3 blade prop for RV-10

I plan to put in an IO540 and a 3 blade prop...not the MT type but a 3 blade Hartzell...Vans does not sell one..and all the currently flying RV10 either have the 2 blade blended Hartzell or the MT 3 blades...
does anyone else consider a 3 blade Hartzell or McCauley prop ? any pros and cons ? and where can I buy one (new)

Son
flying RV6A
RV10 working on fuse

MT Prop

Just out of curiosity, why not the MT 3-blade? I've got one, not flying yet, but it's really a nice piece of engineering and craftsmanship. Also, the few questions I've had about the installation and operation were handled nicely by the MT guys and gals.

You can check with Mark Frederick at Team Rocket. He can get you a 3-blade Hartzell. I use a MT, but the Hartzell is nice too. On the Rockets, it's about 1-3 knots faster than the MT but weights more and is not quite as smooth at cruise. Oh, and it's less expensive too by about $1,500 if I remember correctly.

MT vs. Hartzell , 2 vs. 3 blades

rv8ch said:

Just out of curiosity, why (Hartzell and) not the MT 3-blade?

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American made, cheaper, better performance and 100's of qualified service centers all around the US, who do all levels of maintenance, repair and overhaul. I could argue either side, but let me take the pro Hartzell side. It should be noted that Mickey's RV needs an electric prop so the MT is an excellent choice, really the only choice.

I believe if you check, there are few MT service centers that can work on the MT's in the US, and any major repair must be sent back to Germany. In the list they provide some are nothing more than MT dealers. This is not a put-down, but by the very nature of wood-composite covered blades with bonded metal erosion guards, the repair and maintenance process is much more complicated, so just not anyone can work on them. In fact I read from a MT prop owner that damage to one blade means that all must be replaced at the same time. May be because they have to have matching "Wood" cores. There have been a few metal MT guards come un-glued. That requires you to ship the prop to a service center, whom will than ship part or the entire prop to Germany. I don't think MT's "service centers" in the US can do this repair. I could be wrong but that is my understanding. On the other hand, Hartzell's can be repaired to any level at your near by prop shop, probably at or near the airport you fly from.

Metal has its pros and cons, but blades made of a monolithic material like forged aluminum, makes maintenance and durability better than wood / composite. That is with out debate, composites are more complex bounded structures. However any MT prop driver will be quick to tell you that their prop is smoother and quieter. All true and very good attributes. However because wood/composites are a little thicker than equivalent metal props, so a MT props give away some performance for feel and sound. There is no magic way around physics and aerodynamics, having a thicker airfoil is going to cost performance.

MT props are great products made and needing major service in Europe, that you will pay a premium for, which any Mercedes-Benz, Porsche or BMW driver can tell you. I LOVE GERMAN engineering BTW. Now to be fair Hartzell parts, repair and maintenance is not free, however having owned 4 Hartzell props on 3 different planes, one twin, maintenance between major overhauls involved 10 minutes to grease the hub every year. That?s was all I did to them. Also I might point out a rock-ding on a Hartzell can be dressed out with a file and emery cloth standing on the ramp. A rock ding on a MT prop could be a major deal.

I would not hesitate to buy a MT knowing the pros and cons, especially for an aerobatic plane; however, in my research I found for me and I feel for most RV's, the two-blade blend airfoil Hartzell is the best choice in cost and performance (about 8 mph faster than a 3-bladed MT at 8,000' and 2,500RPM).

For the (I)O-540, Hartzell has very good props, both two and three bladed. I know Hartzell has a commitment to RV's. In fact as they did with the 2 seat RV's they have tested a new prop on the RV-10. They tested a blended Prop, C2YR-1BFP/F8068D, on the RV-10, just as they did on the other RV's. Again the new blended blade added 2 MPH in cruise over the standard blade (RVator 1st issue,2005,Van). Van sells the 80" dia prop new for $5850.00. Not bad, and there are no RPM that need to be avoided.

My question is why not go with the 2-blade Hartzell? Up to about 300-350 HP and aircraft speeds under 250 MPH 2 blades will be faster. The sexy multi blades you see are on C-130's, P-51's and Business and Regional Turbo Props have multi blades because they NEED them due to shaft HP and aircraft forward speed. The best number of blades is usually the min. to get the job done.

I know some may be offended that I don't go all googoogaagaa over the MT. I am sorry, no offense, just my opinion. My hats off to MT for making a good complex product. If it were easy everyone would do it. Hartzell and McCauley make very complex composite props, but they are for large turbo props where the application of composites makes sense (to them). Still many larger props are made of all aluminum. Hartzell manufacturing Also the use of natural materials like wood is not realistic or practical for large-scale aerospace application. MT's are hand made custom props from a small boutique manufacture. Hartzell makes a Composite aerobatic prop, but they do not sell it to the GA public for general use. The reasons are no doubt many, cost being a big one, and the trade offs just don't justify it.

Designing a Prop that is all things to all people is not possible; so pick the prop that fits you best, MT, Hartzell, Aerocomposite, Whirlwind or McCauley. For me lower cost and better speed is most important. Of course buying US made is not a bad thing either.

George

Mickey
The reasons I am hesitating about the MT props are detailed in George's reply
I do like the look and the smoothness of the MT prop (and less weight upfront) but I am waiting for the verdict in the speed difference between the MT prop and the Hartzell prop (MT prop reported 12 mph slower !!!! hard to believe ..) I talked to Vic today and he told me he is very happy with his decision to have the MT prop and will do it again. That is very reassuring so I will consider the MT prop again. Hopefully with many more MT prop installed the serviceability issue will disappear.

