MT Propeller

[KSMooniac]

Just spoke with the MT rep...the SnF special is over.  I have some specific questions he couldn't answer, but he gave me the email of their chief engineer so I plan to ping him.  I didn't ask if there would be an OSH special, but it would not surprise me.  They have 1 E/F/J prop in stock right now, and try to keep 1 of those and 1 K prop in stock as part of their "normal" inventory of 5 props over here.  Otherwise, it is typically 6-8 weeks of lead time, with 50% due on order.

[testwest]

Some updates to this thread, I am copying some data from a PM to KSMooniac for everyone's benefit:

The latest STC'ed 3 blade MT prop (2007) for E's F's and J's is the MTV-12-B/180-59b. It has a swept leading edge profile similar to the Hartzell Top Prop BA...and is probably about as good as the Hartzell BA 2-blade prop for top speed. In case folks did not know, in addition to much better blade profiles and twist distributions achievable only with the latest computer-aided design and manufacturing techniques, these new props sweep the leading edge of the prop signficantly near the tip. Local prop tip mach numbers at high RPM cruise can approach transonic, and the LE sweep helps reduce the tip drag.

The Vans RV guys are really rabid about trying out new props and other speed/efficiency ideas, as experimental amateur-built airplanes they have signficantly more freedoms than we do but their very lively forum on the Vans Air Force website has several informative posts that us Mooniacs may find useful, like this one:

http://www.vansairforce.com/community/showthread.php?t=35385 and this one:  

http://www.vansairforce.com/community/showthread.php?p=251517#post251517

Some RV folks have found the 2-blade Hartzell BA to be faster, but on page 8 of the second (long) thread above is the following which is probably as credible as any post there:

On this Hartzell vs MT comparison, here is some data I gathered while doing Flight Testing on an airframe using an IO-360 Series 180 HP Lycoming;

Using the same baseline Flight Test a/c article (i.e. same s/n and no other Mods but the propellers), the following 4 propellers were tested:

MTV-12-B/180-17

MTV-12-B/183-59b

Hartzell 74 [in] 2 blade metal propeller

Hartzell 76 [in] 2 blade composite propeller ("canoe paddles")

All test data was obtained in a stable non-turbulent air mass with a near standard lapse rate and no inversions; The engine mixture setting was set at 150°F rich (best power) and power was calculated from a digital power model I created from the Lycoming published nominal power chart for the tested engine.

Test points were gathered from about 1.3 Vs to the MCP maximum level airspeed for the tested density altitude and same aircraft configurations (i.e. clean). Data was only collected when all parameters had been stable for a few minutes.

All data was reduced to referred power and referred speed using test BHP, SAT (Static Air Temperature), pressure altitude and, test point weight at time of measurement (a/c was weighed prior to the Flight Test and fuel burned taken from the totalizer). This method essentially brings the data to sea level standard day condition at a unique reference weight (usually max T-O weight); Hence, we are in a position to compare apples with apples.

All test instrumentation had recently been calibrated.

Assuming the MTV-12-B/180-17 as the baseline propeller, that is what I observed for

180 BHP(REFERRED):

- Hartzell 2 blade metal prop: +4.5 KEAS

- MTV-12-B/183-59b: +6.0 KEAS

- Hartzell 2 blade composite: +6.0 KEAS

Further analysis for that that airframe w/MTV-12-B/183-59b propeller revealed that the peak efficiency of that configuration using 135 BHP corresponded to an RPM following :

RPMPEAK = 2450 + (pressure altitude/100)

FWIW, I have found our Hartzell -F7497 2 blade BA Top Prop to be incredibly smooth, and there are no yellow arc restrictions like with the McCauley C212. I sold my old McCauley as is for $1900 on Barnstormers without much trouble. The Hartzell is less expensive than the MT, looks pretty cool on the ground, and is faster than the McCauley (3 ish knots or so) with about the same weight. The MT is more expensive, looks REALLY cool on the ground, "probably" climbs better than the Hartzell, and will be faster than the McCauley, and probably around the same speed as the Hartzell while being lighter.

A back to back comparison of the Hartzell -F7497 and the MTV MTV-12-B/180-59b on the same 200hp Mooney would be informative. I assume at least someone on this thread has the -59b MT prop flying at this time..... 

[knute]

Quote: testwest

A back to back comparison of the Hartzell -F7497 and the MTV MTV-12-B/180-59b on the same 200hp Mooney would be informative. I assume at least someone on this thread has the -59b MT prop flying at this time..... 

 

[testwest]

Awesome data, knute! If you have a stock(ish) cowl on your E you are getting very respectable speeds at those conditions. I was intrigued with your posts and was hoping to see some pictures, have you thought about posting some of your plane?

