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Old 5th July 2005 | 19:49
  #17 (permalink)  
XPMorten
 
Joined: Jan 2005
Posts: 319
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From: north
Some clarifications on ground effect (GE).

there are TWO types of ground effect;

1. Span Dominated GE
This occurs at about 1,0+ span altitude.
Due to less vortex buildup, we get DRAG REDUCTION.
The reduction is logarithmic and is very significant close to ground. A high wing aircraft will not get
as much affected as a low wing.

2. Chord Dominated GE
This occurs at about 1,0 chord altitude.
Due to an increase in RAM pressure below the wing,
we get an INCREASE in LIFT Cl. The peak is around 0,05-0,2 chord - depending on airfoil etc.
The F50 WILL NOT even enter this ground effect,
because of the high wing, short chord and long gear. So, e.g. on landing one has to do a much more pronounced flare.

The result of these two is an increase in L/D ratio
and thereby efficiency of the wing

Cheers,

M
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