That came up about 6 years ago, some one else was building a heli. As I remember, it was the disk causing the prob.
here is the Radial Racer Red Black CS for technoids excellent Radial Racer located here
https://forums.realflight.com/downloads.php?do=file&id=23685
Technoid, your newest download version is nice. I like the physics. I think it should be faster. JMO
I am on the fence about posting my AV I squeezed 200+ mph with a moki 250 7 cylinder with carbon fiber pushrods and High performance valve spring. (there is a link to them on the moki usa site). http://www.mokiusa.com/tuningparts.html