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#1
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IVO pireps wanted.. high performance/high speed...
Ok.. question for those out there with some hands on experience with the
IVO Magnum series electric inflight-adjustable props. What has been your experience with this product.. Any pro's or cons based on your experience... Has the product met your expectations... Where I am coming from: working with a builder making a Mazda powered Velocity. We have kicked around the idea of a controllable pitch/quasi-constant speed propeller. I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a flying RV-4 with a Mazda rotary. His experience was that he had a loss of top end speed with the IVO product compared to a fixed pitch prop... It was enough of a difference that he has chosen not to research using the product any further in his later applications. I am not sure if this is because the blades are unable to "twist" enough or what. This is somewhat disheartening, because the IVO seemed like a cost effective possibility. The electric MT is out of my price range, and I cant seem to find any other electric actuated in-flight adjustable props that can handle 200-250 hp. I am curious if others have experienced similar outcomes using this propeller in applications running in the 170-200 kt/200-250 hp range Dave |
#2
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Dave and everyone interested,
First I have to say that I have no experience what so ever with the IVO, (but other props.) I got this info from a builder in US on the IVO 3 blade, 66" dia prop, electric adjustable pitch from 45" to 105" Max blade width: 5.25" At 25" radius: 0.7" thickness, 4.75" width. Analyze: The blade thickness of almost 15% at the 0,75 radius is maybe one reason for the reported result of the IVO to be less then others tested. "Normal" or often used on wood props is 13% thickness; normal range is from 11% to 14% for wood props. Metal props from 8,5% to 10% Max blade width of 16% of the radius (33") is normal (15%-16.7%) The blade width of 14,4% at the 0,75% radii is a bit wider then normal (12-13%) The adjustable pitch range from 45" to 105" (16deg to 34deg at 0,75% radii) is good. But it is only the outer parts of the blade that is changed in pitch not the inner. What the pitch is here I don't know. What effect does this have? If we think of an adjustable prop (70" dia) that have CONSTANT PITCH along the blade when the .75% radii is sat to 15deg. = 44" pitch At the .45% radii the angle is 24deg. (At the tip it is 11.3deg) IF we now increase the angle of the whole blade 15deg to 30deg at the .75% radii we get 95" pitch. At the .45% radii =39deg = 80" pitch (At the tip 26,3deg = 108,7") This means that the inner parts of the propeller blade will not increase as much as the outer parts in pitch, but this is not all bad, by a number of reasons. But if as in the case of IVO the inner part is not changed in pitch, it will be far from optimum in some stage of the speed range. Especially if the speed range is large as in high performance aircraft. If the inner part is coarse pitch and fixed it will stall during take off and climb. If the inner part is fine pitched and fixed it will make negative thrust at high speed. So, The thicker and wider outer 25% of the blade aren't very effective, the inner fixed pitch isn't good at all speeds! A propeller that have blades that is thicker and wider then normal needs to compensate this by reducing something else, like diameter and or blade area to handle the same power, the pitch should be sat so the blade work at its best L/D for efficiency, so if we reduce the pitch (angle of attack) to compensate for an propeller that have to much drag it is not so good, it is better to reduce the diameter in that case. A thinner propeller is better (obvious) that will give us a larger diameter that moves more air, or if the diameter is limited by tip-speed or structural reasons, more blade area (more blades) For now, Jan Carlsson www.jcpropellerdesign.com "Dave S" skrev i meddelandet hlink.net... Ok.. question for those out there with some hands on experience with the IVO Magnum series electric inflight-adjustable props. What has been your experience with this product.. Any pro's or cons based on your experience... Has the product met your expectations... Where I am coming from: working with a builder making a Mazda powered Velocity. We have kicked around the idea of a controllable pitch/quasi-constant speed propeller. I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a flying RV-4 with a Mazda rotary. His experience was that he had a loss of top end speed with the IVO product compared to a fixed pitch prop... It was enough of a difference that he has chosen not to research using the product any further in his later applications. I am not sure if this is because the blades are unable to "twist" enough or what. This is somewhat disheartening, because the IVO seemed like a cost effective possibility. The electric MT is out of my price range, and I cant seem to find any other electric actuated in-flight adjustable props that can handle 200-250 hp. I am curious if others have experienced similar outcomes using this propeller in applications running in the 170-200 kt/200-250 hp range Dave |
