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Thread: Ivoprop - is anyone else frustrated with them?

  1. #1
    Kiwi ZK-CKE's Avatar
    Join Date
    Apr 2012
    Cambridge, New Zealand

    Ivoprop - is anyone else frustrated with them?

    My Adventurer is equipped with a 3 blade Ivoprop Medium in flight adjustable prop, and the thing is becoming the bane of my flying existence. I have had dramas with it ever since I got it, and I would be interested to know if anyone else has had these issues.

    Firstly, after I brought the prop I discovered that there is a requirement to re-torque the mount bolts every 10 hours, and inspect movement strips before very flight. Not a biggie but additional maintenance that I hadnt considered initially. Fortunately I have a Maintenance approval for this aircraft, otherwise NZ regs say a LAME has to do the retorquing - which would be pretty expensive after a while.
    I'm also really disappointed with the design philosophy, which is frankly agricultural. You know when the prop reaches its travel stops because the circuit breaker pops. You then wait a few seconds, reset it and carry on - standard operating practice! No limit switches or anything like that... The bare ends of the wires from the pitch change motor just slip in between nylon washers as you assemble the prop - no terminations etc. If you put the blades on 30 degrees out of index the wires get pinched by the pitch change cams - no warnings or notes to this effect in any of the brief assembly documentation. Whilst the aircraft was sitting for several months the factory grease in the pitch change motor's planetary gearbox turned into something like hardened chewing gum - I couldnt get the RPM I required as the CB kept popping, indicating full travel, but in reality popping because the motor wouldnt move! I had to totally pull the gearbox apart and regrease with Aviation grade grease. The requirement for re-torquing probably comes from the use of soft nylon as insulating spacers in the hub assembly - over time it compresses which changes the bolt torque loading - at the same time the material gets squeezed out between the contact rings, and the odd frayed end will destroy the contact blocks... Its happened several times to me.
    I've done several 100hr inspections now, which generally dont require anything much on the prop other than the normal re-torque and cleaning bugs off the blades, but each time now I have found the pitch change not working when I do the post inspection runs. I'll have to pull the prop apart this weekend to find the latest issue... I'm getting real good at that now!
    If I had known the Ivoprop was so troublesome I would have tried an alternative, Although there arent many suitable options in this instance. I really need the variable pitch to get decent takeoff performance without overspeeding the geared engine in the cruise (I'm running a 140hp geared Subaru) and the locally built Airmaster is only rated for 100hp max. any changes now would mean huge changes to the cowling and possibly gearbox config, so I'm stuck with it for now. To be fair, when it is working it is a great unit and certainly behaves well, I just don't know when it will decide to misbehave again. Is it me, or are these props normally this crap?
    "If it was supposed to be easy, everybody would be doing it...."

    Proud designer / builder of Avian Adventurer ZK-CKE.

  2. #2
    Mike Switzer's Avatar
    Join Date
    Jul 2011
    Central Illinois
    Hmm... Thanks for posting, I had been considering that one as I will need a prop for approx 300hp. Makes a good old fixed pitch prop look more attractive.

  3. #3

    Join Date
    Sep 2012


    I am not a user nor will I ever be. Ivoprops have had trouble with some designs since day one. The only suggestion I can offer for the electrical controllable pitch model that is giving trouble would be to go over every connection and use aircraft grade wires and methods for all connections.Use design torque settings for all fasteners. Find a suitable summer and different winter grease. The prop should work as advertised or discontinue the flight and its use since an unserviceable prop can be a death trap.

    There are many props out there that can be used safely with a Subaru conversion. I have a number of hours flying a VP 2 equipped with a 3 blade Warp drive and the plane performs very well with the engine delivering about 90HP via the ground adjustable prop. Again, the prop must be adjusted and torqued precisely as the factory recommends. During flight it is a fixed pitch prop of course but it can be ground adjusted to suit the engine performance and whether it is desired to have short field or cruise performance.

    Joe Scoles

  4. #4
    I have a 3-blade IVO prop on a 503 Thunder Gull, and am very happy with it. All the other Thunder Gull and Titan Tornado users who have commented on the prop on Yahoo Groups say the same thing. A friend of mine has a Magnum version on a V-8 Tailwind, and it has worked fine for years. I do not have the manual handy right now, but as I recall you do not need to re-torque every 10 hours. You need to re-torque the hub bolts frequently for the first 10 hours after they have been apart.

    The original version of the Ultralight in-flight adjustable prop had problems with motors burning out, but the new version which has been out a number of years has an improved motor and gear system, and has a good reliability record. The brushes do tend to wear fairly quickly if you do not have the model with the shaft running through the gearbox. On this unit, the brushes run on a much smaller shaft (an inch or less in diameter), instead of running on the prop spacer plates (roughly the same OD as the hub.)

    I clean and grease the cams and threaded pitch-change shaft at each annual. You only need to remove one blade to do this. Then, of course, you do have to re-torque. Re-torquing is very easy: Just remove the spinner, and apply the torque wrench. It only takes a few minutes. No safety wire to fool with.

    I have never had my breaker pop. I either hit it in short bursts, or if I want to go full flat pitch, I hold the switch until the RPM quits changing, and release it. If you are popping the breaker, you must be holding the switch down for a few seconds after it reaches the stop. You must be sure and follow the directions, and NOT shorten the long wire provided between the power connection and the switch/breaker. The long length of wire acts as a low value resistor, and allows the motor to stall briefly without tripping the breaker. It limits the surge current when the motor first stalls. This is strongly emphasized in the manual.

    I assume that your Subaru setup is similar to my friend's V-8 setup, with the IVO Magnum. As I said, his had never had a problem. You do need to operate it differently than other controllable props, and the one drawback I dislike is, you do not have a visual indication of where the pitch is set. You really have to go by RPM changes.

    I have always found the people at IVO prop to be very helpful responsive, and honest. If you have questions or concerns, I would encourage you to call them.

    I am not trying to talk you into or out of anything. If you can't get to a point where you like and trust it, you should probably try to find another alternative, or go with ground-adjustable.


  5. #5

    Join Date
    Sep 2012
    Overland Park, KS USA

    IVO help

    I am useing an IVO 68" Magnum on a Velocity with a Franklin 6A350. Keeping all the components alligned the same way each time you take the prop apart and re-assemble it is important so that the crush plate knureled surface will seat properly with the blade. I have numbered the blades and marked the hub as appropreate to make this easy. The circuit breaker as a limit switch is a bad idea in my oppinion. I designed and built a current limiter that opens the circuit at 25 amps and lights a light. It resets instantly when you release the switch. Email me at if you would like the circuit.

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