Today's Message Index:
----------------------
1. 06:03 AM - Re: Brass vs copper (rampil)
2. 06:58 AM - Re: Re: Brass vs copper (Jim Wickert)
3. 07:26 AM - Re: IVOPROP Magnum (Dale Alexander)
4. 08:51 AM - Re: AeroElectric Connection Fig. 17.6 Dual Battery Installation (Robert L. Nuckolls, III)
5. 09:22 AM - Re: Re: Brass vs copper (Rob Housman)
6. 09:38 AM - Re: Brass vs copper (Robert L. Nuckolls, III)
7. 09:51 AM - Re: Re: IVOPROP Magnum (Robert L. Nuckolls, III)
8. 09:51 AM - Basic wiring questions Try Again (Ralph Finch)
9. 10:34 AM - Re: Brass vs copper (Robert L. Nuckolls, III)
10. 10:42 AM - Re: Re: IVOPROP Magnum (Matt Prather)
11. 10:51 AM - Re: Basic wiring questions Try Again (Hinde, Frank George (Corvallis))
12. 12:54 PM - Re: Basic wiring questions Try Again (Robert L. Nuckolls, III)
13. 12:58 PM - Re: Re: IVOPROP Magnum (Robert L. Nuckolls, III)
14. 01:41 PM - Re: Re: IVOPROP Magnum (Charlie England)
15. 07:36 PM - Re: Re: IVOPROP Magnum (David M.)
16. 10:21 PM - Relay vs Continuous Duty Contactor (tx_jayhawk)
17. 10:21 PM - Re: Misc electrical items for sale (Ron Quillin)
Message 1
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| Subject: | Re: Brass vs copper |
You guys do know that you are discussing resistivity differences
in milliohms or tenths of a milliohm between copper and brass on buss
strips, right?
Aluminum is a particularly bad choice because of rapid AlO2 corrosion forming a
tough skin almost immediately, and consequent resistive
losses and heating
Use unprotected copper in the engine compartment and with the heat
and reactive Nitrogen combustion species floating around, you can watch
it corrode before your eyes. Lets not even mention work hardening
from vibration loads on the connection tabs.
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=238469#238469
Message 2
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| Subject: | Re: Brass vs copper |
Typically Brass is 88% plus copper with tin/silicon and other elements to
alter the grain boundaries' and molecular structure so Ira is right you are
splitting hairs when discussing resistivity. You pick up strength corrosion
resistance and modulus with Brass with the exception of leaded brass which
was used for bearing materials. If you add nickel and aluminum to the tin
and silicon you change brass into bronze. Still all maintaining around 88%
plus copper. Brass and cost are the two considerations. Take care.
Jim Wickert
Vision #159
Tel 920-467-0219
Cell 920-912-1014
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of rampil
Sent: Thursday, April 09, 2009 8:01 AM
Subject: AeroElectric-List: Re: Brass vs copper
You guys do know that you are discussing resistivity differences
in milliohms or tenths of a milliohm between copper and brass on buss
strips, right?
Aluminum is a particularly bad choice because of rapid AlO2 corrosion
forming a tough skin almost immediately, and consequent resistive
losses and heating
Use unprotected copper in the engine compartment and with the heat
and reactive Nitrogen combustion species floating around, you can watch
it corrode before your eyes. Lets not even mention work hardening
from vibration loads on the connection tabs.
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=238469#238469
Message 3
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| Subject: | Re: IVOPROP Magnum |
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
> ________________________________ Message 15
> ____________________________________
>
>
> Time: 12:43:45 PM PST US
> Subject: Re: AeroElectric-List: Re: IVOPROP Magnum
> From: Richard Girard <aslsa.rng@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
>
Message 4
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| Subject: | Re: AeroElectric Connection Fig. 17.6 Dual Battery |
Installation
At 10:18 PM 4/8/2009, you wrote:
>
>Hello,
>
>I am finalizing a single alt dual battery installation in my Lancair
>360 and generally following the diagram in figure 17.6. According to
>this diagram, with both the aux bat and main bat contactors open, the
>aux battery is isolated from the endurance bus and essentially reduces
>total endurance by half. Why not tie both batteries together to feed
>the endurance bus through the E-Bus Alt Feed Switch? Not only do you
>have both batteries working for you, but the current drain from the
>aux bat contactor is eliminated.
