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Old Feb 27, 2012, 12:08 PM
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Originally Posted by Glacier Girl View Post
Guessing you weren't into hot rods. Little bit of this, little bit of that, and bingo you got something way better then stock. Dating myself, but, a flat head 8, offy intake, and stromberg carbs come to mind.

Pure hot rodding, combine the best parts to make the best set up.
Doing the same thing here, just a different end product.
yep but the problem here is the stock cs70 fan is so bad that anything other than stock is way better and basically everyone in here is hot rodding this fan because its necessary seriously the rotor is the only good part in this assembly everything else needs to be changed. the rotor is actually very good the molding,design and materials otherwise guys like Tam and Mark wouldn't even consider using it in their HP fans
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Old Feb 27, 2012, 12:17 PM
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Originally Posted by jcdfrd View Post
yep but the problem here is the stock cs70 fan is so bad that anything other than stock is way better and basically everyone in here is hot rodding this fan because its necessary seriously the rotor is the only good part in this assembly everything else needs to be changed. the rotor is actually very good the molding,design and materials otherwise guys like Tam and Mark wouldn't even consider using it in their HP fans

so for this great rotor what housing could be used with it, beside that wm 400 housing?

1/ mini 480 housing?
2/ het 6904 housing?
3/ any chinese fan housing?

....
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Old Feb 27, 2012, 12:22 PM
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we were using the eflight V15 housing before we switched to the TJ70
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Old Feb 27, 2012, 01:16 PM
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Originally Posted by flylow2011 View Post
so for this great rotor what housing could be used with it, beside that wm 400 housing?

1/ mini 480 housing?
2/ het 6904 housing?
3/ any chinese fan housing?

....
You could use any shroud you choose.

It's just that most aren't up to delivering the most of what can be had. There can be only 1 best, and that is what is being sought in this thread.
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Old Feb 27, 2012, 03:19 PM
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Maximum motor diameter would also be useful. I can't afford to try many housings... terminally unemployed
Ken


Quote:
Originally Posted by flylow2011 View Post
so for this great rotor what housing could be used with it, beside that wm 400 housing?

1/ mini 480 housing?
2/ het 6904 housing?
3/ any chinese fan housing?

....
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Old Feb 27, 2012, 04:06 PM
Extreme CNC Alloy EDF
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Originally Posted by 901racer View Post
Extreme .. Same question, you seem to be quoting some numbers that are not on your site for a 6s setup at 1650watts. I assume it is just out of date or i'm looking in the wrong place.
Keeping up with testing is hard, every time you change the packs used or the weather is different things get better or worse!

My original 6s fan test was 1399 watts for 2.1kg thrust, that was at just over 65 amps, I think this is one of the best balances of efficiency so far. You need just over 39K rpm to get this thrust from an open back fan.

Later tests were 1500w for 2.25kg thrust, warmer packs. Last test I did was 1625w and an extra 1000rpm, did not have brackets on this fan so could not thrust test it, but should be around 2.4-2.5kg.
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Old Feb 27, 2012, 04:16 PM
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Personally I doubt stators will make that much of a change to amp draw, more likely the balance and blade clearance. As for rpm, test with and without an inlet lip and watch the rpm jump heaps without, load the fan up with perfect inlet flow and the rpm drops as the fan ingests more air. Stick a thrust tube on it on the stand and the rpm drops, amps go up, thrust stays the same though. Only way to compare is to have the fans on a known thrust stand with an inlet lip and no exhaust.
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Old Feb 27, 2012, 04:36 PM
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Originally Posted by PikeStaff View Post
For those looking for shrouds that are stiffer, but not in the alloy $ range, the WM400 clone that HK sells has a shroud that's pretty stout. It has fit all the motors I've put in it so far, including the Tacon 2550.

Link: http://www.hobbyking.com/hobbyking/s...nch_70mm_.html

At $13, it's not the cheapest fan they have, but the housing is a good 30% - 40% thicker than the rest.

And - miracle of miracles! - it's in stock.

could you post your test result with tacon 2550?
thanks.
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Old Feb 27, 2012, 04:54 PM
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Originally Posted by Extreme_RC View Post
Personally I doubt stators will make that much of a change to amp draw, more likely the balance and blade clearance. As for rpm, test with and without an inlet lip and watch the rpm jump heaps without, load the fan up with perfect inlet flow and the rpm drops as the fan ingests more air. Stick a thrust tube on it on the stand and the rpm drops, amps go up, thrust stays the same though. Only way to compare is to have the fans on a known thrust stand with an inlet lip and no exhaust.
Wrong....stators is very important direct the airflow.
Some stators are less effecient than other.
Just imagine the wing of your aircraft.
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Old Feb 27, 2012, 05:24 PM
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Post #1091

Regarding the Tacon 2550 orange can motor:

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Originally Posted by PikeStaff View Post
Put it in the rig, VERY preliminary tests, with lip but no tube. The leads on my kv/tach melted off during a run on a 5055/600kv that's going into the F4U, so no rpm recorded. Also, no dynamic balance as yet, just a few turns of the rotor to smooth it out.

