Re: Ivo Prop on O-320

[Dave S]

The following is information I am repeating, but have no first hand
experience with. I subscribe to several forums and lists that have
discussed this from time to time in the context of Canard aircraft and
auto conversion engines.

One person who was running a Mazda rotary/wankel conversion in an RV 4
had a speed penalty incurred by using the product. He had a benefit at
low speed with regards to performance, but broke even with a fixed pitch
cruise prop around 140-150mph (that was installed later) and he had a
signigicant penalty on the high end with the IVO top speed being about
187 mph and with the cruise prop getting him about 210-215 mph. Some of
this is from his website (www.rotaryaviation.com) and some of this is
from telephone conversations with him.

I have given the IVO serious consideration for use on a Velocity with a
Mazda engine conversion, and the IVO magnum used was the higher pitch
variety. Apparently, since the prop adjusts by "blade warping", only the
outer portion of the prop blade changes pitch and the inner portion does
not.

There have been reports of one flavor of lycoming causing problems with
the torque pulses.. but I want to say this was the 360 CID variety of
lycoming. A website forum with a thread on it is www.canardzone.com in
the "Flying and Performance - Prop" subforum. The thread is labeled,
simply enough "Ivo". Also have seen some incidental discussion of the
IVO but not much substantive at "canardaviationforum.dmt.net", another
Canard based forum.

If used, you need to pay attention to detail with regarding prop bolt
torque... the blades are essentially sandwiched between two flanges to
hold them in position. There was a fatal accident caused by a field
repair that was done under questionable circumstances by the pilot (who
didnt have a torque wrench) that caused a slung blade and loss of
aircraft and 4 people. This was more the pilots fault than the props..
the instructions are supposed to be pretty clear about the procedure.

The consensus I have arrived at is that this prop does have utility, but
it is not well suited to high speed applications. Perhaps a bush
plane/cub copy would be able to take advantage of the adjustable pitch
function without having to worry about a penalty at high airspeeds.

Dave



canflyboy wrote:
> Has anyone have anything to say, good or bad, about the Ivo Prop propeller
> for the Lycoming engines? The adjustment feature is quite unique and
> interesting, but I'd like to heard from users in the field for their opinion
>
> Thanks
>
> Canflyboy
>
>

[Paul Lee]

I have an IVO magnum adjustable on my SQ2000 canard and am just
burning off the test hours. The prop is good on takeoff
and climb. So far I could not get more than about 200mph out of
the bird with a 220hp Franklin. It is supposed to cruise beyond 200.
I still have a number of adjustments to make to test for high speed,
EIS ignition timing, fill all the different fairings, etc. so cannot
say conclusively that the prop is a factor. But would be nice to
try it with a standard cruise prop. Anybody could loan me a 66x76
prop to try out?

----------------------------------------------------
SQ2000 canard: www.abri.com/sq2000

Dave S > wrote in message et>...
> The following is information I am repeating, but have no first hand
> experience with. I subscribe to several forums and lists that have
> discussed this from time to time in the context of Canard aircraft and
> auto conversion engines.
>
> One person who was running a Mazda rotary/wankel conversion in an RV 4
> had a speed penalty incurred by using the product. He had a benefit at
> low speed with regards to performance, but broke even with a fixed pitch
> cruise prop around 140-150mph (that was installed later) and he had a
> signigicant penalty on the high end with the IVO top speed being about
> 187 mph and with the cruise prop getting him about 210-215 mph. Some of
> this is from his website (www.rotaryaviation.com) and some of this is
> from telephone conversations with him.
> .........

[Dan Thomas]

The IVO has aluminum bushings in each prop blade for the bolts, and
the plates are supposed to clamp these bushings tightly. We had an IVO
on a Soob conversion and had trouble with blade movement no matter
what torque we used on those bolts. There was fretting evident on the
bushing ends and plates, and the aluminum tape across the blade joints
(which is supposed to betray any movement) did not break. We couldn't
get the prop balanced, either, since the small amount of chordwise
blade swing on the bolts before tightening resulted in a chordwise
imbalance after tightening. We spent time fooling with getting the
blades to sit in the right spots, but it was a waste.
The blades are mostly high-density foam with a carbon-fiber skin.
Therefore, the bushings are buried mostly in foam. The skin is really
thin. I'm amazed that more of these props don't fail.
As you mentioned, the blades are twisted to change pitch, and the
outer half or so is all that changes. Therefore, the inner prop blade
is running at a negative angle of attack at high speeds, contributing
drag instead of thrust.
Surely there are better options.

