MT prop upgrade on a 231

[khedrei]

I know this has been talked about before.  I have read through the threads, most were a bit older.  I am looking for an opinion from someone who as made the change from the 2 blade McCauly to the 3 blade MT on a 231.

I have the 360 LB engine.  I seem to cruise slower than some others with the same plane.  I run 80-90 ROP just over 13 GPH and see TAS around 150KT at 10k.  I also find that my plane is VERY noisy compared to 182's and Bonanzas that I have flown, even ones with metal props.  I am aware of the other benefits of the MT, but I am interested to find out from anyone who has done this if the noise improved  (if so, by how much), as well as their difference in cruise speed.  I am aware that the climb will be better.  MT claims an improvment in cruise speed for the K.  They don't claim it for the J.  I assume that has to do with the turbo being able to maintain sea level power while the J cannot so the drag of the extra blade is then a penalty.

My prop is due for its 10 year overhaul next year.  It will probably cost me about 5k CAD

MT quoted me on a new 3 blade with deice.  With shipping and taxes I am probably looking at 27k CAD and a 8 month lead time.

Also curious...  It was my understanding that the US does not have a 10 year manadtory overhaul on CS props.  Would that mean my existing prop has more value down there?  If I were to sell it to someone in Canada it would need an overhaul before it could be used.  The prop was brand new in 2013 and now has less than 400hrs I believe so I assume the blades should pass inspection.

It seems like a huge investment for minimal gain, even if I could get 7k CAD for my old prop.  Any input is appreciated.

Thanks

 

[KSMooniac]

I'm in tons of MT threads here sharing my opinions and experience. I'd choose it again for my J, and especially on a turbo Mooney that can spin slower and dial up the MP. MTs are optimized for lower RPM in my opinion.

Yes, your prop would have a lot more value in the US since we can operate on-condition instead of by a calendar. I don't know how to conduct a transaction across the border for an item like that. There are always gear-up/prop-strike victims looking for an easier path back to flying.

Sent from my LM-V450 using Tapatalk

[carusoam]

Short of Moving south… or registering with an N number…

The US does not have mandatory time life on things… in GA.

Sooo… if tossing the old because it is time limited… the US is probably a good spot to sell it…

MT has come a long way… they figured out two things… the proper leading edge metal, and the proper paint methodology…

 

I was going to invite Scott… but he just dropped his post above….  

Next invite goes to @aviatoreb because his awesome plane has a four blade MT!

Best regards,

-a-

[Mcstealth]

The main question not withstanding,  I would be concerned about that lowish TAS. When were you last rigged? Do you have a heavy wing in level flight? Have you confirmed your speed with the  three or four way gps speed runs? You know the questions

[carusoam]

Props can have terrible lead times in normal days…

So….  Don’t delay.

Best regards,

-a-

[aviatoreb]

1 hour ago, carusoam said:

Short of Moving south… or registering with an N number…

The US does not have mandatory time life on things… in GA.

Sooo… if tossing the old because it is time limited… the US is probably a good spot to sell it…

MT has come a long way… they figured out two things… the proper leading edge metal, and the proper paint methodology…

 

I was going to invite Scott… but he just dropped his post above….  

Next invite goes to @aviatoreb because his awesome plane has a four blade MT!

Best regards,

-a-

You bet!

[khedrei]

I do have a slightly heavy wing in flight but it's not terrible.  I certainly don't think fixing it will give me more than a couple KTs.  It went in for an extensive annual 4 years ago to a Mooney shop and they did some controle stop adjustments.  The same shop was called in to rig the tail when the avionics shop screwed up putting the trim back together after the GFC-500 Auto pilot was installed. 

 

I guess this thread is a good enough place to ask this as I have been wondering for a while.  A really good experienced pilot friend of mine noticed that in cruise flight, the elevator is slightly up.  The plane is trimmed, and if the AP is disengaged it flies level so there is no issue on that, but shouldn't a movable tail be able to be in a position where no elevator is required in cruise phases of flight?  Perhaps this is a rigging issue?

