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10-03-2011, 05:30 PM
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Join Date: Sep 2010
Location: Sao Paulo, Brasil
Posts: 72
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Composite or Aluminum ?
Would like to hear opinions about the pro and cons of composite against aluminum propellers. Not to mention their price tag, off course...
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10-03-2011, 08:23 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Three blade composite.....SEX APPEAL, says "I had a lot of money but its tied up in my prop". Should climb a bit better, maybe better if ground clearance is important to you, but a bitch to get the cowls off compared to the two blade.
The two blade Alloy..........much better in all respects. The Hartzell Blended Airfoil is hard to go past.
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10-03-2011, 09:19 PM
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Join Date: Nov 2006
Location: Waco, Texas
Posts: 1,658
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Three blade MT for me. Besides the added clearance, the third blade really smooths the engine out. The cowl removal really isn't bad with some minor work on the lower cowl.
There's nothing wrong with either and I've flown behind both in the RV-10. The three blade is a much nicer ride and that's something I expect in a nice cross country plane.
Sure the 3 blade composites cost a bit more, but it's an RV-10 and (in Texas words) "They ain't cheap." If you can afford to finish the airplane then you can afford the extra $5,000 for the prop thats right for you. The prop isn't the right place to get cheap.
Phil
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10-03-2011, 09:40 PM
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Join Date: Feb 2007
Location: Mpumalanga, South Africa
Posts: 1,065
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I'm going for the 3-blade MT for smoothness and ground clearance. By all accounts, you lose a couple of knots in the cruise over the Hartzell blended aerofoil.
__________________
Paul
Mercy Air, White River FAWV
RV-10 ZU-IIZ - "Zeus"
Building Bearhawk Bravo - RV-18 not available
2019 Donation Made
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10-03-2011, 09:51 PM
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Join Date: Jun 2006
Location: 8I3
Posts: 3,564
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Before you guys commit to a MT I seriously advise you to go fly with an owner with an 8068 blade Hartzell especially now they are configured from the factory oriented with the blades in line with the #1 crankpin. Over the years I have become unimpressed with MT's based on their service history and I haven't found them to be much smoother.
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Please don't PM me! Email only!
Bob Japundza CFI A&PIA
N9187P PA-24-260B Comanche, flying
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
N7925P PA-24-250 Comanche, restoring
Not a thing I own is stock.
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10-03-2011, 10:27 PM
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Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,682
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I'll state the obvious since no one else has:
Composite is significantly lighter. I suppose that could be a pro or a con depending on how your CG is shaping up.
Erich
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10-03-2011, 10:34 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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3 for show
2 for GO!!!
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10-04-2011, 03:25 AM
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Join Date: Sep 2010
Location: Sao Paulo, Brasil
Posts: 72
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Maintenance and service ?
The post is about the material used: Aluminum or composite. (not 2 or 3 blades)
What about maintenance and service?
I mean, aluminum props are around for long time, and there are lots of people knowing how to work on it. All they need from time to time is sand and paint. (talking about blades only)
Looks like these fancy compos need very specialised workmanship... I read some place that even the external paint is completely different...
Probably better to "keep it simple".
Would be nice to hear from the two blade blended airfoil Hartzell drivers how they feel. How big is the difference?
Probably more a question about two or tree blades... (and balance)
Read some 25 years ago that theoretically, the most efficient prop would be ONE BLADE...
Shure the new composite looks great and runs quiet and smooth, but is the difference really that great compared to the conventional aluminum???
The big question is: if there where a smoot running aluminum scimitar tree blade(or a 2 blade composite) avaiable, would some go composite or aluminum???
Thanks.
Last edited by bignose : 10-04-2011 at 03:46 AM.
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10-04-2011, 03:45 AM
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Join Date: Jan 2005
Posts: 1,009
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Do you plan to fly in rain?
I've seen some composit props pretty chewed up from a couple of hours in moderate rain. Some use tape on the leading edge. Also understand some of the manufacturers are even adding metal to the LE. If you're a VFR pilot, no issue. If you plan to fly instruments, you'll need to be fully aware of the props limitations-you may have to turn lower RPMs in precipitation. I'm sure someone will respond that they fly instruments with no problem-the question is water droplets. How many and what size.
Still, composite three blade look really cool.
Terry, CFI
RV9A N323TP
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10-04-2011, 07:07 AM
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Join Date: Mar 2010
Location: Calgary, Alberta, Canada
Posts: 130
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Whirlwind composite prop
I have flown 287 hours behind a Whirlwind 151H on my RV-6, the prop blades have about 330 hours on them, they look like they just came out of the box. The blades have an inset nickel leading edge which protects them, I have flown off of grass and through rain with no damage to the blades. The prop was statically balanced at the factory and dynamically balanced after mounting using a Dynavibe and is a very smooth combo. You will find the engine turns over at start up faster than with a heavier metal prop, but be careful if you need the weight up front due to cg considerations. I am now flying behind a Whirlwind 200 RV and notice the acceleration on takeoff and climb have suffered a bit, but I have gained a few on the top end.
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RV-6 tip up,190hp,Pmag,ported/flowed ECI heads, WW200 prop,older glass panel,long range tank,SOLD
RV-3A tip over, 170 hp, dual Pmags, 15 gal wing tanks, CN-1,CN-2 wing mods, D10A, XM396, SOLD
Murphy Rebel Elite purchased and flying
DR-107 One Design project with Schuenemann 21 foot wing, wing tanks, 50% done SOLD
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