>
>I'm definitely electrically challenged so what am I missing here?
The idea behind Figure 17-6 is to provide separate energy
sources for running (1) and electrically dependent engine
and (2) running endurance loads during alternator-out
operations. This architecture is described in more detail
in Figure Z-19 and was conceived to support engines that
had no practical way to run two alternators. This generally
means certain automotive conversions.
During alternator out operations, it was a DESIGN GOAL
to assign separate tasks to the two batteries as described
in the chapter 17 and Appendix Z texts for these figures.
Your engine is very capable of supporting two alternators.
Further, you don't say whether or not your engine is
electrically dependent (other than pumping of fuel).
There are architectures much more suited to your project
namely Z-13/8, Z-12 or (if you're going all out for
full up IFR flight capability from either pilot's
position) Z-14.
I'll suggest you consider Z-13/8 and figure out how
' (or if) it fails to meet your operational design goals.
This configuration is the lightest, least expensive
and most user friendly to have system reliability
that exceeds the vast majority of type certificated
piston engine airplanes flying.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 5
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| Subject: | Re: Brass vs copper |
Just to be sure we understand the science correctly..
Contrary to the direct relationship between composition and conductivity
implied in your message, the effect on electrical conductivity of trace
elements and alloying elements is significant for any of the usual metals
used as conductors (Ag, Al, and Cu), and in the case of brass here's how
conductivity changes with the addition of zinc.
Figure 2. Effect of Zinc Content on the Electrical Conductivity of Brass
A mere 1% of tin (in the absence of any other elements besides Cu) will
reduce conductivity by about 50%.
Your conclusion is of course correct. In this case brass is as good as pure
copper.
Best regards,
Rob Housman
Irvine, CA
Europa XS Tri-Gear
A070
Airframe complete
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jim
Wickert
Sent: Thursday, April 09, 2009 6:55 AM
Subject: RE: AeroElectric-List: Re: Brass vs copper
<jimw_btg@earthlink.net>
Typically Brass is 88% plus copper with tin/silicon and other elements to
alter the grain boundaries' and molecular structure so Ira is right you are
splitting hairs when discussing resistivity. You pick up strength corrosion
resistance and modulus with Brass with the exception of leaded brass which
was used for bearing materials. If you add nickel and aluminum to the tin
and silicon you change brass into bronze. Still all maintaining around 88%
plus copper. Brass and cost are the two considerations. Take care.
Jim Wickert
Vision #159
Tel 920-467-0219
Cell 920-912-1014
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of rampil
Sent: Thursday, April 09, 2009 8:01 AM
Subject: AeroElectric-List: Re: Brass vs copper
You guys do know that you are discussing resistivity differences
in milliohms or tenths of a milliohm between copper and brass on buss
strips, right?
Aluminum is a particularly bad choice because of rapid AlO2 corrosion
forming a tough skin almost immediately, and consequent resistive
losses and heating
Use unprotected copper in the engine compartment and with the heat
and reactive Nitrogen combustion species floating around, you can watch
it corrode before your eyes. Lets not even mention work hardening
from vibration loads on the connection tabs.
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=238469#238469
Message 6
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| Subject: | Re: Brass vs copper |
>You guys do know that you are discussing resistivity differences
>in milliohms or tenths of a milliohm between copper and brass on buss
>strips, right?
>
>Aluminum is a particularly bad choice because of rapid AlO2 corrosion
>forming a tough skin almost immediately, and consequent resistive
>losses and heating
<snip>
Gentlemen,
We're getting our ties wrapped around the axles of
insignificant fact . . .
