Which Prop

[gh6gh6]

I thank you also Les. Ya godda love this group. Ask a question and someone who knows will usually jump in and answer. If the answer is wrong the jumper quickly becomes the jumpee.

Les you wrote:

I suppose that depends on price?

I will happily pay more for a 10 pound lighter and 5 knot faster prop up to a limit.

What do you think the market price-point is for a new Hartzell composite prop?

For me if the Hartzell price for a two blade ASCII comes in under Aero Composite put one on the truck. I would get a little huffy if a big outfit like Hartzell charged lots more than the little guy.

Couple more questions for you Les if you don?t mind:
1. Is the new ASCII prop a blended airfoil?
2. Is the aircraft performance improved with the new ASCII blades?

Paul those Rvators are not available on line are they? If not will you summarize for us the result of the flight tests of the various props in the 2003 article? I spoke with Dick Martin at OSH who said his Aero Composite prop was way faster and lighter than his Hartzell. I never thought to ask if he was comparing the Aero Composite to the new BA Hartzell or not.
Or let me put this question another way;
Does anyone know which is fastest?
the WW RV200,
the Aero Composite,
the Hartzell C2YR-1BFP/F74972

(yes I studied http://www.romeolima.com/RV8/Prop.htm which is a good read)

[lesdoud]

I will get more from these forums than I could possibly give so it's my pleasure if I can contribute something.

I would love to say, "sure, 5 more knots, no problem..." but I can't. Analytically our new props are already in the 87% efficiency range, much more than that would be a very costly iterative process and require enormous patience. The difference between 87% and 90% (rarely obtained) is only a few lbs of thrust. Our current aluminum designs for the -360 are now pushing the limits of our blade forgings. It would require a larger or new forging (= more $) to squeeze-out a little more performance in aluminum, and it wouldn't be much. It probably is not a good knots/$ ratio in my own opinion. Keep in mind that performance is only one factor in blade design. Sometimes other factors limit us from improving performance. Composite designs are not constrained by a forging so they give us a little more freedom. However, composite blades have their own unique hurdles too. Probably the best benefits of a composite blade are reduced weight and from what I'm told, smoothness. It's possible that we would design a new 2-blade composite specifically for a high-speed, -360 powered airplane, but that probably isn't going to happen within the next year. Until then, we'll probably test what we have and see how it works. I'll do my best to keep you updated on this list so please don't call every week asking "is it ready yet?"

Yes, all of our new designs are "blended airfoil" whether aluminum or composite. "Blended airfoil" refers more to the process of blade design rather than a specific airfoil or blade.

I won't comment, throw stones at, or speculate about any competitors; I prefer to let you folks decide what is best.

Regarding cost, that is why we developed the new composite process, to take cost out. I hope its affordable but we'll have to wait and see.

I've been at Hartzell almost eight years and I've come to realize that a significant portion of propeller price goes towards supporting the product. Manufacturing aside, it takes a small army to support the props that are already in the field, let alone what we'll sell in the future. In fact, I was just working on an issue with 1958 Beech Travel Air props to give you some idea... There is a platoon of product support folks to answer the phones and troubleshoot customer problems, a platoon of engineers to work service difficulties when they arise, a platoon of folks to support parts sales and maintain a network of service shops, a platoon to write and maintain all of the tech pubs, a full time position to support accident investigations, etc. etc. When you buy a prop you're paying for a lot more than the materials and manufacturing labor.

In closing, I'll try to answer the question "which prop?" My advice is to purchase what Vans recommends and/or endorses. It seems you can't go wrong if you do that, and it should be safe too. Which one is faster? We rely on Vans to tell us that. Some individuals have done a good job of performance comparisons and publicly-documented their results fairly; I think we compare favorably. In the end if it means you don't buy a Hartzell, so be it, you'll probably be happy if Vans likes it and their endorsement assures some level of safety, which is most important to me.

Les

[gh6gh6]

Good answers Les
Thanks again

[aadamson]

Can I take you off line for a discussion on 6 cyl props and a glass airplane?

If so, drop me an email at aadamson at highrf dot com. I've got a couple of quick questions on the composites, etc?

