Change Sun 12 blade 90mm - Page 5 - RC Groups
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Oct 11, 2011, 04:54 PM
Registered User
Yeah you guys are right, what we should do is just ban anyone new from entering the hobby, that way there will be no accidents

you can destroy any fan with enough power, it seems that CS is above others quality from the reports i've read so let them be, and how about you start educating others rather than complaining that they are here!
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Oct 11, 2011, 05:11 PM
Registered User
OneHundretMoons's Avatar
How about accept criticism ?

I think about it in the big picture and not the narrow.

I had bad experience about this china copies and others suffered the same fate.

Do whatever you feel like is ok.

Oct 11, 2011, 05:20 PM
Registered User
Flip Flop's Avatar
By china copies you mean CS fans?
Oct 11, 2011, 05:22 PM
Registered User
Joe 1320's Avatar
Originally Posted by Flip Flop
Hey guys, just thought I would share this. The guys a X-flight sent me the new Change Sun 12 blade 90mm edf thats going to be coming soon. I tested it with the HET 700-60-1485 motor on 4000mah 8s. It pulls about 105 amps and is alittle over 3000 watts with the thrust at 7lbs installed in my Sniper 90. Before I had the HET 90mm unit with the arc 36-75-1 motor in my Sniper and it put out a little more thrust but I think the top speed with this CS unit was a little better. Here are some pics. Oh and the sound is great, I think im gunna leave this one in.
the first 12-13 seconds of the vid sure sound good to me.
Oct 11, 2011, 05:31 PM
Registered User
Seems like every new fan has a mixture of previous fan designs( hub, blade shape, spinner, etc) .Even full scale turbofans look similar. The new fan from e-jets looks similar too. Bottom line is you are free to buy whatever you want. Every edf enthusiast has a his own budget. Flip flop was right in saying he would not put a $450 fan in a $170 airframe!
If you are one of the guys who owns high end jets then it makes since to use the subi HST, tamjets, stumax or something else along those lines.
Last edited by sheppard559; Oct 11, 2011 at 05:55 PM.
Oct 11, 2011, 05:56 PM
Pursuit of Happiness
Ron101's Avatar
Unbelievable, one guy has one and a bunch of you want to criticize it and havent even touched one. It looks just like the inlet of a 757 to me albeit a bit smaller. So if it looks like a copy of Stumax....... where did Stu get it from? 757??? GE Turbofan?? Rolls Royce??? Pratt & Whitney??? Hmm.
The beauty of this site is we can all voice our opinions, if he didn't want others views then it's not the right place to post it. Sometimes I have posted things and not had the reaction I thought I may have... so it goes with the territory.

Look I want a deal like everyone else... but at what cost? China is copying everything and getting better and better at it.

How would you feel if you spent countless hours of your hard work, years learning what works and hard earned cash in tooling.. just to have it splashed and ripped off? I bet you would be pissed, I would be

One thing I have done to have success in this hobby is use a rule of the plane and power systems get bigger and more dangerous I go with top of the line equipment. This has payed off huge for me in countless trouble free hours of flying. There can still be issues with the good stuff, but those companies stand behind there product a resolve the issue....

At this kind of power level someone can be seriously injured, look at what happenend to sheppard running a cheap high power 120mm fan... he dam near lost an eye.

Not to mention we all need to support the guys out there coming up with this stuff. I have seen my share of burnt up hobby king motors and swollen lipo packs... guys trying to save a buck only to have to spend more to buy new stuff.
I buy good stuff once, instead of cheap stuff over and over.... it leads to more problems than it's worth.

To each there own, the guys that know this hobby know what I mean.... crap parts lead to a crashed plane, lost time and money. That simple.