The FIRST job of any conductor is to take part in
getting the effects of electron motion piped from one
place to another. One consideration is conductivity of
the material. This speaks to efficiency . . . every
Joule of energy waste in raising the conductor
temperature doesn't help run your electro-whizzies.
The second consideration is an evaluation of processes
necessary to secure gas-tight connection between various
pieces. No matter how badly a conductor SURFACE corrodes,
the INTERFACE BETWEEN PIECES of the conduction path are
still capable of carrying energy relatively unimpeded.
The third consideration goes to issues of mechanical
robustness - a study of S/N ratios: How many times
can this material experience a predicted level of
operating stress and not develop stress-cracks?
The last consideration goes to cost of manufacturing
that looks at material cost, $time$ and processes
needed to do the best we know how to do in fabricating
the parts.
Consider these examples of bus structures:
http://aeroelectric.com/Pictures/Grounding/Grd%20Bus%20Sys1.JPG
http://aeroelectric.com/Pictures/Grounding/Forest_of_Tabs_Ground_Kit.pdf
http://aeroelectric.com/Pictures/Grounding/Avionics_Bus_3.jpg
These are SYSTEMS that blend the functional capabilities
(and limits) of raw materials, fabrication techniques,
off-the-shelf components, and the skill of both designer
and installer to meet design goals.
Bar copper bus bars will look butt-ugly 10 years
from now . . . but where they're mashed against
terminals on wires can still be performing as-
new.
Brass bus bars might need to be thicker/wider
to accommodate the higher resistance of the
material but they'll LOOK nicer and they're easier
to build due to machineability of brass versus copper.
Nonetheless, it's where the terminals grab the bus
structure that controls future performance.
Aluminum can be considered too as long as you don't
need to solder to the bus and you've taken measures
to control voltage drop to tolerable levels. Further,
you need to insure integrity of the joints that
are gas-tight today, tomorrow, and ten years from
now.
I'm aware of no bus structure on a TC aircraft where
the weakest links in the chain had anything to do with
mechanical stress of the bus bar material or its resistance
to surface corrosion. Lack of gas-tightness and structural
integrity of individual connections account for the vast
majority of ALL conductor failures whether or not they're
trying to keep a grip on a bus or any other component
of the system.
This product:
http://aeroelectric.com/Pictures/Grounding/gnd_bus.jpg
Combines PLATED BRASS tabs, SOLDERED to BRASS bus
and assembled with alloy BRASS BOLTS, and intended
to accept BRONZE terminals crimped onto COPPER wires.
Irrespective of choice of materials, there are
a variety of conditions that could precipitate
a failure of one or more conductors attached to
this bus.
Inattention to a host of potential toe-stubbers can
contribute a failure factor that has little
if anything to do with selection of copper, versus
brass or even aluminum as ONE OF MANY elements of the
system. Successful and enduring bus structures have been
fabricated from all of these materials. Each was
the preferred material for the designer for reasons
that are now known only to him.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 7
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| Subject: | Re: IVOPROP Magnum |
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- )
----------------------------------------
Message 8
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| Subject: | Basic wiring questions Try Again |
Basic questions again! 2nd try, hello Bob N. or somebody, hope you can
answer these:
I have landing/taxi lights, LED nav lights, a Bob Archer VOR antenna, and an
APRS tx/rx antenna in the ends of the wings of an RV-9A (one antenna in each
tip).
1. For the powered items, can I run a single positive wire of adequate size
to a terminal block, then feed the devices from the block?
2. For the antennas, yes they will be using coax, but should I nevertheless
try to run the coax physically separate from the power wires? In addition
to the above power wire I have a 3-wire bundle run from the strobe power
supply in the fuselage to the wing-tip strobe lights. I installed a conduit
about 18 inches away from the Vans wire holes for the purpose of separating
power wires from very weak signals.
