Principles of Flight Flashcards
Convert 1 nm to m
1nm = 1852 m
Convert 1 m to ft
1m = 3.28 ft
Convert 1 kg to lbs
1 kg = 2.205 lbs
Convert m/s to kts
m/s = 0.5144 * knots
Newton’s first law?
Body will remain in rest or uniform motion unless acted on by an external force
Newton’s second law?
The acceleration of a body in a straight line is proportional to the force and inversely proportional to the mass
Newton’s third law?
Every action has an equal and opposite reaction
What is power?
Force * Speed
What happens to streamlines when faster air is flowing?
They move closer together
What is mass flow?
Avrho = AreaVelocityDensity
What is dynamic pressure?
‘Kinetic energy’ of air:q = 1/2 * rho * v^2
Convert C to Kelvin?
K = C + 273
What happens to density with increasing humidity?
Density decreases.
ISA mean sea temp?
15C
ISA mean sea pressure?
1013.25 hPa
ISA Mean sea density?
1.225 kg/m^3
ISA Lapse rate?
1.98 C per 1000 ft
Temp of tropopause?
-56.5 C
Difference between true and indicated airspeeds?
Indicated airspeeds are derived from dynamic pressure, can be affeced by density, measuring the ‘energy of the air’, ruler bend effect.True airspeed is the fixed speed of the aircraft in terms of metres/second instead of molecules it passes affected by density.
How is dynamic pressure related to true airspeed and indicated airspeed?
q = 1/2 * rho * (TAS)^2 ~ (IAS)^2So as density drops with altitude, to maintain IAS for flight TAS must increase!
What are the differences between the different airspeeds?
Remember ICE T IPCD (Ice T is pretty cool drink)Ias Cas Instroument & Pressure error removed you getEas Compressibility error removed you getTas Density error removedRemove instrument error from IAS you get CAS, remove Pressure error from CAS you get EAS, remove Compressibility error from
How is IAS related to TAS and density?
IAS = TAS * sqrt(rho/rho0)As you go higher, hitting less particles (IAS) so pressure ratio must get less.
What remains constant through a venturi?
Total pressure (dynamic + static) because we can’t create or destroy energy.Mass flow remains the same (Avrho).
Why does velocity increase in throat of venturi?
Because mass flow remains the same, area decreases so velocity must increase.As a consequence, dynamic pressure increases, and because total pressure must remain constant, static pressure must drop.