Thanks

[Nuisance]

Here are some results of prop testing...

http://lazy8.net/proptest.htm

These are just one person's experiences.


Les --

First, as others have said, thank you for taking the time to contribute.

Second, you have me all excited about the possibility of going from 87% to 90% efficiency...that would translate to 3.4 mph gain on a 200 mph airplane!!

Please tell marketing they would sell at least one! To have the performance and weight savings of a compsite prop with the very complete testing done by Hartzell would do it for me!

John

[RV8RIVETER]

Les

Thanks for your insight and information.

To answer one of your questions, I would love to buy a Hartzell, but unfortunately the weight penalty for my -8 is way too much. So I will have to go elsewhere. But from all the builders, and especailly -8 builders I have spoken with I believe there would definitely be a good sized market for a lighter "smoother" prop, especially with the Hartzell name on it.

My question is why does Hartzell feel the need to certify? The experimental market does not require certification. I am sure most will agree, that if Hartzell applies the same company standards to design and manufacturing on all their props that whether or not it is certified would not make much difference, except in the wallet. I would think that besides the cost savings, it would benefit Hartzell to have alot of props flying and gathering data, which would increase product knowledge and decrease testing cost if/when Hartzell decided to certify the prop.

[gmcjetpilot]

Originally Posted by lesdoud

Yes, all of our new designs are "blended airfoil" whether aluminum or composite. "Blended airfoil" refers more to the process of blade design rather than a specific airfoil or blade.

I won't comment, throw stones at, or speculate about any competitors; I prefer to let you folks decide what is best.

Regarding cost, that is why we developed the new composite process, to take cost out. I hope its affordable but we'll have to wait and see.Les

I don't mind throwing stones. Thanks for the input Les. I don't work for Harzell, but the Hartzell BA prop is the best choice in my opinion.

Somw one made an issue of weight and a basis for going with a composite prop.

First consider this, any composite prop is likely to cost more, a lot more. Overhaul? More about that below.

If anyone makes a composite prop approaching the thinness of a metal prop, such as aerocomposites, they tend to be very stiff and not as "smooth" like say the wood core props MT makes. The down side of MT's wood core props, as nice as their props are, is they are thicker and tend to be slower at the speeds we fly. It is just engineering. Time and time again the metal two blade Hartzells, BA or even the older HC-C2YK/F7666 have proven to be faster than any other props, even the high tech aerocomposites and whirlwind RV prop, the three bladed whirl winds and MT's are slower still. Why, thickness is part of the reason in my opinion and three blades are less efficients.

Most important to me is maintenance. A minor nick in a metal prop can be handled on the ramp, with the prop still on the plane with careful blending (with a fine spoon file). A delamination composite prop or dented erosion strip means removing the prop, disassembly and in many (most) cases shipping to the manufacture. I can't stress how important the customer support and wide availability of parts and service is. Some of the "boutique" props can ONLY be repaired at the manufacture and that may be outside of the USA.

Before the you get angry at me, please note I did not say anything bad about the any prop, just facts, mostly about the draw back of composites in prop construction. Second is you can't deny the support system of Hartzell is better than any other of the experimental prop brands. The composites do have things to offer, like smoother "feel" as some report and lighter weight, but they cost more to buy and maintain.

Price a complete overhaul on your composite prop and get it in writing before you buy a new prop. Just saying. Know what you are getting. Van replace an old MT with a Hartzell. It was not because they did not like the MT, but they did not want to spend the money to overhaul the MT, which was about what a new Hartzell cost. Plus they did not want to wait the long turn around time to send it to Germany to be overhauled. Most can get their Hartzell overhauled in a week locally at an approved shop in a short time.

I find a well balanced engine and Hartzell prop run at the "sweat" RPM is very smooth. The price and support makes it a no brainier for me and I think most. I clearly see a desire and need for some to use the composite prop, but most RV's would be best severed by a Hartzell in my opinion.

The weight issue? I never built a RV-8 but my RV-7 needs all the weight on the nose I can get with a O-360 (180HP) engine.

I have a F7666 only because I bought it use and before the BA prop was around. The BA prop is by far the best thing going hands down, IMHO.

[aadamson]

George,

I might have read something into your post that you may not have meant? But you worded it kinda strange.

