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Old Nov 14, 2012, 01:18 PM
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Question
What's the "state of the art" for 70mm fans? ...been out of it for a little while

I was heavy into EDFs about three years back. I had a ball with my EF-16s, various 64mm Starmax EPS planes, some Sapac stuff...I kept a few 50mm planes but for the most part, my jets have been collecting dust.

So where have things gone with 70mm fan technology? The Sapac 70mm fan that I have on my bench looks downright crude compared to some of the stuff I'm seeing now.

Are more blades better? What are the hot setups these days?

Is the HET 6904 still a good fan?
Is Hoffman (beast, storm, etc) all gone?
Do people still run ARC 1-turn motors?
Is the Changesun stuff any good? Seems like it might be cheap...

Thanks to anyone for catching me up!!
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Old Nov 14, 2012, 01:33 PM
killickb
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Spend some time reading the Forum threads, get up to speed and get ready to spend the money!
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Old Nov 14, 2012, 01:55 PM
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The ChangeSun 10 blades seems to be the current great thing, but only the rotor, it seems that people are using the rotor and discarding the shourd
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Old Nov 14, 2012, 01:59 PM
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Originally Posted by killickb View Post
Spend some time reading the Forum threads, get up to speed and get ready to spend the money!
LOL... good advice, of course. I have been doing just that.
A specific question never hurt though, right?

Quote:
Originally Posted by lowkeylaidback View Post
The ChangeSun 10 blades seems to be the current great thing, but only the rotor, it seems that people are using the rotor and discarding the shourd
This is good to hear! IIRC, more blades usually means better sound. What's the downside of the shroud? Too flexible?
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Old Nov 14, 2012, 02:53 PM
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I am using the CS 10 blade along with the shroud. I haven't been running a ridiculous amount of watts through it, less than 1kw. Its holding up fine for me at least. I did have to sand the inside of it a bit to get my outrunner not to rub. Effluxrc has some really nice 9 or 10 blade full alloy fans that are good up to like 5-6 lbs of thrust if I remember right. A lot of people are using the het 6904 or wemo fans. A lot of people have also jumped on the CS fans for the sound. There are also some places (extremerc, edfhobbies, hk, and probably more) that have made an alloy shroud for the CS fan. I know a lot of people are using those too. Don't know what price range fans your looking at, but detrum also has a great combo going. Fan/3000kv motor/ 60a esc, and 4 servos for 47 bucks. Does like 42 oz thrust or so on 4s, and quite a few people running it on 5s all stock with good results. Don't have thrust numbers for 5s. I personally am using the detrum and CS stock fan. The sound of those 10 blades is really something, and with the right airframe it has a great turbine like sound as it flies towards and away from you. The CS fan though is very amp hungry due to all the blades.
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Old Nov 14, 2012, 04:03 PM
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Here's our 70mm Mach EDF running on 6s with a 2900 KV Velocity RC motor. Not our most powerful setup, but plenty fast.
The Jet is a SAPAC composite, with air retracts and scale struts. Flies for 4 1/2 minutes.
Other high power 70mm fans we carry are the Velocity WM400mkII, HET 6904, and Wemotec Minifan Pro. These have been the long standing quality EDF for a number of years and are running at 2500+W today.

Viperjet Demo - Las Vegas 2012 (3 min 22 sec)


Ali Demos our Viperjet at Best in the West (5 min 37 sec)


HET and Wemo rotors are also great in Alloy housings for higher power stuff. The one pictured is Wemo rotor, and Velocity-RC 3200kv motor on 6s, going into my Habu2 foamy right now.
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Old Nov 15, 2012, 06:02 AM
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Quote:
Originally Posted by stingeragents View Post
I am using the CS 10 blade along with the shroud. I haven't been running a ridiculous amount of watts through it, less than 1kw. Its holding up fine for me at least. I did have to sand the inside of it a bit to get my outrunner not to rub. Effluxrc has some really nice 9 or 10 blade full alloy fans that are good up to like 5-6 lbs of thrust if I remember right. A lot of people are using the het 6904 or wemo fans. A lot of people have also jumped on the CS fans for the sound. There are also some places (extremerc, edfhobbies, hk, and probably more) that have made an alloy shroud for the CS fan. I know a lot of people are using those too. Don't know what price range fans your looking at, but detrum also has a great combo going. Fan/3000kv motor/ 60a esc, and 4 servos for 47 bucks. Does like 42 oz thrust or so on 4s, and quite a few people running it on 5s all stock with good results. Don't have thrust numbers for 5s. I personally am using the detrum and CS stock fan. The sound of those 10 blades is really something, and with the right airframe it has a great turbine like sound as it flies towards and away from you. The CS fan though is very amp hungry due to all the blades.
stingeragents,
Thank you! Great info here. Since reading your post, I have been educating myself on these fans and they seem extremely cool. The sound of the CS 10 blade fan is fantastic...it seems that they only sound this good when perfectly balanced (which makes sense)...do they typically require a lot of work? I remember spending hours trying to get the old Freewing fans to balance and rarely having any luck.

Which outrunner are you using in yours? Are you happy with it?

The HK alloy combo that you mentioned (with a motor wound for 4s) goes for $80...is it worth it? How is that motor?


I also found the Detrum combo you were talking about. It looks like a great deal but I'm really leaning towards the 10 blade route.

