NAME_________________________________ CLASS____________________ DATE____________

- Find information at this web site: (http://www.grc.nasa.gov/WWW/K-12/airplane/bgp.html).
Why do different aircraft have different types of
propulsion systems?
- When would you use a ramjet (http://www.grc.nasa.gov/WWW/K-12/airplane/ramjet.html)
on an airplane?
- Find the Mach number (http://www.grc.nasa.gov/WWW/K-12/mach.html)
for a subsonic airplane flying at 650 mph.
M = Mach

M =V/A V = Air Velocity

M = ________________ A = 762 mph. (speed of sound)

- Find the Mach number for a subsonic airplane flying at 525 mph.
M = ____________

- Find the Mach number for a subsonic airplane flying at 725
mph.
M = ____________

- Find the velocity of a subsonic airplane flying at Mach number
of .65.
M = Mach

M = V/A V = Air Velocity

V = ________________ A = 762 mph. (speed of sound)

- Find the velocity of a subsonic airplane flying at Mach
number of .80.
V = ____________

- Find the velocity of a supersonic airplane flying at Mach number
of 1.5.
V = ____________

- Using the interactive Atmosphere Calculator (http://www.grc.nasa.gov/WWW/K-12/airplane/atmosi.html),
find the speed of sound, pressure and temperature at the following
altitudes using English Units.
**ALTITUDE****SOUND SPEED****PRESSURE****TEMPERATURE**1,000 ft.

5,000 ft.

10,000 ft.

20,000 ft.

25,000 ft.

30,000 ft.

- Produce three graphs from the data recorded above, showing speed of sound, pressure, and temperature versus altitude.
- What effect does altitude have on the
**speed of sound**? - What effect does altitude have on
**pressure**? - What effect does altitude have on
**temperature**? - Flying at a constant speed of 600 feet per second, find the speed of
sound and the Mach number at the following altitudes.
**ALTITUDE****SOUND SPEED****MACH NUMBER**1,000 ft.

10,000 ft.

20,000 ft.

30,000 ft.

- Graph the changes in Mach Number
at the different altitudes.
- How does the change in altitude affect
**Mach Number**when flying at a constant speed? - The thrust of a jet engine is also affected by changes in altitude.
Calculate the thrust of a Pratt & Whitney JT8D-17 jet engine (17,000 pounds at sea level)
at different altitudes using the temperature and pressure results
from Question 9, and the following equation:
F = thrust at altitude

F sl = sea level static thrust at takeoff (17,000 pounds)

P = static pressure at altitude

P sl = sea level static pressure (14.7 psi)

F = F sl x P/P sl x

sqrt(T sl /T) T = absolute temp (temp + 460) at altitude

T sl = sea level absolute temperature (520 R)

**ALTITUDE****PRESSURE****TEMPERATURE****#****THRUST**1000 ft.

A.

10,000 ft.

B.

20,000 ft.

C.

30,000 ft.

D.

- Graph the change in thrust with altitude for the Pratt &
Whitney JT8D-17 jet engine.

- Give your conclusions on thrust and flying at different
altitudes.