Les - DOES work for Hartzell, Hartzell announced a new composite prop at OSH - hence Les' comments about composites and how good Hartzell is getting them (rivaling metal).

I guess I just read your note as if you were trying to talk to Les as if he were a builder (oh, btw, which he is, but he just happens to be in engineering at Hartzell as well) and espouse the virtues of metal *over* Composites. Somehow, with the inside info that Les has access too, I suspect he knows exactly how good one or the other is for a given application.

Sorry, if I miss read your post, but it just struck me as odd the way it was worded...

Oh, btw, to back up your claims. Last year at Reno, there was a Gaggle of Lancair Legacys in the Sports Class finals (sliver race). all of them but one was running a Hartzell, he was running an MT with AeroComposite Blades.

For the Final, they quickly pulled another hartzell off of the factory demo and put it on the last airplane (the one with the composite prop). That airplane had been about 10mph slower all day in the qualifications. You can go look at the times on line, but changing out that prop, pulled that airplane up with the others and gained it back those 10mph.

On the Maint topic. Can I offer another perspective? On a metal prop, it's not a matter of if, but when you'll have to purchase a new blade. They just wear out over time. The largest challenge beng "nicks and dings". A Composite by contrast will most likely be much cheaper to repair and may *never* require full replacement, if you get a large nick or ding in it.

Goods and bads on both sides I suppose.

[osxuser]

Originally Posted by aadamson

On the Maint topic. Can I offer another perspective? On a metal prop, it's not a matter of if, but when you'll have to purchase a new blade. They just wear out over time. Either errosion or otherwise. At Composite by contrast will most likely be much cheaper to repair and may *never* require full replacement, especially due to errosion.

Goods and bads on both sides I suppose.

Ususally 20+ years and four overhauls down the road. Not that big a deal after that amount of time.

[gmcjetpilot]

Originally Posted by aadamson

George,

I might have read something into your post that you may not have meant? But you worded it kinda strange.

I guess I just read your note as if you were trying to talk to Les as if he were a builder (oh, btw, which he is, but he just happens to be in engineering at Hartzell as well) and espouse the virtues of metal *over* Composites. Somehow, with the inside info that Les has access too, I suspect he knows exactly how good one or the other is for a given application.

Sorry, if I miss read your post, but it just struck me as odd the way it was worded...

Oh, btw, to back up your claims. Last year at Reno, there was a Gaggle of Lancair Legacys in the Sports Class finals (sliver race). all of them but one was running a Hartzell, he was running and MT with AeroComposite Blades.

For the Final, they quickly pulled another Hartzell off of the factory demo and put it on the last airplane. That airplane had been about 10mph slower all day in the qualifications.

On the Maint topic. Can I offer another perspective? On a metal prop, it's not a matter of if, but when you'll have to purchase a new blade. They just wear out over time. Either errosion or otherwise. At Composite by contrast will most likely be much cheaper to repair and may *never* require full replacement, especially due to errosion.

Goods and bads on both sides I suppose.

No apologies necessary. I know Les works for Hartzell. He said he would not throw stones at the competition, so I said I'll do it. My comments where regarding existing composite props not Hartzell. I don't know Les personally, but I have talked to Hartzell engineering on many occasions since I have an engineering degree and speak geek (sorry Les)

I did not get that Les was "espousing" composites over metal at all. I guess that's what you wanted to read into it.

You need to actually read what Les said about the ASC-II:
http://www.vansairforce.com/communit...6969#post66969

Back to the thread for a second, the "BA" (metal) Hartzell is hands down best value and performance for a RV with the best support. Trust me.

Hartzell's announcement of the new ASC-II composite prop structure is NOT a wholesale endorsement of composite props or the end of metal props, sorry. You are reading way more into it. If they make an ASC-II prop for the RV some day, great, but right now they are for King Airs.

My "oddly worded" comments are my opinions, not designed to influence Hartzell, Les or you. It's info and conclusions from my prop research that the other 4,000 RV builders may enjoy, which may not apply to Lancair builders or Reno racers, no offense.

Hartzell has made and sold composite props for years by the way, one is the claw, for aerobatics and is very expensive. They also make commercial composite props. I wish Hartzell the best of luck with the ASC-II process. As Les said, we shall see.

