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Old Oct 25, 2011, 05:25 AM
Bitten by the RC Bug....
vineet_p's Avatar
India, Andhra Pradesh, Hyderabad
Joined Aug 2011
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Help!
1600kv OR 2840kv??? which of these motors will give me more thrust? Pls help!

Hi. I am making a quadcopter. It will weigh around 700g. I am looking for an economical motor. I've found these :

http://www.hobbyking.com/hobbyking/s...dproduct=5353#
http://www.hobbyking.com/hobbyking/s...idProduct=5482

While one is 2840kv, the other is 1200kv. I will run on a 2S 5000mAh LiPo,
and 7x4 props
  1. Which motor will give more thrust?
  2. Can I use any of these motors with an 18A ESC?
  3. Any other reason(s) why I should prefer one over the other?

Thanks!

Vineet
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Old Oct 25, 2011, 06:27 AM
RTFM // copter damaged
warthox's Avatar
Joined Aug 2009
1,689 Posts
neither of them.

my suggestion for a 700gr quad would be:
motor with 900-1200kv / 35-50gr
prop 8-10"
battery 3s2000-3s3000.
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Old Oct 25, 2011, 08:10 AM
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I already told him Warthox but he isnt in a listening mood so dont bother bruv he'll just keep picking the same crap till another noob comes along and tells him what he wants to hear

just move on
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Old Oct 25, 2011, 09:53 AM
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Try messing around with ecalc Tried with the 2600 kv motor (an hyperion equivilent) and it should work. However, using a high KV motor would probably be less than ideal. It doesn't have enough torque, which is required for the very rapid rpm-changes, thus making it quite unstable (especially in wind).


Quote:
Originally Posted by vineet_p View Post
Hi. I am making a quadcopter. It will weigh around 700g. I am looking for an economical motor. I've found these :

http://www.hobbyking.com/hobbyking/s...dproduct=5353#
http://www.hobbyking.com/hobbyking/s...idProduct=5482

While one is 2840kv, the other is 1200kv. I will run on a 2S 5000mAh LiPo,
and 7x4 props
  1. Which motor will give more thrust?
  2. Can I use any of these motors with an 18A ESC?
  3. Any other reason(s) why I should prefer one over the other?

Thanks!

Vineet
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Old Oct 25, 2011, 10:35 PM
Bitten by the RC Bug....
vineet_p's Avatar
India, Andhra Pradesh, Hyderabad
Joined Aug 2011
789 Posts
Thanks

Quote:
Originally Posted by wizprod View Post
Try messing around with ecalc Tried with the 2600 kv motor (an hyperion equivilent) and it should work. However, using a high KV motor would probably be less than ideal. It doesn't have enough torque, which is required for the very rapid rpm-changes, thus making it quite unstable (especially in wind).
Thanks. I calculated and got my total thrust approximately 3/2 times of my quad's weight.

Vineet
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Old Oct 25, 2011, 10:41 PM
Bitten by the RC Bug....
vineet_p's Avatar
India, Andhra Pradesh, Hyderabad
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...

Quote:
Originally Posted by n3m1s1s View Post
I already told him Warthox but he isnt in a listening mood so dont bother bruv he'll just keep picking the same crap till another noob comes along and tells him what he wants to hear

just move on
It's not that I never listen. Indeed I get really valuable answers especially from you... But my intention behind asking this question once again was to check if I am correct in my estimation : each of the motor I selected gives around 350g thrust. So the total thrust given by all motor will be 350x4 = 1400g. But my quad's weight is just 700g. So my thrust is (almost) double the weight.
So then, I couldn't understand why most people were suggesting me motors that give around 900g to 1200g thrust EACH.
Excuse me if I've asked the same question once again.

Vineet
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Old Oct 26, 2011, 04:04 AM
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It's not just about lifting your quads weight. It's about being able to stabilize it when flying. If your quad is rapidly rolling you need the power to quickly stop it.
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Old Oct 26, 2011, 04:53 AM
Bitten by the RC Bug....
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India, Andhra Pradesh, Hyderabad
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:)

Quote:
Originally Posted by ben123 View Post
It's not just about lifting your quads weight. It's about being able to stabilize it when flying. If your quad is rapidly rolling you need the power to quickly stop it.
Thanks. It's something new that I've learnt.

Vineet
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Old Oct 26, 2011, 04:57 AM
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Quote:
Originally Posted by vineet_p View Post
It's not that I never listen. Indeed I get really valuable answers especially from you... But my intention behind asking this question once again was to check if I am correct in my estimation : each of the motor I selected gives around 350g thrust. So the total thrust given by all motor will be 350x4 = 1400g. But my quad's weight is just 700g. So my thrust is (almost) double the weight.
So then, I couldn't understand why most people were suggesting me motors that give around 900g to 1200g thrust EACH.
Excuse me if I've asked the same question once again.