#3
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Might try NSI
http://www.nsiaero.com/nsiaero2/3.0/....7/3.3.1.7.htm Dave S wrote in message thlink.net... Ok.. question for those out there with some hands on experience with the IVO Magnum series electric inflight-adjustable props. What has been your experience with this product.. Any pro's or cons based on your experience... Has the product met your expectations... Where I am coming from: working with a builder making a Mazda powered Velocity. We have kicked around the idea of a controllable pitch/quasi-constant speed propeller. I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a flying RV-4 with a Mazda rotary. His experience was that he had a loss of top end speed with the IVO product compared to a fixed pitch prop... It was enough of a difference that he has chosen not to research using the product any further in his later applications. I am not sure if this is because the blades are unable to "twist" enough or what. This is somewhat disheartening, because the IVO seemed like a cost effective possibility. The electric MT is out of my price range, and I cant seem to find any other electric actuated in-flight adjustable props that can handle 200-250 hp. I am curious if others have experienced similar outcomes using this propeller in applications running in the 170-200 kt/200-250 hp range Dave |
#5
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And how many of those make electric controllable props that can handle
200-250 hp? Jan Carlsson wrote: Some Prop makers, http://pro.wanadoo.fr/arplast/ http://www.aviapropeller.com/ http://www.bolly.com.au/ http://climbandcruise.com/ http://www.vzlu.cz/vrtule/basis.htm http://www.gt-propellers.com/ http://www.hoffmann-prop.com/ http://www.mt-propeller.com/en/index.htm http://www.sensenichprop.com/ http://www.nsiaero.com/index_yes.html http://www.powerfin.com/ http://www.princeaircraft.com/ http://home.t-online.de/home/3200301.../rospeller.htm http://whirlwindpropellers.com/ http://www.woodcomp.cz/ http://www.airmasterpropellers.com/ http://www.greatplainsas.com/ed.html http://www.jcpropellerdesign.com/ Jan Carlsson |
#6
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You have to make the research, don't you? Just ask them what they can do for
you, I am sure they want to show their best products. I for sure would not put my money on an untested design just because it is cheep, better to be able to come home for dinner. Jan Carlsson "Dave S" skrev i meddelandet link.net... And how many of those make electric controllable props that can handle 200-250 hp? Jan Carlsson wrote: Some Prop makers, http://pro.wanadoo.fr/arplast/ http://www.aviapropeller.com/ http://www.bolly.com.au/ http://climbandcruise.com/ http://www.vzlu.cz/vrtule/basis.htm http://www.gt-propellers.com/ http://www.hoffmann-prop.com/ http://www.mt-propeller.com/en/index.htm http://www.sensenichprop.com/ http://www.nsiaero.com/index_yes.html http://www.powerfin.com/ http://www.princeaircraft.com/ http://home.t-online.de/home/3200301.../rospeller.htm http://whirlwindpropellers.com/ http://www.woodcomp.cz/ http://www.airmasterpropellers.com/ http://www.greatplainsas.com/ed.html http://www.jcpropellerdesign.com/ Jan Carlsson |
#7
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thanks Ken
Ken Sandyeggo wrote: Might try NSI http://www.nsiaero.com/nsiaero2/3.0/....7/3.3.1.7.htm Dave S wrote in message thlink.net... Ok.. question for those out there with some hands on experience with the IVO Magnum series electric inflight-adjustable props. What has been your experience with this product.. Any pro's or cons based on your experience... Has the product met your expectations... Where I am coming from: working with a builder making a Mazda powered Velocity. We have kicked around the idea of a controllable pitch/quasi-constant speed propeller. I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a flying RV-4 with a Mazda rotary. His experience was that he had a loss of top end speed with the IVO product compared to a fixed pitch prop... It was enough of a difference that he has chosen not to research using the product any further in his later applications. I am not sure if this is because the blades are unable to "twist" enough or what. This is somewhat disheartening, because the IVO seemed like a cost effective possibility. The electric MT is out of my price range, and I cant seem to find any other electric actuated in-flight adjustable props that can handle 200-250 hp. I am curious if others have experienced similar outcomes using this propeller in applications running in the 170-200 kt/200-250 hp range Dave |
#8
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Dave S wrote in message thlink.net...
