Is it just me or the landings are much harder ?

[Tord Hoppe]

itael wrote:
Well , reading all the responses I guess I should just practice landing without FSP and then land with FSP and see if there is a
difference
Myabe it is a CG thing , which brings me to the next question ...

The CG to be "optimal" for a stable plane is dead Center right ? (sorry if it's too silly)

Itai

Nothing silly at all, but actually the Center of Gravity or Center of Mass is not in the same spot as the Center of Lift. A plane in that
configuration would be unstable. As you know lift is the opposing force to gravity, when the two are equal the plane is stable in the vertical plane.
The center of lift is usually (AFAIK) behind the center of mass in most planes which means that the tailplane, which also exerts a force, is actually
pulling the tail down. Should the tail brake off the plane will pitch downwards since the lift is behind the centre of mass and therefore lifts the
aft of the plane. There are obviously aircraft models where the opposite is true, but the result is the same. It´s very important to have a correct
centre of mass (handled by loading the plane). Let´s say that the aircraft is loaded very noseheavy. The takeoff speed is just enough so that the
airspeed over the tailplane builds enough force to balance the downward force of the centre of mass. Should you then land with the same weight and at
a lower speed there is a chance that the tailplanes pulling force is not enough to counter the CoM pull and the plane will pitch down with potentially
disastrous results.
Hope this abbreviated text is of some use. Since english isn´t my first language I may use some faulty terms, but it should be enough for a general
idea of the forces at work.

This site is a place to start learning about aerodynamics.

http://en.wikipedia.org/wiki/Center_of_pressure



Post Edited ( 07-11-05 16:08 )