Author: "Robert Anderson" <freightdog77@...> Time: Thu Mar 4, 2004 11:39 am PST Link
anyone have a good idea of the prop weight differences between
hartzell and MT? also, how do the MT props perform compared to the
Hartzell? Anyone using the MT for hard IFR? how do they stand up to
rain?
thanks
Bob
Emp kit ordered
Author: "Kirk" <groves@...> Time: Thu Mar 4, 2004 4:20 pm PST Link
---
Hi Bob,
Don't quote me on this ,but I believe the MT is about 20 pounds
lighter and around 10kts slower than the hartzell. There are guys(and
gals:) who will know much better than I, but I think a three blade
will generally be slower than a equivalent two blade prop. Check out
the fifth issue of 2003 "The RVator" Van did a side by side of
several props.
Have a great day!
Kirk Groves 81925 " fiberglass itches:)
In vansairforce@yahoogroups.com, "Robert Anderson"
<freightdog77@y...> wrote:
> anyone have a good idea of the prop weight differences between
> hartzell and MT? also, how do the MT props perform compared to the
> Hartzell? Anyone using the MT for hard IFR? how do they stand up to
> rain?
> thanks
> Bob
> Emp kit ordered
Author: "Robert Anderson" <freightdog77@...> Time: Thu Mar 4, 2004 6:08 pm PST Link
thanks, im also interested in comparing the 2 blade MT as well. also,
anyone have a copy of the article, or at least give me a brief run
down. my first RVator is in the mail now. i missed last years.
thanks
-8 EMP ordered
--- In vansairforce@yahoogroups.com, "Kirk" <groves@e...> wrote:
> ---
> Hi Bob,
> Don't quote me on this ,but I believe the MT is about 20 pounds
> lighter and around 10kts slower than the hartzell. There are guys
(and
> gals:) who will know much better than I, but I think a three blade
> will generally be slower than a equivalent two blade prop. Check
out
> the fifth issue of 2003 "The RVator" Van did a side by side of
> several props.
> Have a great day!
> Kirk Groves 81925 " fiberglass itches:)
> In vansairforce@yahoogroups.com, "Robert Anderson"
> <freightdog77@y...> wrote:
> > anyone have a good idea of the prop weight differences between
> > hartzell and MT? also, how do the MT props perform compared to
the
> > Hartzell? Anyone using the MT for hard IFR? how do they stand up
to
> > rain?
> > thanks
> > Bob
> > Emp kit ordered
Author: "vanlle2000" <vanlle2000@...> Time: Fri Mar 5, 2004 7:53 am PST Link
-Vans rvator -- last issue of 03, I think -- had an article comparing
mt/hartzell/whirlwind, including weights. It wasn't completely
comprehensive because they didn't have all the possible props to
test, but it's a good start.
-- In vansairforce@yahoogroups.com, "Robert Anderson"
<freightdog77@y...> wrote:
> anyone have a good idea of the prop weight differences between
> hartzell and MT? also, how do the MT props perform compared to the
> Hartzell? Anyone using the MT for hard IFR? how do they stand up to
> rain?
> thanks
> Bob
> Emp kit ordered
Author: Walter Tondu <walter@...> Time: Fri Mar 5, 2004 8:11 am PST Link
On 03/05 3:33, vanlle2000 wrote:
> -Vans rvator -- last issue of 03, I think -- had an article comparing
> mt/hartzell/whirlwind, including weights. It wasn't completely
> comprehensive because they didn't have all the possible props to
> test, but it's a good start.
Randy has a great review of several props he tested on his site
http://www.rv-8.com/Prop.htm
Also, note that WW has produced another prop, three bladed WW151RV.
At this time they will not sell it you if you have Elec. Ignition.
Not sure if they will if you have a higher compression engine. They
will release this hold when the in-the-field props get enough hours
on them.
--
Walter Tondu
http://www.tondu.com/rv7
Author: "mikesrv6" <mikesrv6@...> Time: Fri Mar 5, 2004 8:48 am PST Link
I also missed that issue. Any way to read it??? I din't think Van
sells back issues.
