MT 4 Blade Pirep

[EricJ]

14 minutes ago, exM20K said:

decelerating a 3000# airplane from 75 ->0 in 1000 feet is an entirely different load than pushing on the prop or going to idle in flight. 

It all puts load in the same direction on the same components.   If it caused a problem it may have shown up over the last seventy years or so.

[BravoWhiskey]

5 hours ago, PMcClure said:

Bumping this thread with some questions: Any update from the users of the MT 4 blade composite prop? I spoke to flight resource yesterday and am considering this as an enhancement as we work toward firewall forward replacement. They said negative pitch (reverse) is an option for the Ovation but would require a field approval. Adds $9500 plus field approval cost. Any thoughts on that option? Also, Hartzel has a 3 blade replacement composite prop. Any pireps on that?

I have the MT 4 blade w TKS on my Bravo.  I played around with 31” 2200 and  29” 2400 but recently found 30” 2300 is really smooth and gives me best performance.  No reverse.  

[exM20K]

1 hour ago, EricJ said:

It all puts load in the same direction on the same components.   If it caused a problem it may have shown up over the last seventy years or so.

  The loads may be the same direction, but the force is very different.  But I’m not suggesting I know it is unwise, as you are asserting it is not.  I’m simply saying stopping a Mooney with the prop is untested and not the thrust vector the mounts were engineered to carry.

For me, there are enough unknowns, dubious utility, and significant additional expense that I wouldn’t do it.  That was @PMcClure ‘s question when he resurrected this zombie thread. 
 

-dan

[aviatoreb]

6 hours ago, SkepticalJohn said:

On the jet I fly at work, I'd agree. When it comes to a Mooney Rocket, I couldn't disagree more. Per MT, I have the only Mooney with reverse. My plane will leave the ground on takeoff in ~1,000 ft ground roll. It will not land that short even with my reverse.

I am curious. How short do you land with reverse? and how short a field do you feel comfortable with?

[EricJ]

24 minutes ago, exM20K said:

  The loads may be the same direction, but the force is very different.  But I’m not suggesting I know it is unwise, as you are asserting it is not.  I’m simply saying stopping a Mooney with the prop is untested and not the thrust vector the mounts were engineered to carry.

For me, there are enough unknowns, dubious utility, and significant additional expense that I wouldn’t do it.  That was @PMcClure ‘s question when he resurrected this zombie thread. 
 

-dan

The force magnitude may be different (I don't know), but it's like accelerated age testing in reverse.    Instead of using applications of large force to test durability over a long time, the application of repeated smaller forces over the last seventy-or-so years suggests that the application of a larger force (within reasonable limits) in the same direction on the same components is not likely to do anything surprising.

[PMcClure]

13 minutes ago, aviatoreb said:

I am curious. How short do you land with reverse? and how short a field do you feel comfortable with?

And is there any change to take off and landing distances in the documemtation?

[philiplane]

7 hours ago, PMcClure said:

Bumping this thread with some questions: Any update from the users of the MT 4 blade composite prop? I spoke to flight resource yesterday and am considering this as an enhancement as we work toward firewall forward replacement. They said negative pitch (reverse) is an option for the Ovation but would require a field approval. Adds $9500 plus field approval cost. Any thoughts on that option? Also, Hartzel has a 3 blade replacement composite prop. Any pireps on that?

The Hartzell composite props are a work of art. Durable too.

[DCarlton]

1 hour ago, EricJ said:

The force magnitude may be different (I don't know), but it's like accelerated age testing in reverse.    Instead of using applications of large force to test durability over a long time, the application of repeated smaller forces over the last seventy-or-so years suggests that the application of a larger force (within reasonable limits) in the same direction on the same components is not likely to do anything surprising.

Guessing the dynamic loads on the engine mounts from the mass of the engine and prop hanging out front when the aircraft bounces around and accelerates to its design G limit is greater than the longitudinal thrust loads generated by the prop.  But that’s just a guess… 

[PilotX]

10 hours ago, philiplane said:

The Hartzell composite props are a work of art. Durable too.

Don't see that they are available for the Bravo. 

[PMcClure]

Some real world costs:

Overhaul and balance current 3 blade Hartzell steel prop: $4500 at factory +. freight 3-4 weeks. includes dynamic balancing. 

New Hartzell ASC11 Composite prop: $35,200 with STC and spinner. 16 weeks saves 20lbs. No trade in value, but maybe I could sell the current prop?

