LES BRINDLE OWNS THE STC FOR THE THREE BLADE MT'S
HE HAS A 68 NORMAL THAT DID ALL THE R&D
I THINK I WAS THE FIRST REAL CUSTOMER
PUT THEM ON JANUARY OF 2003
I REALLY LIKE THEM
VERY SMOOTH, MUCH MORE RESPONSIVE, QUIETER, AND I GAINED 60 LBS USEFUL.

TO MY KNOWLEGE THE FRONT AND REAR ARE THE SAME SIZE

Prop
 

hharney
If you don,t mind me asking, what was the cost of the prop and dose he have a web site?
Fred N358

PRICES ARE SET BY MT IN GERMANY. ONE OF THE ISSUES IS FREIGHT. IT'S NOT UNREASONABLE BUT IT IS MORE THAN MCCAULY.

IF I REMEMBER WHEN I PURCHASED, THE COST OF THE MT'S WERE WITHIN A FEW DOLLARS OF FACTORY NEW MCCAULY'S. THE MT'S TOOK LONGER AND THE FREIGHT WAS A BIT MORE.

TALK TO OWEN BELL, HE HAS DISTRIBUTION FOR MT

I'm working on a STC for a 4 blade prop for the 337.

Here's a picture.


Electric pitch control, with automatic sync'ing of the front and rear props. Also, you have 4 "common" rpm buttons that allows you to pitch both props to your favorite rpm with one button. Price for both props are looking like they will be around $18K. A little less than the MT's. They are going through vibration testing now, and having the installation documentation written up.

Also, manual pitch uses the same stock levers.

TOTAL install weight is 33lbs front and 32.5lbs rear.

you should consider marrying it up with an innodyne engine, since they require an electrically controlled prop. 188 pounds, 205 HP. Good power to weight ratio.

Innodyn turbine

I WAS TOLD THAT MORE BLADES LESS SPEED. NOT SURE IT IS TRUE OF NOT BUT THAT'S WHAT I HEARD. I THINK I MAY HAVE LOST 1 - 2 KNOTS WITH THE MT'S. THE CLIMB PERFORMANCE IS BETTER, AND A LOT SMOOTHER.

WHAT IS THE COMPOSITION AND WHERE ARE THEY MADE?

You are correct. More blades = Less speed
Positives are = Better climb, lower noise, and less engine wear.

These are a wood core with laminate skin. They have a polycarbon leading edge that is easily replaced.

My motivation with these were to get rid of the hydraulic system so you can feather / unfeather without the engine running, less weight. I wanted better climb on one engine for safety reasons. At the cost of a few knots.

We are now two years into them. Blades are custom made in Austrialia.

Front
70"
Rear
68"

Anybody interested when we get them done? (1-2 more months)

composite props
 

richard,
Anything new to report on the progress of 4 blade composite props?

Things are coming along.... slowly. Documentation and testing still. Rear is completely done. Front is waiting on spinner. Shouldn't be too long now. Looks good huh?

Composite props
 

Richard,
Great to hear you are making progress. Am interested in hearing how performance is affected. Please keep me updated.

Interesting news. The company making these 4 bladed props have been approached in building them for the INNODYNE turbine. Looks like the same prop will be used.... Innodyne wanted a fast pitch change on the hub, so they started timing the pitch change from fine to feather...... tests are in.... less than 3 seconds!

I bet that'll make them the first wooden props ever used on a turbine.

FYI

I ESTIMATE 1 - 2 KNOTS OF SPEED REDUCTION ON THE 3 BLADE MT'S

2-300 FEET PER MINUTE INCREASE IN THE CLIMB OUT. IT'S A HOMESICK ANGEL

THE MOST NOTICABLE BENEFIT IS THE SMOOTH OPERATION. NO VIBRATION. VERY RESPOSIVE. WHEN APPLY FULL THROTTLE ON TAKE OFF, IT REALLY SETS YOU BACK IN THE SEAT IMMEDIATLY. WITH THE MCCAULEY'S THERE WAS A SLIGHT DELAY AND THEN IT CAUGHT UP.

CAN'T REALLY TELL IF THERE IS A DECREASE IN NOISE. THE SOUND IS DIFFERENT BUT NOT SURE IF IT'S QUIETER.

NEED SOME OPINONS FROM THE GROUND WHEN I TAKE OFF. HAVEN'T EXPERIENCED A GOOD COMPARRISON.