Author: "Randy Lervold" <randy@...> Time: Fri Mar 5, 2004 9:33 am PST Link
Also, Van's article had some of the weights wrong.
Randy Lervold
----- Original Message -----
From: Walter Tondu
To: vansairforce@yahoogroups.com
Sent: Friday, March 05, 2004 8:01 AM
Subject: Re: [VAF Mailing List] Re: PROP WEIGHTS
On 03/05 3:33, vanlle2000 wrote:
> -Vans rvator -- last issue of 03, I think -- had an article comparing
> mt/hartzell/whirlwind, including weights. It wasn't completely
> comprehensive because they didn't have all the possible props to
> test, but it's a good start.
Randy has a great review of several props he tested on his site
http://www.rv-8.com/Prop.htm
Also, note that WW has produced another prop, three bladed WW151RV.
At this time they will not sell it you if you have Elec. Ignition.
Not sure if they will if you have a higher compression engine. They
will release this hold when the in-the-field props get enough hours
on them.
--
Walter Tondu
http://www.tondu.com/rv7
Online help on this group at:
http://help.yahoo.com/help/groups/
------------------------------------------------------------------------------
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[Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Fri Mar 5, 2004 9:35 am PST Link
>>At this time they will not sell it you if you have Elec. Ignition<<
What in the world does having Electronic Ignition have to do with
anything?
Jim
--- In vansairforce@yahoogroups.com, Walter Tondu <walter@t...>
wrote:
> On 03/05 3:33, vanlle2000 wrote:
>
> > -Vans rvator -- last issue of 03, I think -- had an article
comparing
> > mt/hartzell/whirlwind, including weights. It wasn't completely
> > comprehensive because they didn't have all the possible props
to
> > test, but it's a good start.
>
> Randy has a great review of several props he tested on his site
> http://www.rv-8.com/Prop.htm
>
> Also, note that WW has produced another prop, three bladed
WW151RV.
> At this time they will not sell it you if you have Elec. Ignition.
> Not sure if they will if you have a higher compression engine.
They
> will release this hold when the in-the-field props get enough hours
> on them.
> --
> Walter Tondu
> http://www.tondu.com/rv7
Author: "Randy Lervold" <randy@...> Time: Fri Mar 5, 2004 10:32 am PST Link
Also, Van's article had some of the weights wrong. I can verify that the weights on my page are correct having done the weighing myself.
Randy Lervold
----- Original Message -----
From: Walter Tondu
To: vansairforce@yahoogroups.com
Sent: Friday, March 05, 2004 8:01 AM
Subject: Re: [VAF Mailing List] Re: PROP WEIGHTS
On 03/05 3:33, vanlle2000 wrote:
> -Vans rvator -- last issue of 03, I think -- had an article comparing
> mt/hartzell/whirlwind, including weights. It wasn't completely
> comprehensive because they didn't have all the possible props to
> test, but it's a good start.
Randy has a great review of several props he tested on his site
http://www.rv-8.com/Prop.htm
Also, note that WW has produced another prop, three bladed WW151RV.
At this time they will not sell it you if you have Elec. Ignition.
Not sure if they will if you have a higher compression engine. They
will release this hold when the in-the-field props get enough hours
on them.
--
Walter Tondu
http://www.tondu.com/rv7
Online help on this group at:
http://help.yahoo.com/help/groups/
------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To visit your group on the web, go to:
http://groups.yahoo.com/group/vansairforce/
b.. To unsubscribe from this group, send an email to:
vansairforce-unsubscribe@yahoogroups.com
c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed]
Author: Walter Tondu <walter@...> Time: Fri Mar 5, 2004 10:32 am PST Link
On 03/05 5:18, midniteoyl2 wrote:
> >>At this time they will not sell it you if you have Elec. Ignition<<
>
> What in the world does having Electronic Ignition have to do with
> anything?
Lots! Just two quick google searches found some information for you.
