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Old Nov 08, 2014, 10:48 PM
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Joined Nov 2014
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Freewing A10 Changesun 12 Blades Upgrade

I've been searching info for upgrading the Freewing A10 to Changesun 12 Blade EDF for 4S setup. Unfortunately there's not much info so I went ahead and went for the upgrade. The following is my experience and I hope it helps others. (EDFs are balanced, each test was with fresh 3600 40C 4S battery)

1st I found out that the Changesun 64mm 12 Blade 2500kv with 4S setup was the same thrust rating as the Freewing 64mm 5 Blade 3500kv 4S at 850 Grams.

2nd I trimmed the stock cowling to fit in the Changesun. This was not easy as the Changesun is slightly larger.

3rd I measured the thrust. To my disappointment, only 680 grams from Twin EDFs. Surely something must have been wrong.

Next I measure the thrust with the stock Freewing EDFs, the results were better at 1370 grams. Much different. I'm thinking I made a big mistake purchasing the Changesun. I also was wondering at this time why I wasn't getting 1700 "advertised" grams from either of the EDFs.

I built a test stand so I could experiment with both EDFs in a controlled and easier to use environment. The basic stand is a lever for a kitchen scale with no "Thrust Tube". In other words the inside of the cowling is slightly larger than 64mm diameter. I did this to see what thrust would be with limited to no restrictions. Crude, but it just needs to be a standard. I might pretty it up later.

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DATA:

Best single Freewing 64mm EDF on my test stand was 787.4 grams, no thrust tube and Medium Timing. 32 Amps and 497 Watts


Best single Changesun 64mm EDF on my test stand was 918 grams with a thrust tube at 64mm and Low Timing. 40 Amps and 590 Watts
Since the Hobbywing 40 Amp ESC is what comes with this A10 I'll need another upgrade for the ESC.

So I decided to make a new Thrust Tube for the A10 motor mount / Cowling. I bought another cowling to keep the stock setup. Left is stock and right is modified. I used plastic shelf liner fire wire shelving, if you are interested. It paints well too.

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Best Twin EDF setup with Freewing EDFs, 1350 Grams, 60 Amps and 890 Watts. The Thrust Tube chokes down to 50mm. This is almost 22%. I've heard 5%-20% is optimal. 5% if you want more Static Thrust all the way to 20% if you want top Speed.

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Best Twin EDF Setup with Changesun EDFs, 1520 Grams, 70 Amps and 980 Watts. The thrust tube only chokes to 62mm this is only 3%, but it was still good on Static Thrust.

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I have more data I can share if anyone is interested. I think this could apply to other models.

I am open to suggestions on ESCs to run these Changesun EDFs. The sound is so much better than stock. Funny, I haven't even flown this thing yet. I used to do Gliders years ago and now I'm trying the electrics and converting my gliders.

Happy landings!
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Old Nov 08, 2014, 11:00 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
21,151 Posts
The 12 bladers are amp hogs......the only good thing is they sound better.a good mod for you would have been some 64 mm HET fans with @ 3800 to 4000 kV motor. Are you using 1 or 2 batts?
Fly it both ways and see which is better.you haven't measured efflux speed that will make a difference also.the12 bladers will be a shorter flight too.all things to consider.
You said you got 680 g with both fan running??? Then you said you 1500 g with both......not sure but you need a 3600 batt for each fan I think.
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Last edited by AIR SALLY; Nov 08, 2014 at 11:17 PM.
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Old Nov 08, 2014, 11:10 PM
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Joined Nov 2014
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I use only 1 battery. Do you have a link to the " 12 blazer". I'd like to check them out.
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Old Nov 08, 2014, 11:16 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
21,151 Posts
The get 64mm fan only has 4 blades try Dons R/C or Efflux R/C both are vendors hereon rcg.
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Old Nov 09, 2014, 02:11 AM
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United States, TX, Grand Prairie
Joined Nov 2005
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Jasenk

Notice on your own test your pulling 8 more amps on your 4s 12blade compared to the relatively efficient but thin bladed 64mm Freewing fan

but you're also getting around 130 more grams of thrust... so that extra energy is putting out more static thrust

Thrust to watts the CS fan is putting out more static thrust than the Freewing fan... and slightly more efficient (static thrust wise)... just going by your numbers

Look at thrust to watts... on a lot of fans... Big.. small... whatever ....it'll... make things .... "simpler"

Caveat... for this 12 blade don't close down the exit more than say... 10% in order not to stall the blades...

This is an A-10... static thrust was it's game...

That CS setup in a twin can also run EASILY on 5s in case you want to put some stank on it
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Old Nov 09, 2014, 03:54 AM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
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Quote:
Best Twin EDF Setup with Changesun EDFs, 1520 Grams, 70 Amps and 980 Watts. The thrust tube only chokes to 62mm this is only 3%, but it was still good on Static Thrust.
Your approaching this incorrectly. The exhaust is supposed to be a percentage of the fans area(FSA) not diameter. At 62mm you are over 100% of a 64mm fan. The efflux speed of your exhaust is actually slowing after it leaves the stator area.

You need to know the FSA of the unit, minus the motor tube, and go the percentage of area, you require, for the outlet.

Fuzz
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