Dan


Dave S > wrote in message et>...
> The following is information I am repeating, but have no first hand
> experience with. I subscribe to several forums and lists that have
> discussed this from time to time in the context of Canard aircraft and
> auto conversion engines.
>
> One person who was running a Mazda rotary/wankel conversion in an RV 4
> had a speed penalty incurred by using the product. He had a benefit at
> low speed with regards to performance, but broke even with a fixed pitch
> cruise prop around 140-150mph (that was installed later) and he had a
> signigicant penalty on the high end with the IVO top speed being about
> 187 mph and with the cruise prop getting him about 210-215 mph. Some of
> this is from his website (www.rotaryaviation.com) and some of this is
> from telephone conversations with him.
>
> I have given the IVO serious consideration for use on a Velocity with a
> Mazda engine conversion, and the IVO magnum used was the higher pitch
> variety. Apparently, since the prop adjusts by "blade warping", only the
> outer portion of the prop blade changes pitch and the inner portion does
> not.
>
> There have been reports of one flavor of lycoming causing problems with
> the torque pulses.. but I want to say this was the 360 CID variety of
> lycoming. A website forum with a thread on it is www.canardzone.com in
> the "Flying and Performance - Prop" subforum. The thread is labeled,
> simply enough "Ivo". Also have seen some incidental discussion of the
> IVO but not much substantive at "canardaviationforum.dmt.net", another
> Canard based forum.
>
> If used, you need to pay attention to detail with regarding prop bolt
> torque... the blades are essentially sandwiched between two flanges to
> hold them in position. There was a fatal accident caused by a field
> repair that was done under questionable circumstances by the pilot (who
> didnt have a torque wrench) that caused a slung blade and loss of
> aircraft and 4 people. This was more the pilots fault than the props..
> the instructions are supposed to be pretty clear about the procedure.
>
> The consensus I have arrived at is that this prop does have utility, but
> it is not well suited to high speed applications. Perhaps a bush
> plane/cub copy would be able to take advantage of the adjustable pitch
> function without having to worry about a penalty at high airspeeds.
>
> Dave
>
>
>
> canflyboy wrote:
> > Has anyone have anything to say, good or bad, about the Ivo Prop propeller
> > for the Lycoming engines? The adjustment feature is quite unique and
> > interesting, but I'd like to heard from users in the field for their opinion
> >
> > Thanks
> >
> > Canflyboy
> >
> >

[Jim Carriere]

Dave S wrote:
<snip snip>
> One person who was running a Mazda rotary/wankel conversion in an RV 4
> had a speed penalty incurred by using the product. He had a benefit at
> low speed with regards to performance, but broke even with a fixed pitch
> cruise prop around 140-150mph (that was installed later) and he had a
> signigicant penalty on the high end with the IVO top speed being about
> 187 mph and with the cruise prop getting him about 210-215 mph. Some of
> this is from his website (www.rotaryaviation.com) and some of this is
> from telephone conversations with him.

On the Ivoprop website, it says that the prop can be adjusted between
30-90" or 45-105". See http://www.ivoprop.com/inflightmagnumodel.htm

I take this to mean that one has a choice of the baseline pitch
during installation. From that it would follow that you have a
choice of optimising between climb and cruise.

I wonder if the fellow in this example chose the lower pitch range,
and if he would see top speed improvement (and some loss of takeoff
and climb performance) if he had chosen the higher pitch range.

Just my guess...

[Dave S]

Jim Carriere wrote:
>
> <snip snip>
>
> I wonder if the fellow in this example chose the lower pitch range, and
> if he would see top speed improvement (and some loss of takeoff and
> climb performance) if he had chosen the higher pitch range.
>
> Just my guess...
>

Per my telephone conversations several weeks back, this WAS with the
higher pitch range. Considering the engine applications we are using
have quite a bit of surplus HP at sea level, it appears to be a good
tradeoff using the fixed pitch cruise prop.

At this point the best I can tell is if you REALLY want a CS prop on a
higher HP engine that cant support a governor.. then you need to drop
$10 grand and go with the MT. Personally I WANT a CS unit on the
homebuild.. but I am more interested in XC/top end speed. The velocity
will be used mainly off paved, longer runways, no short field bush
stuff, and probably minimal mountain stuff since we are flatlanders..

The pitch range question was the first thing I thought of when I heard
of Tracy's problem. I apologize for not including it in the original post.