"Any modification to the standard engine configuration to include high
compression pistons, electronic ignition, FADEC, tuned induction and
exhaust, and turbocharging or turbonormalizing have the potential to
adversely effect the propeller vibration characteristics and stress amplitudes."
http://www.vansaircraft.com/pdf/Hartzell_c2yk.pdf
"An interesting illustration of how the magneto can change propeller stress
is illustrated in my Magneto Ignition System book where two propeller stress
surveys where performed on the same engine/aircraft but with the only
difference being the brand of magneto. There was a significant difference
in propeller stress between one magneto brand and another."
http://www.sacskyranch.com/propst.htm
--
Walter Tondu
http://www.tondu.com/rv7
Author: shiprv8@... Time: Fri Mar 5, 2004 11:31 am PST Link
Man, I can vouch for that...props are very sensitive to changes in power
pulse....electronic ignition, diesel, etc.......it don't take much to get thangs
shakin'.....when you see the vibe data as a test prop is running it's pretty
sobering
Randy: doesn't WW run instrumented prop tests? that should give them a very
clear indication of stresses on a given engine setup incl
E.I..........."field testing" doesn't tell a whole lot unless something comes off, which is
usually not a good thing.
ship
[Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Fri Mar 5, 2004 5:21 pm PST Link
All the others I see, but one would have a very difficult time
convincing me that Electronic Ignition will do anything.
So, having a e81/82 with point ignition would work, but not a EI
one....?
Jim
--- In vansairforce@yahoogroups.com, Walter Tondu <walter@t...>
wrote:
> On 03/05 5:18, midniteoyl2 wrote:
>
> > >>At this time they will not sell it you if you have Elec.
Ignition<<
> >
> > What in the world does having Electronic Ignition have to do
with
> > anything?
>
> Lots! Just two quick google searches found some information for
you.
>
> "Any modification to the standard engine configuration to include
high
> compression pistons, electronic ignition, FADEC, tuned induction
and
> exhaust, and turbocharging or turbonormalizing have the potential
to
> adversely effect the propeller vibration characteristics and
stress amplitudes."
>
> http://www.vansaircraft.com/pdf/Hartzell_c2yk.pdf
> "An interesting illustration of how the magneto can change
propeller stress
> is illustrated in my Magneto Ignition System book where two
propeller stress
> surveys where performed on the same engine/aircraft but with the
only
> difference being the brand of magneto. There was a significant
difference
> in propeller stress between one magneto brand and another."
>
> http://www.sacskyranch.com/propst.htm
>
> --
> Walter Tondu
> http://www.tondu.com/rv7
Author: shiprv8@... Time: Fri Mar 5, 2004 6:42 pm PST Link
In a message dated 3/5/04 9:01:47 PM Eastern Standard Time,
midniteoyl@... writes:
So, having a e81/82 with point ignition would work, but not a EI
one....?
yes
EI makes a big diff in prop stress levels.....mags are fixed spark timing
optimized for cruise power.....at lower RPM levels the engine is handicapped even
when run oversquare....E.I. advances/retards spark just like your car...way
more efficient at squeezing out power..... with EI the engine will hammer
harder at lower RPM's/high MP....hence prop restrictions at 2000-2200 for certain
props......new Hartzell blended prop added more beef to the blade roots to
handle EI power pulses.
drive an old car with a vacuum line to the distributor (hard to find these
anymore!) ....now pull the vac line....spark will be (almost) fixed like a
mag....drive it again and see how much power you lose......now the car is a Lyco on
mags but in reverse, i.e. optimized for low RPM operation.........prop feels
the difference in a big way
ship
[Non-text portions of this message have been removed]
Author: Walter Tondu <walter@...> Time: Fri Mar 5, 2004 7:23 pm PST Link
On 03/06 1:00, midniteoyl2 wrote:
> All the others I see, but one would have a very difficult time
> convincing me that Electronic Ignition will do anything.
>
> So, having a e81/82 with point ignition would work, but not a EI
> one....?
Proppeller manufacturer recommendations are based upon whatever testing
they do. Certified props have well defined testing parameters.
Experimental prop manufacturers do it a bit differently.