[roundout]

Quote: knute

Good stuff from the Vans people-  thanks! 

I posted a review about a year ago (earlier in this thread), and I should have been more specific in listing the part number for the prop;  I have the MTV-12-B/180-59b.

A year later, I'm still very happy with the prop.  The only issue has been some very fine hairline cracks in the paint about a third of the way in from the tip (spanwise) on each blade, apparently due to an early design that had a transition in the stiffness of the materials.  (The inner part of the blade was wrapped with kevlar and the outer with carbon fiber, or vice versa)  Because of the difference in stiffness, the flex tended to occur more at one spot.  The current iteration of the prop blades solves this problem by using the same material throughout, and MT is picking up the tab to replace the blades under warranty.  (Nice!  This also includes a reseal, which basically zero times the clock for the recommended 72 month TBO)  The cracks were primarily just a cosmetic issue, not visible unless looking VERY closely, only affected the outer paint, and were deemed by MT (and the AP/IA folks at two annuals) to not be an airworthiness issue.  All else being equal, I'm impressed that MT is taking care of it.  The blades are in the process of being shipped to my local MT-certified prop shop, so they should be installed and spinning in front of my airplane in a few weeks.

I was out at Tracy (KTCY) airport here in Northern California a couple of weeks ago, and since Tracy has had some of the cheapest fuel in the area (until their last fuel delivery) they attract a lot of different aircraft.  On this particular occasion, there were a pair of Sukhois, both running an MT prop.  (see: http://www.sukhoiaerobatics.com/SukhoiWest/DemoTeam.html )  They were intrigued that I had one on the front of a Mooney, and asked if I'd had any trouble with erosion from rain, which seems to be a prevalent concern that makes the rounds, but I can honestly say that there really isn't any paint erosion on my blades, and they didn't seem to have the issue either.  Is this a myth?  The leading edge is stainless steel, and it's held up pretty well over the last 250-odd hours I've put on it.

This last summer I splurged and at annual upgraded my M20E to a 201-style windshield (I went with the SWTA version), and this has added another 5-6 knots to my speeds.  On a good day, at 7500 near standard temperature, full throttle, 125F ROP I can see 162 kts in sustained level flight.

I wish I had better direct back to back performance numbers for the change from the original standard 2-blade Hartzell, but looking at average speeds before and after (under a range of different altitudes, temperatures, etc.) my conclusion is that the MT definitely improved the climb, I'm pretty sure it improved the ground roll, and it's pretty similar in cruise; I don't think it generated a cruise speed improvement, but I don't think it lost much either (a knot, maybe?).

Hope that helps!

-Knute

 

 

[knute]

I'm intrigued to note that the standard prop on the Diamond DA40 XLS (the top of the line version of the DA40) is still listed on the www.diamondair.com website specs as an MT prop.  It would not appear that Diamond has abandoned it just yet.

Not to defend the hairline crack too much (I'd prefer not to have the cosmetic issue, all else being equal) but in all fairness, the issue is just that- cosmetic.  The paint is on top of the resin that encases the wood, and as such has little to do with sealing moisture out of the wood or representing a structural issue.  I'm hopeful that the newer blades will solve the issue, and as well I've read on other forums from another owner (Husky or Vans; I forget which and don't have the reference at my fingertips) that MT was also incorporating more elasticizer into the surface paint to make it less likely to crack if/when the blade flexes.

Everyone should make the prop choice based on their own priorities and expectations, but for me I really enjoy the smoothness and low noise level- it is truly pleasant to fly behind.  The 2-blade Hartzell it replaced wasn't anywhere close to the same smoothness, and was much louder.  (Strict European noise restrictions is one of the reasons Diamond was using the MT prop)

If you could point me to references of brand D owners having a bad experience with the MT prop, I'd love to read up on it- I have been unable to find those references via Google beyond the noted cosmetic hairline cracks in the paint.

[roundout]

Call the Diamond service centers at ADS or FXE, or even MT themselves. Since MT won't put out any data that shows the cracking is cosmetic only and not structural, savvy IAs are failing them at annual. To be fair, MT has been providing new blades under warranty. On earlier versions there were also problems with bubbling and delaminating. The Kevlar props seems to have fixed this problem. 

I wouldn't put a lot of weight in the Diamond website since they're not even building airplanes right now. Their largest dealer in the world hasn't taken an XLS with an MT prop in 2 years.

[CoachTom]

Does anyone know of the "best" place to purchase the MT-Propeller from?  That is regarding price and shipping?

 

With the falling Euro, could it be purchased direct from the factory using this great exchange rate?

 

Any ideas of info would be appreciated!

