A plea for suggestions & sympathy

[Quint Van Deman]

All--

I think I'm cursed, or at least this Comanche is.
In trying to diagnose a vibration I had the whole empennage rebuilt (good work but not the vib source).
After going over everything thoroughly, including all of the great suggestions here, my A&P advised that he truly thought it was the prop.
Given that the prop was well overdue for an overhaul, I got a quote for $2900 and sent it in (East Coast Propeller).
My intention was to rehab the 3 blade Mc, get it dynamically balanced, and have a Comanche that was basically redone spinner to tail (overhauled the engine this summer).

Well, the wheels have officially fallen off. I just got off the phone with the prop shop and all 3 blades have failed inspection. Apparently there are stress cracks from 1-2" on all 3 blades from chips left undressed by the previous owner. Now I'm $2k into an overhaul with a good (but 14 year old hub) and no blades. The options being presented to me are:
1. Replace the blades ~$9k
2. Replace with a brand new prop ~11-12k
3. Pursue other options entirely

Does anyone have any advice on the pros/cons of replacing all 3 blades vs. going for a new prop? Does the old hub have any value that I could use to offset the cost of a new prop? Are there any reliable avenues to get an old prop?

At this point I think it's official, the Comanche has bled my flying treasure dry.
After buying her in old but reasonable shape for $30k,
I've doubled that in the first year and now I'm staring at another 5 digit bill.
This may officially be the beginning of the end of my Comanche experiment (which is a shame because she's fast & flies great).

Thanks,

-Quint

[Hank Spellman]

I think that there is an even larger question: are the cracks the cause of the vibrations or the result of the vibrations? In other words, is the problem really something else?

I don't know, but that is the basic question.

As far as the prop goes, there are a number of other options, including going back to a two bladed prop. There are several options there, probably cheaper than a new three bladed. Certainly the three blade looks sexier and gives a little more ground clearance, but the performance increase is in takeoff thrust and climb, not in cruise. A Comanche really does not lack in either takeoff or climb. In my book, sexy is not worth much.

Good luck.

Hank
Henry A. Spellman

[David Pyle]

Hank,

"Sexy is not worth much"...You got that right old guy. Note that I didn't say geezer.

[Quint Van Deman]

Thanks guys, the quote to repair my existing prop just came in at 11.5k.
I'm now getting quotes for a new 2 blade & a new 3 blade.
If anyone that's recently gone through the process has found a shop with a particularly good deal please pass it along.

Regarding the switch back, is the prop governor specific to the prop?

Thanks,

Quint

[Zach Grant L1011jock]

Not on the 180...same gov.
Zach

[Quint Van Deman]

[Quint Van Deman]

Just to ensure my self pity doesn't poorly reflect on a good shop, I will say that the guys at east coast prop were very honest and straightforward. I had issue with the news, but none whatsoever with them. In fact, despite offering multiple times to pay they didn't charge me anything for the inspection. I think they genuinely felt bad that a 14 year old prop was reduced to trash.

[N3322G]

Trying to look on the bright side - at least the prop held together and did not fling off a blade in flight.

Had an Apache friend who had that happen. Before they could get it feathered, the lopsided engine tore away from the engine mounts. At landing, the engine was loose and held in the nacelle by only the cowl skins. If this were a single, you would have had a deadstick landing.

Not making light of your financial outlay but glad it is that vs the alternative if you hadn't addressed the problem.