Installing an IVO

[John Slade]

I completed the installation of my IVO Magnum in-flight adjustable prop this evening and thought that an installation report might be useful to others.

The prop arrived 8 days after the order was placed. It seemed like a very small box for a three blade prop. The three blades come bolted together. A parts bag contains the motor with it's knurled pressure plate, a matching knurled back plate, three plastic (delron?) spacer rings, two aluminum "electric" rings and a machined aluminum end plate that (if you order it right) matches the SAE2 drive plate on the end of engine or, in my case, the redrive. All bolts needed to assemble the prop and various plates are included. The bag also contains a small delron brush holder with two carbon brushes. This has to be mounted so that 12V power is supplied to the two isolated rings which connect to the motor. Also supplied is 16g wire (not quite enough for a Cozy), a 10A CB and a plastic 2 pole (on) OFF (on) switch. When power is applied the motor rotates a steel lever which is engaged in slip fittings at the end of each blade. As the motor turns the blade twists visibly.

My switch seemed a bit sticky and hard to press, so I called IVO. The reaction - I'll express a replacement out today. The replacement is much better, but I might replace this switch with a higher quality metal one. I also ordered some spare brushes and a spare brush holder. Apparantly the brushes need to be replaced every 20 to 100 hrs. IVO says how long they last seems to depend on the customer. Some last 20, some more than 100 hrs.

Mounting the brushes isnt too bad. I checked with Tracy at RWS, then made a flat horseshoe shaped 4130 1/8 steel bracket which is anchored by four of the redrive end-plate screws. The horseshoe has a protrusion as shown in the picture below which is drilled for a 3 inch #5 AN bolt at just the right spot to position the brush holder 1/16th from the power transfer rings. I cut the head off the bolt and threaded both ends for nuts and washers to allow adjustment. The clearance is tight, but entire installation seems very rigid.

Assembling the prop is quick and easy. Took about an hour. It is torqued to 65lb, then checked, checked and rechecked after the first taxi test and during the first few hours of flight. Once settled it needs to be checked about every 10 hours. In my case this will involve removing the spinner.

Speaking of spinners, fitting one is a little tricky. I think it needs one because the motor sticks out the back and looks a bit too "phallic" for my taste. (see picture). Your mileage may vary (a lot ). As shown, the backplate is very close to the brush holder. (about 0.1 inches). I didnt bother with the flow guide because it has to be extended with a ring of aluminum to get it over the brush mount. A brush mount that fits under the flow guide would be a fairly intricate design and tough to make.

In general the prop looks excellent. It seems to be very well made. The blades come in any color you like so long as it's black. They're marked with the final balance weights which are exactly the same to 0.1 grams. Total weight of the entire installation is 27lbs. Its a clever design which to me seems beautiful in its simplicity. The company has been excellent to deal with.

The prop is now ready to go. I mounted the switch close to the throttle and spent a few minutes sitting in the left seat twisting the prop blades back and forth.

All I need to do now is finish off the KNS80/KI203 installation, reinstall the EC2 switch panel and EM2 display, the canard, vortilons, nav lights etc. etc and finish off the trim paint and she's ready to fly. The blue lines in the pictures is masking tape for where the stripes will go. The kitty will have an entirely new trim paint scheme (approved by SWMBO and masked out ready) this time.

I'll report more on the IVO when I get chance to fly it.

Any questions?

[Kumaros]

Congrats John, you are my hero!
Hopefully I'll be able to copy your installation, as I've had Ross's IVO Magnum blades since about one month. I'll have to order the rest of the package from Ivo; I'm glad to hear of the service with a smile policy.
As to the varying wear rate of brushes, I'd attribute it to varying degrees of roundness and smoothness of the slip rings setup and/or vibration of the engine. Given the rotary's general smoothness I'd expect long intervals for your kitten.
Remind me to send you a picture of Pan the phalic god to hang on Slick Kitten, if Charmaine will allow it
Just for laughs, the logo on the top cover of the Toyota 2.2 liter D-4D Clean Power turbodiesel reads D-CAT; what's the matter with cats?
Kumaros
It's all Greek to me

[Waiter]

JOhn, I have to warn you, once you've flown with this, you'll never go back to a fixed pitch again.

If you haven't already done so, you need to notify your FSDO and will drop back to Phase I for the New prop.

Waiter

[MarbleTurtle]

I can't wait to hear the results!

Maybe John should go into the FWA rotary engine business after this.

[John Slade]

once you've flown with this, you'll never go back to a fixed pitch again

I hope that's true. These blades would filet a seagull, deliver it "thin sliced" with wax paper between the slices, and keep right on turning without missing a beat. I'm told that at the IVO office they have on display a Velocity exhaust that's a perfect fit wrapped around an IVO blade. They had to use a new blade because the owner is still flying the blade in question. There was no significant damage to it. Just a small scratch on the surface.

a picture of Pan the phalic god

I was thinking more in terms of a "Cheater"

[argoldman]

John, we are all waiting with Seagull bated breath.

This prop makes a lot of sense, especially econimically. There is nothing like a controllable prop.

I, am not crazy about the 10 Hr torque inspection. Does that go away after a certain number of hours

I anxiously await your results and writings

[rv6ejguy]

Once you've done the re-torque a half dozen times and the bolts don't take any more, you are good to go. IVO supplied some stainless tape to detect blade walk on preflight if you can see it through your spinner.

The brush wear has a lot to do with how much carbon is laid down on the slip rings. First set or two of brushes wear quickly then hey start lasting longer and longer. Don't wipe the rings off. Brushes are cheap and easy to change and you should be checking things under the cowling every once in a while anyway.

IVO has been an excellent company to deal with.

