MT 3-Blade Prop Installation

[Rustler]

The MT 3-blade prop has been installed on my '80 M20J, and I have flown a little over 5.5 hours behind it. It has been a positive experience in all respects. The prop was removed not because of a prop strike but because it sustained a rather large nick shortly after the engine was overhauled. My A&P/AI was not convinced it could be overhauled successfully. The nick had been filed out, but I didn't relish the idea of that tip coming off in flight.

Saturday I flew from San Marcos, TX, KHYI, to Taos, NM, KSKX, in very windy conditions--at one point 55 k directly on the nose. As a result, I can't give you a reasonable report on cruise performance, other than to say that throughout the flight I was calculating TAS of 150 k, almost exactly what I had with the 2-blade.

Climb performance is enhanced. At departure, the temperature was 47 F, no wind, and I was looking at 1200 fpm at 95 knots indicated. This is perhaps 150-200 fpm more than I experienced previously. The airplane just feels more aggressive and powerful.

Cruise is where the most difference is noticed. It is considerably smoother. I jokingly said one could place a quarter on edge on the glare shield and it wouldn't fall over. A stretch, yes, but not by much. With this prop as it came from the factory, the engine runs much smoother than either my former Cheetah did with a dynamically balanced prop or the Mooney did with the balanced prop that we removed to install the MT. This translates into much less body fatigue over a long flight like Saturday's.

The noise level seems to be lower. I have not run pre/post dB or Sone comparisons, but I did not experience as much cabin noise as I did before. I wear an ANR headset that is very effective, so I can't analyze the noise reduction. It was more comfortable to me.

Was it slower to respond to pitch-change input? Not that I noticed. On runup, the time it took to cycle the prop seemed the same as it always has. In flight, it is very responsive. I don't make radical changes in pitch, so I can't comment on that situation.

My A&P/AI said I had a surprise coming the first time I stood outside and heard the airplane taxi. He says it sounds like a small turbine. We'll see.

In the long haul, I think the prop has several advantages. First, it is about 9# lighter than the existing 2-blade, which translates into more engine power going to the prop and less of a stress being placed on the front crank bearings. It also helps reduce forward CG. It is field repairable, including repairing tips in the event of a prop strike, in multiple locations across the country. The vibration-dampening effects of the spruce and beech used in its construction have to be beneficial to the engine. The prop hub is a thing of beauty and guaranteed forever.

Was it expensive? Yes. But since I had to do it anyway, and no insurance was involved, I figured I'd bite the bullet. Judging from this early experience, I'd do exactly the same thing given the same circumstances. Would I just remove an existing 2-blade and install the MT? I'd have to think long and hard about that.

[docket]

Is that a composite prop? 

[Rustler]

Docket--

Yes. It has a wood core (laminated beech at the root and laminated spruce for the remainder of the blade) and is then wrapped with Kevlar, fiberglass, or similar material.

[docket]

cool, that is an awesome prop.  I have a screaming eagle and I was thinking about that prop just because it gives a better climb rate.  in houston, when it is hot, climb rate is king.

[KSMooniac]

Thanks for the PIREP!  That is on my radar too, and I would appreciate some careful TAS runs when you get the chance.  My '77 has the original square-tipped McCauley which is not as good as the later models IMO, so I could perhaps get even more improvement with the MT.

[defrkm20j]

Guys,

being a little patriotic I just want to mention that is made in Germany.

I have been flying this prop on our M20J for quite some years and am very happy with it. 

I flightplan with 150kts which is always achievable. Maybe on the initial T/O the 2-blade is slightly better.

As noise abatement is a real issue on this side of the pawn it´s a real winner. As well if you get a propstrike during landing it will most likely not do any damage to your engine. As well you have a larger gnd clearance which comes in handy on unpaved rwy´s.

Happy landings

[Vref]

Hey there,

Is that the old three blade or the new scimitar MT prop?

It seems the MT scimitars perform better during take-off climb, bit slower below 5000Ft but better then the two blades in the above 7000 Ft range...

What signifigantly is important to me is the reduced weight, less vibration and significant noise reduction in and outside..

rgds

[Rustler]

It'is the new scimitar design. (See pic below)

Living in Taos, NM, I park at 7100' msl, so I regularly fly at 10,000' + and can't tell you too much about performance in the 5,000' range. As I said, on my return trip a little over a week ago, I was truing at 150 k, but the headwinds were so strong, I can't call that a fair representation. I intend to do the standard square pattern one day to see what I'm getting. The climb is better, but the biggest difference I noticed was the smoothness.

 

[Vref]

Hi Rustler,

Thanks for the Pic. Nice aircraft. IN 1994 I visited a friend in ABQ and  I flew in a rented 172 to Taos. Quite impressive flying over there specially when over the rwy threshold the canyon drops..;-)...

Yes I can understand with the three blades take off performance is a bit better..;-)