Brenner Flashcards
Temperature vs Heat
Pressure
Brenner
Temperature measures kinetic energy of molecules within a system whereas heat measures thermal energy transferred between systems.
Temperature scales consist of absolutes like Kelvin and Rakine and relatives like Celsius and Farenheit. An annoying remark about relative scales is that 60 degrees is not twice as hot as 30 degrees because something that is “twice as hot” than 30 degrees C would actually be 333 degrees C.
Pressure is measured in pascals which is equal to N/m^2. A standard atmosphere is 1013.25hpa, 760mmHg, 29.92 inHg
Vx
Brenner
Vx, is the speed at which the aircraft has the largest amount of excess thrust, which means the greatest value of thrust minus drag.
As an aircraft climbs its indicated Vx does not change because total drag will be found at increasingly higher true air speeds.
Vy
Brenner
Vy, the best rate of climb, is the speed at which the airplane has the greatest excess of power, meaning the greatest difference between the available power curve and the power required to maintain flight.
As an aircraft climbs its indicated Vy decreases by 2% for every 1000 feet. Despite true Vy increasing by 1% for every 1000 feet.
Absolute ceiling
Vx = Vy
Vs Vs1g Vsr
Brenner
Stall speed is the speed at which the aircraft cannot maintain flight.
In large commercial aircraft accelerometers measure the moment the aircraft passes through 0.5G. This is defined as Vs1g and is higher than Vs but below Vsr.
Vsr is any stall speed above Vs1g used in performance calculations.
V1
Brenner
Minimum speed to continue with a take off when an engine fails at VEF and still be able to accelerate to Vr and reach the screen height within the available take off distance.
Maximum speed to reject a take off and stop within the available accelerate stop distance.
Ask Esposito/Le about why weight, headwind, and slope are proportional to V1 and why density and flap are inversely proportional.
Net flight path NFP
Brenner
A margin of 35 feet obstacle clearance. FAA mandates an aircraft must clear all obstacles within an Obstacle Accountability Area by 35 feet by its lowest point, usually the wing tip. EASA mandates 50 feet in turns greater than 15 degrees of bank.
Gross Flight Path GFP
Brenner
NFP + margin of safety of
0.8% for twinjets
0.9% for trijets
1.0% for quadjets
Landing Climb
Brenner
Speed required to initiate a go around with all engines operating at maximum thrust.
Approach Climb
Brenner
Speed required to maintain climbing performance with OEI
Reynolds Number
Brenner
Re = p * V * L / u
p = air density
V = free stream velocity
L = distance along the surface
u = viscosity of the fluid
Measures the ratio of a fluid’s viscous and inertial forces to determine the point a fluid transitions between laminar and turbulent flow. It is also used for scaling flow situations of different sizes such as airflow over a model wing to predict fluid behavior on larger applications.
Low numbers are associated with laminar flow and higher numbers with turbulent flow.
Dry Check
Brenner
Method for determining take-off weight on a wet runway. Short wet runways with skid resistant grooves can offer better take off weights because reverse thrust may be used but it is illegal to do so thus a “dry check” is made to keep weights conservative.
