I have a new 40 cc petrol engine which is designed for a four bolt fixing of the prop with a central spigot of 10 mm dia. I hear reports of the bolts shearing and also the prop bursting where the bolt holes are drilled through the hub. Do I, must I bite the bullet and modify the fixing to one central bolt/nut combination or should the designed fixing be sound as long as the bolt holes are drilled correctly ? If the latter then what would be the best orientation of the holes relative to the prop blades?
Terry Masters 2888