RV-7 Constant speed Hartzell vs MT?

[Kahuna]

Correction... Our prop lengths are 76" on all our RV-8's and our single RV-6, but our RV-4 is a 74". Hartzell offers 76", 74", and 72". Im not sure why the 76" is not being offered on Vans, but I suspect you could certainly ordered the 76". It was the 76" that was the recommended length for our planes. I correct my earlier posts so there is no confusion. Sorry about that. Record now corrected.

[gereed75]

Agree with everything Kahuna said.

Disregarding the repair factors, the service life for a Hartzell aluminum prop is at least 8000 hours. You are not likely to get there so that part of the equation is mute.

If I were building again, my choice would be a composite prop, (probably Hartzell), 74" (I'll take the 1" more ground clearance vs 76") with a prop extension to put the lighter prop on a longer weight arm to negate the CG concerns.

The prop extension also gives you the advantage of an extended cowl for better cooling air flow.

Check Hydroguy's 7 for what I think is the optimum four cylinder set up. All IMHO of course.

[hydroguy2]

Originally Posted by gereed75

Check Hydroguy's 7 for what I think is the optimum four cylinder set up. All IMHO of course.

Thanks Gary...I don't know if it's optimum, but seems to work for me.
The WW200RV prop is 38# with the carbon spinner so I used a Saber 2.25" extension. I also tried to mount everything(ELT, Strobe pak, etc) forward if possible. My -7 weighed under 1100# completed and CG is never an issue.

Saber makes a nice product, highly recommended for a light composite prop on a light parallel valve engine.

[Capflyer]

Originally Posted by JPalese

What are the merits of the constant speed Hartzell vs the MT on an O-360 equipped RV-7?

In the Hartzell line would you use the metal or composite prop?

In the MT line, 2 or 3 blades?

The difference can be summed up in one word: Ethics

The decision between these two is very simple. You will come to your own conclusion if you go back and read through many of the problems MT props have had and poor customer service. Do a search for MTV-15 which is their CS metal 2 blade prop. The guy that purchased my RV7 four years ago was just told he needs to replace the entire prop after only 427hrs TT. The MT governor is fine, no issues with that.

True story....when my MT prop on my RV7 with less than 100 hrs on it was spitting grease all over the plane I had to fight with MT in Germany to cover the repair to re-seal the blade shafts in the hub which in essence is a rebuild. They initially told the shop they would not cover the removal and reinstallation of the prop and that they would have to rebuild it while it was on the plane. Nay nay I said and had to continue the fight with them with the MT authorized shop's support......and that was only the first time. The second time was even more of a battle.

I love the Hartzel on my RV4.

[dmeloche]

I have a MTv-11 on a 160hp RV6. I generally like the propeller, it is light and has smooth operation. However it has a recommended overhaul at 72 months or 1000 hrs whichever comes first. The OH cost starts at $2100 and goes up from there.
After about 50 hrs of operation it started throwing grease. It was still under warranty so they repaired (after dealing with Germany) it but I had to remove it and deliver it to a authorized service center. A friend of mine had the same problem, his was outside of warranty by about 6 weeks and they wouldn't cover it. He had to pay to have it repaired. Not good customer service.
The comments about aft CG issues are correct. The airplane becomes a handful on landing when low on fuel with 2 souls and some luggage aboard. If I had to do it again I would take the 20lb weight hit and go with the Hartzell

Doug M
RV6 570hrs

[N941WR]

Great tread for those of us who are researching CS props.

Can I toss in WW props into the mix? How do they compare to the other two?

[ed.] No Please. Let this man have his thread.

[Russ McCutcheon]

Originally Posted by Capflyer

The difference can be summed up in one word: Ethics

The decision between these two is very simple. You will come to your own conclusion if you go back and read through many of the problems MT props have had and poor customer service. Do a search for MTV-15 which is their CS metal 2 blade prop. The guy that purchased my RV7 four years ago was just told he needs to replace the entire prop after only 427hrs TT. The MT governor is fine, no issues with that.

True story....when my MT prop on my RV7 with less than 100 hrs on it was spitting grease all over the plane I had to fight with MT in Germany to cover the repair to re-seal the blade shafts in the hub which in essence is a rebuild. They initially told the shop they would not cover the removal and reinstallation of the prop and that they would have to rebuild it while it was on the plane. Nay nay I said and had to continue the fight with them with the MT authorized shop's support......and that was only the first time. The second time was even more of a battle.

I love the Hartzel on my RV4.

Just a couple of point, the MTV-15 has been around for a long time most have composite blades like my MTV-15B-183-33, only in recent years has MT been putting metal blades on this prop, another thread suggests there are only 48 units out there with metal blades and yes I would avoid those.

I’ve had the good fortune of buying my MT prop on an old flying airplane where the prop is well out of any warrantee, I found a great shop (http://www.nwpropeller.com/) and have about 1300 hours on the prop now since I’ve owned it, it has leaked grease but it has also gone about 1000 hours in a stretch without leaking grease, I like the prop a lot, I have overhauled it twice now, once just after buying the airplane and once a year or so ago, MT USA has done the blades both times and done a good job, NWProp has done a good job and has stood behind their work, they had to reseal it after the last O/H, they came and got the prop and they brought it back. MT in Germany has been great a bought answering e-mail questions I have had over the years but I never had to ask them to pay for anything. All the brands have had problems with grease leaks, I don’t know if MT is worse or not but it may be. All that said I find myself wanting the new Hartzell Composite prop at my next O/H time, it’s a lot of money though.

[Bavafa]

Originally Posted by hydroguy2

Thanks Gary...I don't know if it's optimum, but seems to work for me.
The WW200RV prop is 38# with the carbon spinner so I used a Saber 2.25" extension. I also tried to mount everything(ELT, Strobe pak, etc) forward if possible. My -7 weighed under 1100# completed and CG is never an issue.

Saber makes a nice product, highly recommended for a light composite prop on a light parallel valve engine.

Does the prop extension effect your max G ?

When I was researching during my build, I was told that the G force limit will be lowered and not safe for any aerobatics with a 2.5" prop extension.

[hydroguy2]

Originally Posted by Bavafa

Does the prop extension effect your max G ?

When I was researching during my build, I was told that the G force limit will be lowered and not safe for any aerobatics with a 2.5" prop extension.

I don't know. It has never affected my "G", but in full disclosure, I've only rolled my plane a few times. I've never pulled more then 3 Gs.

[Lindamon]

I have flown Unlimited aerobatics with MT's, both on my 230 and 300L, and never had a problem. Gerd is often at the Sebring contest, and is very forthcoming, I have never heard any of the complaints I see here from anyone in the aerobatic community, and MT's are probably the most common prop there. But I admit it's totally anecdotal evidence, and everyone can have differing experiences.

I put an MTV-9 three blade on my -7, it has counter-weights and a aerobatic governor. I will report if I have any problems.