MT Aluminum Prop

[weriderv8a]

I've been looking at Engine and Prop combos and I got a quote from American Propeller for the new MT Aluminum Constant Speed Two Bladed Prop.Any one know anything about this prop or anyone using it? They say it's 9lb lighter than the Hartzel and that there is no R.P.M. restrictions for undampened Lycoming 360 series engines. It is for experimental only. Any thoughts.

[penguin]

I was in Albuquerque 3 weeks ago and met an RV-6 owner (from Colorado Springs I think) who was flying exactly the prop you are talking about. He was very pleased.

Pete

[gmcjetpilot]

The Hartzell will be cheaper to buy, faster and cheaper and easier to maintain.

As far as restrictions if you go to Hartzell web site you will see the Hartzell blended does NOT have any restrictions on a stock (I)O-360XP. On Lycoming or modified engines (High Compression or Electronic ignition) there are small single point restriction that does no affect normal operations.


How does Hartzell know what these restrictions are/ They test it. Hartzell has a commitment to support the experimental aircraft community, RV's in particular. They have taken the time, effort and expense to do flight surveys of their props on RV's, with Stock Lycomings , Stock clones, modified Lyc or clone and FADEC. The Blended airfoil was made specifically for the RV, fast aircraft. Most of the "restrictions" apply to the older HC-C2YK/F7666. I have one on a Lyc O-360A1A with electronic ignition and do not find it affects the way I fly the plane.

The MT has NOT been tested with modified engines or on the RV airframe as far as I know, and it cost about $1000 more. My guess is they have not tested it and don't know the affects of HC pistons, EI or FADEC. Also you are dealing with a German made product. Not that it is not good, the support in the US is going to be less. There are by far more Hartzell service centers in the US that have the tools, manuals and parts on hand to overhaul them. I don't know anything about the MTV-15 (metal two blade) but like the composite models they may need to be disassembled and shipped to Europe for major repair. JUST BECAUSE THEY (MT) DON 'T PUBLISH RESTRICTIONS DOES NOT MEAN THEY DON'T HAVE ANY. IT IS EXPERIMENTAL AND NO GUARANTEE ON COMPATIBILITY WITH A MODIFIED ENGINE. Hartzell has done the work.

Click on photo guide and click on RV props, and look at restrictions:
http://www.hartzellprop.com/kitplane/index_kitplane.htm

Example: (Hartzell quote)
"SUPERIOR XP-360 RESTRICTIONS:
Hartzell Propeller Model HC-C2YR-1BFP/F7496 is vibrationally approved when mounted on Superior Air Parts model O-360-B1A2 and IO-360-B1A2 engines rated at 180HP at 2700 RPM with magneto ignition and installed in Van's Model RV-6A and similar single engine tractor aircraft. There are no operating restrictions."

Hartzell's are NOT experimental props, they have literally been evaluated to type certificate standard for the RV, and if the RV was a certified airframe tomorrow, the prop could be certified. MT has not done the testing to my knowledge on RV airframes and stock / modified Lycomings / Clones, Hartzell has. Unless they have it in writing don't believe what you hear. Hartzell has well documented test and limitations. Don't believe me research it. Unless you want the "smooth" operation of a composite MT (at the loss of 8mph cruise speed) than I could not imagine why you would want a MT metal two blade-er, when the Hartzell has a better prop in my opinion.

Van's has a OEM deal with Hartzell. For the fastest constant speed prop (with no RPM (range) restriction or negligible single point restriction) the Hartzell is the way to go. As far as performance, the Hartzell in my opinion is faster. Since I have never flown against a MTV-15 (the metal two blade MT) I don't know. Since there is no reliable data** who knows.

** (((Now there is a MT prop dealer that will tell you the MT 2 blade metal prop is better in someways(?) than the older HC-C2YK/F7666-4. He did his own flight test of MT props against the HC2YK/F7666 with a RV-6A and 180HP engine, posting the results on his web site about a year ago, where it still sits today. I just got into a argument on how his MTV-12 data (3-blade wood/fiberglass prop) shows it going faster and faster with altitude (on less and less HP). This is not correct and violates basic performance of any non turbo piston engine RV. I also pointed to the fact a RV should say loose about 1 MPH per thousand feet but he shows the MT gains 4 mph but the Hartzell loosing 20 MPH in 10,000 feet, when 10 mph is normal? Look at Vans data an you can see this does not match the specs for RV's, which by and large use the Hartzell as a base line prop.)))

