Iv'e tried trim adjustments with or without autopilot - no joy...
I also have the payware GW 787 - plane always maintains the right "attitude" position (no wing contrai, and C o G is correct).
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I have FSXSteam - I believe the C of G is way off in the TDS 787 model - no matter what do adjusting the fuel or cargo, it seems to have no effect. The aircraft continually rides nose-up leaving a wing-tip contrail at cruising altitude.