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#1
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Ivo Prop on O-320
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 |
#2
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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 link.net... 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. ......... |
#3
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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 link.net... 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 |
#4
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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... |
#5
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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 |
#6
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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 link.net... 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.. ............. |
#8
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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 news 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 |
#9
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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. |
#10
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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 |
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