(((I plotted to LessDrag data and it is all over the place. I don't make a claim about the data and let you decide if its reliable. He also showed the 3-bladed composite wood MTV-12 was faster than the Hartzell when everyone else who has compared the speeds between it and the Hartzell F7666 finds the Hartzell is faster by at least 5 mph at 8,000 feet and 2,500 rpm. LessDrag Prod found that the MT was not slower? You decide. RPM and altitude does affect airframe drag, prop efficiency and engine power, but this data fits none of the expected trends or known values, IMO.)))

Data from LessDrag Prouducts MTV-15 (metal) vs. C2YK/F7666-4 (click to enlarge)



My opinion is the new Hartzell blended airfoil HC-C2YR-1BF/F7496 is a no brain-er choice: cheaper, faster, better maintenance and customer support and a US made product. Plus vans spinner and cowl are made around the Hartzell. You make your own mind up. I have a HC-C2YK/F7666-4. I have it only because I bought it overhauled for $2,500. If I was buying new today it would be the new blended for about $5,800. The metal MT cost about $1000 more and shipping may be greater. If you want a MT call Less Drag Products and tell him George sent you.

George.

[rv6ejguy]

MT props can be fully serviced in North America. American Propeller in Redding, CA and Western Propeller here and Canada import, sell, service, repair and assemble them. Both excellent companies to deal with.

[penguin]

The Van's advice seems at odds with what George wrote above. Also there is more on the Hartzell site than George has posted (including some limitations). The Van's service letter to builders (http://www.vansaircraft.com/pdf/Hartzell_c2yr.pdf) says,

"Hartzell Propeller Model HC-C2YR-1BF/F7496 is vibrationally approved when mounted on Lycoming model O-360-A1A rated at 180 HP at 2700 RPM and equipped with magneto ignition and/or Lightspeed Plasma II or Unison LASAR electronic ignition installed in Van?s Model RV-8 and similar single engine tractor aircraft with the following operating restrictions:
1. Do not operate above 22? manifold pressure below 2350 RPM.
2. Operation above 2600 RPM is limited to takeoff. As soon as practical after takeoff the RPM should be reduced to 2600 RPM or less.
3. The propeller diameter limits are 74? to 72?.

Hartzell Propeller Model HC-C2YR-1BF/F7496 is vibrationally approved when mounted on Lycoming model IOF-360-A1A rated at 180 HP at 2700 RPM and equipped with Aerosance FADEC engine control installed in Van?s Aircraft Model RV-8 and similar single engine tractor aircraft with the following operating restrictions.
1. Do not operate above 22? manifold pressure below 2350 RPM.
2. Maximum engine RPM must be limited to 2650 RPM.
3. The propeller diameter limits are 74? to 72?."

This says to me that there are restrictions with this prop and that behaviour with injected engines, without the Aerosance system, has not been tested.

I think George's highly negative view of MT propellers is unfounded. Many MT products are certified, and all can be serviced at many repair shops through out the country. Composite & wooden blades are inherently more tolerant of vibration because of the stuff they are made from. They are sometimes slightly slower and cost more. Research what is out there and make an informed choice based on the type of flying that you will do.

I'm going with fuel injection, P-mags and a composite/wood prop. If I use a metal prop it will probably be an MT. Right now a Whirlwind 200RV seems to be the best of the bunch - and it comes with a spinner.

Pete

[gmcjetpilot]

Originally Posted by penguin

The Van's advice seems at odds with what George wrote above. Also there is more on the Hartzell site than George has posted (including some limitations). The Van's service letter to builders (http://www.vansaircraft.com/pdf/Hartzell_c2yr.pdf) says,

"Hartzell Propeller Model HC-C2YR-1BF/F7496 is vibrationally approved when mounted on Lycoming model O-360-A1A rated at 180 HP at 2700 RPM and equipped with magneto ignition and/or Lightspeed Plasma II or Unison LASAR electronic ignition installed in Van?s Model RV-8 and similar single engine tractor aircraft with the following operating restrictions:
1. Do not operate above 22? manifold pressure below 2350 RPM.
2. Operation above 2600 RPM is limited to takeoff. As soon as practical after takeoff the RPM should be reduced to 2600 RPM or less.
3. The propeller diameter limits are 74? to 72?.

Pete you are right you can't believe what you read on the internet. That's my point with the data I referenced. As far as restrictions I think you are confused with what I said. I never said there are NO restriction of any KIND on any engine. Also be careful about restriction and restricted RANGE of RPM's. True it seems what I said is at odds, but there ARE restrictions NO restrictions on a stock Superior (I)O360XP, but there are some on a stock O360 Lycoming. Note, restrictions are not ranges of RPM's by the way.

