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Running engine without spinner


Well Known Member
I’m about to get my hartzell blended airfoil prop back from overhaul and was wondering if it can be run ,to check low pitch stops, without the spinner. I’ve read somewhere that doing so would bend spinner mounting brackets but not sure what setup it was.
I would be hesitant to run it without the spinner if your spinner has the little close outs behind the blades. I would be afraid they would bend out from centrifugal force. Replacing them would be more time than just putting the spinner back between tests. (If the entire spinner and fillets come off, then it’ll be ok to run.) you could also leave every other screw out to save time between run tests, but a drill set the clutch to 1, makes simple work of pulling and installing the screws.

The last two hartzell props took 2 1/3 turns in on the center Alen key. I would start there and will luck, you’ll get it on the first try! I like 2650 RPM static, you’ll get 2700 at about 50 knots
Take the plates off behind the prop blades. If you dont, you will damage them. Everything else will be ok.
To get those plates behind the prop blades off you have to remove the prop…
So install the spinner as normal & deal with the 15 minute R&R time as time well spent.
I lived the blade close out bending nightmare. My setup was a Sensenich fixed prop and aluminum spinner. The damage occurred above 1800 rpm.
Happened to me, too, on a Continental O-470 and McCauley prop. Took a while to get a replacement part and it wasn't cheap, either.