Hey Jack... Stay away from gettting a 3-blade prop. They look nice but
you'll probably lose speed on the cruise side and you could end up with
a vibration that you can't get rid of. That could turn out to more
repairs as the vibration causes other issues to be repaired later. They
aren't really meant for 4 bangers.

Good news for you is that you get to split everything by 3!! :-)

Merry Christmas
Jon Kraus

Jack Allison wrote:
I found out a few months back that we're affected by the recent Hartzell
prop hub AD...requires an eddy current inspection on the front half of
the hub within 50 hours TIS then every 100 thereafter *or* annual,
whichever comes first. So I made it to the prop shop this week and the
good news is that we have no cracks in the hub.

The not so good news is that going the route of replacing the hub
doesn't make sense for us as we might/might not have another overhaul
remaining on our current blades. The prop is original and has three
overhauls on it. The shop took some measurements and it was close
enough to minimums that they wouldn't know for sure unless the paint was
stripped and measurements were taken with the prop off the plane. If we
do have one overhaul remaining, we'd be looking at just north of 4 AMUs
for a new hub and an overhaul. That's a ton of cash to sink into a prop
with a pair of last run blades. Another option would be a reseal vs.
overhaul (along with a new hub)...but we'd still be paying approx. 1/2
the price of a new 2-blade prop.

Next option, repetitive 100 hour inspections. The inspection costs $300
and it's $50-$60 in gas for a round trip to the shop. By the time you
eat two hours off the engine reserves (which is how we handle
maintenance flights), this gets expensive over the long haul. We're
1000 hours from the recommended TBO from Hartzell (2000 hours or 72
months...and we're at 96 months SPOH). Another 1000 hours on the prop
would mean $3500-$3600 down the drain for repetitive inspections and
we'd still need a new prop someday. Nah...at some point before the next
overhaul, we need to consider a new prop.

Next (and most expensive up front) option, a new prop. The quote from
the shop for a McCauley 2-blade prop/hub/parts to use our existing
spinner was 7.002 AMUs. This is with trade-in on our current hub and
blades but doesn't include installation. I didn't get quotes on
Hartzell props nor for a 3-blade McCauley. While I like the looks of a
3-blade, IMHO, the added up front cost and increased overhaul costs
don't justify the performance benefits. Plus, I've read from a few
Arrow/Lance owners that while they get improved climb performance and
less RPM limitations, they lose a few kts. in cruise. Added weight is
about 10 lbs for the McCauley so that's not a big deal.

So, now it's time for the partnership to ponder our options. I'm
betting that we decide on repetitive inspections and to up the per-hour
costs a tad in order to stash some extra cash away for a new prop. Our
existing prop is in good shape so we should have a few years to save up.

As JayH said, it's always something :-)

If someone sees Santa, would you pass along that I'd like a new McCauley
B2D34C213 prop (Piper part # 550-974)?

Merry Christmas all. Here's to hoping Santa brings you some cool flying
toys, maybe some good flying weather, or, perhaps sends the elves to fix
the plane in the middle of the night.