Mounting the Aircraft-World CD-ROM motor into the GWS edf55/64

By Niels Polfliet

First you’ll have to modify the EDF 55 housing. Cut away the middle part as shown. I normally scratch it on front and back side with a knife, and simply twist it out with a pair of pliers. After that it should look like this;

Then insert the stator holder from the back of the housing, and glue it in with CA. Carefully drill 3 large (4mm) holes in the iron plate, to allow the wires to pass. This will lighten it too ;) (not shown on the pics)

Lengthen the leads to the motor with some thin wire. I use 0.65mm isolated copper wire. You can also directly solder the controller on it when the stator is already glued on the holder, if you wish to put the controller in the gondola behind the motor. Isolate the connections and wire with shrink-wrap. This is how should look now...

Replace the stock magnet by the neodymium magnets; using the following recipe;

Stock winding; glue them in NNNNSSSSNNNNSSSSS.

Warning, this configuration is very hard to do, significantly harder than NNSSNNSSNNSS, and very frustrating! Make sure you are in a good mood if you decide to do this...since the magnets strongly distract each other with NNNN or SSSS, the middle magnets will always tend to flip up. Things can go wrong on the last second before gluing. If you still want to use this configuration, I highly recommend the use of 5*5*1 magnets, in NNSSNNSS. This will have the same effect, but it will be much easier to place the magnets...

I used the supplied magnets as you can see...

Other winding; If you’re rewinding anyway, I advise you to put the supplied magnets in the stock NNSSNNSS configuration. The working RPM of the edf55 isn’t very high, so 12 magnets poles will do the job. I think that 10 windings per pole of the thickest wire (probably 0.60mm or 2*0.5, in star configuration should work well, better than stock. I have not tested other windings than the stock winding, but from my numerous previous experiments with cd motors in fans, (See http://www.rcgroups.com/forums/showthread.php?t=140736, I’m the one who actually ”invented” the use of cd motors in ducted fan)

I can tell you this will probably work better.

Now you’ll have to make the shaft a bit thicker. I do this with shrink wrap. Depending on the thickness of your shrink wrap, put 2-3 layers on the shaft end, until its tight fit into the plastic tube of the EDF 55 prop.

You’ll notice the tube is too long to allow the can full access into the prop. Carefully drill it out by hand with a large drill, until the can aligns with the edge of the prop.

Drop some CA on the shrink-wrap and push the can into the prop. The connection should already feel quite strong, and well aligned.

Cut 3 6*6 squares from packing plastic, for instance here I used the packing plastic of a waypoint servo.

Drop some ca on the plates, and insert them in the gap between the prop and the can. It’s easy to align them into the circle, by looking to the fan blades. Center the can into the prop by hand. You’ll notice the plastic isn’t tight fit, but its better like this, since the plastic plates will allow some movement, and it will center exactly while running.... (If you look carefully you can see them)

Now carefully push the edf55 prop with the can inside onto the stator. Test run it by hand to check or everything runs free.

Now here it is, ready for test run. Weighing aprox. 46 grams , with a very clean installation of the motor (even better with a foam tailcone), this motor/fan will easily outperform any speed 300 setup by a little more power with the stock winding (more with modified winding), and much lower weight. The motor doesn't have ball bearing, but by neatly mounting the motor into the prop the bearings are just inline with the blades. This will reduce radial forces on the bronze bearing to a minimum, so it should last quite a while...

With the stock winding I measured on 3S Etec 1200, with a phoenix 10 on standard advance, +-5A with 170 gram static thrust. The winding does get hot, but it will quickly unload once in the air, so it will be ok. 170 gram with 5A not bad, pretty good for a start, and such an easy conversion...

Wishing you much success,

Niels Polfliet

Niels_polfliet@yahoo.com