For an aircraft climbing at a constant IAS the Mach number will
- increase.
- decrease.
- remain constant.
Explanation from PART66Online
Climbing at constant IAS means dynamic pressure is held constant, but as altitude rises the temperature falls and the local speed of sound decreases. True airspeed also rises for a constant IAS as density falls. With true airspeed rising and the speed of sound falling, the Mach number increases with altitude.
M
MridulDev asked · 11 Oct 2012
help!!
Community Comments (8)
P
PART66Online
11 Oct 2012
Mach no. will increase because local speed of sound will decrease with altitude. Mach no = speed / local speed of sound (which depends from temperature (altitude)).
M
MridulDev
11 Oct 2012
thanks.
E
easarabbit
11 Oct 2012
On climbing at constant IAS not only Mach no increases but TAS also increases.
Note this:
(++)=increase
(--)=decrease
During Climb:
Constant IAS= Mach no. (++)=TAS(++)
Constant Mach no= IAS (--)=TAS(--)
During Descents:
Constant IAS= Mach no. (--)=TAS(--)
Constant Mach no= IAS (++)=TAS(++)
ps: TAS will not vary as an aircraft climbs through Tropopause because of the temperature.(as mention by DIMKY) Speed of sound is constant in this region. ^V^
Note this:
(++)=increase
(--)=decrease
During Climb:
Constant IAS= Mach no. (++)=TAS(++)
Constant Mach no= IAS (--)=TAS(--)
During Descents:
Constant IAS= Mach no. (--)=TAS(--)
Constant Mach no= IAS (++)=TAS(++)
ps: TAS will not vary as an aircraft climbs through Tropopause because of the temperature.(as mention by DIMKY) Speed of sound is constant in this region. ^V^
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
P
PART66Online
11 Oct 2012
Hello astronaut.
Please don't dublicate your questions in many topics.
I think answers are:
A - 1
B - 1
C - 2
D - 1
Maybe easarabbit or MridulDev will correct me. :)
Please don't dublicate your questions in many topics.
I think answers are:
A - 1
B - 1
C - 2
D - 1
Maybe easarabbit or MridulDev will correct me. :)
M
MridulDev
12 Oct 2012
i have my doubts on A & B, rest are spot on.
M
max.steelame
24 Jan 2019
A-3
B-3
C-2
D-2
B-3
C-2
D-2
J
Jordi
26 Jun 2020
The correct answer is of course increase.This happens because the formula is M=speed of sound/speed of object (in our case an aircraft).Also dont read max's.steelames answers they are wrong.The correct ones are Dimky's.
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