Changing the point at which the power cycle begins (ignition) has
very dramatic effects on the propeller. I'm not a propeller/engine
expert or engineer but talking to several propeller and engine manufacturers
has me convinced that what I read is true, or that they believe what
they read (and test) is true. You just have to do the homework for
yourself. There is nothing I can say to make you believe me nor do
I want you to.
I don't want to have a prop blade come unglued from the engine (ever).
So I'll play it safe and follow their recommendations.
You really should contact various manufacturers to find the information
you seek.
Cheers,
--
Walter Tondu
http://www.tondu.com/rv7
Author: "tshrem2003" <tshrem@...> Time: Fri Mar 5, 2004 11:57 pm PST Link
So is the LASAR prohibited on any engine/prop combination? I thought
they had PMA for just about every 320, 360 and 540 Lycoming and
airframe under the sun. WITHOUT any changes to the prop. Is this
incorect?
Tim
--- In vansairforce@yahoogroups.com, shiprv8@a... wrote:>
> yes
> EI makes a big diff in prop stress levels.....mags are fixed spark
timing
> optimized for cruise power.....at lower RPM levels the engine is
handicapped even
> when run oversquare....E.I. advances/retards spark just like your
car...way
> more efficient at squeezing out power..... with EI the engine will
hammer
> harder at lower RPM's/high MP....hence prop restrictions at 2000-
2200 for certain
> props......new Hartzell blended prop added more beef to the blade
roots to
> handle EI power pulses.
>
> drive an old car with a vacuum line to the distributor (hard to
find these
> anymore!) ....now pull the vac line....spark will be (almost) fixed
like a
> mag....drive it again and see how much power you lose......now the
car is a Lyco on
> mags but in reverse, i.e. optimized for low RPM
operation.........prop feels
> the difference in a big way
>
> ship
> [Non-text portions of this message have been removed]
Author: "Booger" <booger99@...> Time: Fri Mar 5, 2004 11:57 pm PST Link
where's the weight everything but weight
----- Original Message -----
From: Walter Tondu
To: vansairforce@yahoogroups.com
Sent: Friday, March 05, 2004 8:46 PM
Subject: Re: [VAF Mailing List] Re: PROP WEIGHTS
On 03/06 1:00, midniteoyl2 wrote:
> All the others I see, but one would have a very difficult time
> convincing me that Electronic Ignition will do anything.
>
> So, having a e81/82 with point ignition would work, but not a EI
> one....?
Proppeller manufacturer recommendations are based upon whatever testing
they do. Certified props have well defined testing parameters.
Experimental prop manufacturers do it a bit differently.
Changing the point at which the power cycle begins (ignition) has
very dramatic effects on the propeller. I'm not a propeller/engine
expert or engineer but talking to several propeller and engine manufacturers
has me convinced that what I read is true, or that they believe what
they read (and test) is true. You just have to do the homework for
yourself. There is nothing I can say to make you believe me nor do
I want you to.
I don't want to have a prop blade come unglued from the engine (ever).
So I'll play it safe and follow their recommendations.
You really should contact various manufacturers to find the information
you seek.
Cheers,
--
Walter Tondu
http://www.tondu.com/rv7
Online help on this group at:
http://help.yahoo.com/help/groups/
Yahoo! Groups Sponsor
ADVERTISEMENT
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[Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 12:17 am PST Link
I understand that, ship.. But they didnt say 'only with mags' but
instead, 'no electronic ignition'. Last I looked, points changed
timing just the same as EI.
So where's the diff?
Jim
--- In vansairforce@yahoogroups.com, shiprv8@a... wrote:
> In a message dated 3/5/04 9:01:47 PM Eastern Standard Time,
> midniteoyl@w... writes:
> So, having a e81/82 with point ignition would work, but not a EI
> one....?
>
> yes
> EI makes a big diff in prop stress levels.....mags are fixed spark
timing
> optimized for cruise power.....at lower RPM levels the engine is
handicapped even
> when run oversquare....E.I. advances/retards spark just like your
car...way
> more efficient at squeezing out power..... with EI the engine will
hammer
> harder at lower RPM's/high MP....hence prop restrictions at 2000-
2200 for certain
> props......new Hartzell blended prop added more beef to the blade
roots to
> handle EI power pulses.