 

Thanks for the feedback so far on the prop.  I would love to hear if anyone has gained or lost airspeed in a K model after changing the prop.

[philiplane]

The MT will cost more to own. A 3 blade overhaul in the US today is $5500 and takes five weeks. You can shorten that to two weeks if you use overhauled exchange blades, at an additional cost of $4500. Odds are you will also need to have it re-sealed after 4 or 5 years due to grease leaks. ($1600 US). They've been better about keeping the paint on the blades, but due to the flexibility of the wood cores, there will always be some paint chipping/peeling/cracking along the leading edge strips. The blade face (black painted side) tends to develop tiny vertical cracks since the blades flex forward upon acceleration. You don't even notice them unless you shine a flashlight across the blade, and then you'll see the cracking which looks like dozens of perpendicular XACTO knife slashes in the paint. You have to sand the paint down to the fiberglass and re-apply primer and flat black to fix this. If you let it go, this is how water gets into the fiberglass jacket. The four MT's I currently maintain require sanding and painting annually to prevent water from getting into the fiberglass jacket over the wood core. The jacket is bonded at the trailing edge, and they can separate there. Fortunately they can be glued in the field. MT's maintenance manual covers every conceivable field repair in great detail, but most mechanics just want to pull it and send it to a prop shop.  

For speed comparisons, I have a client with three Diamond DA40s, all identical except for the prop. One has a two blade aluminum Hartzell, one has a two blade Hartzell composite, and one has an MT 3 blade. The two blade Hartzell composite is the fastest, quietest, and smoothest of the three. It has also required zero special maintenance. It's probably the only composite prop that is as durable as an aluminum prop. The Diamond's MT has been off twice for repairs, and once for overhaul within 4 years/1100 hours, and still needs painting & chip filling every 100 hours. The aluminum two blade Hartzell just keeps going and going without special care. I've dealt with a dozen or more MT's on Cirrus, and some are great, and some won't stop leaking grease. My hangar neighbor's brand new MT on his C210 developed spinner back plate cracks shortly after installation. Fortunately he still had his old McCauley, which kept him flying for the couple of months waiting for new parts to come from Germany. 

As for your speed, don't expect that a propeller change will make any change in that. Props aren't magic, they just convert engine power into thrust. The least number of blades will produce the fastest speed, the most number of blades will produce the best climb and best deceleration upon landing. But in any event, we're talking about a couple of knots. Not five or ten. The most efficient prop, for speed, will be a two blade scimitar shaped prop. Like the Hartzell 2 blade composite prop, or their aluminum version. The composite will add a tiny bit of speed since it will take 10 pounds off the nose. But you can also achieve weight shift for speed without spending thousands.  Most slow planes have extreme forward CG's. Pilots fly with two up front and full fuel, which is the worst combination for speed. The POH speeds are based on an optimized CG in addition to running the engine hard. An out-of-rig Mooney with a forward CG will be 5-15 knots slower than book. 

As for noise, most planes that seem noisy inside suffer from door seal leaks, and from engine noise coming through the ventilation system. 231's are also known for transmitting engine vibration to the cabin via old stiff engine isolators, hoses that are tied too tightly to the engine mount, and stiff baffles seals. Props only make noise at max RPM depending on their tip design. The closer the blades get to the trans sonic range, the noisier they will be. This is common on high HP Cessnas with large diameter props, but not an issue on a Mooney 231. 

I recommend that you get the rigging corrected, ensure the engine baffles seals are perfect, and fly it at 65-75 percent power at 12,000 feet with the CG between 60 to 75 percent back in the envelope. This should get you close to the POH numbers. Then make a decision on the prop. 

Edited August 31, 2022 by philiplane

[Parker_Woodruff]

The MT in and of itself probably won't fix your speed issue.

I am a fan of 3-blade metal props for the M20K.

I would look into control and gear rigging first for your speed issue.  Also, you didn't say what MP/RPM settings give you that speed.