Vineet
ahh well look at it like this.......

soon you will build your quad

then hopefully you will get it flying real nice

so nice you will want to add a camera

but wait? yr motors are already at max?

cant add camera

cant add new landing gear

cant upgrade to new flight controller that weighs more

cant swap props to get more thrust

cant add bigger lipo too heavy

solution? buy new motors new props and new esc's to find old lipo gets sucked like man in cat house now needing new lipo oh seeing as i have to get soo much new stuff might aswell get a new frame too lol all of a sudden you got 2 quads

think that wont happen? so did i lol erm while typing im sat in a room looking at 5 built quads if i looked round my house i could most probably find 50 motors not in models

if you use the emax motors i picked with a 6 to 8 inch prop you get the same thrust numbers but draw less amps add a camera and bigger lipo use a 9 inch prop and get the same power to weight ratio add better landing gear go to 10 inch prop

dont beleive EVERYTHING i have said about your motor choice vs mine? no problem buy one of each and stick them both on a cheap plane and go flying for the day ive got 5 of your motors sat here and they worked great! one is on a wing dragon an the other four have broken wires

on the other hand i have 9 of the 925kv motors i picked out in the other thread 4 are in a quad 3 are in a tri and 2 are sat brand new still in their packaging NONE have broken wires
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Old Oct 26, 2011, 05:01 AM
RTFM // copter damaged
warthox's Avatar
Joined Aug 2009
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Quote:
Originally Posted by ben123 View Post
It's not just about lifting your quads weight. It's about being able to stabilize it when flying. If your quad is rapidly rolling you need the power to quickly stop it.
thats it!

its not just the thrust u should look at. a copter with high kv motors isnt able to fly pretty stable and the power consumption will be high.

use what experienced people tell u and u will have fun with your copter...
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Old Oct 26, 2011, 05:34 AM
Bitten by the RC Bug....
vineet_p's Avatar
India, Andhra Pradesh, Hyderabad
Joined Aug 2011
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Quote:
Originally Posted by n3m1s1s View Post
ahh well look at it like this.......

soon you will build your quad

then hopefully you will get it flying real nice

so nice you will want to add a camera

but wait? yr motors are already at max?

cant add camera

cant add new landing gear

cant upgrade to new flight controller that weighs more

cant swap props to get more thrust

cant add bigger lipo too heavy

solution? buy new motors new props and new esc's to find old lipo gets sucked like man in cat house now needing new lipo oh seeing as i have to get soo much new stuff might aswell get a new frame too lol all of a sudden you got 2 quads

think that wont happen? so did i lol erm while typing im sat in a room looking at 5 built quads if i looked round my house i could most probably find 50 motors not in models

if you use the emax motors i picked with a 6 to 8 inch prop you get the same thrust numbers but draw less amps add a camera and bigger lipo use a 9 inch prop and get the same power to weight ratio add better landing gear go to 10 inch prop

dont beleive EVERYTHING i have said about your motor choice vs mine? no problem buy one of each and stick them both on a cheap plane and go flying for the day ive got 5 of your motors sat here and they worked great! one is on a wing dragon an the other four have broken wires

on the other hand i have 9 of the 925kv motors i picked out in the other thread 4 are in a quad 3 are in a tri and 2 are sat brand new still in their packaging NONE have broken wires
Liked your analysis. I understand that you are highly experienced in making the best quadcopters.... and I am very sure the motors you suggested me WILL give me the BEST results. But the thing is, this is my VERY FIRST quadcopter. So I don't need an upgrade, like prop upgrade, flight controller, camera etc. My plan is to first make this cheap quad, which will fly - just fly and no extras. I then want get some experience and then try building a better quad with the motors people like you suggested. I understand that in that case I'll have to buy a better (3S) LiPo, better props (9"-10") and many others. Fine, I'll buy them once again, but for now, a simple quad that can simply fly and give me some experience, not fun is enough...
Anyway, I really liked the way you explained me. Thanks!

Vineet
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Old Oct 26, 2011, 05:52 AM
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so you want cheap? maybe i can go look for some better cheap stuff for you? what do you already have?
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Old Oct 26, 2011, 06:05 AM
Quad is the new black
Australia, NSW, Sydney
Joined Jun 2011
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Quote:
Originally Posted by warthox View Post
its not just the thrust u should look at. a copter with high kv motors isnt able to fly pretty stable and the power consumption will be high.
....with the proviso that you aren't flying a miniquad, small props demand a higher kv.
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Old Oct 26, 2011, 08:20 AM
Bitten by the RC Bug....
vineet_p's Avatar
India, Andhra Pradesh, Hyderabad
Joined Aug 2011
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Quote:
Originally Posted by n3m1s1s View Post
so you want cheap? maybe i can go look for some better cheap stuff for you? what do you already have?
So nice of you... Thanks for the favour. I already have :
  1. 18A brushless ESCs
  2. 2S 5000mAh LiPo
  3. 6Ch TX+RX combo
  4. Balsa wood to make chassis

Thanks!

Vineet
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Old Oct 26, 2011, 09:02 AM
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Troy, MI
Joined Sep 2007
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2s cheap light motor

http://www.hobbyking.com/hobbyking/s...tor_150w_.html

3s choices

http://www.hobbyking.com/hobbyking/s...ner_750kv.html

http://www.hobbyking.com/hobbyking/s..._13A_104W.html

my choice would be

http://www.hobbyking.com/hobbyking/s...idproduct=4700


First give up on the idea of using the 2s5000 pack, 3s2100 packs are dirt cheap, get a couple but build your quad for one, then later when you want longer flight times you can just parallel both packs and increase your flight time...

sometimes being cheap isn't the best way to go about things.... say you buy four motors @ 6.00 each, 24.00 then you find out that they really aren't what you want so you then buy 4 motors @ 12.00 each 48.00 plus the 24.00 means you spent 72.00 when if you would of just bought the right motors in the first place you would of only spent 48.00....

what you should be looking at is motors around 800-1000 kv range, kv means how many rpms you get per volt ie 1000kv on a 3s pack 11.1 volts would be 11100 rpms...

I bet if you ask your question a little differently you would quickly get a best few choices of motors for your first quad....

Bob
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Last edited by snokid; Oct 26, 2011 at 09:04 AM. Reason: typo
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