>
> drive an old car with a vacuum line to the distributor (hard to
find these
> anymore!) ....now pull the vac line....spark will be (almost)
fixed like a
> mag....drive it again and see how much power you lose......now the
car is a Lyco on
> mags but in reverse, i.e. optimized for low RPM
operation.........prop feels
> the difference in a big way
>
> ship
> [Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 12:17 am PST Link
Again - I did NOT ask about mags. I know all about ignitions, thanks.
I asked about a *point ignition* which is still variable timed.
Jim
--- In vansairforce@yahoogroups.com, Walter Tondu <walter@t...>
wrote:
> On 03/06 1:00, midniteoyl2 wrote:
>
> > All the others I see, but one would have a very difficult time
> > convincing me that Electronic Ignition will do anything.
> >
> > So, having a e81/82 with point ignition would work, but not a
EI
> > one....?
>
> Proppeller manufacturer recommendations are based upon whatever
testing
> they do. Certified props have well defined testing parameters.
> Experimental prop manufacturers do it a bit differently.
>
> Changing the point at which the power cycle begins (ignition) has
> very dramatic effects on the propeller. I'm not a propeller/engine
> expert or engineer but talking to several propeller and engine
manufacturers
> has me convinced that what I read is true, or that they believe
what
> they read (and test) is true. You just have to do the homework for
> yourself. There is nothing I can say to make you believe me nor do
> I want you to.
>
> I don't want to have a prop blade come unglued from the engine
(ever).
> So I'll play it safe and follow their recommendations.
>
> You really should contact various manufacturers to find the
information
> you seek.
>
> Cheers,
> --
> Walter Tondu
> http://www.tondu.com/rv7
Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 12:17 am PST Link
Thanks Tim... someone understands..Though I wasnt thinking of the
LASAR :^)
Jim
--- In vansairforce@yahoogroups.com, "tshrem2003" <tshrem@c...>
wrote:
> So is the LASAR prohibited on any engine/prop combination? I
thought
> they had PMA for just about every 320, 360 and 540 Lycoming and
> airframe under the sun. WITHOUT any changes to the prop. Is this
> incorect?
> Tim
>
> --- In vansairforce@yahoogroups.com, shiprv8@a... wrote:>
> > yes
> > EI makes a big diff in prop stress levels.....mags are fixed
spark
> timing
> > optimized for cruise power.....at lower RPM levels the engine is
> handicapped even
> > when run oversquare....E.I. advances/retards spark just like
your
> car...way
> > more efficient at squeezing out power..... with EI the engine
will
> hammer
> > harder at lower RPM's/high MP....hence prop restrictions at 2000-
> 2200 for certain
> > props......new Hartzell blended prop added more beef to the
blade
> roots to
> > handle EI power pulses.
> >
> > drive an old car with a vacuum line to the distributor (hard to
> find these
> > anymore!) ....now pull the vac line....spark will be (almost)
fixed
> like a
> > mag....drive it again and see how much power you lose......now
the
> car is a Lyco on
> > mags but in reverse, i.e. optimized for low RPM
> operation.........prop feels
> > the difference in a big way
> >
> > ship
> > [Non-text portions of this message have been removed]
Author: "Bob & Lucille Olds" <oldsfolks@...> Time: Sat Mar 6, 2004 7:25 am PST Link
You inferior guys ahould listen up ; there is one on this thread who
knows"ALL"about ignitions !! If you can't discuss on the "Einstein"
level with this fellow,then be quiet and let him educate you !!
My opinion only,
Bob Olds RV-4 N1191X
Charleston,Arkansas
do not archive
Author: <endspeed@...> Time: Sat Mar 6, 2004 9:16 am PST Link
Alright boys and girls, I don't know the players in
this debate and who the Einstein is but I do know who
has the answer to your questions. Before we get down
to another fruitless debate, why don't you just
contact Hartzell and ask the people who make the
galldarn things if electronic ignition affects their
props. I do know that not having the right answer to
this question may be harmful to your health. Safe
flying. Bob
--- Bob & Lucille Olds <oldsfolks@...> wrote:
> You inferior guys ahould listen up ; there is one on
> this thread who
> knows"ALL"about ignitions !! If you can't discuss
> on the "Einstein"
> level with this fellow,then be quiet and let him
> educate you !!
