[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]

Get a Blended airfoil Hartzell

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]

Don't believe everything you read on the internet ...

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]

Fair and balanced

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).

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.

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.

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.

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]

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]

3 Blades

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

 

[rv6ejguy]

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

There are 13 official MT dealer/ repair stations in the US and 3 in Canada. I don't think Fedex would have a problem getting a blade, hub or complete prop to one of these facilities in one day. Of course there are many other companies distributing MT products like Van's and Eggenfellner.

Most of the MT owners I have spoken to are happy with their choice. A couple mentioned losing a few knots but those told me the smooth ride was worth it. If you look at one of these up close, they are beautiful. Rotating art. Of course they come with the fine art price.

I have to say I don't like the price but I do like the 16 lb. weight savings on my prop, important in my installation.

 

[gmcjetpilot]

Uncle, White flag, surrender

There are 13 official MT dealer/ repair stations in the US and 3 in Canada. I don't think Fedex would have a problem getting a blade, hub or complete prop to one of these facilities in one day. Of course there are many other companies distributing MT products like Van's and Eggenfellner.

Here is something you might not know. Correct me if I am wrong, If a MT blade is damaged you have to replace ALL the blades on that prop, because they are a matched set! I guess they give you credit on the good blades, but replace all of them since they are are matched set. Also I don't think all "shops" are created equal. Some no doubt are just tear down, ship, re-assemble. Others may have better capabilities, but I was told all composite blade repairs where only done in Germany? Either way like you say Fedex is there for a reason. This is what I do know, work on composite ANYTHING aerospace is highly process dependant (I was an aerospace engineer at one time). You not only need the right equipment, autoclaves, vacume bags, materials and so on, you need highly skilled people. That is the down side of advanced composites. Working on them is not like a file and blending a ding in a metal prop.

MT props are great so are Whirlwind, Aerocomposite.

I understand that MT has a good network of shops and shipping is no big deal. I agree. (I am only going to focus on the positive). My point is Hartzell has been around, had happens to have a real large network of approved shops that can work on them (with out shipping anything back to the mother ship). MT, Whirlwind and Aerocomposite have not been around as long or as long in North America. Fair enough. As long as that is cool with you than repair stations or not, it is a non-issue. I am just use to having one or two prop shops with in a 5-120 minute drive from my base (or on the field). To be fair there are BAD prop shops out there even for Hartzells, you have to shop around. Some one mentioned American Prop in N Cal, they are good, and even do custom paint finishes on Hartzells.

Performance: According to Van's Aircraft and the first issue of the 2004 RVator, the Hartzell had the best performance of any prop, even 2 mph faster than the Whirlwind 200RV.

Cost: For the money the Hartzell (around $5800) from Vans are a bargain and a lot cheaper, in some cases the competition cost close to $10,000.

Testing and certification: I know the Hartzells have small restrictions (except a stock XP360), but those restrictions are the results of testing and analysis. Not being negative but some of the other props are experimental and not tested. The first time you mount some of these props my be the first time it has ever been mounted on that engine, in that configuration, on that airframe and its YOUR airplane. I am all for experimental airplanes but not with my engine or prop. That is just me. Having a certified prop is important to me.

I guess I am going to be negative again, sorry Pete. I think the MTV-15 metal 2 blade (MT's clone of a Hartzell) is not a good choice on an RV, especially if your engine is modified in ANYWAY. If you have HC pistons or electronic ignition I would go with the Hartzell or MT (wood blade). Why? Unless MT has specifically tested their metal prop on modified engines, preferable on a RV or similar fast single engine plane, I would say you are taking some risk. May be they made the blades so thick that they are not harmonic critical, but unless you have it in writing from MT engineering I would only consider using the metal blade MT on a stock O-360 Lycoming. The Hartzell has been tested and the MT models made with wood, which has great fatigue qualities and vibration dampening, I think are better choices.


What about Whirlwind 200RV? I think it is a great prop but it will not be as smooth as the (wood) MT because it has of a much stiffer carbon fiber blade and core. It also can only be worked on at the manufacture and a few (?) shops. I hear WirlWind can be worked on at any McCauley Shop. I talked to one prop shop. They told me they had a customer who asked them to work on their Whirlwind, but refused. They called the WhirlWind (I think before it was sold) and where told to just use a McCauley manual? They declined to work on it with out manuals. They are experimental and thus they did not want to work on them. Last they have short TBO's. This is OK if you know it going in. It is also a positive sign the company, WhirlWind is conservative and wants to control the props and get more field service experience. They are after all a new design from a fairly new company. In time, no doubt it will be a proven design with extended TBO, but for now it is experimental.

