Powerplant Flashcards
how does pressure vary within the combustion chamber of a gas turbine
Theoretically pressure is constant, though in reality a drop of 3-6% is usual
What is Boyles Law
P*V = K
What is Charles’ Law?
V/T = K
What is the Combined Gas Law?
(P*V)/T = K
What is ESHP
Equivalent Shaft Horsepower, equal to Turbine Shaft Horsepower + residual jet thrust
At what temperatures might inlet icing occour?
below +10 degrees c
What is the typical compression ratio of a singe stage of an axial compressor?
1.1/1.2 to 1
What is the typical compression ratio of a centrifugal compressor?
4 to 1
What is the speed of gases in a jet pipe?
Mach 0.5
1 Shaft Horsepower (shp) is roughly equivalent to how many pounds of thrust?
2.5 pounds of thrust
At engine idle, what is the typical speed of the LP compressor of a turbofan engine
25%
At engine idle, what is the typical speed of the HP compressor of a turbofan engine
50-60%
At engine idle, what is the typical thrust produced by a turbofan as a percentage of take-off thrust?
5%
What is the energy output of a turbine ignition system set to high energy?
6-12 joules
What is the energy output of a turbine ignition system set to low energy?
3-6 joules
What does HEIU stand for?
High Energy Ignition Unit
What is the voltage typically required in an old style turbine spark plug
25,000 Volts
What is the voltage typically required in a surface discharge igniter plug?
2,000 volts
what is the rate of discharge of a High Energy ignition Unit?
60 - 100 discharges per minute
At what speed does a jet engine become self sustaining?
30% N2 (HP compressor)
Between what temperatures can icing occour in the induction systems of a piston engine
-7 to +33 degrees C
What, roughly, is the maximum deceleration of a braking plane
on the order of 6m/s/s. above this value brake pressure is automatically reduced
at what speed is the brake anti-skid system deactivated?
20 mph
In RTO (Rejected Take off) mode, at what speed do the autobrakes arm
85 knots
At what speed does the autobrake system normally disarm
20 knots
at what speed is the brake anti-lock system deactivated?
10 mph, though on some aircraft they are never disarmed.
What are the four regions of a tyre
from outer to inner: crown, shoulder, sidewall, bead
what is the inflation pressure of a low pressure tyre?
23 - 35 psi
what is the inflation pressure of a medium pressure tyre?
35 - 70 psi
what is the inflation pressure of a high pressure tyre?
70 - 90 psi
what is the inflation pressure of an extra high pressure tyre?
more than 90 psi (350 psi is typical of a large airliner)
