The recommended way to position a propeller when outside in winter is to have a blade opening on the bottom to allow water to drain.
The sharp edge of the PropPastie cutout is positioned against the sharp trailing edge of the Propeller with the Velcro against the rounded leading edge. Make sure to pull the PropPastie snug against the propeller blade. The edges of the PropPastie should ride up against the propeller blade. Position the PropPastie so there is a slight cone shape to it when installed. The location of the edges of the PropPastie should be above the spinner so that the cone shape will result.
PropPastie works best in winter when the material gets stiff from the cold, and the propeller is in the vertical position. In the summer when the material is more pliable be sure to have the Propeller either vertical or at most 45 degrees. Fixed pitch propellers do not narrow at the hub. PropPastie will not stay in place on a fixed pitch propeller in summer because the material is not stiff as it is in winter. If the cowling of your aircraft interferes with the PropPastie, the PropPastie can be slipped under the lip of the cowling, bent to behind the spinner or carefully trimmed even with the back of the spinner. See the photo of the Cessna 150.
At temperatures of -20F or lower, leave the PropPastie on your spinner until after your preheat is finished and the PropPastie will be above the material's conservative cold cracking temperature specification. If you use an electric heater to keep your engine warm, the PropPastie will be above the critical temperature.
The PropPastie was designed to be used on a propeller positioned vertically as shown or in the near vertical position. For three-blade propellers you will need two PropPasties in the near vertical position in winter. One blade should be down to allow water to drain in winter.
In summer the PropPastie can also be used to protect against bird droppings or water on the propeller bearings when the propeller blade is in the near vertical position.
When shipped the PropPastie is folded in the envelope and the crease that results will almost completely disappear in less than an hour at room temperature when flattened under a book. The function of the PropPastie will not be affected by any creases or distortions as long the edge of the PropPastie is snug against the propeller blade and installed as previously instructed.