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Jun 30, 2003, 01:40 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP

The D-I-Y tapestreamer motor conversion thread.


I'm presenting to you a relatively inexpensive way to make a working E-flight brushless outrunner that will swing a variety of props and should, with a bit of work and luck, fly most small 10~15 oz. parkflyers and slowflyers.

*Disclaimer* first off, I do not gaurantee that your motor will work first time, or that you may have no problems with your BL ESC while testing this motor out. You'll have to be be careful and use some form of current limiting power supply, while testing. I also take no responsibility for your inability to make the various parts for this motor, or injuries or property damage caused by the making or use of the same.

What I will say is that I've made two of these already. One has been flying in my Sopwith 'strutter for almost 4 months now, swinging an APC 9X7 on a variety of 2/3rds AAA nimh packs. The model flies with authority for its 10.5 oz. weight, no, it does not achieve anything approaching vertical climb outs. But it does a good job of being a sport flyer with a good ROG and climbout, especially on 8 cells. I would think that these motors apppropriately wound would run fine on the Etech 700 and 1200 cells in 2S and 3S configurations. With magnet wire other than the Radio Shack medley, probably something around 23# or 22#, you could get some sort of performance out of it. But this is not what I'm trying for. I just wish to make a tractable motor with moderate power conversion. My first motor has the ability to swing a 10X8 on 10 cells without cutting out or getting real hot. It also sips the juice while doing so

continued..
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Jun 30, 2003, 01:47 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
The Ditto drives:

I'm presenting both the Easy 800 and the 2GB models for this conversion as they're somewhat the same. The main difference being that the 800 is a 9 pole armature with half tooths between the main poles, the 2GB has 18 poles with an alloy bearing carrier. There is a third drive that the Germans have been converting, a Colorado drive known as the Conrad drive, it comes with an appropriate neo magnet ring in it's shell but I'm not going to include it this time.

Unfortunately RCgroups is not allowing me to post images right now.. we'll have to wait..
Jun 30, 2003, 02:49 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP

..


..
Last edited by Looooeeee!; Feb 26, 2012 at 10:24 AM.
Jun 30, 2003, 02:52 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP

Getting them apart..


I'll assume that you've got all your peices and parts, the 50 or so .25" X .1" round cabinet door neodymium magnets from Lee valley, and the Magnet Wire Medley from Ratshak. And I hope you got a fair deal on Ebay for the Ditto's, the best place to hunt them down. I've included an image of where to insert the screwdriver to remove the case. Start there and then at the front. pry the fronts-piece and tapedoor-flapper off . Pull the frontpiece and the light tube out of the case, separate the innards from the plastic case bits. You should have a blackish plastic assembly holding the motor and circuitry. The motor has three tabs, one of which is connected to a spring. Pry that off and take a thin bladed screwdriver and remove the thin metal sheeting from around the motor. Prod and pry, it will all come away with some careful persistance. Once the motor is loose, tug loose the multiwire connector for it from the circuitboard.
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 04:48 PM
Heli Bouncer
Looooeeee!'s Avatar
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Here's the insides, although I've already had this drive apart and have driven out the main shaft from the bearings


The motor will have a plastic fan that surrounds the rotating shell that can be cut off with a razorsaw or larger side-cutters, it's glued on so it will need some popping loose. You will now need to remove the friction wheel from the other end of the drive shaft, an aluminum and rubber tire like bit. I used a pair of decent Felco wire cutters, but it should yeild to any stout, smallish bolt cutter applied obliquely to the shaft. Don't attempt to cut the shaft, it's one hard piece of steel, just nip the aluminum enough to break it free, or you could do a tedious hacksaw or file job on it, but you'll get metal bits in the precision bearings. Sheild them with tape if you must.
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 04:59 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
Just a quick but important note about the magnets

Because of the curve to the inside of the rotor shell, you will have to grind the magnets some to get the correct airgap between the armature and the working face of the magnets. You can't blow this step off, it needs to be done and its is tedious and creates some nuisance dust. I'll cover the actual process in a few more post's, but suffice to say get a good dust mask, and a small cup of water to douse the magnets into, as the swarf has a tendencey to accumulate on the end and start glowing and slowly burning when grinding.
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 05:25 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
Btw here's the link to Lee Valley's neodym magnets

http://www.leevalley.com/wood/page.a...=1,42363,42346

and here's Bunting Magnets URL http://www.buntingmagnetics.com/magn..._rareearth.htm

You can get a wider selection of round magnets at bunting but the price is Higher

Also this supplier in Germany will take cash mailed to him and he also does Paypal. All I have is his Email address.