New MT 4 blade composite: $24.500 delivered. in stock. Reversing option about +$12500 including field approval. saves 24lbs 

I filed reverse under the nice, but not much additional utility. The current Hartzell prop I have now is smooth as silk with 16 years and 1650 hours on it.  Rebuild is the obvious economic choice. But going with all new firewall forward, the MT 4 blade is tempting. 

[KER]

Hello All,

I'm the Maintenance Director at Lincoln Skyways, INC in Lincoln CA.  The business owner has recently started brokering aircraft sales.    One of the aircraft is a1981 M20K with the Rocket conversion.  N52EM.  (you can see further details on our website if you're interested.  https://www.lincolnskyways.com/n52em  )   This Mooney has the forward CG issues that many of the Rockets have. Two people up front with plenty of fuel, and you're forward of the W/B window.   So, I was curious...

#1.  Is there and approved MT 4 blade for the Rocket STC?   I've been digging thru the web and haven't found anything solid. 

#2.  If there IS an approved MT 4 blade for this aircraft, would anyone happen to know the weight?  

The business owner is pushing to find out info, meanwhile I'm still trying to run a shop full of other aircraft.

If anyone has any information, I would be grateful!

Kacy R

[LANCECASPER]

Option 4: Since it's smooth as silk and not causing you any problems, I would do an Inspect and Repair As Necessary at a good prop shop,  which should essentially be a re-seal and whatever misc. parts they see the need to replace. On the other hand "overhauls" have mandatory replacement parts and they cut the blades down. This option should be less than $2000

[LANCECASPER]

4 hours ago, PMcClure said:

Some real world costs:

Overhaul and balance current 3 blade Hartzell steel prop: $4500 at factory +. freight 3-4 weeks. includes dynamic balancing. 

New Hartzell ASC11 Composite prop: $35,200 with STC and spinner. 16 weeks saves 20lbs. No trade in value, but maybe I could sell the current prop?

New MT 4 blade composite: $24.500 delivered. in stock. Reversing option about +$12500 including field approval. saves 24lbs 

I filed reverse under the nice, but not much additional utility. The current Hartzell prop I have now is smooth as silk with 16 years and 1650 hours on it.  Rebuild is the obvious economic choice. But going with all new firewall forward, the MT 4 blade is tempting. 

Option 4: Since it's smooth as silk and not causing you any problems, I would do an Inspect and Repair As Necessary at a good prop shop,  which should essentially be a re-seal and whatever misc. parts they see the need to replace. On the other hand "overhauls" have mandatory replacement parts and they cut the blades down. This option should be less than $2000 and very little down time. 

Option 5: Look for a used Hartzell Top Prop 3 blade Scimitar (non composite). Still some weight savings and great performance.

[LANCECASPER]

1 hour ago, KER said:

#1.  Is there and approved MT 4 blade for the Rocket STC?   I've been digging thru the web and haven't found anything solid. 

#2.  If there IS an approved MT 4 blade for this aircraft, would anyone happen to know the weight?  

Paging @aviatoreb -  he has one.

[201Mooniac]

1 hour ago, KER said:

Hello All,

I'm the Maintenance Director at Lincoln Skyways, INC in Lincoln CA.  The business owner has recently started brokering aircraft sales.    One of the aircraft is a1981 M20K with the Rocket conversion.  N52EM.  (you can see further details on our website if you're interested.  https://www.lincolnskyways.com/n52em  )   This Mooney has the forward CG issues that many of the Rockets have. Two people up front with plenty of fuel, and you're forward of the W/B window.   So, I was curious...

#1.  Is there and approved MT 4 blade for the Rocket STC?   I've been digging thru the web and haven't found anything solid. 

#2.  If there IS an approved MT 4 blade for this aircraft, would anyone happen to know the weight?  

The business owner is pushing to find out info, meanwhile I'm still trying to run a shop full of other aircraft.

If anyone has any information, I would be grateful!

Kacy R

I would call Peter Marshal at MT in Deland FL to verify the details, he is very generous with his time and was incredibly helpful to me when I was considering an MT prop

[aviatoreb]

4 hours ago, LANCECASPER said:

Paging @aviatoreb -  he has one.

Ive had a MT 4 blade on my rocket for something like 7 years?  8 years?  I was quite early to the MT 4 blade on a Mooney parade and I was THE first on a rocket.  3 engineers from MT came and measured my plane with their own hands at Oshkosh that year.  Anyway its on a field approval 337 and I got the paperwork done filed and approved for a modest fee by MT USA.

