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Old Jul 24, 2012, 08:07 PM
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unclecrash's Avatar
white lake michigan
Joined Oct 2004
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70mm fan

Working on balancing my fan been here for about 45minutes got it whisper quite with all the stock fan parts and the 2855 motor . I did the clock didnt do much so I then went to the spinner and found the sweet spot. Now Im transfering it to the inside hope it says after the silicone dries. I can't seem to find the 70mm motor data page does anyone have a link or know what page its on. Thanks UC
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Old Jul 24, 2012, 10:44 PM
EDF rules... :)
AirX's Avatar
Joined Nov 1999
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Crash,

is this the thread your looking for?

http://www.rcgroups.com/forums/showt...highlight=cs70

Eric B.
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Old Jul 24, 2012, 11:05 PM
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white lake michigan
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Quote:
Originally Posted by AirX View Post
Crash,

is this the thread your looking for?

http://www.rcgroups.com/forums/showt...highlight=cs70

Eric B.
Yes thats it, I will bookmark it this time Thanks Eric.
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Old Jul 24, 2012, 11:31 PM
Not enough hours in the day
Slaanesh's Avatar
Melbourne
Joined Feb 2009
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I'm running an L2855-2100Kv w/ CS10 on 2200mah 5S 45C in my HET ME-163 EDF version.

Is a super setup! And it sounds awesome - like a deeper thrusty white-noise sound.

I originally chose the 2100Kv as it seemed to be somewhat more efficient than the 2300Kv motor, especially on early tests conducted on 4S.
There also seemed to be only a marginal increase in thrust which seemed worthwhile sacrificing for
the large gain in efficiency.

Is this not true on 5S?
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Old Jul 24, 2012, 11:39 PM
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Australia, VIC, Melbourne
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Increases are generally non-linear... you need more power than the thrust % gain you get.
I don't have those numbers here now, but I remember deciding I want 2300kv thrust for my 5S.
Vaguely it was something like 1.25Kg 2100kv (not sure Amps, but prob just under 50A I would think) and 1.4Kg 2300kv for low/mid 50A's.
I can post correct ones in a few hours.
I guess if you don't need or want speed/ power, then 2100kv is fine.
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Old Jul 25, 2012, 12:07 AM
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Greece, Attica, Athens
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The L2855-2100kv on 5S is a good low amp choice with descent thrust.
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Old Jul 25, 2012, 05:28 AM
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Australia, VIC, Melbourne
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Hmmm the L2855's on 5S were:
2300kv 1.45Kg for 50Amps = 290g thrust per Amp
2100kv 1.35Kg for 44Amps = 307g thrust per Amp

So 2100kv is more efficient, because it is weaker, and as usual if you want more thrust you pay non-linear Amps (Power) increase. (Probably the same reason and maths [squared law] as for speed/drag.... because you are driving air faster). So to drive the same fan faster, for more thrust, gains are a squared law of input power (or something towards that sort of maths) to get that gain. At lower numbers squares are not as dramatic, but as the numbers grow the 'losses' due to that become huge.

For 100g thrust gain, you would probably want to have a good reason to want, or need, that... to make the 6 Amps extra worth it!!

100g/1350g = 7.4% gain
6A/44A = 13.7% cost
Non-linear as would be expected. But if you want it.... you just have to pay for it... LOL
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Old Jul 29, 2012, 03:44 PM
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whats the best het motor for 4s setup and around 80a too many pages to look through lol
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Old Jul 29, 2012, 05:54 PM
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Australia, VIC, Melbourne
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I think they have a 2900 approx motor.
80A should be in that 3000kv area, or even a bit higher.
By then you should bench over 1.5Kg thrust
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Old Jul 29, 2012, 09:43 PM
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United States, CA, Watsonville
Joined Apr 2009
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Here is a video of my Projet A-10 with twin CS 70 10-blades.

Projet A-10 Maiden Flight (3 min 31 sec)
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Old Jul 29, 2012, 09:55 PM
Don't Move I've Dropped My Nut
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United States, AL, Huntsville
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Congrats! Nice runway and landscape!
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Old Jul 29, 2012, 11:45 PM
jbc
WHO's your DADDY!!!
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Now THAT's what I call a runway!
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Old Jul 29, 2012, 11:52 PM
3DHOG
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USA, CA, Aromas
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yes we are spoiled
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Old Jul 30, 2012, 05:48 AM
EDF rules... :)
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Joined Nov 1999
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Quote:
Originally Posted by alanjets View Post
whats the best het motor for 4s setup and around 80a too many pages to look through lol
2w25 but I dont think it will draw 80 amps, more arround 60 amps.

Eric B.
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Old Jul 30, 2012, 08:22 AM
Not enough hours in the day
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Melbourne
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HET 2W-23 is 2950kv
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