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Old Aug 09, 2003, 06:48 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
cd-motor in 50mm homemade ducted fan

Hi guys,

A while ago i read in the 'home made brushless' threat that using cd-motors in edf's isn't possible. Guess what i did

I made the whole fan myself of 1 mm flat plastic plate, hot bend, since i'm to cheap to ruin a good edf 50 . I did use an edf50 fan though, because i wasn't sure my homebrew fan's are able to survive 36000+ rpm

It wheights 48 gram inc. CCphoenix 10 controller. Lots of weight savinbgs can be done though, i'm about to cut it a bit shorter (the fan )...Working on a nice inlet rind etc right now to make it more efficiant.

Here are some measuring results;
-on 3 half blow up 1040 kokams (1st generation)
-with the 2030X3 prop

original magnet;(without prop: 54000rpm)
4.95A, 36500rpm,116 gr static thrust

new 12 pole magnet; (without prop:45000rpm)
4.22A, +-36000 rpm, 110 gr

new sixpole magnet; (63000 rpm on 3/4 stick (didn't dare to go further )
same results as original magnet, but on half throttle I could'n go further, because i don't have kokams that can take the current draw...But more power is definitly possible, i already have the 2030X5 prop laying around

(note the 2030 prop isn't the stock edf50 prop, but the one with more efflux .Thats Why the current draw is so high

here are some pics;

aerodynamical entrance of the copper whire ...

(first see next pics in next post)


Yes, i've already flown it, and mmm, this is kind of abuse for the plane, way to much power It was kind of a pylon racer already at half throttle. The wing didn't like that so much, i can tell you...

I would like to built a cool jet for it, does anyone know a nice platform for this edf? Every plane that flies on a single edf 50 should be able to be overpowered with this one
What do you think?

Niels

(sorry for spelling errors , I learned english from TV...)
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Old Aug 09, 2003, 06:49 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
next pic...

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Old Aug 09, 2003, 06:49 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
from behind ;)

from behind
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Old Aug 09, 2003, 06:50 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
test model...

test model, 'turbo' gws picostick..234gr


this was the last one...
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Last edited by niels polfliet; Aug 11, 2003 at 08:21 AM.
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Old Aug 09, 2003, 07:40 AM
Registered User
Alberta, Canada
Joined Sep 2001
1,292 Posts
I wonder how that will unload during flight? This may be an interesting option for an a-10 power/longevity upgrade.

1200 Etec cells in a 3s2p configuration ought to provide heaps of power and good duration with this setup.
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Old Aug 09, 2003, 08:04 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
Yeah, it would be a "lifetime solution". These cdr never frie. And it won't add much weight...

No idea about unload... But i guess the current drops more than just a bit...

I might be able to test it. If i only had an A10 a another Phoenix ...

I think 3s1p is already enough (9-9,5 A), you won't fly it all open al the time with this much thrust and efflux Maybe 2s2p is an option too, but with the six pole rotors or with the 12 pole rotors and 5 blade fans so many possibility's

Niels

(Anyone knows a cool (fast )jet that flies on 1 edf50 unit?)

update; spelling error
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Last edited by niels polfliet; Aug 25, 2003 at 08:25 AM.
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Old Aug 09, 2003, 09:21 AM
Registered User
USA, PA, Pittsburgh
Joined Jul 2001
1,467 Posts
Get yourself Fantastic Mig-15 or f-86 and voila.

BTW what's the wire thicknes you used and how hot are your turns on the stator?

What' was the Voltage you tested that motor on?

thanks

darmar
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Last edited by darmar; Aug 09, 2003 at 09:35 AM.
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Old Aug 09, 2003, 02:52 PM
Claus at Area 52
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copenhagen Denmark
Joined May 2002
2,538 Posts
or you simply scale down my U-2 design....
at the moment it is for a schaubler 90 mm fan... but it is in acad (dxf) so no problem to make it smaller..
Claus
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Old Aug 09, 2003, 02:57 PM
Claus at Area 52
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copenhagen Denmark
Joined May 2002
2,538 Posts
but with your way of doing it... every model is possible even an airbus 340,
You got to give us all the "recipie" for that motor.. even the brand of the cd motor you used.
Claus..
Ps..
if you want I do have more in the pocket than the U-2.. but the U-2 is the most finished drawing at the moment.
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Old Aug 09, 2003, 04:15 PM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
Hi guys!

glad you're interested.

The voltage i tested on... i don't know exactly.. It was on 3 blow up kokams so te voltage drops a bit faster than normal.. so aroun 10 V I guess

@ claus

mmm, U2.. Sorry, never heard of it. you have a link to a foto, treat? I'm interested in the plans, if it looks cool Which other plans you have? I'm looking for something like an F16 or look-a-like...



mmm, the recipie of the motor/fan I think i'll keep it secret

no, no secret's on this one .
I can already give you some info on the motor;

brand; comes out of a 'plex6' drive from plextor. It has a relative large stator, and i'ts stock ballraced. It comes with a 3 mm steel "rod" (don't know the right name) which i've replaced with a piece of 3mm carbon fiber rod.

The prop (always use the 3"pitch gsw edf prop's!, more efflux...) is drilled out to 2.8 mm and just pressed on. Don't drill it to the end (as on picture in prev.post) This weakens it to much i think.

