I had assumed "vertical development" from my terrible German. Again, patience is required, and some latitude in "judgment" rather then instant rebuke. Rockhound, thanks. I fear no further "conclusions" can be supported without more information, but setting (or resetting) the table of debate serves to polish the basis for further discussion, imo.
Possible. At impact, the VS is proposed to have been "flung" (unfortunate term, eh?) forward, across the top of a Fuselage at 5 degree pitch. The "across the top" follows from "En ligne de vol". Any deviation from the longitudinal axis of the Fuselage would impute a "skid", or "Yaw" relative to direction of "Flight". (Of course "Flight" can only be used advisedly, the BEA concludes accelerations and velocities that preclude this a/c from "flight"). The Vertical vector is longer and fatter than the Horizontal, again following BEA, "strong vertical acceleration" slight Horizontal.
As efficiently as the VS was designed, it wasn't meant to survive much vertical acceleration of any description, only side forces. So on the one hand, its strength to weight ratio defines the engineering consideration, and the architecture of the three joins. Sudden decelaration in a vertical manner suggests that the VS would be driven into its mounts, not "pulled away".
Sudden deceleration in the horizontal would challenge the strength of the hoops in a way they were not designed. However, both vertical and horizontal stresses are handled (imo) quite well in a fortuitous way, because of the structures' need to resist side force. To think that the VS/Rudder "rolled forward" around its forward attachment, after the aft two were sheared, is a challenge; the forward velocity was not high (?).
Possible. At .83 Mach an upset in Pitch caused by high speed Stall would be followed by an almost certain wing drop, resultant Roll, and then Yaw. It isn't necessary to consider a control input to have been the cause of catastrophic failure of the VS/Rudder. Any upset at this a/s would be a bag of snakes, it is highly likely that more than one attitude would be out of limits, not just Pitch.
The Rudder is designed with a taper, of course. Why? Newton. As it deflects and resists the airstream, its load is dependent on the chord of the Rudder and its distance from the Fulcrum (The Fuselage). The shorter chord of the tip produces drag equal to the longer, lower chord, because of its moment arm (leverage). At any deflection more square area is presented to the slipstream at the base than at the top, and for this reason, entertaining the aerodynamic damage to the Rudder at this area is a natural. It also would explain the degree of damage evident in each hoop, with the forward join, as the final and impromptu fulcrum of side load, was shorn.
Conclusion. More possibility of side load and damage at altitude exists than at sea level. If the structure held at the top of this flight, while exposed to enormous air loading, why would it fail (and in the manner proposed) at impact? Arse about. Beyond this, I feel the Spoiler suffered its damage at altitude. Even the condition of the VS suggests this. The battering that the spoiler endured and its subsequent separation speak of Aerodynamic loading, and in lower thicker air than the VS/Rudder had encountered at the initial upset.
In any case, without more from the authority to support the sea level separation of the VS/Rudder, I propose the conclusion needs more basis.
bear
Last edited by bearfoil; 26th Feb 2010 at 19:09.