McCauley Prop. TBO

Robert Eilers · Post by **Robert Eilers** » Tue Jan 08, 2008 8:09 pm

I have the MDM7653 McCauley installed on my 1952 170B. Reviewing the log books I don't find an entry indicating that the prop has ever been overhauled. The aircraft has 2053 hrs on it and I assume so does the prop. The pro is in great shape. However, researching McCauley sites I found SB137AA which states that a fixed pitch prop should be overhauled every 2000 hrs or 72 months. Is 2000 hrs or 72 month consistent with what is occurring in the 170 community?

Post by **GAHorn** » Tue Jan 08, 2008 9:36 pm

No. If your prop is in good condition, there is no reason to overhaul a fixed pitch prop (unless it's suffered damage or sudden stoppage.)
Re-touch and/or refinish it's corrosion protection (paint) and balance it dynamically and that's about all that's necessary for an all metal fixed pitch prop, if you are a FAR part 91 operator. (FAR 135 requires commercial/air-taxi operators to overhaul at mfr's recommended times)

Robert Eilers · Post by **Robert Eilers** » Tue Jan 08, 2008 10:31 pm

Thanks George - good news.

c170b53 · Post by **c170b53** » Wed Jan 09, 2008 3:34 am

From your post it sounds like the prop is not new to you. When was it last removed? If it was on the plane for sometime in my opinion it wouldn't hurt for the the prop to be inspected for corrosion, wear, pitch and track.

Post by **GAHorn** » Wed Jan 09, 2008 4:25 am

That's an excellent point, Jim! Corrosion can be especially insidious on aircraft stored outdoors. Water can get between the prop and crank-flange and corrode, and the prop bolts can also rust.
It's a good idea to remove the prop every 3-5 years and inspect that area in most airplanes, especially those exposed outdoors and seacoast conditions.
According to the Cessna inspection form, the propellor track should be checked every 100 hrs.

Robert Eilers · Post by **Robert Eilers** » Wed Jan 09, 2008 4:53 am

I have owned the 170 for two years and although I inspect the prop at each annual ( and regularly in between) I have not removed it since I purchased the airplane. The log books contain nothing that suggest the previous owner pulled the prop at 2-3 year intervals. However, the prop and bolts are in great condition and reflect routine maintenance. The one thing I have not done and will do is track the prop.

cessna170bdriver · Post by **cessna170bdriver** » Wed Jan 09, 2008 5:13 am

If you ever do pull the prop, make sure it goes back in the same orientation relative to the crankshaft (assuming it's running smooth now). If you lose track of where it went, put #1 cylinder at top dead center and install the prop with the blades at 10:30/4:30 as seen standing in front of the airplane looking aft. If you forget to do this, the vibration will remind you on the next flight. (No need to ask how I know

)

Miles

doug8082a · Post by **doug8082a** » Wed Jan 09, 2008 12:42 pm

gahorn wrote:That's an excellent point, Jim! Corrosion can be especially insidious on aircraft stored outdoors. Water can get between the prop and crank-flange and corrode, and the prop bolts can also rust.
It's a good idea to remove the prop every 3-5 years and inspect that area in most airplanes, especially those exposed outdoors and seacoast conditions.
According to the Cessna inspection form, the propellor track should be checked every 100 hrs.

That's exactly what happened to mine before I bought it (the first time). they found corrosion on the hub where it mates to the flange and ended up replacing the prop.

cpolsley · Post by **cpolsley** » Sat Jan 19, 2008 2:14 pm

I have owned my 170 for 22 years and for the first time removed my prop for overhaul a couple years ago. I had always inspected, cleaned and painted it but thought after 20 years it would be good to have it looked at by a prop shop. The overhaul as they now call it envolved stripping the paint, crack inspection, checking demensions, pitch and balance then re-painting. The overhaul cost was about $600.

The prop does seem have a little less vibration. Our props don't get to much FOD damage like the nose wheel airplanes do.

CP

Robert Eilers · Post by **Robert Eilers** » Sat Jan 19, 2008 10:16 pm

I believe I will also have my prop reconditioned. I suspect it is the original which would make it 46 years old with over 2000 hours on it. Interesting story about props. When I bought my Champ the owner had an old metal prop hanging on the all of the hangar (which I took over). He told me "you can have that prop but it ain't any good". So for a year and a half the metal prop hung on the hangar wall while I flew behind the wooden prop that was on the airplane when I bought it. After a copule trips with my Cub buddies I was disappointed with the performance of the wood prop. On a hunch, I took the old metal prop off the wall and to a Prop Shop and asked them if it could be reconditioned. I was told, "well it is getting a little thin, but we think you can get more service out of it". When I Installed the reconditioned metal prop on the airplane it felt like I had installed a super charger. The improved performance was incredible. I flew behind that prop for two years until the day I sold it.