ONE ASPECT THAT CONCERNS ME IS THE REAR IS VERY SUSEPTABLE TO NICKS AND CHIPS. I HAVE HAD TWO INCIDENTS ON THE REAR PROP IN TWO YEARS. ONE WAS THE SIZE OF A HALF DOLLAR ON THE TRAILING REAR OF THE BLADE. THE OTHER WAS ABOUT THE SIZE OF A DIME AGAIN ON THE REAR OF THE BLADE. OBJECTS CONTACT THE FRONT OF THE BLADE AND BLOW OUT THE FIBERGLASS ON THE OPPOSITE SIDE. NO BIG DEAL JUST USE SOME 5 MINUTE EPOXY AND SOME TIME TO SAND AND PAINT.

Props
 

Do you have Les phone number so I can talk to him about
the Props, I'm sorry I'm a new member and I'm trying to find very one ,but at this time I need more work finding info on the web page. But I'm so glad there was a web page for Skymaster Pilots.
Mark

I think Les has turned this whole thing over to Owen Bell. I don't recall Owen's phone number, but it's listed on the link to web pages.

Actually, it was interesting to re-read this entire thread.... Has anyone heard any updates from Richard on his progress???

It would be nice to know if those were completed or not..

i'd like to hear more about it
 

If it has be completed.. just let me know because it could lower noise and improve climb rate, what is needed for a good skydiving 337.

Since there is already a thread designiated MT Propeller, I figured I'd add a reply to Jack about his interest in the Composite 3-blade props.

I recently mounted them on the front and rear of my bird and I'm quite pleased.

The biggest difference is decreased vibration....think of it like this: the wop-wop-wop of a two blade huey...you can hear it coming miles away. The high-speed buzz of the OH-6 "Loach" (Hughes 500) which is virtually silent until its on ya. or Harley vs. ninja. its smooth....and its quiet.

In fact, the tips actually whistle ever so slightly at idle.

Much of the smoothness may be due to Owen Bell's dynamic balancing.

Whether its the props and proper balancing, or the stars and the moons...whatever it is....I likes it!!!!

Bug juice wipes away increadibly easily (be careful what cleaner you use).

And be SURE you clean the rear prop after EVERY flight. The rear prop os only a few inches from the blistering hot exhaust from the rear engine. No problem...the heat doesnt seem to be bothering it (only 15 hrs so far). HOWEVER, the exhaust carbons get baked onto the prop....turinging a stark white blade....tobacco-tan. Easy enough to clean off if you get it while its freash. But if you wait too long, I have a hunch it will prove increasingly difficult and could theoretically stain the finish permanently.

Take the extra few seconds to use your cleaning cloth to "floss" between the rood of the prop and the base of the spinner. (sorry about the lack of technical lingo....but if you have one, you'll know what I mean).

In all.... I am VERY please.

As with any upgrade ( and I've done A LOT of upgrading) I dont recommend doing it unless the existing quipment is due for replacement or significant repair. But if its time to do "something", I can say that the MT Composite 3-blade is an exceptionally good option.

It wont work miracles. But it will put a smile on your face.

Cole

I have 7 years on my MT's to date. Still love them and would do it again. I will be leaving for Deland, Florida in about a week to visit the US MT Prop facility. There my props will undergo a complete overhaul for a fresh new start. Estimates for the job are around $7K. Not too bad for both ends.

Like Cole described the benefits of the wood-composite blades are very noticeable in smoother operation and less vibration. This is primary due to the wood blades ability to absorb the common harmonics and vibrations of aircraft engines. Whereas the standard metal blades just can't decrease the waves but in some cases transfer it to the rest on the airframe. This vibration dampening with the MT's has been also noted in component life such as exhaust systems. After having this current aircraft for the last 34 years I just thought that having to repair the rear muffler every other annual was normal maintenance. Since having the MT's the frequency of repairs are more than 1/2 of what they used to be.

When I had the airplane painted last year I painted the rear blades, on the engine side, black. Much easier to maintain and no worry of all the cosmetic finish to maintain. I made a suggestion to MT about this and they were very interested because they had not thought about the position of this unit relative to the exhaust. The other benefit of the MT's is the new spinners. The design is much more pleasing and better materials.

All in all it's a winner. You have to replace both front and rear together so this is where most owners find it difficult because of the large cost factor. You won't be disappointed if you do it.

How about FOD on the rear? Has anyone had damage issues?

