Change Sun 10 blade 70mm - Page 414 - RC Groups
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Jan 24, 2013, 08:49 PM
efflux RC's Avatar
"Do you think it will be a combo that you will sell? "


Since we offer many different (quality) EDF and motors, there's so many possible combos that we don't list "combos".
There will probably be a "standard" and aluminum housing available.
Along with suggestions for a few different setups.
Guys usually PM or email me about thier thrust requirements and I can offer suggestions or build them EDFs to thier budget and needs.
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Jan 24, 2013, 09:02 PM
EDF rules... :)
AirX's Avatar
Originally Posted by PeterVRC
IF you want a really 'clean' running fan, I would suggest (even recommend?), the ExtremeRC alloy housing - then whatever manner you use (new 'precision' adaptor or not), to get the balance optimal. The alloy housing is almost as light as the stock plastic... a bonus is better cooling too... but I think the biggest gain is rigidity...
This new version still uses the original shroud and the rotor adapter is a giant step up from the original as long as you seat it right it should hold with decent power but for high power applications I would go with set screw adapters like Marks at Extreme RC or Tamjets as I think the new ones might pull off the shaft given a chance. For me I wont be running more than 700 watts in mine so the collets should be fine.

Eric B.
Jan 24, 2013, 09:04 PM
jcdfrd's Avatar
ok I just got in to work and Tam has a big box of cs70/12's waiting for me so we should have these available very soon, the whole fan unit looks more robust, the plastic housing is redesigned and a lot stiffer, 7 stators is helping that. the rotor looks really good and again much stronger than the 10 blade, we will be testing its ability to handle 7s and possibly 8s power. the new collets I dont particularly care for but ok, if you guys want the stock collet style adapters and strong 7 stator housings we are going to put together a parts kits for the stock cs70/12 parts, which will be the housing with lip and the two collet adapters for now. that could change.
the spinner is also much better and fits the rotor very well, we will see how it messes up the balance or not to determine if we use them or to balancing
Last edited by jcdfrd; Jan 24, 2013 at 09:10 PM.
Jan 24, 2013, 09:07 PM
EDF rules... :)
AirX's Avatar
Originally Posted by efflux RC
Yes the new V-2, CS12 70mm. I'm still waiting for them to arrive. I'm hoping the new collets are better than the old style. (looks like they do, according to airX's post)
I would be careful running high power till you get the rotor real tight, I still like the set screw adapters for the high power applications. The machine work is a tone better, the materal choice might be suspect.

I dont have a high power setup so I cant try 1.5Kw to see if the rotor will hold the shaft. I am sure you guys will find the limits.

Eric B.
Jan 24, 2013, 11:35 PM
efflux RC's Avatar
Originally Posted by AirX
I would be careful running high power till you get the rotor real tight, I still like the set screw adapters for the high power applications. The machine work is a tone better, the materal choice might be suspect.

I dont have a high power setup so I cant try 1.5Kw to see if the rotor will hold the shaft. I am sure you guys will find the limits.

Eric B.
Thanks for your input Eric.
I don't expect to put much more than 1300-1400 watts to the rotors, from what I've seen in the past. But for medium power, guys like the sound of these.
If I decide to make adaptors they will most likey be the set screw type.
Latest blog entry: Updated blog - Oct 2017
Jan 25, 2013, 12:17 AM
Registered User
A drop or two of red loctite 271 on the collect/motor shaft, will remove any danger of the rotor flying off in a high power 7s or 8s set up, The rotor holding up to the stress is a different story.
Jan 26, 2013, 11:42 PM
Registered User
Today I did a bit of "fan shuffling" and testing.

Put the CS10-70, and then a CS12-70, rotor/fan into a Lander Ex-6blade Alloy housing.
The CS10 and CS12 both do approx 1.8Kg Thrust in stock housings, from a Turnigy XK2850-2060kv on 6S. It is not a bad little combo really... a $33 motor, but you really want to use weaker batteries (higher IR) to drop off that power a bit - more like 1.7Kg area or less - because 1.8Kg is 65A+ area and the motor won't like that if you use it too much!

But anyway... the Lander Alloy housing.....
Both setups (10 & 12 blade) put into that..... 780g Thrust approx only!!
Switch them back to their stock housing... IN CASE the motor was damaged... both cases return to full thrust/power!!

The CS10 rotor is of course a little bit smaller diameter than the CS12 but both fit into the Lander. Both give 780g Thrust!! So that pretty well shows that even though the CS10 rotor is a bit smaller, and thus has a fraction more gap around the tips to the housing, that is irrelevant to the result.

The issue must be the inlet lip, which is quite a small radius and nothing like the size of the stock CS10 or CS12 inlet lips.
I have tested fans with NO inlet lip before, so you do get used to the fact that thrust drops of big time if you do that... but this was still surprising.

The Lander, in its prior 6 blade 2550kv form gave 1.95Kg area on 6S !!!
So the inlet lip design did NOT bother that lower blade count fan at all !! It must be the design of 10/12 blades that messes up the inlet airflow effectiveness now.

Note that the Lander 10blade DPS unit - 2960-2200kv motor - does 1.95Kg Thrust. It does have a larger lip, but it is something like halfway between this blue DPS and the stock CS10 inlet lip size.
That 10blade Lander DPS does the EXACT same Thrust and Amp numbers as the C10, or CS12, in their stock housings. So that shows the inlet lip (or something else??) on that alloy housing gets the optimum result from those rotors still.
The stators look the same across all those fan housings....10bl DPS, 6bl DPS, and the stock housings.