My link and quote is from Hartzell, so refer all questions to Hartzell customer service, they will be glad to explain. Van's data by the way is out of date, but the Superior engine with the Hartzell 7496, as I said, has NO RESTRICITONS. Check it out.

If you look at the restrictions for the Lycoming, based on the way most pilots fly, the new prop is not an issue.

The old C2YK/F7666 does have a RPM range, even on a stock engine, limit 2000-2250 RPM for continuous operations, the new F7496 does NOT have this RANGE or RPM restrictions. That was my point. The new prop is pretty good and there are no "RANGE", "RANGES" or bands of RPMs to avoid on any engine (like the older C2YK).

Originally Posted by penguin

Hartzell Propeller Model HC-C2YR-1BF/F7496 is vibrationally approved when mounted on Lycoming model IOF-360-A1A rated at 180 HP at 2700 RPM and equipped with Aerosance FADEC engine control installed in Van?s Aircraft Model RV-8 and similar single engine tractor aircraft with the following operating restrictions.
1. Do not operate above 22? manifold pressure below 2350 RPM.
2. Maximum engine RPM must be limited to 2650 RPM.
3. The propeller diameter limits are 74? to 72?."

Again you are correct, but there are no stay out RPM "RANGES". Just item #1, single point power setting and #2, which I guess is a 50 rpm range kind of, from 2650-2700 rpm. There are not many FADECS are out there, so this is not a big issue. If you do have a FADEC, the 50RPM is going to cost you about 2.5HP to 1.25HP. Considering the FADEC is getting more power anyway, I don't think its an issue. NOW DID MT prop company check their metal MTV-15 prop on FADEC? That is all I am saying. I don't think the MTV-15 has been tested which could be dangerous. MT's (wood/composite) models should not be critical for harmonic vibration because wood is a natural damper. However it would be nice if they did test with them as well on modified engines mounted on RV's in particular.

Originally Posted by penguin

This says to me that there are restrictions with this prop and that behaviour with injected engines, without the Aerosance system, has not been tested.

As I said (I)O360XP (Superior) with mags and stock pistons = NO restrictions. NOW if MT would like to say they have bothered to test their metal prop on FADEC, HC pistons and Electronic ignition I will shut up.

Hartzell says out right: TESTING OF THIS PROPELLER ON THE SUPERIOR AIR PARTS XP-360 ENGINE EQUIPPED WITH ELECTRONIC IGNITION AN/OR FADEC HAS NOT BEEN DONE AT THIS TIME. So we don't know what the restrictions are but should be no more than those of the Lycoming which has been tested. I bet if some RV'er has a XP360 with FADEC, HC pistons or EI, Hartzell will be interested in flight testing it. Pretty good company.

Originally Posted by penguin

I think George's highly negative view of MT propellers is unfounded. Many MT products are certified, and all can be serviced at many repair shops through out the country. Composite & wooden blades are inherently more tolerant of vibration because of the stuff they are made from. They are sometimes slightly slower and cost more. Research what is out there and make an informed choice based on the type of flying that you will do.

I'm going with fuel injection, P-mags and a composite/wood prop. If I use a metal prop it will probably be an MT. Right now a Whirlwind 200RV seems to be the best of the bunch - and it comes with a spinner.
Pete

Pete I could not disagree with you more about going with a metal MT, but it's your life. That prop has not been tested with an electronic ignition. WHY? The Hartzell is cheaper and faster and HAS BEEN TESTED. I would call MT and ask them to put it in writing that electronic ignition is cool. I WILL bet you a beer you will not get them to say OK.

I could not agree with your more about people making an informed decisions. My issue is false data miss leading that the MT (metal or composite) will be just as fast, is not honest. Most every one agrees with the the relative speed deficit but one person , and they sell MT's. At the Risk of being called negative the Hartzell BA is FASTER than the 200RV by 2 MPH, plus the 200RV cost more, has short TBO schedule and can be worked on at few shops (less than the MT). Sorry

I just want people to have the data or at least the rebuttal to NEGATIVE data on the internet, I know in my opinion at least to be untrue. Look at it and tell me what you think. In fact I know of a guy who had a MT and took it off and replaced it with a Hartzell. Speed was more important to him. (here is a link to his experiences with several props: http://www.lazy8.net/proptest.htm )

It may be highly negative to you, but I think it is fair. I hate to see invalid data that might miss lead fellow builders in their decision making, but could care less what the final decision is.