Fod in rear prop
 

I purchased a T337G with two MT props and like most aspects but have had to repair the rear blades twice and that is with no un paved strip exposure. Now at strange airports after a little cool down run I shut off the rear and just taxi with the front as I am perinoid about the damage potential.
Sandy Loutitt
N81C, 1973 T337G

oops
 

Opps, forgot to spell check that,
Sandy

The damage issue to the rear can be annoying but it's not a real big deal to repair. I have found that leading with the rear is a must. On take off I lead with the rear and then bring the nose up a little before adding front power. This has all but eliminated any issues with the rear. If I have a long taxi on a hot day I will taxi with the front as primary but as long as you taxi with the rear and don't use the front to blow anything back to the rear you'll be fine. I have had some bad damage on the original rear prop also. So there is no cure for the potential issue, just live with the system. The only time I bring both engines to power at the same time would be taking off on a short field.

The MT props are fantastic

MT Service Bulletins
 

For those of us with newer MT props, MT released SB 30 r4 a couple months ago. Applies to a small number of MTV 12 props & blades built or overhauled in 2013-2014 & requires replacing blade lag screws.

Here’s the whole list of MT service bulletins:

https://www.mt-propeller.com/en/entw/serviced.htm


The actual Service Bulletin mentioned above
https://www.mt-propeller.com/pdf/sbs/sb30r4.pdf

To be, or not too MT!
 

Hi all,

Bumping an old thread here...

Just got word my front prop is a 'boat anchor' - too much corrosion to overhaul. I am faced with a decision - do I go with new McCauley's, or new MT's? Price is around the same (maybe a small advantage to MT) - but that is not the issue. I want to make the best choice for reliability, damage tolerance, performance and maintenance costs in the future.

Herb has posted some great feedback on the MT's and I am looking for some more views on propeller choices, and why you may choose one over the other.

Thanks in advance.

Jeff

+1 MT Props
 

I like the MT props. But, I am a "concrete" flyer and not a bush pilot--My bird has only touched grass once since I've owned it--everything else has been nice, clean, smooth and long runways.

Consider TBO on the MTV-12D's (2000hr/72 mo, per SB1R5) vs your two-blade.

Mine were installed in 2014, have about 400 hours on them. Mine are "due overhaul" this year, and have an issue with the wrong lag screw installed at manufacture. SB (see prior post) says I must change out offending lag screw at overhaul. MT Props rep highly recommended accomplishing overhaul on time, and taking care of the lag screw issue. I go into annual this winter, so I'll go ahead and get 'em done then.

Got a quote from a "local" MT props shop in Tulsa: approx $8K for both. And, they said they'd come get them and bring them back to me in about 10 days time (I'm a few hours drive from Tulsa). Not too bad, if you compare to Herb's quote in his post from a few years ago.

There seem to be quite a few shops ready to service your MT Props, should you need it.
https://www.mt-propeller.com/en/entw/services_usa.htm

PS: I think you can still get white with red tips like Herb's, or black with white tips like mine.

The McCauleys are also 72 mo and 2000 hr if the model number has a B at the end. You can also have a mod/ SB done at overhaul that will increase it to 2000 hrs.

I have a spare front prop and hub with log book that would bolt right on. Part Number: D2AF34C59-AMP. Looks like 250 hours since disassemble, service, assemble, check track, set angles, balance-complete reseal.

Dave

Dr. Dave - you have my attention...Potentially a much faster way to get back into the air. MT prop lead times are 8 to 10 weeks!

PM or call me; we can discuss a price.

I still have a decision to make though... the front prop that was removed did not have many hours since overhaul, but a few years for sure. The rear prop has way more hours and years on the aircraft, so based on the reason the front got rejected at overhaul, I am guessing the rear is in the same condition and will be scrap at next overhaul as well. The issue is internal corrosion on hub and on blade roots inside hub. This is due to an aircraft that was sitting and not utilized AND being in south Texas in the humid environment. I had to remove the front prop due to an oil leak, but I am pretty confident that the rear prop is not much further behind in giving me problems. These old props are not supported with parts anymore, and McCauley is pushing the current ones.

I believe it's a case of deciding "when" I buy new props, not "if".

Jeff

MT Service Bulletin #30 (blade lag screws) to be an AD
 

Information about the MT Prop Service Bulletin SB-30 is posted below in this thread. It seems the FAA has taken EASA's lead and determined the SB needs to be an Airworthiness Directive.

The latest version of the SB can be found on the MT Prop site here

The Federal Aviation Administration (FAA) plans to issue the following AD effective 16 SEP 2022:
2022-18-02

If the link doesn't work, or you're not enamored with the new FAA Dynamic Regulatory System, I'll attach the proposed AD from the DRS site.