>
> My opinion only,
> Bob Olds RV-4 N1191X
> Charleston,Arkansas
>
> do not archive
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Author: shiprv8@... Time: Sat Mar 6, 2004 2:25 pm PST Link
sort of incorrect
PMA has nothing to do with props or vibrations; PMA represents the paper
trail -- on every nut, bolt, casting, batch, etc. -- on the manufacturing side of
FAA certification meaning that the certified unit is manufactured in
compliance with FAA FAR standards on manufacturing.
editorial comment: PMA is a nightmare when you're certifying an entirely new
engine design!!!
Anything that is FAA certificated must also have a PMA at the manufacturing
level. In some cases (like entire engines, for example) PMA is actually more
difficult to achieve than the certification itself. Anyone manufacturing a
Certificated part must also have a PMA (manufacturing) authorization from FAA.
Superior and ECI got all of their clone technology as PMA manufacturers for
Lycoming components. Perfectly legal.
Re LASAR applications on 320, 360, etc.:
-- each of those engines would've been tested and listed as a certified
installation by Unison.
Re prop/LASAR combinations:
Although LASAR is a mag-based system, it is classified as an electronic
ignition. Any **approved** engine/prop/LASAR combinations would have had to be
tested and certified under FAR by the prop manufacturer for that specific
installation.
Bottom Line:
A quick call to Hartzell or any other certified prop vendor can tell whether
LASAR is approved, restricted, etc. for any of their props. For
experimentals, we're on our own as always.
ship
[Non-text portions of this message have been removed]
Author: shiprv8@... Time: Sat Mar 6, 2004 2:25 pm PST Link
points don't advance/retard same as EI....also very different from automotive
application....not worth going into detail here but suffice to say it's a
reverse relationship to EI
the bottom line is there's a major difference in stress levels at the prop
with EI.....when you run an instrumented prop on mags and EI, the difference is
instantly seen on the data scans.
ship
[Non-text portions of this message have been removed]
Author: shiprv8@... Time: Sat Mar 6, 2004 2:26 pm PST Link
correction: I wrote "....suffice to say it's a reverse relationship to EI
".... "reverse" is not quite accurate; in aircraft "torque" motors (lyco, etc.)
it's more like a "sideways" relationship
oversquare is actually the optimal operation for gas engines but the main
reason for NOT running a mag-ignition engine oversquare is the risk of detonation
and resulting damage due to the over-advanced spark setting from the magneto
points (who uses points in an airplane?) are variable by combination of MP
(vacuum) and RPM (centrifugal) but they don't have any method of dealing with
detonation either.....(yes, yes, there were crude knock sensors and solenoids in
cars before true E.I. but that was cars and very Rube Goldberg)
in aircraft applications, an E.I. ignition map (RPM vs. MP vs. THROTTLE) will
be VERY different than the spark map in an automobile due to the different
loading characteristics placed on the engine.
A car being driven at high load/low RPM (towing that boat up a hill in 5th
gear) would immediately retard the spark way down to avoid damaging the crank,
whereas the E.I. in an aircraft MUST maintain more power at these settings,
hence the aircraft engine is already designed to take the higher combustion loads
than a car engine.....
but the prop is getting HAMMERED at these settings......thus the placards on
the older props designed before E.I.
Ship
[Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 2:27 pm PST Link
Boy, that was helpfull...
Jim
--- In vansairforce@yahoogroups.com, "Bob & Lucille Olds"
<oldsfolks@a...> wrote:
> You inferior guys ahould listen up ; there is one on this thread
who
> knows"ALL"about ignitions !! If you can't discuss on
the "Einstein"
> level with this fellow,then be quiet and let him educate you !!