Batt is an older 4000mAh, 30C, 5s. Start volts 18.301, steady around 17.44; max amps 76.3; max 1373w.; pull on scale max 1680g, settled at 1570.

Also - using 60a. Pentium with medium timing and 16khz switching.

Looks like I need a bigger esc.
Since that time, I have not pursued more testing with this setup, having other things I wanted to get done first. Also, didn't have a decent 6s battery at that time.... do now, so I will get this one back under way. Just received 2 new 10-blade fans in the mail today.
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Old Feb 27, 2012, 05:48 PM
Extreme CNC Alloy EDF
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Originally Posted by Tamjets View Post
Wrong....stators is very important direct the airflow. Some stators are less effecient than other. Just imagine the wing of your aircraft.
Ok I was not clear enough, bad habit LOL. Comparing stators on quality housings, not going to find huge differences as most follow proven design, but what they are saying then is the eflite housing is a poor design??? As thats what they are comparing your housing to.
Looking at the figures my end results are on par with yours, so safe to say similar design quality...
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Old Feb 27, 2012, 06:19 PM
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Originally Posted by erh7771 View Post
Has Bob ever done any experiments with "pre" chambers?

Much like 6th order bandpass?

With 6th order band passes in audio subs you can concentrate the frequencies and with 1000watts levitate a nice sized floor rug.

The "pre" chamber in EDF cases would add a "pre swirl" at x degrees so that the fan at y RPMs would a lot more efficient due to it being able to "bite" on to way more CFM than if the pre swirl chamber wasn't there.

At RPMs before the "preswirl" efficiency the thrust would stank though but one properly designed could get enough static thrust to get a plane in the air then get it nasty after some ground speed increases.

Dunnoh, I'm no genius ....someone has prolly already done this.
You have to be careful with a pre-swirl to the air entering the fan, depending on the direction and the angle it can add load or take load out of the rotor.
The WM400 fan was calculated to take advantage of pre-swirl from the purposely designed IGV shroud. IGV's in compressors are designed to control load on the compressor, the same is true with the compressor side of a GT. In this application I don't think you want to have an IGV as the rotor is already loaded well over most of what motor combinations can efficiently handle. So adding load will effectively make the fan unusable for 28mm motors, taking away load will cause efficiency to drop.

OBTW using the WM400 shroud with this rotor is probably not going to work that well. I have not looked at one in several years though, if anyone gives it a try please post the numbers.

Cheers,
Eric B.
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Old Feb 27, 2012, 07:21 PM
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Originally Posted by AirX View Post
OBTW using the WM400 shroud with this rotor is probably not going to work that well. I have not looked at one in several years though, if anyone gives it a try please post the numbers.

Cheers,
Eric B.
Curious why you think this shroud won't work too well. It is orders of magnitude more rigid than the stock 10 blade shroud - too bad there's no readily available entry lip for it, would make stand testing more enjoyable.
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Old Feb 27, 2012, 08:09 PM
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Originally Posted by Extreme_RC View Post
Keeping up with testing is hard, every time you change the packs used or the weather is different things get better or worse!

My original 6s fan test was 1399 watts for 2.1kg thrust, that was at just over 65 amps, I think this is one of the best balances of efficiency so far. You need just over 39K rpm to get this thrust from an open back fan.

Later tests were 1500w for 2.25kg thrust, warmer packs. Last test I did was 1625w and an extra 1000rpm, did not have brackets on this fan so could not thrust test it, but should be around 2.4-2.5kg.
Thanks for the response Extreme. You are right that it is hard to keep up with testing and absolutely correct about battery technology getting better all the time.

You never know, I may pick up one. I do like the efficiency. Let me know if you want your numbers published in the consolidated testing list in this thread?
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Old Feb 27, 2012, 08:22 PM
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Originally Posted by Glacier Girl View Post
Derek, I have a flying bud who's my go to guy on prop power. He's dropping a pair of the CS fans with those Turnigy 2100's in his SR 71 Blackbird. So I'll report back when I hear how they worked for him.

And another question. The new fans don't have a washer for the nut to ride on for the adapter. Me, I'm not too crazy about the idea of the nut pinching/deforming the rotor when it's tightened down. Seems to me that's going to be a self induced weak spot, that could lead to rotor failure down the line.

Am I missing something here?
Wow, this is an active thread!! Hard to keep up. Yes, please let me know the results. I have two 2500kv on the way, so we can compare the two kv's.

My four CS10 fans do not have washers. I am just putting the nut only. Is this bad?? Should I make a washer?
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