When it comes to metal props, Hartzell is the leader. I can't understand why you decide to go with a METAL MT and not their wood core props. The metal MTV-15 is not made for the RV like the Hartzell Blended Airfoil. The BA will eat the MTV-15 alive in speed, I am sure. Since the metal MT will not have a smoothness advantage why spend $1000 more to go slower and not get any other advantage.

Originally Posted by rv6ejguy

MT props can be fully serviced in North America. American Propeller in Redding, CA and Western Propeller here and Canada import, sell, service, repair and assemble them. Both excellent companies to deal with.

You say American Prop can overhaul the metal prop; cool good info and Thank You. American Props is a good company I am familiar with. I do know work on a MT composite blade must be done at the factory in Germany. This is not negative and with world-wide air-shipping this is not a big issue, except more expense.


Yes I am a BIG FAN OF HARTZELLS and THINK THEY ARE THE BEST and advantages should be mentioned. One of the advantages is speed. Some would like to discount that and mitigate it, but it ain't true (to use bad English). Some think the MT prop is BEST and go on and say so. That's cool. Again the only thing I am truly negative about is the DATA you see floating around the internet about MT prop vs. Hartzell's (LessDrag).

The MTV-15 (metal 2-blade) is in my opinion does not have the advantage of their composite models they and still has less performance. It makes no sense to go with that particular model of MT, in my negative opinion.

WHAT IS THE REAL SPEED PENELTY. People like Van, Randy Levord and others have done some good work, consistent with each other to show the difference. Still there are a few ridiculous claims to support the MT camp. I am negative to that, you betcha. Why do 3 or 4 sources all agree about the speed differential and advantage the Hartzell has over the MT but one? You decide or believe what you want.

The MT prop is a good prop, but speed is not its strong point. Also Hartzell, American Made in the USA, has a strong commitment in supporting RV'ers and this is where the Blended airfoil comes from, a RV. The MTV-15 is just an existing "O-360" model. At least the old Hartzell C2YK/F7666 standard was adapted from Mooney's and Comanche's, which have comparable RV speeds. The old F7666 design was originally conceived over 30 years ago, is still in production, can handle HP from 180-250HP and up to 2,900 RPM. Not bad.

I would buy a MT if I had to have an electric constant speed prop (I don't but lets say). I would also consider one for say a Pitts where gyroscopic loads are an issue and top speed is not so important. The Harmon Rocket II and F-1 team Rocket Guy's find the big two blade Hartzell causes more buffet (not vibration) of the airframe. The 3-blade Hartzell has less buffet but is heavier than the 3 blade MT. The w/3-blade Hartzell is still faster then the MT on Rockets, but guy's find the (up to 5 kts) loss in speed is worth the reduced "smoother" MT. You have plenty to spare in a Rocket so what the heck.

So Pete please don't paint my comments into a corner; I am not a fan of MT props nor am I anti or negative. I do recognize the unique characteristics of wood core blades, which is they dampen vibration better than metal blades. Metal will be more durable and easy to maintain. I am open minded but feel someone has to raise Hartzells flag in light of the negative and faults data posted on the web. Cheers George

[rv6ejguy]

Bob Honig from American Propeller said they can do most blade repairs (where the blade is repairable) in house. They have considerable composite blade experience from offering their new all composite (no wood core) aerobatic props.

Mike Wagner from Western Propeller says they can repair and overhaul MT and Dowty composite props including leading edge replacement.

As far as reliability, there are many users of MT props which have had excellent reliability with a lot of flight hours. Some were previous unhappy Hartzell users who have not shared the same luck as George has had with his. No hub leaks, way smoother operation they say. I'll let you know what I think when I fly my MTV-18-B/193-53a. Just ordered it. Ouch, that hurt, but no other reasonable choice for the big turbo Subie at this time.

Not everyone wants a Hartzell. I found MT in Germany easy to work with and fairly prompt and thorough with their replies. They will tailor blades and hubs for your application in most cases if it's away from the norm.

[robertahegy]

Without getting into a P***ing contest, I am very pleased with my Hartzell BA prop. It is smooth and my 7A exceeds Van's numbers with an 0-360 A1A.

The restrictions, if valid, are really a non issue as far as flying goes. Flying below 2350 and above 22" is a rarety, if ever, and would probably only be for brief periods. I believe the restriction is intended if the parameters are used for extended periods. I don't ever recall having been impeded by these restrictions.

Can anyone tell me when these restrictions would be a problem? Maybe I'm missing something.

