I respectfully could not disagree more
aadamson said:
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/community/showthread.php?p=66969#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.