>
> My opinion only,
> Bob Olds RV-4 N1191X
> Charleston,Arkansas
>
> do not archive
Author: n667sr@... Time: Sat Mar 6, 2004 2:27 pm PST Link
Ok everybody,
I was going to stay out of this, but I have a few points to make or at least some more questions to solve. If a mag is set up for 25 degrees fixed, that means that your engine is ultimatly set up for one power setting and anything below that your ign would be firing to soon and anything above that your ign. would be firing to late. Now having said that the further you get on either side of the ultimate setting the more your power pulse's will change. If you run and electric ign. the timing will change with the rpm which should hold the power pulse's more in line. So I think the E.I. ign would be smoother, but that's just my opinion.
PS. Does anyone know of a prop that came apart due to electric ign.
PSS. What that prop company will tell you over the phone is a lot different then they will tell you at a fly-in.(Most of their answers are lawyer driven).
> Alright boys and girls, I don't know the players in
> this debate and who the Einstein is but I do know who
> has the answer to your questions. Before we get down
> to another fruitless debate, why don't you just
> contact Hartzell and ask the people who make the
> galldarn things if electronic ignition affects their
> props. I do know that not having the right answer to
> this question may be harmful to your health. Safe
> flying. Bob
>
> --- Bob & Lucille Olds <oldsfolks@...> wrote:
> > You inferior guys ahould listen up ; there is one on
> > this thread who
> > knows"ALL"about ignitions !! If you can't discuss
> > on the "Einstein"
> > level with this fellow,then be quiet and let him
> > educate you !!
> >
> > My opinion only,
> > Bob Olds RV-4 N1191X
> > Charleston,Arkansas
> >
> > do not archive
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Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 5:02 pm PST Link
Thanks for the correction - Was confused for a moment :^)
>>points (who uses points in an airplane?)<<
Lotta soobie and VW conversions do. Dual points are very popular in
these cases. This is why I asked... If WW wont sell to anybody
unless they have a Mag Ignition, then whats the point of selling to
the Experimental sector at all?
Jim
--- In vansairforce@yahoogroups.com, shiprv8@a... wrote:
> correction: I wrote "....suffice to say it's a reverse
relationship to EI
> ".... "reverse" is not quite accurate; in aircraft "torque" motors
(lyco, etc.)
> it's more like a "sideways" relationship
>
> oversquare is actually the optimal operation for gas engines but
the main
> reason for NOT running a mag-ignition engine oversquare is the
risk of detonation
> and resulting damage due to the over-advanced spark setting from
the magneto
>
> points (who uses points in an airplane?) are variable by
combination of MP
> (vacuum) and RPM (centrifugal) but they don't have any method of
dealing with
> detonation either.....(yes, yes, there were crude knock sensors
and solenoids in
> cars before true E.I. but that was cars and very Rube Goldberg)
>
> in aircraft applications, an E.I. ignition map (RPM vs. MP vs.
THROTTLE) will
> be VERY different than the spark map in an automobile due to the
different
> loading characteristics placed on the engine.
>
> A car being driven at high load/low RPM (towing that boat up a
hill in 5th
> gear) would immediately retard the spark way down to avoid
damaging the crank,
> whereas the E.I. in an aircraft MUST maintain more power at these
settings,
> hence the aircraft engine is already designed to take the higher
combustion loads
> than a car engine.....
>
> but the prop is getting HAMMERED at these settings......thus the
placards on
> the older props designed before E.I.
>
> Ship
> [Non-text portions of this message have been removed]
Author: shiprv8@... Time: Sat Mar 6, 2004 5:02 pm PST Link
Steve,
you're correct on the "too soon" aspect w/mags at lower RPM's.... but the key
factor is power setting.....fixed timing works both ways, i.e. limits power
on both sides of the optimum RPM at the risk of potential harm from detonation
at high MP settings....that's why the the fuel (power) component is so
critical on oversquare operation...minimize the detonation
EI runs smoother BUT the prop is getting hit harder nonetheless....all you
need to do is see the data from an instrumented prop test....it's astonishing
how much difference there is
the improved "smoothness" you feel in seat-of-pants from EI is due to better
firing balance.....the prop, on the other hand, is doing dances from the
increased power pulses from the optimized spark timing....these vibes are WAY above
the ability to feel.
metal props are by far the most affected by "EI vs. Mag"....composites are
far better able to handle the pulses........BUT they are not immune to EI....WW
did have problems initially with loose fasteners (as you know)....the vibes
are insidious....
