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Old 06-25-2019, 01:48 PM
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stevenramos1
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I have a 1045 propeler and my model weights around 1kg, how Many kvs would you recomend for this ? Please
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Old 07-10-2019, 04:51 AM
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Originally Posted by stevenramos1 View Post
I have a 1045 propeler and my model weights around 1kg, how Many kvs would you recomend for this ? Please
Somewhere around 1500kv for 3-4s battery?
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Old 07-12-2019, 03:37 PM
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Higher Kv value will pull more current. Lower Kv will pull less. So that prop can actually be used on a wide range of motor Kv values. A little low Kv value Park 450 with a Kv of 980 for example will only "pull" around 140 watts from a 3S pack and the motor will run fine. On the other hand a bigger motor with a peak rating of up around 350 watts and a Kv of up around 1500 to 1700 might cause the motor to pull the whole 350 watts. All on the same prop.

Bottom line is that you don't generall fit the prop to the model and then go shopping for a motor. You pick a motor that will tolerate the sort of power you want for your model and based on the information provided by the motor maker you pick the prop. Or to some extent you can look at similar power and Kv motors that do have prop vs power information and figure on them being roughly the same.

Kv isn't a power rating. It's an abbreviation for how many revs per volt of battery power the motor will turn with no load.

Your 1Kg flying wing will need power (watts) to fly it in the way you desire. For gentle mostly level flying around with moderate climb ability you want to go with a motor that will provide around 140 watts/Kg. So a motor that can safely run at 140 watts without overheating. To be sure you get that I'd suggest a motor rated for more like 160 to 180 watts max power. That way it's loafing along. If you are intent on using the 1045 prop then a suitable motor for such flying would actually be that E-Flite Park 450 or equivalent in some other brand running on a 3S pack.

If you want more sporty flying ability and a strong near vertical climb aim at more like around 220 watts/Kg. Again to make it so the motor isn't stressed and overheating go for a motor that lists more like a 250W to 280W max power. And perhaps in this case go with a lower Kv and run it on a 4S pack. Or opt for around a 1500 for Kv value and run on 3S.

At any rate these values are not chiseled in stone. Buy yourself a wattmeter and use it when setting up new motors and trying to pick a prop that works for you.
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