If you’re flying like me, you’re probably replacing propellers and bending motor shafts like there’s no tomorrow. This is especially true if you’re flying from a grass field. The problem is that when your propeller hits the ground, either it takes the force of the impact or, if it’s still turning with throttle, it can bend the motor shaft.
Early on when I started flying RC I kept hearing about prop savers. I didn’t really get the benefit until I used one myself. Now I use a prop saver on every 3 or 4 mm motor shaft! I’d love to say I have no more broken props or bent shafts but all I can say is that it has drastically reduced prop fatalities and shaft replacements.
Here’s how a prop saver works
It’s a small aluminum ring that fits on the motor shaft like on Figure 1. It has two milled, threaded holes where little screws go and it comes with one or two rubber bands (you only need one).
After putting the prop saver on the shaft you tighten the screws so that it doesn’t spin free from the shaft or slide off the shaft. You then put the propeller onto the front of the prop saver and attach the rubber band from one screw, around the front of the propeller and onto the other screw.
Now your prop has some room to flex back-and-forth and spin free from the motor a little. So if you hit the ground, the rubber band takes the force a little instead of passing it to the prop or shaft.
They come in all shapes and sizes but all do the same function: save props… and shafts.