Roberta

[gmcjetpilot]

Originally Posted by rv6ejguy

Bob Honig from American Propeller said they can do most blade repairs (where the blade is repairable) in house. They have considerable composite blade experience from offering their new all composite (no wood core) aerobatic props.

Mike Wagner from Western Propeller says they can repair and overhaul MT and Dowty composite props including leading edge replacement.

As far as reliability, there are many users of MT props which have had excellent reliability with a lot of flight hours. Some were previous unhappy Hartzell users who have not shared the same luck as George has had with his. No hub leaks, way smoother operation they say. I'll let you know what I think when I fly my MTV-18-B/193-53a. Just ordered it. Ouch, that hurt, but no other reasonable choice for the big turbo Subie at this time.

Not everyone wants a Hartzell. I found MT in Germany easy to work with and fairly prompt and thorough with their replies. They will tailor blades and hubs for your application in most cases if it's away from the norm.

I stand corrected, but that is one or two shops in a BIG North America.

For the record:
I think the MT wood/composite props are GREAT. I think it is a great company and they are here to stay for the long haul. I hear they are smooth. They do cost a more (negative statement I guess but true). The smoothness of the MT will cost cost some speed (yes negative but also true); Many are willing to compromise some speed for the smoothness. Wood core / composite blades are thicker and cost speed, no way around it. Add the fact most are opting for the 3-blade models, where aerodynamic theory states it will be less efficient than a 2-blade prop. Facts, not negative view.

Also anyone using an auto engine and wants or needs a constant speed prop usually needs an electric prop. The MT is an excellent choice and would NOT hesitate to buy one for that application. Also the Rockets like the MT for smoothness. With the extra speed reserve these planes have a hand full of Knots don't make as much difference. Peace and Love, To all Holiday Cheer and Merry Christmas, Happy Holiday and Happy New Years, to you and yours. I am done, whoooa!

George

[tacchi88]

Here are finding of 3 bladed Hartzel blade on a Piper Arrow with IO360 B1B. equiped with LASAR. Reason for installation, tip damage to prop. Cost of repairs near that of new 3 bladed.
The three bladed prop added 18# to the nose of an already nose heady AC. Extending gears was always exciting. Ran out of trim as well. Top speed was lost, about 12 kts., vibration throughout the entire operating band, and climb increase negligeable. The engines red zone operating areas was up 50 rpms, bottom 2000 now 2050 top 2200 now 2250. Both prop shop and Hartzel notified. Neither offered much help, except that the dealer, when asked if the limit stops could be changed, he stated that Hartzell has them set at the factory for my particular application, and Hartzell said no no.
I told the shop that this aircraft was smooth before, now it lost performance and added vibration. I asked about moving the stop and he reluctently agreed on doing so.
The stop adjustment was turned in increments until performance was satisfactory. Vibration at cruise power to top speed dramatically reduced, though not as well as with the two bladed, but acceptable. At lower engine speeds (rarely used) it still vibrated. Cruise and top speed improved, but only before LASAR was installed, certainly down 3 to 5 Kts from the two bladed.
Did some research after purchase (dummy me), one a Piper Arrow and the other a Mooney. The only gain was the Mooney, ground clearance. Both lost top end ad cruise, and neither experienced much in the way of climb increase. Both had vibration that were not present before, but acceptable.
The axiom about gear up landings came to be true. Three light gear extention indication, only to find that 2 did not lock. Bottom line, the 3 bladed wonder bit the dust. Insurance company paid for damage, nut I opted for a new 2 bladed. Since that prop was no longer made, a new one was made up from available new parts.
New 2 blade was installed and the broken Arrow flown back to home field with a ferry permit. At first experience, the engine was it's old smooth self, climb back to normal, and top speed not able to check due to ferry permit limitation of gear down and locked provisions. Though after repairs, top speed was not only back, but improved due to engine major due to prop strike.
All the text books tell us that fewer blades are best. More blades may be added due to engine power, and even ground clearance purposes, still fewer is better. 3 bladed do look sexy.
I have also observed that in 6 cylinder conversions, 3 bladed seem to actually enhance smoothness though no appreciable increases in performance. I believe that this is in part due to a 6 cylinder crankshaft lay out of 120 deg which compliment 120 deg of the prop blades. where as a four cylinder has 180 deg spread, vs 120 of the prop.
In the end, the text books, aside from the vibration issues, are correct, fewer for our small engines is better.
My RV 10 will have a 2 bladed.
T88
N968TP