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15 results for “performance”

Formulae (15)

COP = \frac{Q_C}{W}

Efficiency measure of a refrigerator or heat pump.

\eta = \frac{P_{out}}{P_{in}}\times 100

Ratio of useful output to input power.

TAS \approx IAS + (IAS \times 0.02 \times \tfrac{alt}{1000})

Quick estimate: true airspeed increases about 2% per 1000 ft of altitude above indicated airspeed.

ROC = \dfrac{\Delta h}{t}

Vertical speed is the altitude gained per unit time (ft per minute).

D = \tfrac{1}{2}\rho v^2 S C_D

Aerodynamic drag force on the aircraft, analogous to lift with a drag coefficient.

DA = PA + 120(OAT - ISA_{temp})

Pressure altitude corrected for non-standard temperature; higher DA reduces performance.

T = \dfrac{W}{L/D}

In steady level flight, thrust must equal drag, which is weight divided by L/D.

E = \dfrac{1}{c}\dfrac{L}{D}\ln\dfrac{W_i}{W_f}

Longest time aloft for a jet, maximized at maximum L/D.

s = \dfrac{V_{LO}^2}{2a}

Approximate ground-roll distance assuming constant acceleration to lift-off speed.

\gamma = \dfrac{T - D}{W}

Climb angle (as a fraction) equals excess thrust divided by weight.

GR = \frac{\text{horizontal distance}}{\text{altitude lost}}

Distance traveled forward per unit of height lost.

V_s = \sqrt{\frac{2W}{\rho S C_{L,max}}}

Minimum speed to maintain lift.

ROC = \frac{\text{excess power}}{W}

Vertical speed from excess engine power.

E = \frac{\text{fuel}}{\text{fuel flow}}

Time an aircraft can stay airborne.

X = \frac{N}{T}

Number of operations completed per unit time.