My guess, the ASC-II will be too expensive for the homebuilt market, and the performance will be no better than the existing metal BA prop for RV's. You can quote me. Hartzell says it's better than existing "thick" (fat) composite props. I believe that. If Hartzell makes a ASC-II "BA" prop for RV's that performs better than the existing metal "BA" RV prop, I'll publicly state Lancairs and composite planes are better than metal. Never happen.



RENO?
"For the Final, they quickly pulled another Hartzell off of the factory demo and put it on the last airplane"

Sorry, no offense but you're leaving off too much info. What Hartzell? What composite prop? What airplane? What speed? There is more to the story, but I'm 100% sure it does not apply to RV'ers.

I'm not going to argue Reno data. You say Sportsman silver class has many/mostly composite props in it? OK, that's cool to know but has little to do with RV's and proves nothing.

Racers use composites props not for speed but in part because they can't find a tested metal prop for their highly modified engines IMHO. Many use the metal Hartzell's and go fast. Hartzell does an excellent job but can't test every homebuilder / racers engine who does weird things (cams, compression, exhaust, electronic ignition). Metal prop's do need to be tested on every engine config they are mounted.

Performance - You demand I need to backup my claims, that the Hartzell "BA" prop is faster than any other c/s prop for a Lycoming 4 banger on a RV, here is the backup data you requested. (click, twice, read it and weep )



The only thing faster was the METAL Sensenich fixed pitch prop at that condition, typical cruise condition. It's been shown time and again the "BA " prop is faster, even against a later "new" MT prop. Rocket builder/pilots with 540 cu-in Lycs also find the Hartzell faster than the composite new MT by 5-8 MPH. You are WRONG. The fastest c/s prop for a RV's (and Rockets) is the Hartzell. btw prove I'm wrong.



"On the Maint topic. Can I offer another perspective? On a metal prop, it's not a matter of if, but when you'll have to purchase a new blade. They just wear out over time. Either erosion or otherwise. At Composite by contrast will most likely be much cheaper to repair and may *never* require full replacement, especially due to erosion."

I totally and respectfully disagree with everything you stated in the above Par. about maintenance, 100%. Again you got it 180 degrees backwards IMHO. Most metal props will out live the pilot with indefinite fatigue life (withstanding life limit for the F7666 on engines w/ HC piston/EI). Metal Hartzell's can go forever, in theory. What is the service life? (Les?) Yes, they "wear" or erode below dimension limits (thickness or chord) at some point (10k - 20,000 hours?).

If you fly ANY prop fast in heavy rain or out of gravel strips, composite props, even with their erosion strips, are subject to the wear, tear and damage. Erosion strip delimitation is a big issue on all the composite props. If Hartzell says they can refinish the new ASC-II forever, it's a great sales pitch. How much is that "re-finish" going to cost? Ouch

What is the high time GA composite prop (AeroComposites, MT, Whirlwind)? As far as I can tell they just scrap many damaged and high time blades and sell new ones. It cost more to do NDT (non-destructive testing) and repair than just build new ones.

We'll have to agree to disagree again. Composite blades are NOT forever props. Despite Hartzell's "press release" they last forever by refinishing them, no offense Les, true in theory but lets see. Even if true, I don't see it works in favor of low utilization personal flying. Purchase price? Drop a ASC-II prop into a non-warrantied pot-hole, there goes forever. Besides forever is longer than I need. Does Hartzell offer a "lifetime" guarantee?



There's no doubt in my mind at this time, average cost of composite prop ownership is greater, short or long term, than a metal one. There's no need to soft sell or spin this fact. They cost more to manufacture, buy and repair. I guess you don't get the RVator news letter. Bottom line the MT overhaul was over double what the Hartzell overhaul, which only took days to do, not weeks (or months) the MT would take. So the MT was removed from the demo plane for cost and service reasons. The MT was also slower. What's a ASC-II overhaul cost?

Any way sorry if I confused you, but AT THIS time composites props cost more, perform less and service is more expensive and spotty. Will ASC-II change this? Questions? Comments? Corrections? For now the answer is the "BA" prop for most.