Ship
[Non-text portions of this message have been removed]
Author: shiprv8@... Time: Sat Mar 6, 2004 6:29 pm PST Link
In a message dated 3/6/04 8:15:31 PM Eastern Standard Time,
midniteoyl@... writes:
Lotta soobie and VW conversions do. Dual points are very popular in
these cases. This is why I asked
ah yes...the older auto engines....no aircraft engine designer in his right
mind would specify points if he were designing from a clean sheet....far to
much failure mode in a set of points (burn, break, dwell setting, capacitor fade,
etc.)....and of course there's the distributor to fail as well.....yummy :-)
that's why mags are mags and why airplane engines use them :-)
as for WW, that's a good question....although I suspect it's merely an
oversight but you'd need to call them and ask....not too many VW engines I'm aware
of that can swing a prop the size of a WW.....I'd be curious as to their answer.
ship
[Non-text portions of this message have been removed]
Author: shiprv8@... Time: Sat Mar 6, 2004 6:30 pm PST Link
In a message dated 3/6/04 6:12:38 PM Eastern Standard Time,
n667sr@... writes:
PS. Does anyone know of a prop that came apart due to electric ign.
PSS. What that prop company will tell you over the phone is a lot different
then they will tell you at a fly-in.(Most of their answers are lawyer driven).
Lots of props have stress-shed a blade even without EI. If it were just a
matter of legal-speak, every prop would have placards. Hartzell blended foil
does not. Why? Because it meets vibe and stress criteria whereas the older
design doesn't. (personally, I'm not a big fan of metal props but they do work)
Running a formal, instrumented prop test is like going into a sausage
factory....it's a lot uglier than you imagined and once you've seen it, you never
forget it. It makes you think twice about sticking "any old prop on any old
engine". That's not to say it's unsafe, just that it's unknown. (I should
copyright that line!!)
The prop mfr's (including WW) are rightly very conservative.....but without
actual test data there is NO way -- none, zero, zip, nada -- to predict what's
going on in the prop for a given engine, power setting, etc.
Been there. Done that. Have data. Big surprises. Made changes. Rinse.
Lather. Repeat. Things are better now. Testing right now as we speak.
Ship
[Non-text portions of this message have been removed]
Author: "midniteoyl2" <midniteoyl@...> Time: Sat Mar 6, 2004 9:56 pm PST Link
>>Been there. Done that. Have data. Big surprises. Made
changes. Rinse.
> Lather. Repeat. <<
LMAO!
Thanks for the info, ship
Jim
--- In vansairforce@yahoogroups.com, shiprv8@a... wrote:
> In a message dated 3/6/04 6:12:38 PM Eastern Standard Time,
> n667sr@c... writes:
> PS. Does anyone know of a prop that came apart due to electric ign.
> PSS. What that prop company will tell you over the phone is a lot
different
> then they will tell you at a fly-in.(Most of their answers are
lawyer driven).
>
> Lots of props have stress-shed a blade even without EI. If it
were just a
> matter of legal-speak, every prop would have placards. Hartzell
blended foil
> does not. Why? Because it meets vibe and stress criteria whereas
the older
> design doesn't. (personally, I'm not a big fan of metal props but
they do work)
>
> Running a formal, instrumented prop test is like going into a
sausage
> factory....it's a lot uglier than you imagined and once you've
seen it, you never
> forget it. It makes you think twice about sticking "any old prop
on any old
> engine". That's not to say it's unsafe, just that it's unknown.
(I should
> copyright that line!!)
>
> The prop mfr's (including WW) are rightly very
conservative.....but without
> actual test data there is NO way -- none, zero, zip, nada -- to
predict what's
> going on in the prop for a given engine, power setting, etc.
>
> Been there. Done that. Have data. Big surprises. Made
changes. Rinse.
> Lather. Repeat. Things are better now. Testing right now as we
speak.
>
> Ship
> [Non-text portions of this message have been removed]