As these blades are flexible, I have noticed strange vibrations in turbulence and with strong tailwinds on the ground. Cessna Caravan pilots report the same things with the composite blades. The IVO will have a sweet spot with engine rpm and airspeed. With too much pitch, they will start to cavitate and set up a growl. It's telling you to go finer.

It will be interesting to see if you'r will absorb your hp at higher altitudes.

Also to note, I use an ammeter to judge prop pitch in my RV. This is the way to go if you don't use IVO's CS box.

[Nathan Gifford]

What happens on the IVO if the breaker trips? Does it hold the last pitch setting?

[rv6ejguy]

Yes, with no power, pitch freezes there. You can just reset the breaker. I recommend that you don't pop the breaker which takes over 20 amps. One friend broke a trunion on his running hard to the pitch stops. The last few degrees really pulls a lot more amps and the motor sounds strained. With the ammeter, I never go past 15 amps and never pop the breaker.

Without the ammeter or the C/S box, you have little idea of where the pitch is. The ammeter allows you to see neutral pitch (lowest amp draw) and as you run in the coarse or fine direction, amps keep building. I run 3 amps in the fine direction for takeoff and circuit work. About neutral for climb and then coarsen for cruise once manifold pressure is set to get the desired rpm. As you climb at higher altitudes, I have to touch the switch every 2000 feet or so to keep my rpms where I want them due to the lower air density.

Coming back in to land, my pattern check brings pitch back to 3 amps on the fine side.

It should be noted that if the prop goes u/s for some reason in cruise set very coarse, that is what you are stuck with for landing. Make sure you don't have to go around as it could be kinda iffy depending on power available. Turbos help here.

[John Slade]

I run 3 amps in the fine direction for

Sh... I have to fine room for another gauge How is the ammeter wired? In series with the power to the motor?

set very coarse, that is what you are stuck with for landing

Just like old times with the Performance Prop.

[karoliina]

That is great news. That is actually excatly we talked about today with our forthcoming build supervisor (he is going to look after us that we don't do dangerous mistakes while building, no worries, he is a good and reasonable guy). He said that it would be good to hear some results from IVO users before going for it. I am not sure if I really wanted to pay 8000 for propeller (MT) unless there is no other choice, so for that IVO really is truly intriguing. We would like to hear some flight performance data, e.g. speed, climb rate, takeoff distance, landing distance etc. compared to a fixed pitch prop. It is quite sure that we want to equip the plane with a CS prop and it is later to be determined what, but any detailed feedback of any of those would be greatly appreciated.

[Dale_R]

Originally Posted by John Slade

Sh... I have to fine room for another gauge How is the ammeter wired? In series with the power to the motor?

It would have to be. You'd only want to measure the current going through the prop motor. The actual ammeter could be a "sampling" type that routes to the ammeter only a portion of the current going through a series shunt in the line to the motor. That would save some fairly large gauge wire going all the way from the panel to the prop.


Regards,
Dale R. ......................|......(___.......|
COZY MkIV-R13B #1254 .........|----==(___)==----|
Ch's 4, 5, 9, 16 & 23 in progress ..o/ | \o
http://www.canardzone.com/forum/showthread.php?t=1388

[argoldman]

Originally Posted by John Slade

Sh... I have to fine room for another gauge How is the ammeter wired? In series with the power to the motor?

Just like old times with the Performance Prop.

It would seem like some enterprising EE or amature could design a simple circuit that would indicate the relative pitch of the prop. The major obsticle to overcome is the fact that whether flat pitch of high pitch, similar loads on the pitch motor would give similar readings. I'm sure that some sort of logic could be built to overcome this and give you a graphic indication of pitch.

As part of this circuitry, it would be nice to enable you to select T.O. Climb and cruise settings with the flip (turn of a switch). This circuitry would also allow you to fine select by hand...

I'm not crazy about the fact that the pitch motor doesn't turn itself off at the extremes of travel, and necessitates you looking at an ammeter to ascertin this. Under normal circumstances, Big deal. But add distractions, emergencies etc. That may be a different story. The shutoff could be designed into this.

Does the C/S attachment make this situation moot, and what has been the reaction of the IVO flying public to this piece of hardware???

[John Slade]

Does the C/S attachment make this situation moot

Probably. I've heard two stories so far. One "distant" third hand where the user had problems with it and one local, in my hangar where the user says it works fine up to a certain rpm but doesnt go higher. He need to adjust it, he says. By the way, he's flown without the CS unit for many (200+?) hours and didnt mention a problem knowing where the pitch is set. I'll ask him about it.

One problem with the CS unit is that it has a sensor that mounts next to the brushes and "looks" at the prop going by - therefore you cant fir a spinner backplate in the way.

[rv6ejguy]

My system is all wired with 16 gauge. The ammeter is placed in series between the buss fuse and the IVO CB, then the switch, then the prop motor. The ammeter reads in the same direction irregardless of motor direction. I use a 0-20 amp panel meter- really industrial looking and bone ugly!

The MT is certainly nicer and probably performs better in cruise but it is also $6000 more.

With an atmo engine, not as big a deal to judge prop pitch as with a turbo engine, just look at the tach, not enough rpm, go finer.
Really I don't spend much time playing with it.

I have several friends using the IVO all with pretty good success and all have had excellent service. None on pusher apps so far though so John's experiences will be interesting. The flexibility of the blades passing through the wing wakes could be an issue although many IVOs are used on smaller pusher configurations with no such issues. My only negative is its inability to absorb high cruise power above 12,000 feet in the thin air. Had I chosen a different redrive ratio, this would be a non-issue as the prop would be turning faster. Live and learn. With John's higher cruise rpm on the rotary, he may be ok even with the smaller diameter. We shall see.