Took 5 minutes with wind. 
30k:  turned wind off, let it settle.  No real difference noticed.
40k:  a little wonky.  speeds around 250 indicated.  
50k:  Flew around like a zeke with 5-6g flat turns.  Weird indeed =]  
Put it in a nose dive and never really broke the 600 mph barrier.  Wings ripped at 2k and death ensued.
2nd try I turned wind off at 35k, stalled and began to spin.  I could NOT recover no matter what I did til about 4k.  odd