3. The Bob Archer antenna has two lugs; instructions say to strip the coax
cable and attach the stranded core to one lug, the shield to another lug. I
would like that coax to be just a couple feet long, ending in a BNC or
similar connector, so I can easily remove the fiberglass wingtip from the
wing. Will the coax connector introduce too much impedance?
Thanks,
Ralph Finch
Davis, CA
RV-9A QB-SA
Message 9
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| Subject: | Re: Brass vs copper |
At 04:44 PM 4/8/2009, you wrote:
>As Bob stated brass does not conduct very good.
>
>Copper 101 or 110 does not machine very good.
"very good" is non-quantified. if you're doing
a ground bus like:
http://aeroelectric.com/Pictures/Grounding/gnd_bus.jpg
. . . just how large are anticipated voltage drops
for any accessory's ground point with respect to
the rest if the conductivity of the base material
is say 1/20th or even 1/50th that of copper?
When we're talking about hundreds of amps in
the cranking circuit, short lengths of poor
conductivity can produce significant voltage
drops . . . say in excess of 100 millivolts.
However, at the current levels comprised of the
sum total of panel mounted hardware spread over
the sheet resistance of a brass base, I'll suggest
that the voltage drops are insignificant.
>Now that is not the case for copper 1451 It machines terrific.
So should we recommend that everybody endeavor
to acquire this material for the fabrication
of their bus bars? More importantly, are products
offered by B&C for this purpose to be avoided
as falling short of compliance with design goals?
Keep in mind that all the overhead wires that
carry power across the countryside are aluminum
and steel. Would we wish they were "better" conductors?
Sure. Are all copper conductors even possible much
less practical? Probably not. Has the recipe
for success been "tuned" for the best we know
how to do? Don't know . . . but in honorable,
competitive, free-market endeavors, you can
bet the most successful players have paid due
diligence to fine tuning.
The recipes for success should take consider
capabilities and limits for ALL ingredients
against the design goals. But the recipe may
NOT get better because we've sliced and diced
the comparison between competing materials.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 10
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| Subject: | Re: IVOPROP Magnum |
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-
> <nuckolls.bob@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- )
> ----------------------------------------
>
>
Message 11
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| Subject: | Basic wiring questions Try Again |
1) Sure..But ti depends if you need to switch said devices independantly..For example,
with LED Nav lights you might want to combine those with the LED NAV lights..LED's
consume almost no power and last forever. When running the APRS you
can have the NAV lights on.
But you wouldn't want to run the landing lights with the Nav lights due to the
significant power draw of the landing lights.
2) I never had the sligthest noise interference with coax near power wires or sheilded
strobe wires for that matter.
3) Yup that's how I did it on the 7..Simply use a bulkhead BNC on the outer wing
rib and plug in your antenna coax..Works great.
Frank IO360 7a electrically dependant..including the fuel pumps!
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ralph Finch
Sent: Thursday, April 09, 2009 9:48 AM
Subject: AeroElectric-List: Basic wiring questions Try Again
--> <rgf@dcn.davis.ca.us>
Basic questions again! 2nd try, hello Bob N. or somebody, hope you can answer
these:
I have landing/taxi lights, LED nav lights, a Bob Archer VOR antenna, and an APRS
tx/rx antenna in the ends of the wings of an RV-9A (one antenna in each tip).
1. For the powered items, can I run a single positive wire of adequate size to
a terminal block, then feed the devices from the block?
2. For the antennas, yes they will be using coax, but should I nevertheless try
to run the coax physically separate from the power wires? In addition to the
above power wire I have a 3-wire bundle run from the strobe power supply in the
fuselage to the wing-tip strobe lights. I installed a conduit about 18 inches
away from the Vans wire holes for the purpose of separating power wires from
very weak signals.
3. The Bob Archer antenna has two lugs; instructions say to strip the coax cable
and attach the stranded core to one lug, the shield to another lug. I would
like that coax to be just a couple feet long, ending in a BNC or similar connector,
so I can easily remove the fiberglass wingtip from the wing. Will the
coax connector introduce too much impedance?