George
the main reasons I prefer the 3 blade prop are smootheness and quietness. the tip speed of the 3 blade are slower due to the shorter blades hence lass noise and vibration. 2 mph cruise penalty is an acceptable trade off FOR ME
also not to dismiss is the sexiness factor..somehow TO ME a 3 blade prop plane is more appealing than a 2 blade one....

Randy thanks for the tip I will call him

thanks to Mickey, George and Randy for your comments and advice
Son

gmcjetpilot said:

I believe if you check, there are few MT service centers that can work on the MT's in the US, and any major repair must be sent back to Germany.

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Pure fiction, an urban legend that won't die. When I dinged my prop as OSH, I had a repaired prop in my hands in less than 4 working days. And that was not a SHOW SPECIAL either. A prop shop in Chicago picked up my prop and delivered it free of charge. The only deal I got was the blades at cost because the guys from MT felt sorry for me. (I did put on a long face!)

gmcjetpilot said:

In fact I read from a MT prop owner that damage to one blade means that all must be replaced at the same time.

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True, but they give you credit for the undamaged blades. They do this because they are balanced at the factory and come as a set.

gmcjetpilot said:

That requires you to ship the prop to a service center, whom will than ship part or the entire prop to Germany. I don't think MT's "service centers" in the US can do this repair. I could be wrong but that is my understanding.

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Not entirely true. I think it might be cheaper if you have the blade repaired than to swap out new ones. Your choice. They will ship the blade to Germany for repair, but the prop shop will put things back together again for you. Germany or California, it doesn't matter. These things are priority shipped and arrive in one day regardless. Now, if you hit something there's less of a chance that your blade is repairable. That's a drawback.

gmcjetpilot said:

Now to be fair Hartzell parts, repair and maintenance is not free, however having owned 4 Hartzell props on 3 different planes, one twin, maintenance between major overhauls involved 10 minutes to grease the hub every year. That?s was all I did to them.

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George is having much better luck than most of my friends flying Hartzell. Many of the guys I fly with have had many persistent problems related to leaking seals. Now, it could be related to the way they are installed or maintained, so take this with a grain of salt. Hartzell makes a good product I'm sure.

gmcjetpilot said:

Also I might point out a rock-ding on a Hartzell can be dressed out with a file and emery cloth standing on the ramp. A rock ding on a MT prop could be a major deal.

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It takes more than a rock ding, but point well taken. Of course, if you touch something more substantial with a Hartzell, you are looking at a mandatory engine accessory case teardown, about $3,000 not counting the pain of removing your engine. In my case, the engine never stopped turning and was at idle. Aerosport didn't think a teardown was necessary and neither did other engine guys I spoke to. Overall, it probably cost me about the same than if I'd had a Hartzell and had to do a teardown, only MUCH, MUCH easier.

gmcjetpilot said:

My question is why not go with the 2-blade Hartzell?

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As long as you don't mind a very annoying thumping around 2200 RPM, go for it. At least on the Rocket airframes, this mild thumping wears on you at cruise. I don't know if the RV-10s suffer from the same problem. I was told it's a harmonic problem between the 540's and the 2-bladed props, but perhaps this doesn't apply to the RV-10s. I haven't looked that closely at the -10 so I don't know.

I agree with George that both props are good props and have their pros and cons. I agree that the Hartzell is cheaper, made in America, a little faster, and heavier. The MT is smoother (noticably by those who have flown both) and lighter, but comes at a higher cost.

Thanks Randy

Thanks Randy,
for the corrections, good to know, appreciate it. I am especially happy to hear MT has good field support and you are happy. It is much better than I had thought to be sure. I stand corrected. This is key to any aerospace product, field support. The best prop technically in the world could be the worst choice if there was poor factory support. Clearly MT knows this and their business plan is to provide the best support they can, despite the distance to the manufacture, cool. George

Mt Usa

MT has there own shop in the US, its MT USA in Florida, my prop is there now for repair. They seem very nice and are trying to get me the best solution to my problem. Parts and or parts availability looks like a problem that will slow the process, even if I would like to just replace the prop there are none available, looks like 2 or 3 months weight for a new one but as it stands now it looks like they can use my blades and replace everything else (hub ect.) and get me going sooner and cheaper I hope.

My prop (MTV-15) broke a pitch block 10 years and 300 hours out from overhaul; this was caused by lack of grease in the hub that apparently ate the bearings and hub causing extreme resistance that lead to breaking the pitch block on one of the blade farrells, this caused a nice vibration as one of the blades was not being controlled. Sense no one saw any evidence of this prop slinging grease after overhaul I wonder where it went or maybe someone forgot to put it in?? I like the sound of being able to grease you Hartzell on the plane.

I don?t think I can use a Hartzell though with an IO-360 that has 10 to 1 compression and no counter weights on the crank, I had heard that this is not a suitable combination with the Hartzell. Any comments are welcome about this; maybe people are doing this with no problems? It is also on a -4 so CG could also be an issue.

I will let you know how MT USA does when this is all finished.

Russ

Someone at Firewall Forward Inc knows how to do it for the C177RG and M20J. They have a 10:1 kit for the IO-360 with a two blader (I think it might be a McCauley come to think of it).

Also technically according to Lycoming, any prop-strike requires a tear-down inspection. There is an AD to that effect.