MT Propeller

[Rustler]

Has anyone had experience with MT Propellers' 3-blade composite on a J model? I am getting closer to overhaul time and have wondered if that prop might not be a good addition to a new engine.

Thanks.

 

[fantom]

I believe Tom at Top Gun in CA has one on his J, and is working on an STC for it.

http://www.topgunaviation.net/topgunaviation/index.html

 

 

[Rustler]

As I read it, the STC exists, so that shouldn't be a problem. What I'm interested in is anyone's experience with the prop.

The reason this is on my mind is that my local Mooney shop grumbles about 3-bladed props, as well as PowerFlow exhausts. My experience with the latter has been excellent, so I'm really curious about the prop. It just seems intuitive that the lower weight up front would be a plus, and it is my understanding that climb is enhanced with the 3-blade.

 

 

 

 

[KSMooniac]

I concur with Jim's assessment, as long as your McCauley is the model that came on the '78+ 201s.  It is better than my '77 version, so an upgrade is on my wish list.  I've read good things about the MT, and the typical complaint about 3-bladers on 4-cylinder Lycomings (ie vibration) does not apply to the lightweight composite MT prop.  The wood core and composite skins on the blades damp out engine pulses much, much better than metal, so once it is installed and balanced it ought to run smooth.  I think the main problem is the price...   I would also be concerned about longevity and service costs, but I don't know much about the details of the construction and MX requirements either.

[Rustler]

The problem, all other issues aside, is the price. I called today, and they're great to chat with on the phone; but the bottom line is that the MT prop for a J model is going to run in the neighborhood of $14,000 + by the time it is installed. I'm sure they're great, but it is very difficult to justify that much expense, especially when the McCauley drags that airplane along at only 2-3 knots less than the 3-blade.

Thanks for the responses.

[KSMooniac]

Did you get a breakdown of the expenses that add up to 14 AMU?  I thought it was in the neighborhood of 10 AMU complete, with an STC so you wouldn't have any field approval expenses.  I think the newest Hartzell Top Prop 2-blader is ~7 AMU.

[Rustler]

The basic prop is ~12.5 AMU. It can come to you two ways: assembled, crated, and shipped in a wooden container from Germany, or in pieces and shipped to a distributor near you, there to be assembled and installed. There are shipping and crating expenses either route you choose; there are assembly charges the latter route.  It comes out to be around 14AMU. It comes with STC, no field approval necessary.

[KSMooniac]

Yikes, that is not even remotely competitive.  When we had this discussion not too long ago on the MAPA email list I thought it was reported to be in the 10 AMU range.  At twice what a Hartzell costs and 8-10 times what an overhaul costs I don't think they'll sell any.

[Rustler]

Accdording to the conversation I had yesterday, they have to be special-ordered from Germany. 3-5 weeks or more lead time. That means to me that they aren't selling many.

[dlthig]

What about the 2-bladed scimitar prop that's approved for the Arrow?

[Rustler]

Just had that conversation with a fellow at San Antonio Propeller this morning. I'm having to have the prop-blade seals replaced on my McCauley and asked about both the scimitar and the Hartzell 3-blade.

He didn't recommend the scimitar because he said they have experienced vibration on C-182 installations. I don't know exactly how that relates to Mooneys, but that was the gist of that conversation.

He did recommend the Hartzell 3-blade, however. They'll sell one for $8900 and give you ~1 AMU for you old prop. The weight difference is 17-19#.

 

[KSMooniac]

Wow, can't believe he would discourage the 2-blade Top Prop on your 4-cylinder Mooney and encourage a 3-blader!  It would be heavier, more expensive, and slower....perhaps it was because they had one in stock?  The C-182 installation has no bearing on the Mooney installation as you suspect too.

[airkraft]

I would be very hesitant in installing a 3 blade prop. on a 4 cylinder Mooney.  The M-T prop may be an exception, but it's very pricey.  I've read many an account of negative vibration issues with the metal 3 blade, as well as reduced cruise speeds.

I have had the Hartzell two blade scimitar Top Prop on our 1966 E model for almost a year now.  No vibration problems and picked up 2-3 KTAS in cruise.  We paid somewhere around $7K direct from Hartzell.

The original "pointy" spinner as supplied with the kit developed a crack before 25 hours in service.  Hartzell was outstanding in their warranty efforts.  The new style spinner is holding up just fine. 

[Rustler]

He didn't discourage a 2-blade, just that one.  He also didn't encourage the 3-blade, just indicated what he thought. We have had a Mooney owner on our field remove the 3-blade that his plane had on it when purchased, replacing it with an original 2-blade, which gives me pause.

For now, I think I'm leaving well enough alone. If I continue to have problems with the blade seals leaking, then that will be another story.

[knute]

Howdy!  I guess I felt my ears burning;  I have an MT prop on the front of my E model...