The motor is rewound with 8x0.5mm, Y configuration. For the next one, i'm going for delta configuration, for more power and better sense signal. I'll have to have more windings though.
It has new neodym magnets, 12 pole, 5*5*1, but the standard ring will also work, but it will draw 0.6A more...

When pressing on the carbon rod en removing the old magnet, make sure you don't force it!!! It bends easely, and at 30-40000 rpm things may go seriously wrong. That's why i advise you not to make a ducted fan from your first cd-rom conversion...

the fan...

The hardest past is to find tubes that have the right inner diameter for the fan. The inside diameter of the fan (the tube inner diameter should be larger!) is 51 mm. This is a good value for the gws props. You'l also have to find a tube with the outer diameter around 50 mm.

Here's how to make the outer and the inner "duct tube" ;

Get yourself some plastic plate of +- 1 mm thick. I used 1 mm, but I think thinner will do (lighter...)

Cut a piece wide and long enoug to roll the tube. The best is to make it a bit longer. Take your paint remover (or a very hot hair dryer) and make the piece so hot it starts to curl. when it's warm, quickly lay the tube with the 50mm diameter on one end roll it over, so you get a tube that is about round. the end will overlap, so cut it little by little till the overlap is less then 5 mm

Then put the tube you just formed in the tube with +-53mm inner diameter. This will give you almost a duct with 51mm inner diameter. Now cut the overlap further until iI'ts less than 1 mm.
Heat the duct again while it's in the tube, and press it with a broom stick until you get a nice round duct... The plastic crimps a bit, so you schould be able to get lost of that 1 mm overlap just by adding heat.

Work the same way for both duct tubes, and the hardest part is done.

for the fan stators...Cut some pieces of the right size, and bend them on a bended aluminium plate . Glue everything together with medium ca and accelerator spray...

Hope this was a bit clear, mayby i'll make some construction pics later, if you beg enough for them

Niels

(sorry for spelling errors , I learned english from TV...)
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Old Aug 09, 2003, 09:43 PM
Houng-wen Lin
GWS4CEO's Avatar
Shijr, Taiwan. DungGwan, China. City of Industry, California.
Joined Sep 2001
19,445 Posts
Geee~~ Wow~~

Smart and great result!

Don't for get to see new GWS EDF64 and EDF55!
R/C Groups Discussion > Vendors > GWS (Grand Wing Servo) > EDF55 test datas
http://www.rcgroups.com/forums/showt...hreadid=140125

R/C Groups Discussion > Vendors > GWS (Grand Wing Servo) > Gws Edf64
http://www.rcgroups.com/forums/showt...ighlight=edf64
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Old Aug 09, 2003, 11:18 PM
Registered User
Alberta, Canada
Joined Sep 2001
1,292 Posts
Could an outrunner motor like this be something that gws could make? It would make a fantastic (pun intended) powerplant for the 50 mm fans.
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Old Aug 10, 2003, 08:52 AM
Crazy Cessna Owner
Robbie d's Avatar
Australia, SA, Windsor Gardens
Joined May 2001
1,935 Posts
you have made a large step forward as far as small ducted fans go. well done. cd roms are so cheap now, just buying them for the motors would be worth it.
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Old Aug 11, 2003, 12:41 AM
Registered User
USA, PA, Pittsburgh
Joined Jul 2001
1,467 Posts
Well, I made one and it works fine on 2s etec 1200 cells.

I must admit that it gets little warm after test runs on 5-bladed edf50 prop.
You can hardly hear it running on full trottle and sounds like it has some guts, not like Gws stock one that screams like it's gonna lose it any minute.

Did not test the thrust and amps yet. Good news is that cc 10 phoenix does not gets hot and works fine for 8 minutes I let it run and after that still 360 mah left in the pack, voltage 7.5 v.

The bad side of the story is that controlers are not cheap regardless of getting motors for free.

Motor is from 4x cd-rom year make 1996 nine pole stator
revound to 8t delta conf. with 26 gauge wire-green stuff from RADIO SCHACK
stock magnet 12 pole
weight 36 grams including fan and conector

darmar
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Last edited by darmar; Aug 11, 2003 at 07:00 AM.
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Old Aug 11, 2003, 04:28 AM
cd brushless motors rule!
niels polfliet's Avatar
Sint-Gillis-Waas, Belgium
Joined Nov 2002
316 Posts
thanks for the kind words guys!

Wow Darmar, that's fast!

How did you make the fan? pics?

there are some differences though, mine doen't get warm, even after a long flight, you can hardly feel it has run. My controller get pretty warm though. I'ts not about the amps, but it seems to get warm because it has to 'switch' a lot.

The weight seems ok, my weight (48gr) is inc the contoller.

Quote:
The bad side of the story is that controlers are not cheap regardless of getting motors for free.
Yes, feels bad doesn't it? But hey, if make some crazy calculation;

-a phoenix costs about 68$, you save +-14$ on the fan by building it yourself (minus prop). You dont buy a brush controller of about 20$. So the system cost about 60-14-20$=26$ more than a normal edf. Don't you guys wonna pay 34 bucks more for one that has more power and lasts forever? If you fry 4 motors, the difference is zero

I think i'm gonna make another one, but with 0.5mm plastic The weight should be close tot the original edf 50 because the motor weights the same

Niels
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