[Yooper Rocketman]

I also have the MT 4 blade.  I like the benefits of the 20 pound weight reduction but have had paint issues that MT has claimed to have fixed years ago.  Since I’m probably going to have MT in Deland, FL make an attempt to resolve this lingering problem this winter, when I’m in Florida, I’ll reserve final comment until after I see how they deal with this issue. 
 

Otherwise I’ve been pretty happy with the prop and associated nose weight reduction!!

Tom

[PMcClure]

4 minutes ago, Yooper Rocketman said:

I also have the MT 4 blade.  I like the benefits of the 20 pound weight reduction but have had paint issues that MT has claimed to have fixed years ago.  Since I’m probably going to have MT in Deland, FL make an attempt to resolve this lingering problem this winter, when I’m in Florida, I’ll reserve final comment until after I see how they deal with this issue. 
 

Otherwise I’ve been pretty happy with the prop and associated nose weight reduction!!

Tom

What color is yours? I see a statement that “flat black is most durable”. I take to mean other colors are not durable.

[201Mooniac]

2 minutes ago, PMcClure said:

What color is yours? I see a statement that “flat black is most durable”. I take to mean other colors are not durable.

My 3 blade MT is white with red stripes and the paint has been very durable, it still looks great after 4 years.

[SkepticalJohn]

The front of my 4-bladed MT is gray with white stripes, the back (facing the cockpit) is black. I've had no issues with paint.

[Yooper Rocketman]

9 minutes ago, PMcClure said:

What color is yours? I see a statement that “flat black is most durable”. I take to mean other colors are not durable.

Mine is flat black with white on the tip and one stripe.  It’s been painted 3 times, on the tips the last two, and the white paint doesn’t stick.  That said the factory paint was coming off within 2 years.  

Hoping it’s a paint or an application issue!

Tom

[glenn reynolds]

I just had my 4 blade balanced and the engine is now silky smooth.  Even my wife noticed how smooth the plane now runs.  The part that gets me is the three blade prop I replaced had been dynamically balanced as well, so I wasn't expecting that much of an improvement.  All the comments about faster response and landing braking are true.  I now handle my prop control much more gently than I ever did before.  I had a mechanic friend advise me that he has seen composite blades chipped by careless actions in hangers associated with maintenance so he insists that when I drop the plane off for service I leave it with blade covers to protect the blades.  I made my blade covers from closed cell foam floor pads and so far so good, 

[SkepticalJohn]

Similar smoothness experience here - the mechanic got mine dynamically balanced (ie: installed on a running engine producing 100% power) within .02 ips.

Coincidentally, .02 was the same target we used to seek, balancing the props on a King Air 200 I used to fly. The MT 4-blade is literally turboprop-smooth.

John

[aviatoreb]

3 hours ago, SkepticalJohn said:

Similar smoothness experience here - the mechanic got mine dynamically balanced (ie: installed on a running engine producing 100% power) within .02 ips.

Coincidentally, .02 was the same target we used to seek, balancing the props on a King Air 200 I used to fly. The MT 4-blade is literally turboprop-smooth.

John

DEFINITELY - it is super super smooth.

[Yooper Rocketman]

I scheduled with MT in Deland for a repaint, hoping to get it done in October when I go down for a cruise.  I will be in Florida about a week..  MT said they need "TWO" weeks to paint the prop, and they will NOT do it if the prop is past 72 months since overhaul (without overhauling it too).  Luckily for me, it is only 50 months old.  They remove the blades to paint, said it takes 3 days just for the painting, and then a balance before reassembling the prop.   I scheduled for late January because my winter trips are usually 2 full weeks or more anyway.

Now the prior owner that bought that prop (the guy I bought my Rocket back from) is asking me what the warranty is on the repaint, since they wouldn't do anything for him when the paint started peeling in under a year.  And my wife is asking what it's going to cost (I guess I should ask that question).  MT did say the paint process is very specific and detailed.  I hope that means the paint will stay on.  I don't mind "paying" for a prop that looks as good as the rest of the plane.  I appreciate the feedback on those having props without paint issues.  I like the prop with the exception of that.  Maybe the U.S. shop paints them better the the factory.

In conversation with the last owner, he did acknowledge a drop in cruise speed with the MT.  I've noticed my speeds with the prop are definitely down 3-4 knots from what what they were with the 3 blade the conversion came with.  That said, the better CG and lighter nose is well worth a bit of speed loss.

Tom