Captain Mucura wrote on Feb 10^th, 2009 at 11:03pm:

Gross weight : 100.000 pounds Flaps : 100% CL max : 2.5 (could someone explain us what is cl max ?)

Hey,
about CL max:
CL is the constant of lift in the formula used to calculate lift: L=1/2*r*V²*S*CL
in which:
L is the force of lift
r is the air density (normally the Greek letter 'rho' but I couldn't find it)
V² is the air speed squared
S is the reference area of the wing
and CL is the constant of lift.

CL is dependant on a lot of factors, like the angle of attack, the shape of the wing (with flaps and slats etc.), the mach number, the reynolds number.
basically, CL max is the best CL a specific wing can have.
CL max in a certain condition is the CL shortly before the plane starts to stall.
CL max in total is the best CL in the perfect conditions.
With the highest CL, the wings generate the max possible lift in that condition.

about the formula
1/2*r*V² is the dynamic pressure.
any aerodynamic force can be calculated by taking the dynamic pressure, multiply it with the reference area (in the case of CL the wings) and with a constant.
besides CL (constant of lift), there is CD (consant of drag), CT (consant of thrust when talking about props) etc.
all this constants have no dimension.

hope this helps a little, otherwise you can find quite a lot on the internet.

Tyrion