View Full Version : Propeller adapters & IVO Props?
06-06-2007, 07:24 PM
IVO Medium Prop bolt patterns & adapter plates
Examples for IVO adjustable Medium and Magnum on a RAF/AAI.
For a 2.2L the suggested IVO is the Medium. It has the correct bolt pattern for a Sub, but requires nearly 7 inch bold. 2 1/2" is solid extra spacers other than the prop hardware. There should be an adapter plate that could use two sets of bolt like the Magnum. But I can't find a solution.
For a 2.5L the suggested IVO is the Magnum. It has a larger bolt pattern on the IVO and an adapter for the Sub. But not enough spacer to clear the tail brace. I believe a 1.5" spacer is need to give the 5" clearance required by the manufacture.
Am I missing something? Or is there someplace that has all kinds of cool adapters and spacers?
Example of guys building their own.
06-14-2007, 08:42 AM
Requesting suggestions on Medium variable pitch IVO prop attachment.
I currently have a modified RAF with a 2.2L and an IVO variable pitch IVO prop. When I took the prop apart, I could see where one washer had movement on the inside of the sproket. A torque wrench would have had to turn the bolt all the way through the spacers to the nut on the inside of the sprocket.
In the pic you can see the long bolts AN6-76A bolts holding the IVO prop, bushing plates, 2 spacer plates, and the RAF sprocket. I turn the bolts around so the nuts are to the outside. This is mostly for torque reasons. I don't like the idea of such long bolts.
There are also holes between the sprocket and 1st adapter plate that could take AN5-32A bolts (6). A nut would fit on these bolts, but the clearance is not enought for a washer without grinding the washer. Note also the nuts are close to where the brushes ride.
1. Would adding the 6 bolts help to firm up the whole set of spacers?
2. Should I consider milling the spacer so a washer and nut can be turned with a wrench? (You can see the one bolt without a washer in the first pic.)
3. Is there a better solution?
If you purchase the Magnum IVO like Stans, the IVO bolt pattern does not match the subs and thus the very long bolts are not required.
06-14-2007, 07:39 PM
Larry: I took some more pics of my Ivo-magnum prop hub. Maybe these will help.
The first pictures shows the 1.25 inch spacer that bolts to the lower drive pulley with 6 allen head bolts. Then there is an insulating plastic disc that is 1/16 inch thick. This is followed by the first 1/4 inch thick commutator disc...followed by another 1/16 inch insulating disc....then the second 1/4 inch commutator disc....followed by a third 1/16 inch insulating disc.
This then has the last 1/2 inch thick crush plate that goes next to the prop.
The last picture shows the brushes from the brush box that is mounted to my upper crankshaft bearing plate. You can clearly see the brushes tracking on the two 1/4 inch commutator rings. These feed the power to the rear pitch change motor. The switch just changes the polarity of the brushes from + to -.
06-14-2007, 09:12 PM
I don't want to hijack your thread. But after spending the last 3 hours trying to put some order the the prints of my SparrowHawk build, which haven't seen the light of day for 2 or 3 years it's nice to know your out there in Cyber-land ready to help your fellow Gyro pilots with their questions. Your The Man.
06-15-2007, 07:10 AM
I'm really intrigued by that IVOPROP. What model did you use and what did it cost?
06-15-2007, 09:37 AM
I have the 68" (now 67") medium variable pitch IVO on a 2.2L that Ken J SanDiego installed, Stan has the Magnum on his 2.5L. This is the reason for the difference in bolt patterns.
Ron Menzie just purchased the ground adjustable magnum IVO for his 2.5L. He had a custom spacer built.
They are based on HP, but IVO has a large range in the HP that each prop will fit.
IVO says you need 5" clearance forward and aft due to the flex in the prop. I believe the prop striking the support brace in the pic below occured last year when we chalked the tires and were checking the engine at higher rpms when we were looking for a better idle mixture setting. If I remember correctly I have about 3.5" clearance. But most people are smart enough to not chalk the wheels and pitch in the prop.
Two of the three blades do have a roughed up tip from the strike. I cut 1/2" off each blade based on instruction from IVO. IVO molds the props all the same and just cuts to lenght per customer's request in even inches.
Below are some pics we took in May at Ron's in Searcy AR.
1. Comparison between Ron's tail support mod on a RAF vs mine unmodified.
2. Prop strike on tail support..Yes, I now believe the 5 inches.
3. Measurement of my unmodified tail support from prop to brace.
4. Ron's measurement of modified tail support from warp drive prop to brace.
5. A Sparrowhawks measurement tail support from prop to brace.
I believe the IVO is a great blade, but I would not put it on an unmodified non-CLT RAF. Stan with his cam grind and 2.5L says he can start to unload the rotors on take off. He has that much power. I'll bet it would push a standard RAF right over frontwards.
06-15-2007, 06:34 PM
Bob: I have the Magnum model...it was $2340.00
Bob....I want to invite you to St. Joseph tomorrow,,,about 25 miles south of me. I am going to an ultralight fly-in to a nice cookout. We eat at one...if you want to come on down....would love to have you.
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