Air Craft
DataSheet

 AIR CRAFT DIY MOTOR SETS
AC-DIYMOT-DD
AC-DIYMOT-GD
Pricing HERE

Well, the state of the art in "Do-it-Yourself" motors is certainly advancing...  These new AIR CRAFT DIY Motors are real beauties - featuring precision-machined components throughout, careful design, innovative magnet technology, top-quality double ball bearings, AND two variants to suit your needs!  The magnets are pre-installed in the bell, so all that's left for you is to wind the stator and do the simple parts assembly. Should take less than an hour, even the first time!

Here's a picture of both types, with some mounting options shown.

The two motor sets are identical, with two exceptions:
* Motor Shaft Dimensions
* Dimensions of the bearing carrier (the purple front part of the motor)

AC-DIYMOT-DD ("direct drive") has a 3mm diameter motor shaft, 30mm long.  This is ideal for mounting a prop-saver wobbly adapter for direct drive applications at lower RPM.  The purple bearing carrier is the same diameter as the motor bell, 25.6mm. 

AC-DIYMOT-GD ("gear drive") has a 30mm-long, M3 shaft, too, but has a 2.3mm end.  The 3mm section is 20.5mm long, then it steps down to the 2.3mm section which is 9.5mm long. This allows fitting of motor to gearboxes and ducted fans made for Speed 400 motors.  Likewise, the purple bearing carrier is 27.5mm in diameter, which is exactly the same as Speed 400 motors - so that the motor fits properly in the gearbox or fan unit.  Although we call it the "Gear Drive" type, note that the AC-DIYMOT-GD can also be used direct drive, depending on the size of wire and number of turns you choose.

Weights without connectors or prop adapter installed:
AC-DIYMOT-DD  28 grams
AC-DIYMOT-GD  29 grams
Typical weight for motors with connectors and prop adapter installed would be 31g to 34g.

Otherwise, the two motor sets are identical. Here are the features in common:

*Custom Steel Bell with installed super-strong magnets
*9 pole stator
*0.32 mm wire (enough for two or three winding sessions)
*2.0mm Shrink tube for the wire
*2.4mm Gold Connectors for ESC <> Motor connection
*4.0mm Shrink tube for the connectors
*Hardened steel motor shaft
*(2) 7mm x 3mm x 3mm ball bearings
*(2) washers
*Mounting screws
*16 mm and 19mm by M3 mount patterns

Click on the pictures below to get details on each part:

Included
Motor Bell		 Included
GD Shaft*		 Included
Stator		 Included
Shrink		 Included
Fem Conn		 Included
Male Conn

*DD shaft is M3x30mm

Option Shaft Front or Back Mount Stick Mount Prop Saver for DD Prop Adapter for GD (used direct) GD Gearbox option GD Gearbox option

The motor sets come as pictured below.
However, the green loctite (#638) is supplied as a courtesy and may not always be included, subject to stock status.
Any green "sleeve retainer" grade permanent loctite can be used.  I do NOT recommend using CA glue.



To wind the stator for DD version, use the supplied wire in a single strand with 26 turns per pole, Delta.  If you have the GD version, and plan to run direct or in a ducted fan, use the same wire but double it as you wind, with 12 turns per pole, Delta.  Here's a diagram (courtesy Takao Shimizu) to show you the Delta wiring pattern, on right:

When winding the stator, make the loose ends about 7cm long (3") to be sure they are long enough. You can trim them to final length later, but adding length is much more difficult!

*When the stator is wound as above, you'll start assembly by fixing the stator to the bearing carrier (purple part) with a LITTLE BIT of loctite. One stroke of loctite on either side of the carrier is enough.  If you need to remove the stator later, you can heat it with 100W soldering iron to loosen the loctite.

[note:  If installing the GD version in GWS gearbox: (1) drill a hole in the gearbox matching the wire outlet in the bearing carrier (2) Insert bearing carrier into GWS gearbox frame (3) Run the stator wires through the outlet holes (4) Loctite the stator to carrier.]

*Use a TINY bit of loctite to retain the outer bearing in the carrier:

*Loctite the motor shaft to the bell.  Degrease both shaft and hole in the bell. Use a piece of the stator wire to run a thin film of loctite around shaft end and inside the hole in the bell. Set Bell on flat table, facing up.  Insert shaft into the bell.  Don't touch it for 10 minutes.  Now apply some alcohol to a tissue, press tight around shaft and press into the bell, and twist to remove any loctite remaining around the shaft/bell junction.

*Install the inner ball bearing into the bearing carrier.

*Usually a washer is not needed between bell and inner bearing, but really aggressive winding that sticks way up may require one.  Test fit the bell to carrier to see about that.

*Now cut the motor wires to desired length. Use paint remover to remove the enamel coating on the end of the wires; about 5mm (1/4") of clean wire is enough. Twist each wire set togther and tin with solder. Use the 2mm heatshink to insulate the motor wires.  Solder on the male gold connectors [the connectors are hollow inside, so hold them in a clamp parallel to the floor when soldering to avoid filling them entirely]. Insulate the connectors with the 4mm shrink tube.

YOU'RE DONE!!
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Here's an example of a GD setup for gliders:

With the Double winding (12T) and PQ-850-2S, 3.84:1 ratio, Graupner 8x4.5 Folder, the setup draws 5.8A.  The motor should easily handle 10A with this winding, so 3S and PQ-880 or PQ-1100 would be perfect, I think...  Even better, perhaps, would be the 4.64:1 ratio and 10x8 folder.

Here's a closeup of Back-Mounted DD Motor Set using the AC 3DPRO 400 Mount.

The stock 3mm shafts do not have a clip retainer system, so if you want to back-mount the motor you will have to do one of these two things:

The supplied shafts also DO NOT have any provison for retaining the front bearing (which is why we loctite it in!) That alone works fine on a front-mounted, tractor model.  However, when using the motor as a front-mounted pusher any play between the prop adapter and the front bearing will allow the bell to back away.  Use a spacer to reduce this play to ~0.5mm (for spacer: 3mm aluminum wheel collar, a few 3mm washers, etc...).

Or this prop-saver adapter, which has a tapered back that can reach the bearing, can eliminate the need for other spacers:

 

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The motors take punishment, both in physical abuse and in watts, extemely well.  Both traits can be traced to the solid constuction of the bearing carrier and bell.  The aluminum bearing carrier is a super heatsink for the stator, as is the thick iron bell for the magnets. You can find motors with same size magnets and stator up to 10% lighter, but initial tests show that the DIY motors can handle up to 30% more current, and are much more crash worthy.  Looking pretty good so far....

I hope to do more testing over the next few weeks with various winding configurations.  For example, I'll be looking for a setup to draw about 3A on 9x6 to 10x4.7 props, for IPS replacements.  I'd like to see how much we can get out of an EDF-75 Fan, too..

One thing is certain, though.  The strong magnets and bell, combined with the smooth ball bearings and general precision of all the parts, make for a VERY efficient motor.  We tested the DIY DD motor against a strong CD-ROM based motor, which uses 1mm magnets.  Both motors used identical 32T machine-wound stators.  The DIY DD motor, however, turned an 8x3.8 prop at the SAME rpm as the CD-ROM motor, but used 1.1A LESS current to do the job (that's 18% less amperage!)

We welcome your data, too, so please send it in to help everybody...

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