Dave

[Paul Lee]

Dave,

You might want to contact Rick Lavoie of http://www.lavoiegraphics.com/
He recently sold his Velocity canard with an IVO prop.
http://www.lavoiegraphics.com/velocityrg/
Find out from him about actual performance. He had a lot of loged
time on it.

Dave S > wrote in message et>...
> Jim Carriere wrote:
>.......
> At this point the best I can tell is if you REALLY want a CS prop on a
> higher HP engine that cant support a governor.. then you need to drop
> $10 grand and go with the MT. Personally I WANT a CS unit on the
> homebuild.. but I am more interested in XC/top end speed. The velocity
> will be used mainly off paved, longer runways, no short field bush
> stuff, and probably minimal mountain stuff since we are flatlanders..
> .............

[Paul Lee]

Dan,

The newer IVO's have knurled plates which hold the prop blades
better and I did not notice any aluminum bushings in blades, just
composite hard core stuff. I have over 10 hours and do not have
to retighten after third time. There are successfull higher power
installations of the IVO prop - see
http://www.lavoiegraphics.com/velocityrg/
and http://www.ida.net/biz/arlfrd/

My concern at this time is if the high speed performance is an issue.

(Dan Thomas) wrote in message >...
> The IVO has aluminum bushings in each prop blade for the bolts, and
> the plates are supposed to clamp these bushings tightly. We had an IVO
> on a Soob conversion and had trouble with blade movement no matter
> what torque we used on those bolts. There was fretting evident on the
> bushing ends and plates, and the aluminum tape across the blade joints
> (which is supposed to betray any movement) did not break. We couldn't
> get the prop balanced, either, since the small amount of chordwise
> blade swing on the bolts before tightening resulted in a chordwise
> imbalance after tightening. We spent time fooling with getting the
> blades to sit in the right spots, but it was a waste.
> The blades are mostly high-density foam with a carbon-fiber skin.
> Therefore, the bushings are buried mostly in foam. The skin is really
> thin. I'm amazed that more of these props don't fail.
> As you mentioned, the blades are twisted to change pitch, and the
> outer half or so is all that changes. Therefore, the inner prop blade
> is running at a negative angle of attack at high speeds, contributing
> drag instead of thrust.
> Surely there are better options.
>
> Dan
>
> .........

[Ron Webb]

I have a Lycoming io-360 modified to about 220 HP (high compression pistons,
Ellison throttle body, and electronic ignition on one side). I went looking
for a prop, and talked to someone at Ivo. This was several years ago (5
maybe) but I remember that they wouldn't even sell me one for a direct drive
4 cylinder.

The problem is that saying 220 HP does not tell the whole story. You have to
look at when and how often the torque pulses are generated. The average
torque may be the same, but if you have fewer but BIGGER pulses. A 4
cylinder direct drive has only 2 piston firings per revolution of the prop,
so they have to be BIG suckers to keep the average torque up. That's harder
on the prop. A geared V8 or rotary will give many smaller pulses, and so is
much easier on the prop blade mountings. That's one reason you don't see
many Lyc's with Ivo props.

I ended up with a Warp Drive, and I'm happy with it, but the blade mounting
arrangement is different, and much more secure.Look at how Ivo does it vs
Warp drive, and you'll understand.


Ron Webb




"canflyboy" > wrote in message
...
> Has anyone have anything to say, good or bad, about the Ivo Prop propeller
> for the Lycoming engines? The adjustment feature is quite unique and
> interesting, but I'd like to heard from users in the field for their
opinion
>
> Thanks
>
> Canflyboy
>
>

[[email protected]]

On Thu, 07 Oct 2004 21:38:26 -0500, Jim Carriere
> wrote:

>Dave S wrote:
><snip snip>
>> One person who was running a Mazda rotary/wankel conversion in an RV 4
>> had a speed penalty incurred by using the product. He had a benefit at
>> low speed with regards to performance, but broke even with a fixed pitch
>> cruise prop around 140-150mph (that was installed later) and he had a
>> signigicant penalty on the high end with the IVO top speed being about
>> 187 mph and with the cruise prop getting him about 210-215 mph. Some of
>> this is from his website (www.rotaryaviation.com) and some of this is
>> from telephone conversations with him.
>
>On the Ivoprop website, it says that the prop can be adjusted between
>30-90" or 45-105". See http://www.ivoprop.com/inflightmagnumodel.htm
>
>I take this to mean that one has a choice of the baseline pitch
>during installation. From that it would follow that you have a
>choice of optimising between climb and cruise.
>
>I wonder if the fellow in this example chose the lower pitch range,
>and if he would see top speed improvement (and some loss of takeoff
>and climb performance) if he had chosen the higher pitch range.
>
>Just my guess...

