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Has anyone any info on lift performance between different diameter rotors on the same machine? Just interested if any back to back comparisons have been done and if there is a substantial improvement. Ken
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Ken, a few weeks ago I conducted a comparrison between 30' tapering, thining, and negative twisted Patroney blades, and 28' AK blades. This was at the same gross weight and only 1/2 an hour apart.The 30' blades were spinning at 325 rrpm and the engine 4600 rpm.The 28" blades were spinning at 360 rrpm and the engine 5000 rpm. The AK blades were more pitch stable than the Patroneys. That was the reason I actually conducted the comparison when I had a chance to fly the AK's.Aussie Paul.[
]www.firebirdgyros.com
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Ken, Rotary Forum had SportCopter/Dragon Wing Blade comparisons, good deal of feed back info. GyroRon was involved from memory. A search will get you more detailed info.Mitch.www.thebutterfly.info
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So Paul,Were the chordal areas of the two blades the same?How much difference would there be in the rotor volume?What would you put the increased pitch stability on the AK's down to - higher gyroscopic stability or the differences between the taper?Cheers,Nick.
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Thanks Paul and Greg. Nick, who really cares. kenThe reason I asked was I reduced my Larkins from 28 to 27ft. They still fly great although lift capacity has reduced substantially.28ft- ballast 72kg and 15lt fuel plus res. RTR speed 315rpm. Had to fly at 5300rpm to maintain hgt.27ft- ballast 58kg and 5lt fuel plus res. RTR speed 365rpm. Had to fly at 5300 rpm to maintain hgt.My strip is 1460ft and I couldn't get above 1760ft. I have ordered 29ft AK's and am hoping for a big improvement. Any thoughts?I also have my radiator close to the prop like Eric Hoskinsons and Ian Morcombes . Has anyone tried it in a flatter position like the yellowsingle seater in Pacific Flyer with the push bike wheels? I thought this may improve airflow to the Prop. Ken
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Ken,I do, because these things have a bearing on the outcome.Lift = density x area x velocity ^2 x coefficient of lift / 2Vary any of these items and you vary the lift, if Paul is saying he is using blades of a different plan form and lift coefficient but are a larger/same/smaller diameter then the difference cannot be put down to the change in diameter alone, if you want to ignore this, fine for you, but there are other people on this forum who may like to know, like myself, I appreciate you don't care about that.Cheers,Nick.
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Excuse my ignorance.......What are AK blades...????????RDC
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Russell,AK = Advanced Kinetics They are a brand of rotors built by Jeff Henley-Smith in Sydney.Solid 6061-T6 extrusion. No rivets or bonded sheet.L.Magner
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Nick, the Patroney blades are 9" chord at the root and 8" at the tip. The AK blades I am not sure of, but I think that they are 8 1/2". Jeff, help me out here before I make a fool of myself again. I don't want to catch up to Nick!!!!!!!!! LOLAussie Paul.www.firebirdgyros.com
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Marty,I apologise. You were right.Cheers,Nick.
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Paul you catch up i thought you were the leaderMark
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Mark, do you mean leader in the s**t or in the good stuff??? LOLAussie Paul. []
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