Take off shudder

[BB-Rayner]

Hi guys,

I fly in IL-2 v 4.12.2 HSFX v 7.0.3

The game has run without any hitches for months but just in the last week or so a strange thing has crept in.

When taking off (in any plane) as soon as I get to about 45 mph the plane gets a violent shudder and I lose rudder control until I'm airborne.

It's almost as if the tailwheel lock suddenly turns itself on.

Any ideas what could be casing this?

thanks for your thoughts