[A64Pilot]

It’s my understanding that for a J model that the factory two blade is about as good as it gets, speed wise, but I’ve not flown a J before and after a prop change. I think your not far off speed wise, people tend to be a bit optimistic with speed.

Leading edge of an elevator being slightly high in cruise is normal for pretty much everything I’ve flown, most of us fly around slightly fwd CG and that can have an effect on elevator position.

I disagree about props though, my initial belief was that a constant speed prop would vary pitch and absorb all the power an engine could make and the thrust would be very close one prop to the next.

I’ve flown and Certified about three or four different props on turbines, and let me tell you the performance difference can be quiet substantial, really surprised me, we were looking at takeoff distance and climb at max gross, not speed but the difference was large, seemed wide cord blades performed best. We got to calling them paddle blades.

There are some general rules, like the fewer the blades the better, but I’ve often seen a good three or four blade prop significantly outperform a prop with fewer blades, because I’m sure the prop with fewer blades wasn’t a good match in that application, but the prop with more blades was so it overcame the drag increase and then some.

I think before I spent that kind of money I’d at least try getting the guys in Deland Fl to put one on for you to give it a try. Can’t hurt to try, but it would mean a flt to Fl if they agree.

Just from watching others, I’ve not been impressed with MT’s service record myself.

While I believe in most cases a Hartzell composite prop is far superior as it’s a “real” composite, sit down before you price one, way out of my price range.

[Aerodon]

I've explored all these ideas.  Just overhaul your 10 year prop and move on. First overhaul is unlikely to have any surprises, unless there has been blade damage.  I'm just having a second 10 year overhaul being done on a 3 bladed prop for my Seneca.  All turned out well, but I have to admit to being nervous.  

I'm not a fan of MT props.  I've just heard of too many maintenance related issues and less than helpful service centres.  Like particular blade models no longer being made and you have to buy a new version.  And buying a full set of blades when one is damaged.  And issues with props just out of warranty.  And 7 year overhauls instead of 10 years, along with ridiculous costs of shipping 3 bladed props. etc.  Yes there is a performance and weight advantage, but that comes at a really high price.

 

Aerodon

 

 

 

 

 

 

 

 

[Will.iam]

2 hours ago, philiplane said:

The MT will cost more to own. A 3 blade overhaul in the US today is $5500 and takes five weeks. You can shorten that to two weeks if you use overhauled exchange blades, at an additional cost of $4500. Odds are you will also need to have it re-sealed after 4 or 5 years due to grease leaks. ($1600 US). They've been better about keeping the paint on the blades, but due to the flexibility of the wood cores, there will always be some paint chipping/peeling/cracking along the leading edge strips. The blade face (black painted side) tends to develop tiny vertical cracks since the blades flex forward upon acceleration. You don't even notice them unless you shine a flashlight across the blade, and then you'll see the cracking which looks like dozens of perpendicular XACTO knife slashes in the paint. You have to sand the paint down to the fiberglass and re-apply primer and flat black to fix this. If you let it go, this is how water gets into the fiberglass jacket. The four MT's I currently maintain require sanding and painting annually to prevent water from getting into the fiberglass jacket over the wood core. The jacket is bonded at the trailing edge, and they can separate there. Fortunately they can be glued in the field. MT's maintenance manual covers every conceivable field repair in great detail, but most mechanics just want to pull it and send it to a prop shop.  

For speed comparisons, I have a client with three Diamond DA40s, all identical except for the prop. One has a two blade aluminum Hartzell, one has a two blade Hartzell composite, and one has an MT 3 blade. The two blade Hartzell composite is the fastest, quietest, and smoothest of the three. It has also required zero special maintenance. It's probably the only composite prop that is as durable as an aluminum prop. The Diamond's MT has been off twice for repairs, and once for overhaul within 4 years/1100 hours, and still needs painting & chip filling every 100 hours. The aluminum two blade Hartzell just keeps going and going without special care. I've dealt with a dozen or more MT's on Cirrus, and some are great, and some won't stop leaking grease. My hangar neighbor's brand new MT on his C210 developed spinner back plate cracks shortly after installation. Fortunately he still had his old McCauley, which kept him flying for the couple of months waiting for new parts to come from Germany. 

