Hi,

I take it ur using a plastic spinner, all you really need to do is drill a hole or use a prop rememer avalible from most hobby shops to enlarge it big enought so it fits, but dont make the hole too big, just enought to fit over........... when you drill or use the prop remer remember to both sides of the backplate to get an even fitting........

The Tutor 40 is a great plane to learn on, was my first and i still have it, althou i had big problems with the stock fuel tank, so i would recommened ditching it and getting a sealed one like a SLEC tank or something similar

Hope thats of some help........