I have a Stu Max SM 110-52 with over 100 flights on it at 3700 watts, never an issue, just flight after flight of joy... setup and balanced by Stu.
I now have the new Stu Max 80mm in my Habu and feel this design is one of the finest EDF's I have ever flown.... it has such grace and power, and is very effiecent for the power level it gives out

I have flown tons of fans, and Stu's are among the very best in the business... but hey try this thing out, just stand back and renew you health insurance
Oct 11, 2011, 06:13 PM
Mike Warren's Avatar
Originally Posted by rfodor
Unbelievable, one guy has one and a bunch of you want to criticize it and havent even touched one. It looks just like the inlet of a 757 to me albeit a bit smaller. So if it looks like a copy of Stumax....... where did Stu get it from? 757??? GE Turbofan?? Rolls Royce??? Pratt & Whitney??? Hmm.
You are funny The Computational Fluid Dynamics involved in fan blade design does produce blades that surely look similar........doesn't matter if it is a full size GE90 or a Stumax.
Be assured that Stuart does his own CFD in designing the blades for his fan, they're his own quite modern design.

I would bet that ChangeSun can't even spell "CFD" as opposed to "CRO" - (cheap rip off)

Jim: only that middle paragraph applied; the last wasn't directed at you. Of all people you know the value of intellectual property and hard design work
Oct 11, 2011, 06:31 PM
Team White Llama!
gundamnitpete's Avatar
no body made a fuss like this when the WM400 was cloned? or the wemo?
Oct 11, 2011, 06:34 PM
Team White Llama!
gundamnitpete's Avatar

wemo clone with a different shroud. personally seen them to only about 600 watts

WM400 clone

looks like the eflight delta-V to me.

here's some ammo, have fun guys
Oct 11, 2011, 06:34 PM
Registered User
LuvEvolution7's Avatar
Ron, while I agree with you completely, if you design something and put it on here or any other forum, or word gets out, the Chinese will copy it if it's good. and being that you are in the hobby and understand what goes on, you know this information before you ever design the piece. so those who design stuff and don't expect it copied are living in a dreamworld. I wonder how long it'll take for someone to bring out a $200 version of Red Leader's Tazor or his Typhoon. lots of good products out there that cost way too much for the everage Joe to buy. unfortunately, this is what the copy artists thrive on and know the numbers are far higher than the guys that can afford the good stuff all the time. it's why companies like Kia and Hyundai are starting to sell more cars than anyone. they appeal to a broader market because of lesser costs for the same or more product.

I'm not saying that I agree with this, but it's economics in its dirtiest form and it won't change no matter what industry it is. I hope that this isn't a cheap plastic copy and that they've actually done a little homework into proper construction technique. I hope its design can live up to the amazing sound coming out of it. if it does, it's a win win for everyone. if it's not, I guess it'll go the way of the fans of yesteryear. I don't see a direct copy here, so not sure why everyone's so bent out of shape about it. they've obviously taken design cues, since that much is evident, but isn't that the way all ideas are thought up in the first place....................simply a better version of a previous design, made better by re-invention. I can't speak for stu personally, but if his fans were my design, I wouldn't look at this one as a copy of mine. sure there are similarities and perhaps copied ideas, but not a direct copy. if they were making a direct knock off, I'de be pissed off, for sure.
Oct 11, 2011, 06:58 PM
Carbon fiber is our friend
Steve C's Avatar
Originally Posted by gundamnitpete
no body made a fuss like this when the WM400 was cloned? or the wemo?
Oh yes they did. You either weren't around or just didn't see it.

There was quite a fuss about Tams looking just like Daniels too.