As for your speed, don't expect that a propeller change will make any change in that. Props aren't magic, they just convert engine power into thrust. The least number of blades will produce the fastest speed, the most number of blades will produce the best climb and best deceleration upon landing. But in any event, we're talking about a couple of knots. Not five or ten. The most efficient prop, for speed, will be a two blade scimitar shaped prop. Like the Hartzell 2 blade composite prop, or their aluminum version. The composite will add a tiny bit of speed since it will take 10 pounds off the nose. But you can also achieve weight shift for speed without spending thousands.  Most slow planes have extreme forward CG's. Pilots fly with two up front and full fuel, which is the worst combination for speed. The POH speeds are based on an optimized CG in addition to running the engine hard. An out-of-rig Mooney with a forward CG will be 5-15 knots slower than book. 

As for noise, most planes that seem noisy inside suffer from door seal leaks, and from engine noise coming through the ventilation system. 231's are also known for transmitting engine vibration to the cabin via old stiff engine isolators, hoses that are tied too tightly to the engine mount, and stiff baffles seals. Props only make noise at max RPM depending on their tip design. The closer the blades get to the trans sonic range, the noisier they will be. This is common on high HP Cessnas with large diameter props, but not an issue on a Mooney 231. 

I recommend that you get the rigging corrected, ensure the engine baffles seals are perfect, and fly it at 65-75 percent power at 12,000 feet with the CG between 60 to 75 percent back in the envelope. This should get you close to the POH numbers. Then make a decision on the prop. 

Is there a two blade Hartzell composite available for a 231 or 252?  I thought they only offered 3 blade versions. 

[Ethan]

I've got a 231 with a heated two-blade prop. According to all book values my Mooney is also slow. No matter what I do, I cannot match book for almost any cruise profile the book says - I'm always 5 kts slow and I have a nice, clean, well-rigged airplane.

That said, if you are actually burning 13 GPH, you should be going faster than 150 TAS at 10K. Perhaps your pitot static system has some leakage leading to an underestimation of your airspeed? 

[philiplane]

2 hours ago, Ethan said:

I've got a 231 with a heated two-blade prop. According to all book values my Mooney is also slow. No matter what I do, I cannot match book for almost any cruise profile the book says - I'm always 5 kts slow and I have a nice, clean, well-rigged airplane.

That said, if you are actually burning 13 GPH, you should be going faster than 150 TAS at 10K. Perhaps your pitot static system has some leakage leading to an underestimation of your airspeed? 

calculate your CG for your flight. Five knots is the speed penalty for a forward CG.

[T. Peterson]

7 hours ago, philiplane said:

The MT will cost more to own. A 3 blade overhaul in the US today is $5500 and takes five weeks. You can shorten that to two weeks if you use overhauled exchange blades, at an additional cost of $4500. Odds are you will also need to have it re-sealed after 4 or 5 years due to grease leaks. ($1600 US). They've been better about keeping the paint on the blades, but due to the flexibility of the wood cores, there will always be some paint chipping/peeling/cracking along the leading edge strips. The blade face (black painted side) tends to develop tiny vertical cracks since the blades flex forward upon acceleration. You don't even notice them unless you shine a flashlight across the blade, and then you'll see the cracking which looks like dozens of perpendicular XACTO knife slashes in the paint. You have to sand the paint down to the fiberglass and re-apply primer and flat black to fix this. If you let it go, this is how water gets into the fiberglass jacket. The four MT's I currently maintain require sanding and painting annually to prevent water from getting into the fiberglass jacket over the wood core. The jacket is bonded at the trailing edge, and they can separate there. Fortunately they can be glued in the field. MT's maintenance manual covers every conceivable field repair in great detail, but most mechanics just want to pull it and send it to a prop shop.  

