Page 459 - PPL-engelsk 2025
P. 459
Principles of flight
Induced drag forms at the
wingtips and occurs
because the overpressure
on the underside of the
wing attempts to equalize
with the low pressure on
top of the wing.
This equalization occurs at
the wingtips, where vortices
form.
These vortices are called
wingtip vortices.
The longer the chord line at the wingtip, the larger the area where vortices can
form. Thus, it is better to have a long wingspan and a short chord line.
It is said that the aspect ratio should be large to reduce vortex formation.
The aspect ratio is the ratio of the chord length to the wingspan.
The wingspan is the distance from wingtip to wingtip.
Gliders have a large aspect ratio, which reduces the formation of wingtip vortices.
The larger (heavier) the aircraft, the
larger the wingtip vortices.
Since wingtip vortices can cause
turbulence long after the aircraft has
passed, it can be extremely
dangerous to fly through the airspace behind a larger aircraft.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 459
