Yet another prop balancing thread

**RknRusty** Sun Aug 05, 2012 8:26 pm

I was about to post this as an answer to Ron's comment in the "Where is everybody" thread, but since I've been asked via PM about the topic, I'll start yet another prop balancing thread.

cribbs74 wrote:
RknRusty wrote:I've been sitting at the work table meticulously balancing props, a time consuming affair that I always put off too long. Now that I'm having to take it easy for a few days, sitting, sanding, reaming and staring at props going slowly round and round is amazingly relaxing. And I was able to concentrate enough to realize I've been doing some things the hard way and others just plain dumbly wrong. Ohmmmmmmmmmmmmmmmmm

Looks like things have picked up today Rusty. I need to buy more props to balance. I have busted 3 in about a week. The grey 5x3's work great unfortunately they snap like twigs on rough landings.

I'm a big fan of the Windsor Master Airscrew 6x3, by far my favorite prop. I cut them all down to 5", 5.25", and 5.5". Sometimes one will balance right out of the bag. Most have a heavy blade and it's always the blade that has 0603 stamped on it. The first thing I do is cut it to size and shape the tips. The front hole holds the screw too tightly to allow it to center on the engine or the balancer. So next I ream the front hole till the screw has adequate play, and then plug a 1/8" long fuel tube donut into the wide rear hole(the one that's always centered) and balance it. It fits loosely, so I moisten the balancer rod to insert it so when the donut expands with the rod(same with the prop screw), it will not deform. Like all props, the rear hole is the one that is centered when it's molded. You have to use the flat sides of both cones.

If you tape a patch of 220 sand paper to the edge of the table, it makes it easy to press and evenly sand the whole backside of the heavy blade. Once in a few you have to knock off a tad of one side of the hub. Usually 15-20 minutes of sanding and testing nails it perfectly.

I twist a fresh prop screw through it to hold the spacer tube and drop it in the "balanced bag." They stay balanced for a long time and lots of punishment too. I've never broken one.