IVO prop

Rick E

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Just wondering if anyone has ever done a comparison thrust test with IVO inflight adjustable props and other fixed pitch props?
I am finding my IVO prop not quite as good as the old fixed pitch for getting airborne.
Once airborne and pitch set though it goes extremely well.
 

Uncle Willie

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Consider that the climb rate is a factor of Power.
RPM is an indication of Power but is not the same thing. POWER is King!
The IVO Prop allows you to adjust the load on the engine to achieve maximum Power only if set properly.

Assuming that your engine makes maximum power at 5800 RPM at Wide Open Throttle (WOT), Any RPM less than 5800 and/or any throttle setting less than WOT means that you are not producing maximum Power.

If you typically set the prop to Full FINE before taking off, you will find the prop trying to over-rev in the climb.
If you reduce the throttle, you reduce Power.
5800 rpm means little unless the throttle is Wide Open at the same time.
The correct response would be to increase pitch.
Now, understanding that adjust the pitch during the takeoff roll is too much of a work load to add to all the other activities that demand your attention, it is understandable that pulling off a little throttle is a quicker/simpler solution.

The trick is to set the proper pitch before the takeoff roll.

On your next flight, establish a Vy climb at WOT and adjust the prop pitch to achieve the recommended RPM for your specific engine.
Now, without changing the Pitch, Land the plane.
With the plane stopped and the brakes set, throttle up to WOT and record what the RPM is. This is your Static RPM Target.

The next time you go flying, before taking the runway, set WOT and adjust the pitch to achieve the Static RMP that you now know will produce maximum power in the climb.
It might be 400-600 rpm low while stopped on the ground but will increase to the ideal rpm once you get moving.

Food for thought:
A 500lb plane, climbing at 1000 ft/min, uses 500,000 lb·ft/min = ~15 HP for the climb.
All the remaining engine power is being used just to maintain level flight.
If you were to lose just 10 HP because of a misadjusted Prop, you will lose 2/3rds of your climb rate. 1000 ft/min becomes 330 ft/min.
Lose just another 5 hp and you'll start to descend.

Most of the engine's power is used just to maintain level flight, therefore even a small change in power has a major effect on the climb.
 

All_In

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What great advice Willie!!!
 
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rcflier

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Yes, food for thought.

That's why I'm considering a ground ajustable IVO prop, 60" dia., 3 blades, for my Rotax SCSI 503.

So sooner or later, I'll be able to find the best thrust compromise for both takeoff and cruise.

Cheers
Erik
 
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bilguun

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IVO prop does not work for Cavalon . The prop motor is good. When I push on switch (fine - coarse) LED s blinking only 1 or 2 seconds then stopping not working .
I checked prop motor , Rocker switch and LEDs its ok good . please help me . how am i fixing ???
 

CLS447

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bilguun;n1126045 said:
IVO prop does not work for Cavalon . The prop motor is good. When I push on switch (fine - coarse) LED s blinking only 1 or 2 seconds then stopping not working .
I checked prop motor , Rocker switch and LEDs its ok good . please help me . how am i fixing ???
I never owned an in-flight adjustable , but I have 2 ground adjust IVOs.

So.....while sitting on the ground, you can run the prop through it's entire adjustment range with the switch ?

If so....It doesn't work properly while flying ?

I would think you have a contact problem with the electric "brushes" that feed power to the motor with the prop turning.

The weakest link !
 

Vance

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When I have something electrical that doesn’t work I take things out of the system until it does work.

If I am reading you post correctly is sounds like something in the wiring is not working correctly or you are tripping a circuit breaker.

Bypass all of that and go directly with power to the wires to the brushes and see if it works. If it does; work your way back through the system.

Please remember a propeller is always trying to kill you so use extreme caution abound a propeller.
 

ventana7

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Willie,

Great explanation-- thanks.

I realize I am using nowhere near my engine's full power

It also brings out why a constant speed prop might make more sense than an in-flight adjustable. More $$$ for sure but reading about the Airmaster with its governor you can twist a knob to set for T/O - 5800, climb 5500, cruise 75%, power, or an economy setting- takes all the guesswork out of the equation and all the knob twisting.

Rob
 
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