On Thursday, September 22, 2016 at 1:27:08 PM UTC-5, Papa3 wrote:
IIRC, the Duckhawk was to be built in various versions including one with a VNE in excess of 400KPH. As far as I can tell, serial production was never started. I wonder if they'd build one to order? You know, for someone that just HAS to break a world record....

P3

Take a look at this: Polish aerobatic glider from 1949 IS-4 Jastrzab (Hawk)with Vne of 450 kph (243 kt):

https://en.wikipedia.org/wiki/IS-4_Jastrz%C4%85b