2009 Lawsuit

BobW:

Assuming a condition where the C of G is out of limits, how would that affect the flight characteristics in a way that would result in the accident as it played out (unintentional stall-spin transforming into a spiral dive which then wound up tight enough to generate g-forces sufficiently high so as to break the wings)? - I'm currently going through the reference material I have on hand as I found, to my embarrassment, that I wasn't at all certain about the various effects of C of G on flight characteristics.

I assume that only a too far aft C of G could be a problem in this case. An aft C of G makes a stall-spin easier to get into and can result in the spin being unrecoverable in extreme situations correct? I would think that an aft C of G would also make it easier to induce positive g's with the elevator and would make the elevator control lighter and "twitchier" making it easier to overstress the glider during the subsequent spiral. I can't see how the C of G would lead to the spiral dive being unrecoverable though.

I recall a Nimbus 4DM accident in which it was suggested that after a certain number of turns in a spiral dive when g forces and airspeed had built up high enough that it would be impossible to roll level and recover - I wonder if the lawsuit was suggesting something similar about the 29? It doesn't seem too likely that that would be the case though.

Not knowing the C of G position for sure, especially in a glider which lets you alter wing loading and tail weight to the degree a modern competition ship would seem to be a prerequisite for flight to me. Even my old 15b (without ballast bags) has been up on the scales, leveled and weighed during an annual just to put my mind at ease. (it was imported from Germany to Canada in 1998 and the German records indicate that it was reweighed every 48 months when it was there!)