15  🌬️ Drag

Drag model based on drag polar coefficients.

from openap import Drag
drag = Drag("A320")

15.0.1 Drag(ac, wave_drag=False, backend=None)

Parameter	Type	Description
ac	str	ICAO aircraft type (e.g., “A320”)
wave_drag	bool	Enable wave drag model (experimental). Default: False
backend	MathBackend, optional	Computation backend. Default: NumpyBackend

15.0.2 clean(mass, tas, alt, vs=0, dT=0)

Compute drag at clean configuration (cruise, climb, descent — no flaps, gear up).

Parameter	Type	Unit	Description
mass	float	kg	Aircraft mass
tas	float	kt	True airspeed
alt	float	ft	Altitude
vs	float	ft/min	Vertical rate. Default: 0
dT	float	K	ISA temperature deviation. Default: 0

Returns: Total drag (N)

drag.clean(mass=60000, tas=250, alt=30000)

37192.35192276492

15.0.3 nonclean(mass, tas, alt, flap_angle, vs=0, dT=0, landing_gear=False)

Compute drag at non-clean configuration (flaps deployed, gear extended).

Parameter	Type	Unit	Description
mass	float	kg	Aircraft mass
tas	float	kt	True airspeed
alt	float	ft	Altitude
flap_angle	float	degree	Flap deflection angle
vs	float	ft/min	Vertical rate. Default: 0
dT	float	K	ISA temperature deviation. Default: 0
landing_gear	bool	—	Landing gear extended? Default: False

Returns: Total drag (N)

drag.nonclean(mass=60000, tas=180, alt=5000, flap_angle=20, landing_gear=True)

43298.09038943537