Replace the Propeller on a GB05 gearbox

The GB05 propulsion unit was designed for lightweight propulsion of flying Micro R/C models and it has some ingenious features.

The axle of the GB05 gearbox remains stationary and the spur gear rotates with the propeller. The gear is held onto the axle by a thrust bearing, and this thrust bearing is actually the head of the axle "pin" The Spur gear is a combination gear and we use a prop adapter to physically connect the propeller to the spur gear - all the while leaving the axle and thrust bearing free in the center of the gear.

This design allows us to more easily mount a carbon fiber propeller to the gearbox. The Propeller and Prop adapter are mated to each other, and then the prop adapter can be mated to the spur gear of the GB05. A small amount of medium viscocity CA glue can hold it in place although the POM plastics of the spur gear are a bit slippery, we can get a good enough bond to the polystyrene plastic of the prop adapter. A good interference fit also helps to keep the propeller on the gearbox, but will break away before damaging the gearbox itself.

To Remove the prop adapter, it helps to use the right tool for the job. Get the Sprue Cutters here
In this case a set of our sprue cutters can be used to surround the prop adapter and the blades are approximated together just enough to wedge under the prop adapter and lever it off of the spur gear. Give it a little squeeze , rotate everything a bit, squeeze again and the prop pops right off. Be careful that you don't squeeze too hard - use just enough force to wedge under the prop adapter glue line

Now you can repair or replace as required. Remember to only use a little bit of glue when re-attaching the prop adapter to the gearbox - one miniscule droplet of CA glue in the wrong place can ruin your GB05 gearbox, so make sure you apply only the smallest amount of glue from the tip of a toothpick or Microbrush dipper.

Watch the video tutorial to see how it's done/