Oct 11, 2011, 07:27 PM
Registered User
Flip Flop's Avatar
I am going to say that there is probably alot of people that have had a great deal of luck with there crapy china products. Me myself have had great luck with my Turnigy lipos, motors and escs, and have them in planes that have close to 100 flights on them as well without issue. Every one is entitled to there own opinion, but most of the more critical people in this thread are known for mostly flying high end expensive products and more than likely dont shop at hobby king. So how can you be so critical on products you dont use?
If all of these cheap china products were banned there would be alot of us on the sidelines watching you guys fly your several thousand dollar jets.
Oct 11, 2011, 07:31 PM
Registered User
Flip Flop's Avatar
For those that are interested the new 10 blade 70mm (I am not sure who they copied that one from) but it will be out in one to two weeks, and for the fan only it will cost $13-15.
The 90mm he said should be ready in a month or so.
And the 120 sounds like it might be another few months.
Any other questions you can e-mail X-flight.
Oct 11, 2011, 07:32 PM
Registered User
LuvEvolution7's Avatar
kinda like me commenting on a BVM plane when I've never owned one. I can only comment on the insane price tag that my wife won't let me spend. LOL.
Oct 11, 2011, 07:37 PM
The blade numbers go up to 11
stumax's Avatar
I guess it was inevitable that someone would copy my stuff, it's taken a while. Certainly their 5 bladed 90mm fan looked like they got a TF2000 rotor and 3D laser scanned it, made a mould and presto, instant product development. Impossible to prove unless I had both sitting in front of me, but I do know from speaking with my wife and her family (who happen to be Chinese) that copying stuff and stealing things is just a way of life there. Go to a public toilet (even in an expensive restaurant) and you'll find no toilet paper, go to McDonald's and you'll find no serviettes, straws, salt, pepper etc for self service. Why? Because people will just take it all home with them and think nothing of it, because that is how things are done there, they're goal in life seems to be to get something for nothing, which is why gambling and lotteries are so popular. Apparently there's a city in China which is known as the place where things are copied. If you have a western product you wish to manufacture and sell, just take it there and there will be someone there who will have what it takes to replicate it exactly. On my first trip to China I was amazed at how many Honda motorcycles there were. that was until I got a closer look and found their badges read "Hando", in exactly the same font and design as Honda's. Whether it's a copy or not is hard to say, we'd need to see how each blade is retained. Having the spinner locate on that alum ring sure looks similar, esp if that alum ring clamps around the front of the blades to retain them.

Originally Posted by JimDrew
I didn't realize that they copied the blade retention. I guess we all have Tom Cook to thank for that idea - he was the first one to do this.
Jim, you obviously haven't seen inside the hubs of my rotors, they're quite different from what Tom came up with. Sure, there are front and rear discs clamping the blades together, but mine have wedge shaped rings attached which, when clamped up, force the blades radially inwards, locking it all together. Tom found even with front and rear rings the rotors were failing so he put a web to bridge the front retaining lug on the rotor blade, and subsequently, the front rings need to have 11 grooves machined in them to clear this web. I also found two rings not enough, but added a third ring at the very front which also serves to locate the spinner. Once the front and rear rings are clamped up, the rotor is put in the lathe, mounted on a dummy shaft and the front of the rotor blades machined true to accept the spinner locating ring. This ensures the spinner locates dead true with respect the shaft axis, which is very important, especially with bendy 5mm dia shafts. Then the dummy clamp clamping the front and rear rings together is removed and replaced by the spinner and its clamping bolt, this bolt being what holds the entire rotor together. The spinner is then checked for runout, I now apply a runout tolerance of 0.03mm to the very tip of the spinner. The design is 100% axisymmetric so there's nothing in there (such as slight variations in screw length or tapped hole depth etc) which could cause an imbalance. My rotors, if correctly fitted to the motor, will run literally turbine smooth at full throttle because of the care taken to assemble them.

As for Chinese R&D, I'll give an example of what I experienced there recently. I went to a model factory to see about getting built up large scale aerobatic models and large warbird kits to import. I looked at a 55cc sized Extra. The engine mount was a 6mm plywood box glued together with not a lot of white glue. It had locating tabs etc, which were providing a lot of initial strength, that is, until the vibration destroys the glue joint. I asked the manager if they could do mine with epoxy, and then fibreglass over the entire engine mount. No way. they had flown theirs a couple of times and the engine didn't fall off, so it must be OK. They have had no customers complain of the engine falling off, so it must be OK. I did mention that the first thing their customers do when assembling these models is to epoxy and glass the engine mounts. "So why do we need to do it for them?" was the reply.

Last comment. Nothing is sacred, I took the pic below in a town called Yangshuo. I'm sure John Cleese would be thrilled.


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