Prop tracking correction
 

Hi All,

I have a new APC 13x6 prop and I have balanced it on a Dubro balancer. I checked the tracking and it is off by about 1/16" to 3/32" at the very tip of the prop. First, Is this to much out of track and if so how does one correct it?

Thanks

Tom

RE: Prop tracking correction
 

Don't know. Never checked that. I just balance them.

RE: Prop tracking correction
 

It is hard to correct it if it is already bored to fit the crankshaft (did you use the appropiated tool?), you have to be careful to avoid excesive vibration which may cause harm in the engine, servos and/or the airframe.
The indicated measure (1/16 or so), is not to be worried about but good to tell to the manufacturer so they can improve that.

Best regards.

Alfred

RE: Prop tracking correction
 

The track changes again as the engine is run because the Blades flex

The drive washer and prop washers should help correct this?

Were you checking the prop on the engine or on the balancer mandrel?

RE: Prop tracking correction
 

I checked it on the balancer. But, Now that I think about it, thats not a good way of checking it. The balancer holds the prop by way of the shaft hole, but the tracking will be determined by the allighnment after the prop is installed on the prop shaft with the hub tight between the washers. So, I believe the tracking will be more dependant on the truness of the hub faces, particularly the rear face. I am going to check it after installing it on the engine, after all, that is where it will live it's life.

RE: Prop tracking correction
 

It is 100% dependant on the trueness of the hub, not the hole. All the hole does is locate the prop to the center of the shaft and provide a location for the nut to clamp the prop to the hub. To check tracking, install the prop and tighten it. If it's off, you can sand the back of the hub and rebalance. For future reference, do that first before balancing since you may need to remove material to get it right.