[email protected]
Jun 30, 2003, 06:12 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
Now come the fun part...

Give the motor a spin, nice isn't it.. We should attempt to try and break the motor shaft free from the bearing as carefully as possible, as the shaft is green Locktited to the inner races of the shaft bearings. I have not been successful at this though, as I've brinneled both of my Ditto 800's bearings in this proccess, and only with the 2GB was I able to get the bearing free without damage. Heat to the shaft is the key. A small butane pen torch will work but since the Easy 800 has a plastic bearing carrier this is real risky. The only other choice is a long application of some nasty solvent like MEK or worse and it didn't work well either. Steve McBride says that the 800's he's dealt with, some came apart fine, some were a real bear. Must be the luck of the draw.... How I got them apart requires a fair bench-vise and a small 1/4" drive socket.
If you have heated your 800's shaft carefully enough to slightly change the color , (do this at the extreme end where the friction wheel sat, and then a little bit of heat at the brass bushing end of the shell, you're trying to heat the shaft to about 600 degrees, and yet not melt the bearing carrier { I know someone is going to ruin one of these doing this}..) You should get the shaft to pop free of the inner-races with out distorting them. By placing the shaft with the 1/4" socket, (sized so the 4mm shaft can pass through within) against the brass bushing of the magnet shell, between the vice jaws, (all squared up) slowly apply some force while watching the shaft to see if it's yeiding before you have to really "Put the Herman on it" as my Dad used to say. On the Ditto 2GB you can heat with impunity, just don't get things smoking. In either case don't over do the pressure. If it's not moving, *heat carefully again*, but really be careful with the 800

the following images show our more than adequate, antique industrial strength vice and a shot of an equally overkill acetylene airmix torch for the heating job on the shaft..
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 06:18 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
The shaft is loose and I've moved it in about 3/4". you want it to have a little overhang on the back side of the bearing carrier, you don't really need all that much sticking out the front of the rotor shell, at least a 1/2" or maybe a bit more.
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 06:43 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
the Magnets;


Get out your stack of .25"X.1" round magnets from Lee Valley and assemble a stack of about 20 of them. Now get a long strip of duct tape and fasten it to some clean flat surface at one end, then fold it over so the sticky side is out, folding under the other end so that it stays put on the surface your using

You'll need some kind of bench grinder, but a Dremel with a caburundum barrel bit will work too. If you're using the Dremel set it at the slowest speed and fix it in a vice or clamp it fixedly somehow. Also get a small cup of water.

While the grinder spins you're going to rest the stack of magnets *very* lightly against the spinning abrasive and let the magnet in contact radius its edge as it also spins in contact with the grinder. You should eyeball the angle, but approx. 15~20 dgrees from perpendicular to start, then feather it inwards. Don't attempt to get it done in one swipe, allow the magnet at the end of the stack to spin a bit with the friction of the grinder. (Also don't worry about it not being perfectly hemispherical, if you have a slightly irregular 3mm diameter patch of nickle plating, untouched in the center of the magnet you did fine.) If you'll remember my earlier image, of the radiused ring on one side of the magnet, that's how it should look. Don't over do it. you just want them to sit slightly tighter to the curve of the rotor shell. The swarf will sometimes shoot some sparks and start a slow burning, just dunk the end in water, shake the excess off and finish. Now pry that magnet loose from the stack and stick onto the duct tape. Now flip your stack end for end and do the same again. Keep repeating the process untill you have 12 magnets. Remember to switch the ends you grind so you have an equal number of North and South poles. That's why you flip the magnet stack end wise after each grind.

Now carefully take all the magnets residing on the duct-tape and roll them around on the strip of the fifth universal force, try to remove all the swarf and powder from the magnets, roll 'em till they're clean on both sides. (Despite the duct tape's overwhelming tackiness, you're going to find that the magnets are going to find each other out of sheer power of attraction, try to keep them separated. But don't worry if you find some mating, opposites attract.... ) And try to keep the freshly cleaned ones from congregating with the dirty ones, once they're clean, stack them separately away from the ones that still need to be rolled around.

