I'm not saying this is the reason, you'd have to ask MT, but if you check the O-470 TCDS note 5 says the K has a different crankshaft damper configuration. Myabe the earlier (A&J) damper isn't compatible with the MT props.

All variations of the -470, -520 or -550 on C180/182/185/206/210 are approved on our STC for the MT prop conversion. The 3-blade requires at least 270 HP to drive it...PPonk engines always dyno more than book power.
John

I posted this on my resto thread, but thought it would be good info on this thread also...

The 82" McCauley 2A34C20390D I removed was 55lbs. The 2 blade MT was 41. (spinners not included)

Is the MT 82" as well Greg?

Greg,

I'm curious as to the length (diameter) of the MT prop you're going to? Is it longer than the removed McCauley?

I have no experience with the 180 MT prop installations. I do have a lot of experience with the smaller MT props and some with the MT props on the bigger engines.

I can tell you that much if not most of the "information" out there regarding the durability of the composite props is provided by folks who have no direct operating experience with the props. In other words, there's a lot of hearsay out there. We all know that hearsay is the staple of aviation, of course.....but.

Before I put an MT prop on our Husky, I did a lot of talking with operators of composite props.....we installed the first MT prop on a Husky in the US....via field approval, almost minutes before the STC was approved.. so there wasn't much in the way of track record for MT props in this country at the time. The MT props had been in service in Europe previously, though, and I spoke with those folks.

But, to me, one of the real testaments that put the durability question to bed was talking to the Chief of Maintenance of an operator of Beech 1900s that operated largely off gravel runways. Those airplanes were all equipped with composite props (not MT, but still....), and consider that those props are driven by huge power, are operating very close to the surface, and are mounted directly forward of the main wheels of a heavy aircraft, where they are most apt to get hosed by gravel coming off those main wheel tires, as well as the spray of gravel coming off the nose tire.

I asked that gent about maintenance on those props. He laughed and said their biggest maintenance expense is Marine Tex. Huh? He said there is no leading edge erosion, as on metal props, because the leading edges of the blades are stainless, just like the MT props. The leading edges get beat up, but eventually, at overhaul time, they get new leading edges....much cheaper than new blades. And, he pointed out, they never had to replace a blade due to a crack initiated by a rock ding, like sometimes happens with metal blades.

The Marine Tex? That's to seal up the small dings on the face of the blades, where a rock ding knocked a small ding in the surface.....

So, props that spend much of their daily work sorting gravel are holding up really well. Go figure.

We put an MT on our Husky, and ran it for many hours--on floats, skis and wheels, and nary a problem...till an incompetent instructor pilot borrowed the airplane and managed to get it upside down on a gravel bar.

That pretty much ruined the prop, but the good news there was that even though that prop took a hell of a whack, the prop shattered, and the expensive part of the drive system...the crankshaft, was straight as a string when the engine was torn down. Everything in that engine was re-usable. I doubt that would have been the case with a metal prop.

I bought an MT prop from Flight Resource for my 170 with O-360, and it was simply the best thing I ever did for that airplane. In that case, the difference in weight of the props and spinners was 19 pounds. That said, the MT prop was also 3 inches larger in diameter than the Hartzell it replaced. I was also able to remove a ten pound harmonic damper assy, which had allowed me to run the 80 inch Hartzell, so my total weight reduction was 29 pounds.

Smaller prop, of course, but FWIW.

MTV

I'm pretty sure I have the same prop on my 180 with O 470 K. It is 83 inches. I took a 1999 year of mfg, 88 inch Mac with big polished spinner off. The MT spinner is definitely lighter than the chrome one I removed

180Marty wrote:I'm pretty sure I have the same prop on my 180 with O 470 K. It is 83 inches. I took a 1999 year of mfg, 88 inch Mac with big polished spinner off. The MT spinner is definitely lighter than the chrome one I removed

So how was the performance difference Marty? Besides the weight, does the MT pull harder than the 88" Mac?

I can't give any pulling test results but find it smoother and quieter. I think I believe the test numbers on the MT website.

Thanks Marty. I guess I was wondering more if you find it pulls harder. I can't seem to find pull tests on the MT website, but maybe I'm not really sure where to look on that on either. Most of the comparisons that they make are with a 82" metal prop, no mention that I could find vs the 88".

http://flight-resource.com/Performance.aspx

Down at the bottom where the asteriks are they mention the 88 inch in the 180 PDF

OK. Ya I spoke with John today. He said they couldn't get a hold of an 88" 2 blade when they were doing their testing, and thus couldn't post the results. He says performance wise they are very very close, but the MT will he smoother, quiter, and like to run at a lower rpm then the macs due to the wider chord. John is a great guy and very pleasant to speak with. I thoroughly enjoyed the time he spent speaking with me about it.

MTV,

Question for you. I have a Cessna 175TW with the 0-360 and the Hartzell Top Prop. It's a great prop but there is a good deal of weight up there. I've been watching this thread and considering the upgrade to the two blade MT. Was the Top Prop the one you changed out for the 83 inch MT prop? Will it out pull the Top Prop? Thanks.

Apart from being smooth, and light, quick power response is nice on the MT, and my favorite is the braking power, full pitch retard throttle and it is like an airbrake, great for short strips, you can do very steep approaches.

motoadve wrote:Apart from being smooth, and light, quick power response is nice on the MT, and my favorite is the braking power, full pitch retard throttle and it is like an airbrake, great for short strips, you can do very steep approaches.

So did your old two blade not give that air brake feel? I feel that my hartzell 3 blade is like a brake as well. When I push it in, it will pull me into my harness if I want it too...

