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Old Nov 01, 2012, 01:02 PM
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Can't you just take a bigger motor?!

Hi there,

I am planning on getting a Flamewheel F550 and I was wondering, what would happen, if I decided to take way bigger motors, than the once that come with the kit?! Including higher rated esc's of course?! Wouldn't I be able to increase the payload that way?! Has anyone tried it?!

thanks,

G
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Old Nov 01, 2012, 01:07 PM
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WiseDuck's Avatar
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Sure. But the increase in torque will twist the arms and that is not good. When you're at that point it's better to move on to a stiffer frame.
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Old Nov 01, 2012, 01:11 PM
Stop me before I build again!
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1. Bigger motors mean heaver = decreased flight time
2. Compensate with bigger battery = diminishing returns
3. Bigger motor with bigger props might bring more efficiency..... but you may need to step up to a larger frame ( see #1 )

Bigger also brings with it more likely to do real damage to itself or what it hits when it crashes.
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Old Nov 01, 2012, 01:44 PM
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United States, NY, Rochester
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Quote:
Originally Posted by WiseDuck View Post
Sure. But the increase in torque will twist the arms and that is not good. When you're at that point it's better to move on to a stiffer frame.
+1

I have explained this to so many customers I lost count.

I feel the stock DJI motors are perfect for the F series frames but the much bigger Avroto motors are too big and powerfull.
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Old Nov 16, 2012, 08:58 PM
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Originally Posted by WiseDuck View Post
Sure. But the increase in torque will twist the arms and that is not good. When you're at that point it's better to move on to a stiffer frame.
Makes sense...

thanks, G
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Old Nov 16, 2012, 09:02 PM
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Originally Posted by brontide View Post
1. Bigger motors mean heaver = decreased flight time
2. Compensate with bigger battery = diminishing returns
3. Bigger motor with bigger props might bring more efficiency..... but you may need to step up to a larger frame ( see #1 )

Bigger also brings with it more likely to do real damage to itself or what it hits when it crashes.
Interesting. Everything you said, does not apply to any of my helis or cars?!

thanks,
G
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Old Nov 16, 2012, 09:03 PM
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Originally Posted by Z06 Tony View Post
...but the much bigger Avroto motors are too big and powerfull.
... and that is a problem because...?!

thanks,

G
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Old Nov 17, 2012, 10:40 AM
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you are going to need larger props to use larger motors and a large payload...The size of the DJI 550 fram is limited so you will need a larger frame...You must match your thrust to the amount of payload you want to carry and that would mean taking the prop size thrust and multiply that by how many motors you are using...you must also match the motor to your prop size...
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Old Nov 18, 2012, 01:14 PM
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I have a DJI f550 with Avrotos and 12x3.8 apc props lifting an AG5650 and NEX5n. I have the arm extension kit on it to allow for the bigger props. It has no problem lifting the weight and I have had 8 min. hover time with 2ea. 4s 4000mah batteries running parallel. It weighs around 4kg AUW. For slow, smooth video it will work fine, but as I have heard, flying it too fast will most likely result in flexing of the arms and unpredictable behavior. Eventually I will probably get a stiffer bigger frame but for now it'll be gentle flying.
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Old Nov 18, 2012, 01:21 PM
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Kingdom of Sweden, Dalarna County, Sater
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Quote:
Originally Posted by Z06 Tony View Post
+1

I have explained this to so many customers I lost count.

I feel the stock DJI motors are perfect for the F series frames but the much bigger Avroto motors are too big and powerfull.
Indeed. I actually tested a bunch of fairly powerful (310w) NTM motors on my TBS frame. In a hover it works fine, but as soon as you punch it or go over 70% throttle or so it loses control completely. I think this is because of the not so stiff arms.

So yeah, stick to the DJI motors or something in the same ballpark. They're good frames for bashing and for getting a feel for hexacopters and whatnot, but I wouldn't use them for any serious work.
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Old Nov 18, 2012, 01:48 PM
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Originally Posted by skizziks View Post
you are going to need larger props to use larger motors and a large payload...The size of the DJI 550 fram is limited so you will need a larger frame...You must match your thrust to the amount of payload you want to carry and that would mean taking the prop size thrust and multiply that by how many motors you are using...you must also match the motor to your prop size...
That I understand. What limits the size of the props?! Could you theoretically make the props so big that they overlap, meaning one prop sits on a longer shaft?!

thanks,
G
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Old Nov 18, 2012, 01:49 PM
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Originally Posted by isaacintheclouds View Post
I have a DJI f550 with Avrotos and 12x3.8 apc props lifting an AG5650 and NEX5n. I have the arm extension kit on it to allow for the bigger props. It has no problem lifting the weight and I have had 8 min. hover time with 2ea. 4s 4000mah batteries running parallel. It weighs around 4kg AUW. For slow, smooth video it will work fine, but as I have heard, flying it too fast will most likely result in flexing of the arms and unpredictable behavior. Eventually I will probably get a stiffer bigger frame but for now it'll be gentle flying.
Good info, thanks. Not sure what a AG5650 is though?!

thanks,

G
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Old Nov 18, 2012, 01:51 PM
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Originally Posted by WiseDuck View Post
Indeed. I actually tested a bunch of fairly powerful (310w) NTM motors on my TBS frame. In a hover it works fine, but as soon as you punch it or go over 70% throttle or so it loses control completely. I think this is because of the not so stiff arms.

So yeah, stick to the DJI motors or something in the same ballpark. They're good frames for bashing and for getting a feel for hexacopters and whatnot, but I wouldn't use them for any serious work.
Interesting. So it is more the F550 that limits the use of more powerful motors, rather than the size of the F550 itself.

thanks,

G
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Old Nov 18, 2012, 01:55 PM
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Originally Posted by skizziks View Post
you are going to need larger props to use larger motors and a large payload...The size of the DJI 550 fram is limited so you will need a larger frame...You must match your thrust to the amount of payload you want to carry and that would mean taking the prop size thrust and multiply that by how many motors you are using...you must also match the motor to your prop size...
Actually, I do have one more question about what you said... Are you saying that if I use a bigger motor, I have to use bigger props?! I was under the impression that you can use the same props, but just amp up the motor?!

thanks,

G
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Old Nov 18, 2012, 02:06 PM
Stop me before I build again!
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Quote:
Originally Posted by neavissa View Post
Actually, I do have one more question about what you said... Are you saying that if I use a bigger motor, I have to use bigger props?! I was under the impression that you can use the same props, but just amp up the motor?!

thanks,

G
Do you mean up the voltage, since the only way to get more out of the motor is by putting bigger props or running them at higher voltage. Most motors have a watt limit after which they will start to overheat and eventually fail. Upping the voltage does make the motor less efficient in terms of grams/watt.

You don't just up the amps and upping the voltage can result in lower amp readings during non-peak operation.
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