Change Sun 10 blade 70mm - Page 369 - RC Groups
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Oct 24, 2012, 04:06 PM
Big gov never Works
St. Martin's Avatar
Will a changesun rotor work in a HET 6904 shroud?
I test fit the CS rotor in the HET and minifan shroud. Less clearance than the CS shroud, on both. The CS shroud is slightly larger I.D. than the HET and minifan. You will have to be careful in setting the motor in the mount. This to make sure you have equal clearance. Plus, at high power, the blades may stretch some. Most glass filled nylon rotors do. So rubbing may occur.

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Oct 24, 2012, 04:14 PM
Registered User
anlucas's Avatar
Originally Posted by pencon
Thanks Chas650r , So I guess the 1w-40 is too hot for this fan ?
Should be ok on 4s but you will need good 4s batteries. Should draw around 90amps +-5. My Cyclone Power 3300kv draws around that much.
Oct 24, 2012, 04:37 PM
Registered User
OK thanks guys
Oct 24, 2012, 06:26 PM
well it looks like it would be in the 90 amp range on 4's . imo it takes a lot of battery to support that kind of current draw. i guess it depends on what u put it in and what u want it to do. in the upper end of the wattage range higher cell count and less current is always better, but in this case that would take lower kv.

Oct 24, 2012, 06:35 PM
Registered User
I assume you had that motor in a 4,5,6 blade fan before. 3300kv, and the Amps it will run, mean a costly battery needed. But when you have a motor, and want to make use of that, you can often end up needing BIG compromise - in this case costly battery, and lower efficiency of huge currents.
It is a nice motor, but just not greatly suited to a CS10. A shame. 3000kv would have been nicer.
By the time you hit these power levels due to KV at 4S, you really would have wanted to plan a 6S system (or at least 5S), so you can use far more economical battery solutions (much lower C only required).
But an $80 nice motor...... makes it hard to 'waste' it...... but add up what OTHER waste that using it will cause too!
Oct 24, 2012, 06:59 PM
Life begins at transition
Higher voltage doesn't mean you need a lower C rating at all.
If the battery pack remains the same weight, there is no difference in the capacity / current ratio

A 6s 4000mAh battery, and a setup that pulls 80A. That's 20C.

A 4s 6000mAh battery (same weight), a motor with 1.5x the kv, so the same power output, but a current of 120A. That's still 20C...

Using a 6s 6000mAh battery is not a level playing field - that's when the C can be reduced, but that's not a fair comparison.
Oct 24, 2012, 07:42 PM
Registered User

1330W 4S 90A 5000mAH to get 3.3mins WOT, 65C costs $71
1330W 6S 60A 3300mAH to get 3.3mins WOT, 65C costs $66
So for a start that was cheaper.... $5 of waste (same brand batteries for comparison - same total 'current leeway above what was needed))

Even though mathematically you 'need' the same C to get the same 'current leeway', the 6S could use 45C fine but the 4S with such huge current numbers would be less impressed supplying that at 45C. The larger the currents the less they 'like' doing it.

Then the ESC.... needing 100A instead of 70A..... more cost, for no benefit in outcome = waste.

90A instead of 60A... more current 'dangers'/heats and issues. (not a great deal, but still worse than lower current)

Inefficiencies of higher current.... need larger wires to be equal, larger connectors, or will drop a fraction more volts.... = waste (relative to a lower current system)

Had to have motor capable of 90A, not just 60A (same Watts capable... that is a different limit).
So that will be choice/range limiting...and likely even cost. TONS of 28mm motors can do 60A fine, but not many can do 90A!

There is no way a 4S "equal power' system is ever better, or even equal, to a 6S combo.
It is just a wasteful economy of scale.
I would say there is a cut off CURRENT point.... something like 60A to 70A, where you just don't do that, you move UP in VOLTS instead.
(in 90mm that is more up around the 100A or so point - though pref to still move up volts instead by the 90amps or so area I think)
Last edited by PeterVRC; Oct 24, 2012 at 07:51 PM.
Oct 24, 2012, 07:43 PM
efflux RC's Avatar
The Velocity-RC 2900 kv, 4mm shaft (geniuine Velocity-RC motor) is another option for 5s


MEGA 16-40-1.5RC (2270) with a 5mm shaft, for 6s
Last edited by efflux RC; Oct 24, 2012 at 11:52 PM. Reason: correction for MEGA KV and link
Oct 24, 2012, 07:59 PM
Registered User
Looks nice specs on that Velocity... but I would think more for 4S for a CS10.
By 5S you would really be running huge demands.... 80A to 90A.
2500kv, or a bit more (to 2600kv?), is about 5S useful limit (already 70A area) ad big output numbers.
At $84 it looks and specs much like a HET (similar price area, 2W23 but the 4mm shaft on the Velocity is a winner), or even Leopard have much the same spec/size/look motor too (with 4mm shaft).
Oct 24, 2012, 08:07 PM
efflux RC's Avatar
I corrected the MEGA motor. I meant the 2270kv version. It's similar to the E-flite BL32 motor( for the Habu 32), only 120KV higher, and 61.5mm long.

(Thx Gryphon!)

Your right peter, I forgot the rotor won't take much more than 46K rpm. ....4s for the Velocity-RC motor.

6s for the MEGA.

I'm used to the higher power, faster stuff. 80-90A is quite satisfactory.(even a bit low for WOT)
Last edited by efflux RC; Oct 24, 2012 at 08:18 PM.
Oct 24, 2012, 08:15 PM
The best in EDF since 2005
Extreme_RC's Avatar
And double the price, the Eflite BL32 and HET 2W30 are still the picks for 6s operation in the CS10 fan.
Oct 24, 2012, 08:24 PM
efflux RC's Avatar
Originally Posted by extreme_rc
and double the price, the eflite bl32 and het 2w30 are still the picks for 6s operation in the cs10 fan.

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Oct 24, 2012, 08:30 PM
Registered User
Mine haven't exploded yet (2W30 6S CS10 twin)....
But I use 30C and probably (forget if ever measured) about 35k rpm area (more?) due to voltage drop. I would think 65C's could go more towards 38k RPM
2000kv area is more a "good power" level to use, but 2200kv should be fine as a "high power" level - not excessive and explode the fan. But it is getting up towards there.

Maybe there was some other reason it (they?) failed?
Oct 24, 2012, 08:31 PM
The best in EDF since 2005
Extreme_RC's Avatar
So fit the mega motor to a CS10 and post up the results, if its substantially better than the BL32 then it may be an option for some people. As it is the BL32 is 75 bucks and the mega is double.

Oh and I dont sell BL32 motors, doesnt mean I dont think they are an excellent motor...
Oct 24, 2012, 08:55 PM
efflux RC's Avatar
I decided not to talk negatively of others and edited my post. Maybe they were poorly balanced.
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