I have to do some investigating, modding etc, on this blue Lander DPS housing to see if I can get it to run at the full pwer capability.....

Jan 27, 2013, 01:37 AM
Registered User
Still Wow....

I put on a CS10 Inlet Lip.... it can only butt up ontp the housing as they are the exact same diameters, but that is OK as it taped all solidly in place fine.

Test.... result.... EXACTLY the same 780g Thrust result!! (59 Amps, as per the prior time too of course).

The gap around the blade tips is much the same as in the CS10 shroud.

So all that leaves to explain the drop is the HOUSING itself.... and a "tube" isn't going to alter anything... "a tube is a tube", LOL. So it almost has to be the STATORS. Though they look fine, and so similar to the CS housing ones anyway. But "Similar" is not "The same".....

I have put them into Freewing 6 blade housings in the past and they work totally fine! Full expected power.
So this just seems weird really. It is the amount of drop like I have seen from NO inlet lip tests, of any fan types.
It seems it must be the housing, for one reason or another, but I am not convinced.....

Jan 27, 2013, 01:49 AM
Registered User
Your now exploring stator desing and how it affects performance. This is great reading and more test have to be done to come to solid conclusions.

Remember the CS18 smart fan. I think it was missing some tests like the ones your doing now.
Jan 27, 2013, 01:57 AM
Registered User
Could be. But that was a whole new fan design (do we know)? So that had a number of unknowns. At least all these bits are KNOWNS, except the housing.... which you would think "Well that makes it EASY to work out!!" LOL
And really that is that... it must be the housing... but exactly WHY?

They also have their Lander Grooves up the front end inside the housing... so maybe that is critical to have the rotor RIGHT over those. Something I have to check.... but I don't want to undo my shaft adaptor! hehe
Jan 27, 2013, 02:09 AM
Registered User

Closer investigation of the housing..... check the Lander stator angles etc, check the CS10.... gee they are very similar.... "How much could a SMALL angle/shape difference matter??"

As it turns out, after a more attentive check, it wasn't such a small difference at all......
It is COUNTER-ROTATING version of the fan !! DOH.
From HobbyKing it is just listed as... ummm... "DPS fan".... not the listed 'counter rotating' one they have also. But which way is 'normal' or 'counter' anyway!! To Lander..... or HobbyKing....

So that explains it all.....

That is going to end up as one useless alloy housing then......

I also have a 4370kv Alloy Lander, but that is the "68mm" one.... and yep... just 2 mm too small for the CS10 rotor. But I can always grind/turn one down to fit that.....
Jan 27, 2013, 09:36 AM
Registered User
4stripes's Avatar
Have any of you taken apart a Turnigy L2855 outrunner? The bearings seem to have excessive play side to side. The play makes it impossible to dynamically balance the fan properly.
Jan 27, 2013, 09:39 AM
Registered User

stators designed for rotors...

since Ejets offer their Jetfan rotor now separately and encourage people to try those rotors in all kinds of shrouds, there is a discussion in German forums about how well stator and rotor should be matched for good efficiency, being no expert myself I will just recount what I read.
Ejets say, if you use the Wemo, Schuebeler HDT or Deiss shrouds, things have been tested to be very good, and also the shrouds developed for more slowly rotating fans like the Schuebeler HST, Change Sun or Stumax should actually work fine, however they might not sound as good as the original shroud with the Jetfan rotor. Oliver Wennmacher of WeMoTec points to the fact - which has been touched upon here - that some stators are not only profiled but also twisted: The Wemos are not since the twist is already "incorporated" into the rotor design, Jetfan shrouds and some Stumax are twisted, others not. It would be better to use a matching shroud, but measurements of a Wemo rotor in a (twisted) Aeronaut "shroud" showed a drop in efficiency of 4%, and other trials in a Schuebeler DS51 shroud showed similar results.
So the upshot seems to be that, compared to other losses in ducts etc., this is not an awful lot (and it is deemed likely that Lander or Change Sun don't even design - or copy - their rotors to such a detail as to know the corrrectly matching twist to give their stators)...
Jan 27, 2013, 10:42 AM
Originally Posted by 4stripes
Have any of you taken apart a Turnigy L2855 outrunner? The bearings seem to have excessive play side to side. The play makes it impossible to dynamically balance the fan properly.
well i could never tell if the problem was the bearings because the shaft fits so loose in the bearing id that it also rattles around. chances are the bearings are not what they could be either. but to be sure u are not the only one w/ an issue trying to get consistent balance . there has been talk of using loktite on the shaft to bearing area but imo there are 2 problems w/ that: it's a crap shoot how centered the shaft will be and will u be able to get it apart later.

yet us know what u do!

Jan 30, 2013, 02:01 PM
Registered User
4stripes's Avatar
Problem solved with the 2855!
Was having a tough time balancing the 70mm 10 and 12 blade fans with the Turnigy 2855 outrunners. Couldn't ever make it run as smooth as I would like. Finally found that the motors needed balancing first! First mount the motor backward in the shroud and leave the retaining "C" clip off the shaft. Ran the motor without fan/adapter and used the clock method just placing small pieces of duct tape on the outer bell. Pulled the bell/shaft out and added a dab of thick CA in between the magnets where needed. A few more runs adding tape in various locations until the right amount of glue was in place. The fans balanced much better and quicker with the motor running smooth first.

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