Propeller hub dressing ?

[Darren S]

I just got my baby back from an annual. One snag that was found was the Hartzell C/S prop was rubbing on the spinner and the backplate when at full coarse setting.

At rest there is adequate clearance but no one has ever checked the clearance at full coarse otherwise the problem would have been found earlier !!

I will post a picture when I get home, but wanted some opinions on how to dress this area.

I've read posts on dressing the blades but nothing on the hub of the prop right around the spinner.

There is wear through the paint but no deep grooves in the hub, just looks like scratches on the aluminum. There is exposed aluminum though !

It wouldn't take much effort to smooth it out. My idea was to use 400 grit, 600 grit then 1000 grit wet/dry sandpaper. I could likely keep the affected area to the size of a penny.

This will smoothen things out but how to alodine, prime and paint ? I don't want to paint the whole prop. Can I just use a paint brush to do the applications?

Should I even fart with it or just suck it up and take the prop off and take it to a prop shop ?

Thanks,

Darren

[Ironflight]

Post a few pictures Darren - we had a similar problem on Louise's -6 a few years back, except you could actually feel a groove in the aluminum, not just the paint. Prop shop told the local A&P to simply dress it out, and it turned out fine. She repainted the whole prop, but only because the whole prop needed it - I'd think that you could easily do a spot touch-up.

Definitely open up the holes in the spinner as well - you can easily move the prop through the range of pitch with a couple of 2x4's strapped to the blade as a lever.

Paul

[Flying Scotsman]

Originally Posted by Darren S

Hartzell C/S prop was rubbing on the spinner and the backplate when at full coarse setting.

Was it actually rubbing on the *backplate* itself? Or just the spinner or fillers?

[Darren S]

Ok, will post some Picts as soon as I quit digging in peoples' mouths

And the prop was hitting the fillers not the back plate. My mistake. Hopefully it is something I can do myself, including the paint

[777drvr]

I was wigged out when I noticed some grooves caused by the same issue . I took detailed pictures and had a prop guy at Leavan's Brothers in Toronto look at them . He just said to dress them out . I did and put a little primer over it .

Marc

[Darren S]

I took these today on my way home. My plan is...... unless someone advises against it, is to lightly file the one spot that is the deepest, then use 400, 600 grit wet dry sand paper till she is smooth.

Then mask off the small area, spray with Zinc Chromate and then black automotive paint. The area should be small and once smooth should be better than leaving as it is.

The picts are of the damaged areas.

Let me know your thoughts. Thanks.

Darren

[mcencula]

...by following what Dan Horton advised in this thread.

Mark's pictures at the end of the thread show a good repair...the same kind of thing necessary for the prop.

[Walt]

Some good info here on propeller inspection and repair:

http://rgl.faa.gov/Regulatory_and_Gu...C%2020-37e.pdf

[Toobuilder]

Originally Posted by Darren S

...I've read posts on dressing the blades but nothing on the hub of the prop right around the spinner.

There is wear through the paint but no deep grooves in the hub, just looks like scratches on the aluminum. There is exposed aluminum though !...

First off, the pictures appear to show scratches in the blades, not the hub... I looked at this thread to try figure out how your hub (the thing bolted to your engine which keeps your blades from flying out) was "moving".

Anyway, I had to open up my spinner to provide clearance for the blades at full coarse. I needed this modification to the spinner after I modified the coarse stop to provide more angle (was running out of angle in a dive, causing overspeed). Your scratches don't look too bad, but they should certainly be dressed. Stress risers are a killer! I lost 4 inches off the tip of a prop once as a result of a tiny nick on the trailing edge. This progressed from a "flyable, I'll get to it later" minor nick to complete failure and forced landing in ONE flight!

If you decide to blend, keep in mind that each area of the blade has different damage limits, with the most critical near the root. There should be plenty of guidance on the particulars of your prop, but if all else fails, call your prop shop for advice.