2 different props available - high pitch and low pitch.

[Paul Lee]

I have considered a Warp drive and talked to them about using ts on
my SQ2000 canard with 220 hp Franklin. But they cautioned against it
saying the props were not suited for canard high end performance.
So it really is shoping for the "right" prop for your particular
application.

"Ron Webb" > wrote in message >...
> I have a Lycoming io-360 modified to about 220 HP (high compression pistons,
> ................
> I ended up with a Warp Drive, and I'm happy with it, but the blade mounting
> arrangement is different, and much more secure.Look at how Ivo does it vs
> Warp drive, and you'll understand.
>
>
> Ron Webb
>

[Ron Webb]

"Paul Lee" > wrote in message
om...
> But they cautioned against it saying the props were not suited for canard
high end
> performance.so it really is shoping for the "right" prop for your
particular application.



There are applications where NO prop is a really good option. A high
horsepower
pusher with the prop in disturbed air is one of those. A small diameter
running at high prop RPM makes it even worse.

A carbon fiber prop has almost no damping. Any cyclical vibrations will just
build and build as energy is input on each cycle and not dissipated.
Eventually a warp drive prop as a pusher in a disturbed airflow (
http://beta.communities.fr.msn.ca/AdventurerExperimentalAmphibian/general.msnw?action=get_message&mview=0&ID_Message=260&LastModified=4675399668152588100 )
has failed with cracks longitudinally at the tips. That's why wood props are
popular with canards. Energy is dissipated as fast as it's input, so big
vibrations do not build up.

The problem with wood is that (at least in my experience) is not very
efficient. Everyone I know (including myself) who has switched from wood to
carbon has seen a large increase in performance.

Like I said - no good option.

[Ron Webb]

> That's not been my experience. Certainly carbon isn't as good at
> damping as wood, but it's much closer to wood than it is to aluminum.

It's not that carbon damps better than aluminum, it's just that it's a
hellova lot stronger and lighter.It can stand up to much bigger vibrations
with no ill effects.

Cast aluminum has a very small fatigue strength. If you stress it more than
about 5KPsi, it will eventually fail. and the stuff is heavy so vibrations
have a large force behind them.

Carbon fiber has about 650 KPsi theoretical tensile strength. Even when
viewed in the worst possible light, it still has about 200 KPsi in
compression, (That's right 5 KPsi vs 200 KPsi) and it's much lighter.

So carbon doesn't break as readily as aluminum, but that is not damping,
that's because of a radical strength advantage.

[Corky Scott]

On Thu, 14 Oct 2004 08:30:51 -0800, "Ron Webb"
> wrote:

>The problem with wood is that (at least in my experience) is not very
>efficient. Everyone I know (including myself) who has switched from wood to
>carbon has seen a large increase in performance.
>
>Like I said - no good option.

How about a wood prop core, overlaid with carbon fiber? I think
that's what MT does for their props.

Best of both worlds?

Corky Scott

[Drew Dalgleish]

On Thu, 14 Oct 2004 13:28:45 -0400, Corky Scott
> wrote:

>On Thu, 14 Oct 2004 08:30:51 -0800, "Ron Webb"
> wrote:
>
>>The problem with wood is that (at least in my experience) is not very
>>efficient. Everyone I know (including myself) who has switched from wood to
>>carbon has seen a large increase in performance.
>>
>>Like I said - no good option.
>
>How about a wood prop core, overlaid with carbon fiber? I think
>that's what MT does for their props.
>
>Best of both worlds?
>
>Corky Scott
>
And in a fixed pitch prop I think prince props are wood and carbon as
well. They also claim to flex a bit to give a quasi constant speed
effect

[Ron Webb]

"Bashir Salamati" > wrote in message
>
> Take wood dowl, an aluminum rod, and a piece of carbon fiber/epoxy
composite.
> Suspend from a string. Tap each with a small hammer. See which one rings
> longest.


Hmmm...a very interesting thought experiment.

It is obvious that the aluminum would ring like a bell, the composite might
ring a little, but not much, and the wood would go "thunk". I had not
thought of it like that. I'm not sure how much of this result would apply to
the propeller situation but on the surface at least you seem to have a
point.

I'm going to have to think about that...