Hi Chris, I have exactly the same problem with my BH Mossie. What a kack design! Seeing as I bought the plane secondhand by unflown is probably why it is still in one piece as I saw another post where the plane spiralled into the ground on its maiden. Problem is once the plane is built you can't get this horn out so I have opted for filing a flat on the bar to stop it from turning. How did you fix your problem? Peter.