For speed comparisons, I have a client with three Diamond DA40s, all identical except for the prop. One has a two blade aluminum Hartzell, one has a two blade Hartzell composite, and one has an MT 3 blade. The two blade Hartzell composite is the fastest, quietest, and smoothest of the three. It has also required zero special maintenance. It's probably the only composite prop that is as durable as an aluminum prop. The Diamond's MT has been off twice for repairs, and once for overhaul within 4 years/1100 hours, and still needs painting & chip filling every 100 hours. The aluminum two blade Hartzell just keeps going and going without special care. I've dealt with a dozen or more MT's on Cirrus, and some are great, and some won't stop leaking grease. My hangar neighbor's brand new MT on his C210 developed spinner back plate cracks shortly after installation. Fortunately he still had his old McCauley, which kept him flying for the couple of months waiting for new parts to come from Germany. 

As for your speed, don't expect that a propeller change will make any change in that. Props aren't magic, they just convert engine power into thrust. The least number of blades will produce the fastest speed, the most number of blades will produce the best climb and best deceleration upon landing. But in any event, we're talking about a couple of knots. Not five or ten. The most efficient prop, for speed, will be a two blade scimitar shaped prop. Like the Hartzell 2 blade composite prop, or their aluminum version. The composite will add a tiny bit of speed since it will take 10 pounds off the nose. But you can also achieve weight shift for speed without spending thousands.  Most slow planes have extreme forward CG's. Pilots fly with two up front and full fuel, which is the worst combination for speed. The POH speeds are based on an optimized CG in addition to running the engine hard. An out-of-rig Mooney with a forward CG will be 5-15 knots slower than book. 

As for noise, most planes that seem noisy inside suffer from door seal leaks, and from engine noise coming through the ventilation system. 231's are also known for transmitting engine vibration to the cabin via old stiff engine isolators, hoses that are tied too tightly to the engine mount, and stiff baffles seals. Props only make noise at max RPM depending on their tip design. The closer the blades get to the trans sonic range, the noisier they will be. This is common on high HP Cessnas with large diameter props, but not an issue on a Mooney 231. 

I recommend that you get the rigging corrected, ensure the engine baffles seals are perfect, and fly it at 65-75 percent power at 12,000 feet with the CG between 60 to 75 percent back in the envelope. This should get you close to the POH numbers. Then make a decision on the prop. 

Wow! I am not the OP, but I am a new Mooney owner and new to GA. Thank you for that excellent education! 

[Ethan]

Good point - I do find the airplane flies better with some junk in the trunk. The performance charts are silent as to CG position when the test flown. I'm guessing most of us fly with one to two up front, leading to a forward CG and slower speeds.

[Fly Boomer]

1 minute ago, Ethan said:

Good point - I do find the airplane flies better with some junk in the trunk. The performance charts are silent as to CG position when the test flown. I'm guessing most of us fly with one to two up front, leading to a forward CG and slower speeds.

I suspect they were test flown with a second pilot who climbed into the baggage compartment after takeoff.

[LANCECASPER]

58 minutes ago, Ethan said:

Good point - I do find the airplane flies better with some junk in the trunk. The performance charts are silent as to CG position when the test flown. I'm guessing most of us fly with one to two up front, leading to a forward CG and slower speeds.

Plus the marketing dept. at Mooney back in the mid 70's to late 80's (201 through TLS) pushed hard for every knot that could be published in marketing materials, POH, etc. Realistically those could never be duplicated by anyone other than a factory test pilot.

[Guest]

Noise is a fact of life in most Mooney’s that I’ve run.  I had a three blade MT on my last E model for a while, just for fun.  It wasn’t any faster in cruise than either of the Hartzell two blade propellers I had on it.

I’ve got a three blade MT on my Comanche now because it was the only option and in nine years I haven’t experienced any issues other speak of.