Neb12 wrote:MTV,

Question for you. I have a Cessna 175TW with the 0-360 and the Hartzell Top Prop. It's a great prop but there is a good deal of weight up there. I've been watching this thread and considering the upgrade to the two blade MT. Was the Top Prop the one you changed out for the 83 inch MT prop? Will it out pull the Top Prop? Thanks.

There are three (actually just two....one with shorter blades) Hartzell props approved on the O-360:

One is a 74 or 76 inch prop, mounted in the compact hub. The original engine STC called for a
74 inch prop, but I know a few which have had 76 inch blades installed. The Standard Husky prop (and Scout, etc) is this prop with 76 inch blade diameter.

Second is the compact hub with an 80 inch blade diameter. This prop requires a 10 pound harmonic damper assembly to be mounted as well. This prop was originally used on the small engine Pawnees, with blades of 84 inch diameter, but the blades were cut down for harmonic vibration when adapted to the O-360.

Finally is the MTV-15 prop, which is 83.5 inches in diameter.

I ran all three of these props (the 74 inch Hartzell, the 80 inch Hartzell and the MTV 15 prop) on my Cessna 170 on floats, wheels and skis. I also ran all three of these props on a couple of different Husky airplanes, again on floats, wheels and skis. I have around 2000 hours total in aircraft with MT props.

The MTV 15 prop out pulls the 74/76 inch Hartzells, hands down, in every category imaginable. Period.

The MTV 15 prop and the 80 inch Hartzell pull about the same on takeoff, or at least close enough that it's pretty hard to tell the difference. The MTV 15 prop climbs better than the 80 inch Hartzell, and in cruise, there is simply no comparison. The MT prop loves relatively low rpm operation. Pull that prop back to 1900 rpm or so, and watch your fuel flow drop way off and your cruise speed is still great. Think about the big turboprops.....since they are reducing turbine speed to drive the props, they can choose any rpm range they want for maximum prop efficiency. And they mostly run around 1800 to 1900 rpm or lower rpm. That is where a propeller is most efficient, generally.

In addition, consider that the MTV 15 prop is 29 pounds lighter than the Hartzell with 80 inch blades......That is an honest difference, and it's HUGE, especially taken right off the bow.

The MT props are turbine smooth as well. The Hartzell with the harmonic damper is better than the non dampened Hartzell, but nowhere near as smooth as the MT prop. Not even close. Is smooth important? Consider the wear and tear on fasteners, airframe, avionics and instruments as well as fatigue on you and passengers......

Finally, I vowed to never buy another Hartzell product. Hartzell has apparently adopted a liability averse program of simply issuing AD notes on their propeller hubs at various intervals. So, while you may save a couple bucks initially on a Hartzell prop, within a few years, I'm betting Hartzell will issue an AD that will either condemn your hub or require it to be overhauled. I had two Hartzell hubs condemned by two different AD notes, issued by Hartzell. That's when I went to the MT prop on my 170.

I wouldn't hesitate a bit to put another MTV 15 prop on an airplane with an O-360. Also, the support from Flight Resource is phenomenal. You can't beat that combination in my opinion.

MTV

My old prop was a 2 blade Hartzell, it didnt give me as much braking as the MT, the difference is impressive.

mtv wrote:.... consider that the MTV 15 prop is 29 pounds lighter than the Hartzell with 80 inch blades......That is an honest difference, and it's HUGE, especially taken right off the bow.
..... Hartzell has apparently adopted a liability averse program of simply issuing AD notes on their propeller hubs at various intervals. So, while you may save a couple bucks initially on a Hartzell prop, within a few years, I'm betting Hartzell will issue an AD that will either condemn your hub or require it to be overhauled.
....

Losing 29 pounds is great, but taking it off at the extreme forward end of the airplane maybe not so much depending on where your CG is now. That will shift the CG aft, so better be sure to crunch some numbers to see where the loaded-to-the-gills CG would be with the lighter prop-- both with lots of fuel and after burning most of it off.
Re Hartzell ADs-- while I've never owned a Hartzell, MTV's comments mirror the experiences some of my friends have had. Maybe they should rename the company AD Prop.

O360 Lycoming use...

I cross-dress with floats, nothing beats MT for durability, W/B, smoothness and sound. Aluminum (alloy) props have cost a lot in corrosion for me next to salt water, MT has had zero corrosion. It is still "out of the box" shinny and being used in brackish water. Being introduced to MT was a tremendous delineation, blows my mind what that prop does.

MTV and all,

Thanks for the input. You folks have a wealth of knowledge and your honest sharing is appreciated. I dislike all the extra weight I currently have up front with the Top Prop. I've been trying to justify getting rid of a perfectly good prop with only 200 hours on it in order to buy one that's even more expensive (the MT). I think all your comments have pushed me past that decision point now. I'll let you know how things work out. Thanks again.

Neb12 wrote:MTV and all,

Thanks for the input. You folks have a wealth of knowledge and your honest sharing is appreciated. I dislike all the extra weight I currently have up front with the Top Prop. I've been trying to justify getting rid of a perfectly good prop with only 200 hours on it in order to buy one that's even more expensive (the MT). I think all your comments have pushed me past that decision point now. I'll let you know how things work out. Thanks again.

Don't forget that a 200 hour Hartzell with a compact hub has value. Those props are the favored prop amongst the RV crowd. Do some advertising, and I'll bet you can recover a fair bit of your original investment.

I really don't think you'll regret the switch to an MT prop. Give John and Larry at Flight Resource a call.

As to removing 29 pounds from the front, bear in mind that ten of that is the harmonic damper assembly, which wasn't required for the original prop. So, in effect, you're only removing 19 pounds from the nose. In my 170, it really wasn't an issue at all. I always hit max GW easily before I could get it out the back of the CG envelope. Of course, I never put heavy stuff in the aft baggage.......Intelligence in loading is always a good practice, and if you're loading one up, there's always ways to move the CG with the load.

MTV