The venturi and NVA for the OS10 fit the FSR,FP and LA motors . I had for a long time thought that these had been discontinues till I lookes at the tower site and found that they still existed. That said they are sized right for a os 10 motors and fit all well.
My flying Clown had a Fox 15X on it and it was quite a speedy little ship, Little being the word here. This is not a large plane and any modern 15 makes it into a fast plane, the 10 should be perfect for it.
Dennis