 

[WAFI]

Quick question on the MT 3 blade on a M20J 201, does it remove the yellow arc (Vibration Range)? 

[Will.iam]

The only prop i have found to be lighter than my mccauley 2 blade is the 3 blade MT composite for a 231 / 252. I would love to get a 2 blade composite for even lighter weight but there seems to be none available. 

[A64Pilot]

30 minutes ago, WAFI said:

Quick question on the MT 3 blade on a M20J 201, does it remove the yellow arc (Vibration Range)? 

I don’t know, but bet it does, hop on over to Deland, it’s in your backyard

[A64Pilot]

2 hours ago, LANCECASPER said:

Plus the marketing dept. at Mooney back in the mid 70's to late 80's (201 through TLS) pushed hard for every knot that could be published in marketing materials, POH, etc. Realistically those could never be duplicated by anyone other than a factory test pilot.

That’s pretty much every plane, and there is nothing a factory test pilot can do that any pilot can’t do. None meet the sales speeds.

But you take a stripped min instrumented etc airplane that’s brand new and any tricks anyone knows of like gear doors being real tight or whatever, then using parallax error when you look at the instruments etc you can get there. If your within 5 kts I’d say that’s good, I can only get 168 kts out of my 201 and that’s 7 kts off of 201 MPH.

I’m also burning 19 GPH too.

Your allowed a plus or minus airspeed error too and from memory it can be a few kts. When we Certified the S2R-H80, I corrected the airspeed by having a .030 step machined in the static port, this increased indicated airspeed a couple of kts, but within allowable limits.

You could fly the H-80 in formation with its Sister the T-34 and there was 5 kts indicated difference. 34 read a little low, the 80 a little high.

Many factories push the indicated airspeed error to close to max allowable, the newer Pipers I know did

[carusoam]

6 hours ago, Ethan said:

Good point - I do find the airplane flies better with some junk in the trunk. The performance charts are silent as to CG position when the test flown. I'm guessing most of us fly with one to two up front, leading to a forward CG and slower speeds.

Terrible assumption…. 

All MSers know….

That sliding their chair back in flight is…

• More comfortable…
• Better B in the WnB calculation….
• More Kias….

Remember…

The tail plane is generating negative lift…. To balance the plane in flight…

The more it needs to pull down, the more drag it generates…
 

Everyone has a WnB calculator…

Experiment with the calculations to see how far back you can move the Cg…..  before it falls out the back of the graph…

Make sure you know that the WnB calcs and graphs apply to your current plane’s weight…

Don’T load the plane up with people the first time you experiment with WnB… bags of sand tied in place work pretty well too…

 

Pp thoughts only, not a CFI…

Best regards,

-a-

[carusoam]

15 hours ago, khedrei said:

. 

 

 A really good experienced pilot friend of mine noticed that in cruise flight, the elevator is slightly up. 

 

You need to bring your pilot friend up to speed with Mooney operations…. Take him flying more often!  
 

by changing the WnB… the elevator position changes…

The more forward your B is… the more visually obvious the elevator weights become…. They stand out on the ends… chances are you are seeing the weights, not the elevator…

 

Next time you bring him flying…. See if HE can take a video while you adjust the trim….  When you are putting flaps in, the trim changes a lot….

Max flaps and Maximum trim up for landing…. Your tail is going to show what you are doing….

 

At the other end of the speed envelope… Say… your balance is on the back line of the envelope….   And…. if you trim nose down for Vne… I bet the elevator and horizontal stabilizer are much better aligned….   

Are you thinking this is a rigging issue?  This is more of an everyday flight in different regimes with different loads issue….

If the elevator was always nicely aligned… we would be building gorilla arms because the trim isn’t working…

Another note to go with this… as the tail gets canted forwards…. The elevator may move in the opposite direction… (it does on the ground for the Mooneys with spring bungees…. Like the M20C… the LBs don’t have the springs and elevator sags on the ground….

PP thoughts only, not a mechanic…

Best regards,

-a-