User Info

 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?

MultiRotorUK ShoutBox

Refresh History
  • Kellarly: hehe, nothing changes there then!
    Today at 09:26:19
  • Bad Raven: Is the issue Turnigy or Turnigy Nano-Tech? I have found that mid-blue Turnigy tend to be low on their stated "C" discharge rating.
    Today at 08:37:09
  • ched999uk: RaceDayQuads have some cheap but good batts out now. Josh B tested and stats say very good especially at price. HobbyRC have 1300mAh 4S just under £20. Not had luck with Turnigy lipos either!!
    July 15, 2018, 22:48:51
  • Reman: Just realised that I hadn't gone through my stored Li-Po's for about a month. I try to visually check them every Saturday, And prod the plugs with a multimeter about once a month. Todays seen 12 more bulging packs go out to the incinerator..... All but one was a bloody Turnigy! Part of me wan't to burn the rest now and just get a load more Tattu packs, But I've spent good money on these packs and wan't to at least get a little more use out of them. :(
    July 15, 2018, 19:54:53
  • Bad Raven: Pre MR's I used to buy a lot from J.Perkins. Their website showed all items and stock or due date, go to dealer and buy with confidence. Then they went all "lifestyle" and all the site had were pictures or people. I wasn't after people. I never bought again. Yes, you'd think they'd learn...........
    July 15, 2018, 17:51:40
  • ched999uk: Reman sounds like amazon search. I find it ok unitil you want to search by price then amazon falls apart.... You would think both companies would get it right...
    July 15, 2018, 16:54:55
  • Reman: It's strange. The original setup they had about 5 or 6 years back wasn't too bad (Except for them occasionally getting accounts hacked), But they changed it to the last one that was clunky and slow, Now they've replaced that with a flashier one that's also clunky and slow ?!?!?! Most companies learn from what they do wrong. I don't buy from HK half as much as I used to, Mainly because it takes forever to trawl through 100 pages of totally unrelated stuff while looking for something you were thinking about getting when you saw it there the previous week !!!
    July 15, 2018, 16:27:21
  • hoverfly: I don't think there is a search button on H/King. They updated the site and forgot to  relabel the search button with  Random bo##ocks..
    July 15, 2018, 09:47:35
  • Bad Raven: Agree - The Search is abysmal!!
    July 15, 2018, 08:40:52
  • Reman: I see HobbyKing's revamped their site again...... Shame they haven't made the search function work any better, Or worked out why the whole site goes slower than a pensioner in a Nissan Micra. :)
    July 15, 2018, 08:28:14
  • Reman: How thick is Google? You buy something online, Then for the next week you get targeted adds for the item you've just got?!?! That's the one item you're NOT going to be buying again at that point so it's wasted effort of there part. :)
    July 14, 2018, 08:50:51
  • DarkButterfly: ~~
    July 13, 2018, 23:56:20
  • Kellarly: as does my ability not to realise what i've already typed
    July 13, 2018, 22:25:42
  • Kellarly: Wahooo, my whoop now lives!
    July 13, 2018, 22:25:19
  • Kellarly: yay, the whoop lives!!!
    July 13, 2018, 22:18:43
  • DarkButterfly: Had to replace the battery connector
    July 12, 2018, 10:57:47
  • Kellarly: good work! what was up with it?
    July 12, 2018, 10:39:33
  • DarkButterfly: Fixed my tiny6
    July 12, 2018, 10:23:59
  • Kellarly: FFS, bought the wrong FC for my whoop. Saw D16 and thought it was EU-LBT ok, but nope :(
    July 12, 2018, 08:32:22
  • Reman: The ergonomics of the TGY feel better, But every new revision of the firmware brought more bugs (The last version had a bug where opening the gimble menu would cause the TX to crash and reset to factory defaults !!!). So what I was hoping was to end up with a stable FS-i10 with a nicer layout.
    July 11, 2018, 06:25:19

Who's Online

Theme Selection



Forum Default

Permanently

Author Topic: 1104 motors but which kv?  (Read 648 times)

Offline aburn09

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 456
  • Liked: 74
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
1104 motors but which kv?
« on: December 06, 2017, 20:49:40 »
 I'm looking for some new 1104 motors for my latest micro build but I'm a little confused as to what kv I should go for ?
Just as an example if I chose a motor from this Banggood page should I go for higher or lower kv ? Some are around 5000kv where others are 7000kv which should be better ?
I'm going to be running a 3s battery.

https://m.banggood.com/search/1104%20Brushless%20Motor.html

Offline Cheredanine

  • Trade Count: (0)
  • Hero Member
  • *****
  • Posts: 4737
  • Liked: 1232
  • Country: gb
  • Cleverly disguised as a responsible adult
Re: 1104 motors but which kv?
« Reply #1 on: December 06, 2017, 21:36:00 »
Props mate?

