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neilsenrm(at)comcast.net
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 Posted: Wed Jul 04, 2007 7:03 pm Post subject: Prop Comparison |
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John
Steve Bennet at Great Plains Aircraft told me he did a test of Warpdrive, Ivo and Powerfin props a few years ago. He tried to make it as close to a apples to apples test as he could. The report I got was that Powerfin produced the most thrust followed by Warpdrive then by a larger margin Ivo. He also found that Warpdrive had the most inerita by a wide margin then Ivo then fairly close was Powerfin. Again I'm only telling you what I was told from what I consider a reliable source. I don't have any more details than this.
Like you I have only flown one of these props and the Powerfin has server me well. It also has taken some abuse and got me home. I origionally selected the Powerfin prop because it had good thrust performance and maybe more importantly its low inerita. My old VW redrive was incompatible with heavy props. The new redrive appears to tolerate heaver props. Not everyone has the same engine/gearbox as you so others might want or need a lighter prop or more thrust. I'm not tring to talk you into changing props or anyone else. I'm just trying to provide a balance to the prop selection process.
I did fly a wood prop on my direct drive VW powered MKIIIC and turned one prop into tooth picks when the prop struck a tree branch were it was about 1/8 inch dia. For that reason I will never own a pusher with a wood prop.
Rick Neilsen
Redrive VW powered MKIIIC
[quote]-------------- Original message --------------
From: "John Hauck" <jhauck(at)elmore.rr.com>
[quote] --> Kolb-List message posted by: "John Hauck"
> The Powerfin prop will give more thrust than a warpdrive, has alot less
inertia and will break off if it srikes something substatial instead of causing
gearbox or engine problems. I think even a warpdrive pilot would do a
prcautionary landing after a propstrike. How rugged do you want the prop to be?
Can you live with the trade offs?
>
> Rick Neilsen
>
Hi Rick:
Curious about the Powerfin producing more thrust than a Warp Drive. Where did
you discover that info?
What is the major advantage of less inertia? My Warp Drive is well w ithin the
safe operating parameters of Rotax for my 912ULS.
I want my prop to be rugged enough to get me home, no matter what the
circumstances. During an extreme emergency situation, my least concerns are
whether I am damaging the prop, gear box, or engine. I want something to get me
to a safe landing spot so I can get "me" back on the ground. I can always
repair or replace the mechanical stuff.
I have had good luck with the Warp Drive. Seen it demonstrate its toughness and
its performance. I can back that statement up with many, many hours of very
realiable performance over some very long distances and over some mighty hostile
terrain and ice water.
Whether or not that other prop produces more thrust than my Warp Drive, I don't
care. I get all the thrust I can handle with what I have. 
Take care,
-------- > ====== ===============
[b]
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lucien
Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM
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| Posted: Wed Jul 04, 2007 7:53 pm Post subject: Re: Prop Comparison |
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Just FWIW,
I've flown all these props and my general finding about them is about the same - powerfin F model gives the best thrust, warp drive really close, IVO behind the others.
Not rocket science on why, either. The Powerfin F model has the most blade area for a given length, but is also thicker. So, that blade will generate more lift, but at a lower AOA. This makes it not so good on a faster plane, since it "unloads" more at higher airspeeds.
This was definitely true on my FS II, my powerfin 68" 3 blade outclimbed the warp drive 68" by a small bit, but unloaded pretty good in the air. The warp drive, though, gives the best overall performance, good thrust but doesn't unload as bad in the air.
It has a little less blade area, so blades run at a little higher AOA..
The IVO gives slightly less thrust than the other two, but works great in 2 blades on a fast plane (60mph or more). I'm not 100% sure why this is, though I suspect the blades change pitch in the air, maybe increase in pitch a little once you get up to speed.
I have the adjustable pitch medium IVO on my titan and, well, that's the best thing since sliced bread for me prop-wise ...
But the warp drive is the best prop overall on my FS II....
As for MOI, the warp drive is the highest, followed by the IVO and the powerfin is the lightest. The 912 gearbox, though, supports a pretty high MOI, if I recall my reading in the manuals correctly. I saw a figure around 10,000 kg/in I think... almost twice the figure for the 2-stroke C box.... So you can spin quite a monster on the 912...
The main advantage to lower MOI is throttle response. It's quick in any event on the 912, but a low MOI prop like the powerfin vs a heavy one like the warp drive makes a BIG difference here on a 2-stroke...
LS
[quote="neilsenrm(at)comcast.net"]John
Steve Bennet at Great Plains Aircraft told me he did a test of Warpdrive, Ivo and Powerfin props a few years ago. He tried to make it as close to a apples to apples test as he could. The report I got was that Powerfin produced the most thrust followed by Warpdrive then by a larger margin Ivo. He also found that Warpdrive had the most inerita by a wide margin then Ivo then fairly close was Powerfin. Again I'm only telling you what I was told from what I consider a reliable source. I don't have any more details than this.
Like you I have only flown one of these props and the Powerfin has server me well. It also has taken some abuse and got me home. I origionally selected the Powerfin prop because it had good thrust performance and maybe more importantly its low inerita. My old VW redrive was incompatible with heavy props. The new redrive appears to tolerate heaver props. Not everyone has the same engine/gearbox as you so others might want or need a lighter prop or more thrust. I'm not tring to talk you into changing props or anyone else. I'm just trying to provide a balance to the prop selection process.
I did fly a wood prop on my direct drive VW powered MKIIIC and turned one prop into tooth picks when the prop struck a tree branch were it was about 1/8 inch dia. For that reason I will never own a pusher with a wood prop.
Rick Neilsen
Redrive VW powered MKIIIC
[quote]-------------- Original message --------------
From: "John Hauck" <jhauck>
| Quote: | --> Kolb-List message posted by: "John Hauck"
> The Powerfin prop will give more thrust than a warpdrive, has alot less
inertia and will break off if it srikes something substatial instead of causing
gearbox or engine problems. I think even a warpdrive pilot would do a
prcautionary landing after a propstrike. How rugged do you want the prop to be?
Can you live with the trade offs?
>
> Rick Neilsen
>
Hi Rick:
Curious about the Powerfin producing more thrust than a Warp Drive. Where did
you discover that info?
What is the major advantage of less inertia? My Warp Drive is well w ithin the
safe operating parameters of Rotax for my 912ULS.
I want my prop to be rugged enough to get me home, no matter what the
circumstances. During an extreme emergency situation, my least concerns are
whether I am damaging the prop, gear box, or engine. I want something to get me
to a safe landing spot so I can get "me" back on the ground. I can always
repair or replace the mechanical stuff.
I have had good luck with the Warp Drive. Seen it demonstrate its toughness and
its performance. I can back that statement up with many, many hours of very
realiable performance over some very long distances and over some mighty hostile
terrain and ice water.
Whether or not that other prop produces more thrust than my Warp Drive, I don't
care. I get all the thrust I can handle with what I have.
Take care,
-------- > ====== ===============
[b] |
| | - The Matronics Kolb-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
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LS
Titan II SS |
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