Ok.. question for those out there with some hands on experience with the IVO Magnum series electric inflight-adjustable props. Dave, I have an IVO prop with a 220hp Franklin. But am just starting testing phase and have not tested the high end. But you should be aware that IVO makes two pitch ranges for their magnum props: [30"- 90"] and [45" to 105"]. I have the higher pitch range prop whose average pitch is greater than the pitch recommended for my aircraft with fixed pitch props and should be expected to do better at higher end. Somebody getting the lower pitch range can expect good takeoff performance but probably average cruise. I don't think that IVO is a perfect substitute for the expensive constant speed props, but is a lot better than a fixed pitch and may be satisfactory for your needs if you select the right pitch range - and is a very decent price to boot. ----------------------------------------- Paul Lee, SQ2000 canard: www.abri.com/sq2000 |
#9
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Dave S wrote in message thlink.net...
Ok.. question for those out there with some hands on experience with the IVO Magnum series electric inflight-adjustable props. What has been your experience with this product.. Any pro's or cons based on your experience... Has the product met your expectations... Where I am coming from: working with a builder making a Mazda powered Velocity. We have kicked around the idea of a controllable pitch/quasi-constant speed propeller. I have corresponded with Tracy Crook (www.rotaryaviation.com) who has a flying RV-4 with a Mazda rotary. His experience was that he had a loss of top end speed with the IVO product compared to a fixed pitch prop... It was enough of a difference that he has chosen not to research using the product any further in his later applications. I am not sure if this is because the blades are unable to "twist" enough or what. This is somewhat disheartening, because the IVO seemed like a cost effective possibility. The electric MT is out of my price range, and I cant seem to find any other electric actuated in-flight adjustable props that can handle 200-250 hp. I am curious if others have experienced similar outcomes using this propeller in applications running in the 170-200 kt/200-250 hp range Dave This came over the Velocity mailing list -- ============================================= Carbureted/magneto Franklin, electric IVO. Nothing special. I wanted to get more data, but clouds below 5000 was a problem. The best speed we saw was at 7500 feet altitude, full throttle, the first altitude where we actually achieved full open throttle. 182KTS TAS, 2520 RPM, 23.1 inches MAP, 12.4GPH. I was more impressed however, with putting more pitch in the prop. At this same altitude, I took data at progressively slower RPM's (same throttle). 174KTS TAS, 2300 RPM, 23.5 inches MAP, 10.8GPH. We stabilized a climb through 8000 feet at 120 kts indicated, 144kts true at 700FPM rate. Levelling at 9000, going through various MAP/RPM settings, I was impressed by the economies achieved: KTS TAS RPM MAP GPH 1 147 2370 19.7 9.5 2 180 2520 21.8 12 3 175 2400 21.9 11.2 4 162 2200 22.1 9.9 At line 1, this is at 120 kts indicated (where I started data collection), 147TAS. This is partial throttle operation. Not bad for 9.5GPH, but look at line 4, full throttle, slower RPM. Faster speed, with just a little more fuel flow. I find it surprising that pumping losses account for a 5% penalty between lines 1 and 4. That's 15.5 nautical miles/gal and 16.4 nautical miles/gal for lines 1 and 4. The most economical was at 7500 feet: 174KTS TAS 2300RPM 23.5MAP 10.8GPH, making that 16.1 nm/gallon. I don't know why I didn't get at data point at 2200RPM. It would have been better yet. What this says to me is pick a MAP/RPM combo that is the economy setting you want, then fly the altitude that will give you that power setting at WOT. It was hot too. 95F on the ground, adding about 3000' for density altitude. |
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