You should have a nice stack of 12 magnets, 6 of North, and 6 of South.

Looee
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jun 30, 2003, 11:20 PM
Me and a guy with a mustache
babblefish's Avatar
Great job so far Looee. I just wanted to list a few other sources for rare earth magnets:

1) http://www.magnets-ceramic.com/product.htm
2) http://www.amazingmagnets.com/
3) http://www.wondermagnet.com/dev/main.shtml
4) http://www.engconcepts.net/Magnets/Magnets.htm
5) http://www.engconcepts.net/Magnets/P...x_Magnets.html

And magnet wire:

1) http://www.powerwerx.com/category.asp?CtgID=1059
2) http://www.mcmaster.com/ (go to page 695 of their on-line catalog)
Jun 30, 2003, 11:37 PM
.................
Dylwad's Avatar
Thanks for starting this thread looooeeee! i just ordered the 2GB from ebay.......paitiently waiting for the finale



Dylan
Jul 01, 2003, 08:04 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Hi Loooeeee,

Very nice pics, keep up the good work.

Met vriendelijke groet Ron van Sommeren
diy outrunner brushless e-motor discussion.
Electric fly-in & lrk meet, June 22nd, 2003, Nijmegen, the Netherlands.
Jul 02, 2003, 02:47 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP

Mounting the magnets.


Placing of the magnets in the shell:

Before we go on to winding the armature, lets get the magnets in place in the shell. Now I'm guessing that some of you will opt for some other kind of magnet besides the Lee Valley cabinet catch neodyms that I'm using, and by all means go ahead with experiments with other magnets.. If you find a type that works well for you, (by all means,) add it to this thread. I'm using the LV magnets 'cause they're easily purchased online, they're cheap.. (big reason) and they fit and work without a lot of trouble and shimming. Those of you who've done other motors with the rectangular and bar magnets will recognise that a round shape isn't as optimum for this purpose, and I suspect it has to do with some loss of efficiencey. But for the price of the materials , I'm not complaining. My motors do work.

First off get out your rotor shell/ shaft assembly and notice that it has a ferrite ring magnet inside it's circumference. Removing this can be fun, as it's just barely glued in and it's a rubber/ferrite ring with a definate seam to it. Get in some strong light and you should see where the ends of the strip meet. Lay the shell down on a firm, sturdy table and get out a small, thin bladed flat screwdriver and wiggle the blade in between the shell edge and the magnet ring on either side of magnet rings seam. Due to the softness of the magnet you should just start cutting throung the glue and the ring will start to come apart in chunks as you work you way around. My first motor I converted, the ring nearly fell out after breaking the bond, but these rings vary in their glue jobs, yours may take a little more work. Best to get all the little bits out and afterwards scrape and clean the metal surface that the neodym magnets will glue to. get all the bits and glue out that you can as you want some uniformity in the height of the magnets in the shell periphery....
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.
Jul 02, 2003, 02:52 PM
Heli Bouncer
Looooeeee!'s Avatar
Thread OP
There are a couple of ways to get the position of the magnets equal to one another, one of which is to take a small protractor to set the angle and place marks on the edge, setting them apart 40 degrees from each other. This works but is a bit tedious, I found an easier way which is to just place them in the inside of the shell at an approximate (i.e. TLAR method..) spacing, observing that you did place them in an N-S-N-S-N-S positioning, then if you have a micrometer, or vernier caliper, make a feeler gauge/spacing guide of about .160" width to get the final positioning. This is not just some arbitrary measurement, I fussed with this for at least several minutes with a file and a chunk of aluminum sheeting to get it close. Although you may find enough difference in your shell diameter that you may need the gauge thicker, (or thinner ). You might start at .162 or so and file it in little bits, so that when inserted between the magnets, it slides home without moving the adjaceent magnets. I should also note that in my image, I'm showing the spacing between the magnets at the closest point, near the top, you actually want to slide home the gauge between the magnets at the base, resting it on the rotor shell ring inner surface. Sorry for the confusion.
Last edited by Looooeeee!; Feb 26, 2012 at 10:25 AM.


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