Thanks,
Ralph Finch
Davis, CA
RV-9A QB-SA
Message 12
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| Subject: | Re: Basic wiring questions Try Again |
At 11:48 AM 4/9/2009, you wrote:
>
>Basic questions again! 2nd try, hello Bob N. or somebody, hope you can
>answer these:
Sorry Ralph.
>I have landing/taxi lights, LED nav lights, a Bob Archer VOR antenna, and an
>APRS tx/rx antenna in the ends of the wings of an RV-9A (one antenna in each
>tip).
>
>1. For the powered items, can I run a single positive wire of adequate size
>to a terminal block, then feed the devices from the block?
How would you control these devices? All ON/OFF at
the same time with a single switch? Recommend you
stay with
>2. For the antennas, yes they will be using coax, but should I nevertheless
>try to run the coax physically separate from the power wires? In addition
>to the above power wire I have a 3-wire bundle run from the strobe power
>supply in the fuselage to the wing-tip strobe lights. I installed a conduit
>about 18 inches away from the Vans wire holes for the purpose of separating
>power wires from very weak signals.
Don't worry about it. A rudimentary feature of coax cable
provides isolation between what goes on INSIDE the cable
from what goes on OUTSIDE the cable. In the big airplanes, coax
cables and all manner of airframe systems wires share common
wire bundles.
>3. The Bob Archer antenna has two lugs; instructions say to strip the coax
>cable and attach the stranded core to one lug, the shield to another lug. I
>would like that coax to be just a couple feet long, ending in a BNC or
>similar connector, so I can easily remove the fiberglass wingtip from the
>wing. Will the coax connector introduce too much impedance?
No. Connectors to address your needs are commonly
available and install with the same tools as your
cable-male BNC connectors. See:
http://www.aeroelectric.com/Pictures/Connectors/Coax/BNC_Cable_Female_1.jpg
http://www.aeroelectric.com/Pictures/Connectors/Coax/BNC_Cable_Female_2.jpg
http://www.aeroelectric.com/Pictures/Connectors/Coax/BNC_Bulkhead_Female.jpg
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 13
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| Subject: | Re: IVOPROP Magnum |
At 12:40 PM 4/9/2009, you wrote:
>
>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>
>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- )
----------------------------------------
Message 14
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| Subject: | Re: IVOPROP Magnum |
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@dslextreme.com>
Sent: Thursday, April 9, 2009 9:23:37 AM
Subject: AeroElectric-List: Re: IVOPROP Magnum
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
> ________________________________ Message 15 ____________________________________
>
>
> Time: 12:43:45 PM PST US
> Subject: Re: AeroElectric-List: Re: IVOPROP Magnum
> From: Richard Girard <aslsa.rng@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
>
Message 15
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| Subject: | Re: IVOPROP Magnum |
Message 16
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| Subject: | Relay vs Continuous Duty Contactor |
All,
In comparing the continuous contactor (S701-1) to the relay (S704-1), I assume
that the reason people choose the relay is due to the lower coil current draw?
Drawback is obviously that it is limited to 20 amp. Should the 20 amp limitation
be based on the max continuous or max intermittent current draw of items
connected to the relay? Also, in looking at some other 12V coil units, they
listed the max continuous voltage at 13.2 volts. I assume that is not a concern
with the S704-1?
Any local sources for equivalent relays / contactors?
THanks,
Scott
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=238585#238585
Message 17
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| Subject: | Re: Misc electrical items for sale |
I'd like to have a look at the list...
Thanks
Ron Q.
On Tue, Apr 7, 2009 at 8:12 PM, DEAN PSIROPOULOS <
dean.psiropoulos@verizon.net> wrote:
> dean.psiropoulos@verizon.net>
>
> Since my airplane is now finished I have some various finishing and
> electrical parts available for sale. Email me for a list of what I have
> available.
>
> Dean Psiropoulos
> RV-6A N197DM
> Flying 16 hours
>
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