Again, thanks a million for the input.
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Old Nov 15, 2012, 06:05 AM
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Quote:
Originally Posted by efflux RC View Post
Here's our 70mm Mach EDF running on 6s with a 2900 KV Velocity RC motor. Not our most powerful setup, but plenty fast.
The Jet is a SAPAC composite, with air retracts and scale struts. Flies for 4 1/2 minutes.
Other high power 70mm fans we carry are the Velocity WM400mkII, HET 6904, and Wemotec Minifan Pro. These have been the long standing quality EDF for a number of years and are running at 2500+W today.

http://www.youtube.com/watch?v=vNVGe...3&feature=plcp

http://www.youtube.com/watch?v=Tt7KPFIa2_M

HET and Wemo rotors are also great in Alloy housings for higher power stuff. The one pictured is Wemo rotor, and Velocity-RC 3200kv motor on 6s, going into my Habu2 foamy right now.

Amazing stuff.
When I asked what the "state of the art" was, I had no idea! You guys sell some gorgeous equipment! It also sounds like it performs as good as it looks.

When I eventually build a composite jet, I will be giving you guys a call...but stuffing one of these in a $49.99 Squall sounds like a $20 shine on a $3 pair of boots.
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Old Nov 15, 2012, 09:29 AM
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Hey, yea I forgot all about efflux's all metal fans. Look great and lots a power but out of my price range for the time being. I personally haven't used the allow shroud CS fans, just the all plastic ones. I think most of the guys that go with the alloy shrouds are putting a lot of power in their fans. If you have a look at this thread . http://www.rcgroups.com/forums/showthread.php?t=1601868 , it has a bunch of test results for the stock fan on multiple different setups. I personally went the cheap route for my first fan. Stock fan , and an exceed 2700kv outrunner. I don't have a watt meter yet so not sure on the figures I'm getting (have one that should be in , in a few days so ill be able to tell you). If you don't mind ordering from hobbyking, you can get several different motors (ones in that thread I just posted), for even cheaper than the exceed one. I just am impatient and didn't wanna wait. As for the sound, yes you need to balance it, but what most have figured out is the sound comes from the intake/ exhaust. Something to do with turbulence in either of those. I tested this myself and its true. All you gotta do to change the sound is move your hand around behind the thrust tube. As far as speed with the setup I used, not 100% sure. I have been doing scratch built edf's so they aren't the best airframes, and my intakes haven't been perfect. I don't know if your familiar with tomhe's plans for pusher jets, but I dropped this fan and a thrust tube into his F22, and it flies pretty good. Over 1:1 thrust ratio on a 29oz plane. From what I have seen, as I've done a lot of searching also, you get the best sound from this fan when its put into a kit airframe. Can't think if I've heard how one sounds in a squall or not. As far as difficulty balancing, I actually used a heli blade balancer on mine. Did take me a bit more work just cause its not a magnetic one, but I did get it right. Depending on the phone you have (need an accelerometer), you can also dynamically balance it with your cell phone. I tried to do this, but it ended up being more trouble than it was worth to me, so I just stuck with the static balance and haven't had any problems. As far as the detrum fans, on 4s they have been tested to 700 watts with 42oz thrust. Also found some figures last night, 1000 watts on 5s. Has been a good running setup also for me but of course sound isn't there. My GF ordered me a phase 3 16 a few days ago and was debating on the power system last night. I bought another one of the detrum combo's as well as another CS fan. My plan is to use the detrum 3000kv motor from the combo in the change sun fan. Should give me around 1100 watts or so. Will probably have to keep it on 4s though. Do take a look at that thread though. Should give you a general idea on what sorta amps/ watts you can expect for a given setup.


Oh, and I just saw, there is now a 70mm CS 12 blade fan. http://www.x-flight.com.hk/index.php...&cat0=4&id=176
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Last edited by stingeragents; Nov 15, 2012 at 09:37 AM.
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Old Nov 15, 2012, 10:30 AM
killickb
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Yes and they say best motor for the 12 blade is 3400Kv (4 cell). What sort of amps will that be pulling! My 10 blade went off the scale until I dropped down to 2300Kv.
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Old Nov 15, 2012, 04:06 PM
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Interested in where this goes. I have a Sapac JAS39 that I will be building and am wondering about the power setup. I have had 2 previously and modded them for a 90mm Midi Pro on 6s. Flew great (hand launched) but now that the 70mm have really improved, I am thinking of going that route to keep the weight down and to keep from modding it alot. Will be watching this thread.
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Old Nov 15, 2012, 07:08 PM
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The info is massively appreciated!
I just ordered up one each of the 10 blade and the 12 blade from X-Flight.
The ten bade will likely be the go-to power setup for the Squall! and I look forward to expirimenting with the 12.
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Old Nov 15, 2012, 09:19 PM
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Be sure and post up some test results from the 12 blade. Ill prolly wait until a us seller gets them. I hate ordering from hk
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Old Nov 16, 2012, 02:17 AM
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my vote goes to the Efflux fan ....and you can get good perf on the ole HEt 6904 with a hot motor in it ...just does'nt sound as good as the Mach fan. ck my F-20 thread out for state of the art airframe.
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Old Dec 01, 2012, 08:51 AM
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thanks again to everyone for their input.

My order from X-flight arrived today.... I paid for a 10 blade and a 12 blade, only the 12 blade was in the box!!!

Has anyone had problems with X-Flight before? How were they in handling the problem?

I'm worried because you can't prove what wasn't in the box.
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