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nuckolls.bob(at)aeroelect
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 Posted: Wed Apr 08, 2009 10:58 am Post subject: IVOPROP Magnum |
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At 09:48 AM 4/8/2009, you wrote:
| Quote: | Gosh Bob, you haven't even begun to bed in the prop blades, yet. The
fun is just beginning.
Rick
|
"bed in"??? You'll have to help me out here.
I herd electrons for a living.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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aslsa.rng(at)gmail.com
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| Posted: Wed Apr 08, 2009 11:43 am Post subject: IVOPROP Magnum |
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Bob, The IVO prop mounts composite blades between knurled plates bolted together. The bedding process is done bringing the bolts up to torque as the knurling bites into the base of the blade. It's an interesting idea in theory, but becomes very labor intensive, very quickly, in practice.
Rick
On Wed, Apr 8, 2009 at 1:56 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
[quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
At 09:48 AM 4/8/2009, you wrote:
| Quote: | Gosh Bob, you haven't even begun to bed in the prop blades, yet. The fun is just beginning.
Rick
|
"bed in"??? You'll have to help me out here.
I herd electrons for a living.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
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dalexan48(at)dslextreme.c
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| Posted: Thu Apr 09, 2009 6:26 am Post subject: IVOPROP Magnum |
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Boy, you said a mouthfull there! Back when Velocity builders were putting
these things on real aircraft engines, there was a large amount of failures
due to prop hub torque maintenance. Now to be fair, builders were putting
IVO props on IO-360 Lycomings against the stated recommendations of IVO. He
made this recommendation as the big four cylinder has huge torque pulses
that really beat the heck out of the aluminum components. That's
understandable. BUT, the torque procedure for the prop blade mounting is a
multi-step task that requires re-torqueing and checking the metal "safety
tape" for movement.
In my opinion, any procedure that requires as many staps as the IVO prop
mounting is begging to be shortcomed owing to human nature. You know, the
"I'll do it later" or " it's probably OK by now" type of thinking. And sure
enough, we lost a couple of Velocites due to blade seperation from the hub
and had many owners stating that the blades moved around quite a bit AFTER
the procedure. As a result, IVO's don't get used on the 360 engine. But the
overall design does not look robust enough for service in any appilcation
other than air boats and ultra-lights for which they were originally
intended.
Please be careful with IVO props.
Dale Alexander
| Quote: | ________________________________ Message 15
____________________________________
Time: 12:43:45 PM PST US
Subject: Re: Re: IVOPROP Magnum
From: Richard Girard <aslsa.rng(at)gmail.com>
Bob, The IVO prop mounts composite blades between knurled plates bolted
together. The bedding process is done bringing the bolts up to torque as
the
knurling bites into the base of the blade. It's an interesting idea in
theory, but becomes very labor intensive, very quickly, in practice.
Rick
|
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nuckolls.bob(at)aeroelect
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| Posted: Thu Apr 09, 2009 8:51 am Post subject: IVOPROP Magnum |
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At 02:41 PM 4/8/2009, you wrote:
| Quote: | Bob, The IVO prop mounts composite blades between knurled plates
bolted together. The bedding process is done bringing the bolts up
to torque as the knurling bites into the base of the blade. It's an
interesting idea in theory, but becomes very labor intensive, very
quickly, in practice.
|
Hmmmm . . . this seems like an exceedingly process-
sensitive design . . . and gives pause for wondering
if this is the best we know how to do. A blade retained
in tension with a grooved or headed shank and immobilized
in torsion with a spline seems a more robust alternative
for keeping a grip on components highly stressed,
modulated load . . .
I presume the technique you describe applies to ground
adjustable props. The ones with gear-boxes and flight-
adjustable features are very different?
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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mprather(at)spro.net
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| Posted: Thu Apr 09, 2009 9:42 am Post subject: IVOPROP Magnum |
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The variable pitch Ivo is a different animal from a normal (Hartzell,
McCauley, etc). The pitch adjustment on the Ivo comes from twisting the
mid-tip of the blade different from the root via a torsion rod that runs
from the hub through the center of the (hollow) blade. There aren't any
pitch bearings per-se. The flat root end of each blade is clamped to the
hub by a back plate into which is mounted the pitch adjustment motor.
http://www.ivoprop.com/inflightmagnumodel.htm
It's a fairly ingenious design, being relatively simple and light weight.