That is my point EXPERIMENTAL vs. CERTIFIED PROPS. The only choice for me is Hartzell because of the *history, support and testing. If that is negative OK, but I don't read anyone else pointing out the positives of buying certified props.

George

*Hartzell has been around since WWI, and yes historically they have many years of experience, prop designs and thus their share of AD's. I had a Piper Apache with the reoccurring inspection, but hey they where 1940's or 50's designs and they liked steel hubs back then. MT, Whirlwind, Aerocompoite did not even exist then. However the new props being sold are AD free as far as I know. For example the older C2YK/F7666 is different than one 10 years ago. MT has had AD's and blade loss. However as I said Hartzells are certified and on thousands of planes flying for decades. That is important to me and not a put down of any other prop brand or model.

 

[rv6ejguy]

Here is something you might not know. Correct me if I am wrong, If a MT blade is damaged you have to replace ALL the blades on that prop, because they are a matched set! I guess they give you credit on the good blades, but replace all of them since they are are matched set. Also I don't think all "shops" are created equal. Some no doubt are just tear down, ship, re-assemble. Others may have better capabilities, but I was told all composite blade repairs where only done in Germany? Either way like you say Fedex is there for a reason. This is what I do know, work on composite ANYTHING aerospace is highly process dependant (I was an aerospace engineer at one time). You not only need the right equipment, autoclaves, vacume bags, materials and so on, you need highly skilled people. That is the down side of advanced composites. Working on them is not like a file and blending a ding in a metal prop.

I only talked to American and Western. Both said they can do any repair in house where the blade is repairable. I have no idea if the other 14 shops in North America have this capability.

I guess the second point is that the composite MTs have a SS LE strip so it's pretty unlikely to damage that very much from rocks etc. A couple of composite MT and IVOs have swallowed various exhaust/ engine parts parts on hovercrafts and pushers with merely paint dings surprisingly enough. Checked out, returned to service with no repairs.

IVO said I could replace any number of blades when I destroyed two as they are balanced to the same spec. I believe I read that you can do the same with MT on another site I can't find any more but I could be wrong on that. Certainly if you ding the tips of a composite prop on the ground, the blade will be toast but it's easier on the crankshaft.

 

[gmcjetpilot]

That is way cool

Yea, I hear you and agree. I just want readers who really are in the decision mode to know whats what in composite props.

Composite props are special and have wonderful characteristics, but with that comes some unique issues, not the least of which is maintenance and repair. The likely scenario with a MT prop or other composite prop is you can expect maintenance free operation to TBO and beyond several times over. With incident or accident trauma that is a different story but than even a metal prop will be toast.

As far as the "SS" erosion strip, yes that should reduce or help erosion and protect from some damage. I do know of one case where another composite prop (aerocomposite) slung it's SS erosion strip off. Again bonding metal to composites has been done successfully for a long time but it is "process dependent", but if done right its almost indestructible. The old boring blades made from solid machined aluminum forgings is pretty fool proof. However with a semi-homogeneous material like aluminum, you have weight and fatigue issues but at a cost advantage. For me I need the weight on the nose and cost is important. Metal fatigue is not an issue if designed properly, with service life more than more than most pilots fly in a lifetime. These issues are what points me more to the traditional than the composite, while others are lead to composites for other reasons. The balance of engineering, cost, performance and maintenance is not a single solution. No "one size fits all" and Viva La Difference.


With these issues, for a daily drivers. Hartzell feels the metal prop is the best fit for the general GA fleet. Hartzell's only composite prop for small planes is their special aerobatic prop.

http://www.hartzellprop.com/pdfs/Hartzell_Scan.d_Intro._Broc.pdf

Clearly composites has great advantage in many cases. For me the big draw back is cost, but composites are more expensive to produce, at least in small quantities.

Thanks for the info. Obviously MT sees the need to have excellent customer support and service in the US and is addressing that issue very well, which is good to know.

Merry Christmas George