Offline aburn09

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 456
  • Liked: 74
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
« Last Edit: December 07, 2017, 07:07:29 by aburn09 »

Offline Paul01

  • Trade Count: (1)
  • Hero Member
  • *****
  • Posts: 1392
  • Liked: 313
  • Country: gb
Re: 1104 motors but which kv?
« Reply #3 on: December 07, 2017, 06:35:18 »
 Hi aburn09,

Have a look at fpvmodel.com they have dragonfly 1105 7500kv which are awesome on gemfan 2035 quad blades. They are also very well made motors.

Sent from my SM-G950F using Tapatalk

FrSky Taranis X9D Plus with TBS Crossfire Micro
FatShark Dominator V3 with RealAcc Pro Diversity
Armattan Chameleon
DJI Mavic Pro
https://www.youtube.com/c/paul01

Offline Elmattbo

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 911
  • Liked: 310
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
    • Youtube
Re: 1104 motors but which kv?
« Reply #4 on: December 07, 2017, 07:15:54 »
For 3s I’d say as a rule you’re looking at the ~7000kv ones. I’ve got the 4500kv emax but that’s on 4s.


Sent from my iPhone using Tapatalk

Offline aburn09

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 456
  • Liked: 74
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
Re: 1104 motors but which kv?
« Reply #5 on: December 07, 2017, 07:58:50 »
I already have emax red bottom motors on my 5" and it does give it a nice punch out.......So if I went with the emax 1106 they come in 4500,6000,7500kv I assume the higher kv will give better performance but less flight time than if I went with the 4500kv ?
I will be flying with 3s.......but the set up could take 4s ?  ;)

Offline Elmattbo

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 911
  • Liked: 310
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
    • Youtube
Re: 1104 motors but which kv?
« Reply #6 on: December 08, 2017, 00:20:00 »
Not quite. You need to match the kv with the battery and prop. As a rule, you need to drop the kv with higher cell count batteries or they will burn out with the higher current draw. Also more aggressive props will demand higher current too.
With micro builds, 3s and even 2s can perform really well, particularly since higher cell count batteries weigh a lot more.
However, if it’s 4s your after then you probably need the lower kv ones. I have read people use the 6000kv ones on 4s, but they won’t last too well and you’ll have to be careful with props.


Sent from my iPhone using Tapatalk

Offline aburn09

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 456
  • Liked: 74
  • Country: gb
  • Tricopter, one prop short of a Quadcopter
Re: 1104 motors but which kv?
« Reply #7 on: December 08, 2017, 06:29:40 »
Thanks Elmattbo I realistically will only be using 3s so with the gemafan 2035 as a maximum angled prop I'll be using I'll probably go for the emax 7500kv motors  ~~

Offline mo_miah

  • Trade Count: (0)
  • Sr. Member
  • ****
  • Posts: 323
  • Liked: 62
  • Tricopter, one prop short of a Quadcopter
Re: 1104 motors but which kv?
« Reply #8 on: March 15, 2018, 15:27:39 »
whats the rule with quad motors kv - battery V - props?

with RC cars we aim for set rpm (30-50k rpm max) at the pinion/motor and gear for torque/speed
if the motors cant handle the gearing we gear down or drop kv and increase the supply the voltage

Offline Cheredanine

  • Trade Count: (0)
  • Hero Member
  • *****
  • Posts: 4737
  • Liked: 1232
  • Country: gb
  • Cleverly disguised as a responsible adult
Re: 1104 motors but which kv?
« Reply #9 on: March 15, 2018, 16:35:58 »
As a basic rule the cell count of the lipo governs the voltage

The motor kv is the rpm per volt it will try and spin at when at wide open throttle

The prop puts load on the motor, how much load depends on the weight o& the prop, the number of blades, the pitch of the blades, the flexibility of the blades and the shape of the blade. That is a lot of variables.

The load on the motor from the props makes the motor need more force, force comes from electrical power, which means the motor drags more amps and ultimately won’t meet the target kv

Just to complicate it even more, as the motor increases the rpm and it’s amp draw increases, the lipo tries to provide this, and in doing so the voltage sags, a# the voltage sags, the speed the motor tries to hit drops etc

A lot complex varriables there that can not realistically be modelled.
So you need some sort of reference.
Manufacturers specs help however they are not always accurate (understatement)
Manufacturers like xnova understate their specs so you are very safe and the motors will outperform expectations. Less reputable or cheaper motor manufacturers overstate to make their motors seem appealing, this can result in underpowered quads or burned out motors

So a far better reference is independent thrust tests.
For 5 inch quads the undisputed god of this is Ryan Howell and miniquadtestbench.

For smaller quads the best I know of is Engineerx who runs a YouTube channel with tests (and also posts on rc groups)

Get the test, match the motor and prop, look at the thrust and amp draw for your cell count. Bear in mind you have 4 motors and you will lose something like 30% off the amp draw in the air rather than on the bench. Then make sure your lipo can handle that.

Also watch the review, Engineerx is pretty good at pointing out sweet spots and the quality of motors, just because he tested a motor or prop combo doesn’t mean it is a good idea and he will point it out.