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Oh, can't wait. I realized, that i can not play without this tiny thing, so am sitting and waiting for update Many thanks.

ferram4, Van Disaster: Thanks, now i start to understand what is going on.

Thanks for your answers. But, probably, i have not stated my goal properly. Yes, control surfaces are angled downward and center of lift is in front of center of mass, because they are set as flaps and are in the 3rd position (fully lowered) Tail-wings will definitely solve the problem, I've already tested it. But the goal of this model is to understand how FAR's aerodynamic works. I know, that: - we have no lift at all with zero angle of attack, only increasing drag. It is realistic and rather expected. - for the plane to be stable, the center of lift should be behind center of mass (but that does not mean it will fly) - to increase lift should use flaps. Lift is proportional to flaps deflection, but deflection should not exceed stall angle. But, i can't understand why when the center of lift is ahead of center of mass, the tail is in the air first. As i understand, in that case we should have a clockwise torque (and this is really what i need to increase angle of attack and take off, gain speed and fully retract the flaps). With the center of mass in front of center of lift we should have counter clockwise torque. Now i have only 1 explanation - when using flaps lift force is applied to control surfaces themselves (not to the point where blue vector is drawn) so that actual center of lift is slightly (or even more) shifted back. As a result the actual center of lift appears to be behind center of mass and causes tail in the air first. Or am i missing the meaning of center of lift arrow? In fact there is another question. As I've noticed lowered flaps push center of lift forward to the nose of the plane. In many cases it was true, but on some designs it was more complicated. Position 1 pushed center of lift forward to the nose, however remaining 2 pushed center of lift back to the tail (sometimes even further than with flaps fully retracted). In all cases the main wings surfaces were not angled.

Hi all. First of all, Big thanks ferram4 for this awesome mod. The picture below shows my test model. When i tested this model it turned out that the plane's tail takes off earlier than the nose. But the plane's Center of Lift is slightly ahead of Center of Mass. Can anybody explain why this happens? I know how to handle this, but it's more important for me to understand 'the right design' basics. http://imgur.com/nxwKfzU PS Sorry for Google translate