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Question
Please a little help with my set-up
I'm dumb to electrics.... ok now thats out the way, i bought a rim fire outrunner 28-22-1300kv I also have a APC slow fly prop 9x3.8 with a great plane 12amp esc silver series speed controller. now im running a 11.1 volt 640mah lipo packs on a 10 oz epp plane. It flies good for about 4 minutes. But it does not have the rocket power I want. What motor should i get or what else. I dont want to get a different ESC though. Bigger lipos??? Any suggestions???
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I am by NO means an expert on this sorta thing.. just learning myself. But, you could try a different prop. not all props perform the same. Look for one with a more exaggerated pitch. It will move more air and thus make your plane fly faster. Seems to be the most cost effective means of improving performance.
Good luck, ~Erik Quote:
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I think that is far too big a prop for that motor.. if you look at Motocalc you can see how slow the RPMs are and how miserable the efficiency. Try a smaller, higher pitched prop.
Motor: Great Planes Rimfire 28-22-1380 (#4505); 1380rpm/V; 0.4A no-load; 0.3067 Ohms. Battery: Thunder Power TP730 (G4 ProLite 20C) (20C); 3 cells; 730mAh @ 3.7V; 0.081 Ohms/cell. Speed Control: Castle Creations Phoenix 25; 0.0065 Ohms; High rate. Drive System: 9x3.8 (Pconst=1.69; Tconst=1) direct drive. Airframe: Anything you want. Motor Amps = 8.4 Motor Volts = 9.0 Input (W) = 75.9 Loss (W) = 41.0 MGbOut (W) = 34.9 MotGb Ef(%) = 45.9 Shaft Ef(%) = 37.2 Prop RPM = 5986 (only 48% of Kv x V!) Thrust (oz) = 13.5 PSpd (mph) = 21.5 This is still not great, but a heck of a lot better: 53% efficiency and more than twice the pitch speed. Motor: Great Planes Rimfire 28-22-1380 (#4505); 1380rpm/V; 0.4A no-load; 0.3067 Ohms. Battery: Thunder Power TP730 (G4 ProLite 20C) (20C); 3 cells; 730mAh @ 3.7V; 0.081 Ohms/cell. Speed Control: Castle Creations Phoenix 25; 0.0065 Ohms; High rate. Drive System: Direct; 7x6 (Pconst=1.17; Tconst=1) direct drive. Airframe: Anything you want. Motor Amps = 7.1 Motor Volts = 9.3 Input (W) = 66.3 Loss (W) = 24.2 MGbOut (W) = 42.1 MotGb Ef(%) = 63.4 Shaft Ef(%) = 53.3 Prop RPM = 8651 (67% of Kv x V) Thrust (oz) = 9.0 PSpd (mph) = 49.2 |
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Last edited by Dr Kiwi; May 18, 2010 at 01:25 PM.
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Quote:
I'd also recommend going as high as possible with the "C" rating, because if you are basically draining the current one in 4 minutes, that's about a 15C discharge (~10A more or less). A bigger pack will anyway provide more current simply because its bigger, but if it is a 20C or larger, it can't hurt. But also (again) pay attention to weight, because a larger C usually weighs more than a smaller C, assuming both are the same capacity (mAHr). I haven't looked to see whether you are running your motor in an efficient range or not. So there could be some improvement there, but not as much as a bigger battery I think. |
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