TAS} = mathrm{IAS} sqrt{frac{rho_0}{rho(a)}} , $$
where $ rho_0 $ is the air density at sea level and $ rho(a) $ the air density at altitude $ a $, which depends on pressure $ P $ and temperature $ T $:
$$ rho(a) = frac{M cdot P(a)}{R cdot T(a)} , $$
where $ M $ is the molar mass of air and $ R $ is the universal gas constant.
Using the international standard atmosphere for $ P(a) $ and $ T(a) $, one can plot the TAS as a function of altitude:
The ground speed (GS) is then given by the vector addition of the TAS and the wind speed:
$$ mathrm{GS} = mathrm{TAS} + v_mathrm{wind} cos(alpha) , $$
where $ alpha $ is the angle between the wind direction and the track of the aircraft ($ alpha = 0^circ $ for tailwind, $ alpha = 180^circ $ for headwind). This step is independent of pressure or temperature and as such independent of altitude. This means for a given TAS and headwind component, the ground speed is the same at all altitudes (for your example: 100 mph GS with 20 mph headwind implies 120 mph TAS at all altitudes).
answered yesterday
BianfableBianfable
1,635520
$endgroup$
add a comment |
$begingroup$
The true airspeed (TAS) can be calculated from the indicated airspeed (IAS), which is derived from the pitot tubes and static ports, as follows:
$$ mathrm{TAS} = mathrm{IAS} sqrt{frac{rho_0}{rho(a)}} , $$
where $ rho_0 $ is the air density at sea level and $ rho(a) $ the air density at altitude $ a $, which depends on pressure $ P $ and temperature $ T $:
$$ rho(a) = frac{M cdot P(a)}{R cdot T(a)} , $$
where $ M $ is the molar mass of air and $ R $ is the universal gas constant.
Using the international standard atmosphere for $ P(a) $ and $ T(a) $, one can plot the TAS as a function of altitude:
The ground speed (GS) is then given by the vector addition of the TAS and the wind speed:
$$ mathrm{GS} = mathrm{TAS} + v_mathrm{wind} cos(alpha) , $$
where $ alpha $ is the angle between the wind direction and the track of the aircraft ($ alpha = 0^circ $ for tailwind, $ alpha = 180^circ $ for headwind). This step is independent of pressure or temperature and as such independent of altitude. This means for a given TAS and headwind component, the ground speed is the same at all altitudes (for your example: 100 mph GS with 20 mph headwind implies 120 mph TAS at all altitudes).
answered yesterday
BianfableBianfable
1,635520
$endgroup$
The true airspeed (TAS) can be calculated from the indicated airspeed (IAS), which is derived from the pitot tubes and static ports, as follows:
$$ mathrm{TAS} = mathrm{IAS} sqrt{frac{rho_0}{rho(a)}} , $$
where $ rho_0 $ is the air density at sea level and $ rho(a) $ the air density at altitude $ a $, which depends on pressure $ P $ and temperature $ T $:
$$ rho(a) = frac{M cdot P(a)}{R cdot T(a)} , $$
where $ M $ is the molar mass of air and $ R $ is the universal gas constant.
Using the international standard atmosphere for $ P(a) $ and $ T(a) $, one can plot the TAS as a function of altitude:
The ground speed (GS) is then given by the vector addition of the TAS and the wind speed:
$$ mathrm{GS} = mathrm{TAS} + v_mathrm{wind} cos(alpha) , $$
where $ alpha $ is the angle between the wind direction and the track of the aircraft ($ alpha = 0^circ $ for tailwind, $ alpha = 180^circ $ for headwind). This step is independent of pressure or temperature and as such independent of altitude. This means for a given TAS and headwind component, the ground speed is the same at all altitudes (for your example: 100 mph GS with 20 mph headwind implies 120 mph TAS at all altitudes).
answered yesterday
BianfableBianfable
1,635520
edited yesterday
answered yesterday
BianfableBianfable
1,635520
answered yesterday
BianfableBianfable
1,635520
answered yesterday
BianfableBianfable
1,635520
1,635520
add a comment |
add a comment |
Thanks for contributing an answer to Aviation Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faviation.stackexchange.com%2fquestions%2f62465%2fwhat-is-the-effect-of-altitude-on-true-airspeed%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
2
$begingroup$
Learn to make the mental calculation of adding 2% to indicated airspeed for every 1000 ft above SL, and you can get a TAS value that is accurate enough for most situations.
$endgroup$
– John K
yesterday