Reading through this thread, a couple of points of clarification are in order:

1)  the MT prop that Tom and Mark Rouch have on their "F" model is the older rounded tip blade; I have the newer "scimitar" blade which is supposed to be more efficient, but I don't have hard numbers to compare.  Both props have an STC for the E,F,J models.  (There are also variations for the K and the Bravo, as far as I know)

2)  Be VERY cautious about putting one of these on order before doing the checking to make sure the STC is compatible with the STC for the Powerflow exhaust.  I had an aircraft on the ground for two months because I have a Horizon digital tach that was STC'ed for specific engine/prop combinations (related to restricted RPM ranges)  The horrible irony in my case was that although the MT prop does not have a restricted range, the Horizon could not be programmed for it within the bounds of the STC because the MT prop wasn't on the list.  I have not reviewed the Powerflow STC or the MT STC, but I'm gunshy of such paperwork incompatibilities.  For practical purposes, I don't see much of a problem, because Diamond put basically this prop in front of an IO-360 on one of the recent versions of the DA40.

3) The prop is deliciously smooth-  I recently had a dynamic balancing performed, and it got down to .009 inches per second, which is about as good as it gets.  I love it!  Smoothness is definitely not a problem with this prop.

4)  I can't speak to the current pricing or lead time, but when I ordered mine back in November, 2006 it was less than $10,000.  There was a several month wait for the prop to be manufactured, but the bigger problwm was that the expected STC did not materialize until November of 2007.  I also learned that if you do enough sleuthing, you can find out which FAA examiner is working on the STC, and if you ask them really nicely, they'll tell you what the status and open issues are before they firmly tell you to please not contact them anymore.  The MT guys were very communicative during the process, but equally frustrated by the slow pace of the STC approval.  I learned that "almost completed" means another year or so in aviation speak.  Now that the STC exists for this prop, not an issue!  The price of $14,000;  is that current, or does that take into account recent fluctuations in exchange rate that make the euro a better buy for our american dollars?  Sounds high to me.

5)  The blades have virtually unlimited life.  The leading edge has a (replaceable during overhaul) metal strip, so even though the blade is wood encased in resin, the metal strip takes the brunt of whatever gravel or crunchy bugs the prop swings through.  Aluminum experiences "work fatigue", wood does not, and because the wood is completely impregnated and encased in the resin, it does not rot because it isn't exposed to oxygen or moisture.

6)  I've heard of spinner issues with the Top Prop, but the MT spinner I have has had little or no issues.  It required a small shim of mylar tape to fit snugly on the bulkhead, but no cracking or creaking of any kind.

I'm very happy with it!

-Knute

'66 M20E - KSQL (San Carlos, CA)

[knute]

Sorry- I almost forgot...

Cruise speed was pretty much unaffected; it's about the same.  (I see 152-156kts TAS in cruise between 6-9000 ft).  Climb rate improved significantly, and on a good day at sea level, I can see 1,300fpm with the 3-blade.

-Knute

[Rustler]

Thanks, Knute, and welcome!

The price quote I got was from Flight Resource Center, Gloomer, WI, on the 14th. I don't know what euro/dollar rate it reflected.

I still like the idea that wood doesn't set up harmonics, hence vibration. My current prop id down about .01 ips, so I'm OK there.

[Rustler]

Today's update. MT-USA in Florida has one. Cost breakdown as follows.

Prop $9500; Spinner ass'y $1250 ($10,750)

If shipped: $300 crate + shipping to your location.

Weight: 46# w/spinner

Big difference from what I was quoted by Flight Resource.

 

 

[KSMooniac]

Is that the scimitar design that Knute referenced?

[fantom]

Excellent rewview, Knute! Thanks.

I imagine your take off roll was reduced as well.

[fantom]

From the MT-Prop people at SNF last week:

Cost for all Lyc IO-360 engine props is $9,500....Spinner is $1,250....Shipping is free, less 10% when you mention SNF - but only for a short time. It is the Scimitar design blade, spinner and prop weight is 46 libs. when installed, and it replaces both McCauley and Hartzell props.

Claims almost vibration free, bonded on stainless steel edge for excellent corrosion/erosion protection, unlimited blade life, major inside and outside noise reduction, and equal or better preformance. Plus.......it looks cool!

MT-Propeller USA, DeLand, FL, 386-736-7762.  Caveat Emptor, as usual.

 

 

 

[KSMooniac]

Hmmmm....I think I'm gonna make a phone call tomorrow. 

[Guest Anonymous]

Quote: knute

Sorry- I almost forgot...

Cruise speed was pretty much unaffected; it's about the same.  (I see 152-156kts TAS in cruise between 6-9000 ft).  Climb rate improved significantly, and on a good day at sea level, I can see 1,300fpm with the 3-blade.

-Knute

[KSMooniac]

RFB, do you have an MT or something else?  Your pic looks like a McCauley to me.

[Guest Anonymous]

Yes,  it is a Mac.  I was referring to the 3 blade specualtions regarding vibration made earlier.  Sorry I didn't clarify.

RFB