 

 

[KSMooniac]

Tom, I called around a bit last year and found a distributor in MI or WI (I think) that was selling for as-good or better than the main MT office in FL, even with their Sun-n-Fun or OSH special prices.  I can't remember the name just now and my notes are at home so I'll try to dig them up later.  Like you, I'm hoping the plunging Euro would lead to a noticeable price reduction for us and plan to shop for one in earnest at OSH this year.  There are a few vendors advertised in Trade-a-plane and the back of Sport Aviation too.

[TonyPynes]

Would like to resurrect this thread and see how the MT is working for everyone today. It has been a few years - should be sound experience.

[KSMooniac]

I'm happy with mine.  I had paint peeling issues early on, and after a local repaint by an MT distributor, and finally got my blades replaced with overhauled ones direct from Germany.  They're holding up much better so far.  It is much lighter and smoother.  I bought it directly from MT after talking with them at OSH in 2010, and it was delivered a couple months later.  

[carusoam]

I considered their 4 blade composite last fall. STC was not complete at that time. It was a few pounds lighter than the Hartzell that I went with.

A few pounds lighter would be nice. One less Charlie weight in the back as well.

Best regards,

-a-

[Rustler]

I have nothing but good things to say about the MT. It has been on my J for about 200 hours and looks like it did the day it went on. Takeoff acceleration is better, the engine runs smoother, and cabin noise level is lower. I have suffered no decrease in speed, usually running about 150k true out of Taos at 12,000-14,000 feet.

 

As some of you know, I'm selling my J and purchasing a 231, and I intend to put an MT on that airplane, too.

[rasman]

Recent experience with MT propeller. Lost 14 kts at 2500 ft msl. Basically I get approximately 70% thrust at 100% power. It is however quieter possibly that's due to the lack of power.

Mooney 231

[carusoam]

Do you get it back higher up?

This sounds like something isn't matching up right. 14kts is a sizable difference from any other discussion we have had for prop changes.

A discussion with MT regarding your experience may be helpful.

Best regards,

-a-

[KSMooniac]

Recent experience with MT propeller. Lost 14 kts at 2500 ft msl. Basically I get approximately 70% thrust at 100% power. It is however quieter possibly that's due to the lack of power.

Mooney 231

Something is terribly wrong with your installation then... Did you buy your prop directly from MT or through a distributor?  You should be bringing this to their attention as it is a safety concern with such a performance hit.

[SAMFOX]

Anyone have any updates on this post? Curious if anyone has been running the MT 3-Blade composite for a few years/few hundred hours on the J and would be willing to share their experience with the product over the extended period, maintenance, product quality, Weight C/G issues, durability...thanks for the update if you have one! Cheers BK

[DonMuncy]

I've only had mine on my 231 for a little over a year, so I can't speak to long term issues. But the weight savings off the nose, the smoothness, the quicker take off and the braking effect on retarding the throttle are all great. Not to mention the cool look.

[Rustler]

Ditto Don's remarks. The weight delta was a big issue to me; that's a lot of weight from which the crankshaft is relieved over an extended period of time. It might be interesting to see if there is a study about the replacement of crank seals with MTs and heaview props.

Sam, I responded to your message; if you didn't get it, let me know.

[jetdriven]

Somw bonanza guys has issues with lightweight props messing with the magneto drive couplers and gears. The theory was the low mass wouldn’t absorb the power pulses and the gears were ringing. 

[KSMooniac]

Still very happy with mine on my J. Would do it again.

Sent from my LG-US996 using Tapatalk

[FlyWalt]

On 12/9/2017 at 12:02 PM, DonMuncy said:

 Not to mention the cool look.

Don, I thought that the cool look came from the fact that you were flying it :-)

[DonMuncy]

Just now, FlyWalt said:

Don, I thought that the cool look came from the fact that you were flying it :-)

Well, there is that too  

[Bob]

Don, I think you should start a sexy prop thread!

I agree with Don's feedback.  The 231's are very nose heavy, so he and I both felt a major change.  No more full trim up upon landing.

I have run mine now for about 2 years and think it was a wise choice over my 3 blade McCauley.

Some have had issues, including myself, with "kickback" upon startup and have broken starter adapters.  Mine was caused by the timing being set too advanced.  If the injection and timing are set properly, you will have no issues.  Basically, the prop no longer has extra weight to absorb error in proper tuning. I think a heavy aluminum three blade hides issues.

Sorry no info on the J specifically!

[Jim F]

Don and Bob,

What are your numbers on takeoff, climb, and cruise?  From what I have read sounds like a shorter takeoff run and better climb and a negative in cruise.  Is that true?

In cruise do you have numbers for 18-20K?

Thanks,

Jim

Edited December 17, 2017 by Jim F