But arguably its current incarnation doesn't well support the large
torsional loads imposed by a direct drive four cylinder engine. I find it
interesting that the design hasn't be revised to make it more robust. It
doesn't seem to me that it would be terribly difficult to make the blade
mounting method quite a bit more robust without incurring any significant
tradeoffs.
In Ivo's defense, there are Hartzell props which also have problems with
the large four cylinder Lycomings - careful study is required for the
engine/airframe installation, and many times there are RPM ranges wherein
the engine/prop shouldn't be operated continuously.
Regards,
Matt-
| Quote: |
<nuckolls.bob(at)aeroelectric.com>
At 02:41 PM 4/8/2009, you wrote:
>Bob, The IVO prop mounts composite blades between knurled plates
>bolted together. The bedding process is done bringing the bolts up
>to torque as the knurling bites into the base of the blade. It's an
>interesting idea in theory, but becomes very labor intensive, very
>quickly, in practice.
Hmmmm . . . this seems like an exceedingly process-
sensitive design . . . and gives pause for wondering
if this is the best we know how to do. A blade retained
in tension with a grooved or headed shank and immobilized
in torsion with a spline seems a more robust alternative
for keeping a grip on components highly stressed,
modulated load . . .
I presume the technique you describe applies to ground
adjustable props. The ones with gear-boxes and flight-
adjustable features are very different?
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
|
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Apr 09, 2009 11:58 am Post subject: IVOPROP Magnum |
|
|
At 12:40 PM 4/9/2009, you wrote:
| Quote: |
The variable pitch Ivo is a different animal from a normal (Hartzell,
McCauley, etc). The pitch adjustment on the Ivo comes from twisting the
mid-tip of the blade different from the root via a torsion rod that runs
from the hub through the center of the (hollow) blade.
|
<snip>
| Quote: | In Ivo's defense, there are Hartzell props which also have problems with
the large four cylinder Lycomings - careful study is required for the
engine/airframe installation, and many times there are RPM ranges wherein
the engine/prop shouldn't be operated continuously.
|
Interesting. I'm still in conversation with IVOPROP
trying to understand their electrical dynamics. This
fixed length feeder combined with a special breaker
chosen for it's response to overload is not the
best we know how to do. Perhaps I can help out.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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ceengland(at)bellsouth.ne
Guest
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| Posted: Thu Apr 09, 2009 12:41 pm Post subject: IVOPROP Magnum |
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I had the blades move in a knurled hub on an O-320. The sad thing about it is that the fix would have been easy; just use lugs in the hub like a normal prop. If the blades were made with proper twist for high speed planes, it would be a great concept. I missed what plane it's on, but for faster homebuilts (over ~150kts) I've never seen anyone report equal or faster speeds than a wood prop on the same airframe, even with the higher twist blades.
Charlie
From: Dale Alexander <dalexan48(at)dslextreme.com>
To: aeroelectric-list(at)matronics.com
Sent: Thursday, April 9, 2009 9:23:37 AM
Subject: Re: IVOPROP Magnum
--> AeroElectric-List message posted by: "Dale Alexander" <dalexan48(at)dslextreme.com (dalexan48(at)dslextreme.com)>
Boy, you said a mouthfull there! Back when Velocity builders were putting these things on real aircraft engines, there was a large amount of failures due to prop hub torque maintenance. Now to be fair, builders were putting IVO props on IO-360 Lycomings against the stated recommendations of IVO. He made this recommendation as the big four cylinder has huge torque pulses that really beat the heck out of the aluminum components. That's understandable. BUT, the torque procedure for the prop blade mounting is a multi-step task that requires re-torqueing and checking the metal "safety tape" for movement.
In my opinion, any procedure that requires as many staps as the IVO prop mounting is begging to be shortcomed owing to human nature. You know, the "I'll do it later" or " it's probably OK by now" type of thinking. And sure enough, we lost a couple of Velocites due to blade seperation from the hub and had many owners stating that the blades moved around quite a bit AFTER the procedure. As a result, IVO's don't get used on the 360 engine. But the overall design does not look robust enough for service in any appilcation other than air boats and ultra-lights for which they were originally intended.
Please be careful with IVO props.
Dale Alexander
[quote] ________________________________ Message 15 ____________________________________
Time: 12:43:45 PM PST US
Subject: Re: Re: IVOPROP Magnum
From: Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)>
Bob, The IVO prop mounts composite blades between knurled plates bolted
together. The bedding [quote][b]
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ainut(at)hiwaay.net
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| Posted: Thu Apr 09, 2009 6:36 pm Post subject: IVOPROP Magnum |
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