An aircraft flying above the tropopause descends at a constant True Airspeed, its Mach No. will
- remain the same.
- decrease steadily.
- increase at a constant rate.
Explanation from PART66Online
Above the tropopause, in the lower stratosphere, the temperature is essentially constant, so the local speed of sound does not change. With the sonic speed fixed and true airspeed held constant during the descent, the Mach number stays the same.
M
MridulDev asked · 10 Oct 2012
please explain.
Community Comments (8)
P
PART66Online
10 Oct 2012
Above the tropopause temperature is constant. Speed of sound is depends from temperature. If temperature is constant, speed of sound is constant, so mach no. also remain the same. :)
P
PART66Online
10 Oct 2012
Check this picture: apollo.lsc.vsc.edu/classes/met130/not...
As I told, from tropopause till about 20km temperature is constant.
As I told, from tropopause till about 20km temperature is constant.
M
MridulDev
10 Oct 2012
oh, i got tricked in this one , i was expecting a/c to descend further down to troposphere level :) thanks
P
PART66Online
10 Oct 2012
Uhu, website contains some tricky questions, users so many times reports me they as wrong...
Most often are questions about binary coded decimals, users confuse bcd with simple binary. And human factors module contains question about how alcohol acts on reaction times.
Most often are questions about binary coded decimals, users confuse bcd with simple binary. And human factors module contains question about how alcohol acts on reaction times.
M
MridulDev
11 Oct 2012
thanks for the heads up, i'll focus more from now on-wards :D
A
astronaut
11 Oct 2012
Sir Dimky.. would u plz!! ans.these below Que...need ur help!THx! in advance..
A.In transonic speed range:
1.the centre of pressure movement may become ocillatory.
2.the position of the wing centre of pressure remains constant.
3.the centre of pressure initially moves forward then back.
B.The vertical fin of a single engined aircraft is:
1.parallel with both the longitudinal & vertical axis.
2.parallel with the longitudinal axis but not the vertical axis
3.parallel with vertical axis but not the longitudinal axis.
C.Wing loading is:
1. the maximum all up weight multiplied by the total wing area.
2.the maximum all up weight divided by the total wing area.
3.the ratio of the all up weight of the aircraft to its basic weight.
D.An engine which produces an efflux of high speed will be:
1.less efficient
2.speed of efflux has no affect on the engine efficiency.
3.more efficient
A.In transonic speed range:
1.the centre of pressure movement may become ocillatory.
2.the position of the wing centre of pressure remains constant.
3.the centre of pressure initially moves forward then back.
B.The vertical fin of a single engined aircraft is:
1.parallel with both the longitudinal & vertical axis.
2.parallel with the longitudinal axis but not the vertical axis
3.parallel with vertical axis but not the longitudinal axis.
C.Wing loading is:
1. the maximum all up weight multiplied by the total wing area.
2.the maximum all up weight divided by the total wing area.
3.the ratio of the all up weight of the aircraft to its basic weight.
D.An engine which produces an efflux of high speed will be:
1.less efficient
2.speed of efflux has no affect on the engine efficiency.
3.more efficient
J
Jordi
26 Jun 2020
A=2,B=1,C=2,D=1.
G
Gioppo
16 Mar 2026
Please be more specific with this question. Say "An aircraft flying above the tropopause descends at a constant True Airspeed. DURING THE DESCENT INTO THE THROPOPAUSE its Mach No. will"
The capital is to higlight the changed part. Change is needed so it is clear the plane is still into the thropopause when it's considered.
The capital is to higlight the changed part. Change is needed so it is clear the plane is still into the thropopause when it's considered.
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