The 170 that I'm buying has a 180hp conversion with a Hartzell constant speed. The prop looks kind of short and fat. The part # is F7666A. Does anyone know anything about this prop? Good, bad, or otherwise?

Pundy
This may be a start for you particularly the second thread on VAF about the prop not being within service specs. good luck.
http://www.google.com/search?q=hartzell ... =firefox-a

Thanks Glider. I have Googled it and saw that. My mechanic says it's an approved prop and has and AD that states the hub needs 100hr inspections. But, what I'm really looking for is whether anyone here has real life experience with it.

Yes, I have real life experience with that propeller on a 170B with a 180 hp engine. That is the propeller AVCON specified on its 180 conversions, but cut down to 74 inch diameter. I believe the minimum spec length for that prop is 72 for service limits.

The prop works okay, but performance would be MUCH better with a different propeller.

The bigger issue to me was and should be, the AD for 100 hour inspections. My propeller shop told me a couple years ago that they would do one more of those inspections, and then no more. What has happened is that Hartzell has basically dumped the liability for propeller hub failure onto the prop shop doing the inspections, and SOME prop shops have said, no more.

The inspection itself is no big deal, and not that expensive (I paid $150 each time).

So, I'd check with a prop shop in the neighborhood, and see what they have to say. And, remember, they can decide NOT to conduct the inspection at any time in the future. Also, figure a flight to their facility every 100 hours, and you CANNOT over-fly that time, period.

The other alternative is to have the propeller overhauled, and install a new hub. You'd be looking at around $4500 to $5000 for that piece of work.

Depending on the asking price of the plane, I'd tell them to overhaul the prop, or deduct the price of the overhaul from the asking price.

I would NOT buy one of those props without planning to overhaul it.

I bought a used MT propeller to replace my Hartzell, and if I have anything to say about it, I'll never own another Hartzell propeller. They condemned TWO hubs on my propeller before I finally came to my senses and bought a GOOD propeller.

MTV

The part number you reference F7666A is the blade profile. There should be something like HC-CY2K-1BF Additionally the hub SN is where the AD comes into play. A number without a suffix is bad. An A or B preferably would indicate the AD not applicable. I have this prop on an experimental with the A suffix. I like it fine, although I'd love to loose 20 pounds and go composite. So let me know if you need an A hub prop. MT props seem to be doing much better now but I know they had some growing pains. Overhauls having to go overseas and lots of downtime etc. There are a lot of folks who like MTV felt they got burned by hartzell on these props. I believe when the AD first came out they had a discount on replacement hubs, but it was still a chunk of change, especially if you had a pretty new prop. We have hartzells on several AG aircraft that get worked hard and they have been pretty good to us so I have some loyalty there.

Standard disclaimer about internet advice etc...

Jr.CubBuilder wrote:Did MT come up with an STC for our planes, or did you go with a one time approval? I think I asked you about the prop before, but I can't remember if you had it in the air or not at that point.

Joe Birkemeyer at Baumann floats has the STC for that prop on the 170. Baumann is part of Basler in OSH now, don't know if the STC belonged to Baumann or to Joe.

When the AD first came out on the Hartzell props, they offered to sell a new hub for "only" $1500, BUT the prop had to be overhauled. I had almost new blades, and in the overhaul, the blade butts have to be shot peened. You can only do that twice, apparently on the same blades. And, this was only about ten years after Hartzell came out with an AD for hub corrosion. My understanding is that virtually NO hubs passed that inspection, and mine didn't.

So, it would have cost me on the order of $4000 to go to the new hub and overhaul practically new blades. I suspect that in another few years, Hartzell will generate another AD to ensure that their liability risk is minimal.

MTV

I have a Maule Tricycle (MXT-7) 180, 0-360-C1F with Hartzell CS prop. Here is the info on the prop that came standard on the plane.
Propeller Model HC-C2YR-1BF/F7666A
Blades, F7666A
Hub Model, HC-C2YR-1BF
I don't know if it approved on the 170

Jim

I have that prop on my RV-8. I think it is a 76", then cut down from there. Mine is 72", with the new hub. It works well on my RV. I will agree, hartzell has a terrible track record

Pundy wrote:The 170 that I'm buying has a 180hp conversion with a Hartzell constant speed. The prop looks kind of short and fat. The part # is F7666A. Does anyone know anything about this prop? Good, bad, or otherwise?

Who's STC is it Pundy? Check and see if this prop assembly is even approved for that application.

I'm really looking for a prop that will get me the best climb. MTV, did you notice a large difference in climb performance when you switched to the MT?

Glidergeek wrote:

Pundy wrote:The 170 that I'm buying has a 180hp conversion with a Hartzell constant speed. The prop looks kind of short and fat. The part # is F7666A. Does anyone know anything about this prop? Good, bad, or otherwise?

Who's STC is it Pundy? Check and see if this prop assembly is even approved for that application.

That is the prop specified in the AVCON STC, with the proviso that the prop is limited to 74 inches. I doubt anyone would notice the difference if you had a 76 inch prop, though.

Pundy,

Yes, the MT prop makes a huge difference in both acceleration and climb. It's an 83 inch diameter propeller, and has a better profile than the Hartzell. There are a couple options if you want more pull: Buy an 80 inch Hartzell prop (same hub, different blades, plus a harmonic damper assy) or the MTV 15 prop. Both are stc'd. Hartzell owns the STC for the 80 inch prop, and Joe Birkemeyer (or Basler) own the STC for the MT prop. Both pull MUCH harder than the shorter props. A 74 inch Hartzell in really good shape is probably worth around $4500 to $5000 on the RV/Glastar market.

MTV