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Mar 17, 2021, 09:47 PM
Team30 Micro EDF
NitroCharged's Avatar
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More fiddling around getting the fan and duct right than building


I've been stuffing around getting the case worked out.

I ended up putting the tail cone inside the rear case all as one piece and a lip on the front of the fan case and a couple of mounting brackets.



The fan case then slides back against the rear case (the rear case will be glued in place) and screws onto ply supports that will be placed either side where the mounts on the fan are.



The ducting tube is thin lipo battery heatshrink from hobbyking. I shrunk it down over a 19mm pvc pipe. I then cleaned it with IPA and spray painted it lightly with matt black including down the front hole. It's quite snug so I just have to push it into the lip of the case and it's there to stay.



If I need to remove the fan I will simply slide the tube forward.

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Mar 19, 2021, 10:56 AM
Pro Hoarder
turbonut's Avatar
That looks really good
Latest blog entry: In flight
Sep 12, 2021, 11:54 PM
Team30 Micro EDF
NitroCharged's Avatar
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...annnndddd..... I finally got around to completing the fan unit this weekend (so much other family and house stuff to do nowadays).

I had to design and 3D print a support bracket that attached to my lathe to hold my dremmel tool in place that I use to trim the blades down.

I am super happy with the result of trimming. I have the gap between the blades and the case at a mere thickness of a piece of paper! Then came the balancing... 3 pieces of electrical tape on one side of the hub and 2 holes on the other side to make it sing. The motor has a rasp mid throttle but that is the actual motor shaft, not anything else (I ran it up before attaching the impeller and it had a noisy spot - oiling it with dry silicone helped a little) but once past that it runs perfectly true.

I can now mount it into the fuse and continue with the build.
Sep 13, 2021, 08:14 AM
Team30 Micro EDF
NitroCharged's Avatar
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Not very exciting without a video! Here it is:

20mm EDF unit - ready to install into Huckebein jet! (5 min 40 sec)
Sep 14, 2021, 10:54 AM
Pro Hoarder
turbonut's Avatar
That super cool!
Latest blog entry: In flight
Sep 15, 2021, 05:11 AM
Team30 Micro EDF
NitroCharged's Avatar
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Microbuilder and I have been discussing as to why these little motors don't have bearings running at these speeds. I thought I bought a couple of these with bearings to try so I went looking for them. It turns out - I am using them already. The green editions are supposed to have 'high quality NMB Japanese bearings' fitted:
Racerstar BR0703B outrunner teardown! (4 min 7 sec)
OK, so as you see in my video, they are a no show. I checked my parts boxes and still had a few sets of 1x3x1mm bearings from the old days when I was first hand building micro outrunners.
So, I removed the top and bottom bushings of the stator shaft. At first glance it looks like the bearings will drop straight in but the bushings are 2.85mm diameter! Of course they are.
That means I have to drill out both ends to accommodate the bearings! The first end went well as there is nothing much around the shaft.
The other end was a bit more nerve wracking. I had mounted the drill bit in my lathe chuck and the stator unit in the drill chuck of the lathe to keep things aligned but when you see the windings and the drill coming together I really wasn't sure if I would clip the closest windings or not. I think I missed by about 0.1mm!!
Next, I will mount the bearings and see if it runs any smoother than the screecher it is right now.

.
Sep 15, 2021, 06:00 PM
Team30 Micro EDF
NitroCharged's Avatar
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Top bearing is a smidge off centre and so angles the shaft and the bell rubs... bummer.... back to building the Huckie.
Sep 22, 2021, 10:22 AM
RC-addicted
Serge Roth's Avatar
Have you seen the new Happymodel 0702 motor with 28000kv?
Sep 24, 2021, 09:22 PM
Registered User
AntiArf's Avatar
Quote:
Originally Posted by NitroCharged
Top bearing is a smidge off centre and so angles the shaft and the bell rubs... bummer.... back to building the Huckie.
The bearings on these tiny motors can be a bummer. Came to the conclusion the front bearing on my micro Comet (GP inrunner) is not quite ideal, after spending some time messing around with balancing to determine that it doesn't seem to be the issue. Could fly it again, but it sucks when something is less than ideal on these tiny models.

You've probably thought about this, but being an unorthodox problem solver I'd experiment with thin layers of CA applied with a piece of wire to true up the bore, then use an exacto to do any necessary "machining". CA will tolerate the motor heat, and I've trued up drilled out prop adapters perfectly, that most wouldn't bother using and would have scrapped.
Sep 25, 2021, 10:16 PM
Team30 Micro EDF
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Serge, I have the 26,000 6x3 to try in a 15mm edf when I finish messing with the 20's. I think the 7x2 might still be small enough not to hamper the airflow. Well worth trying maybe even for a one cell version?

Antiarf - yes - I was thinking of just lathing a new shaft. We'll see. Got lots of projects running at the same time and it's really slowing me down.
Sep 25, 2021, 11:36 PM
Registered User
AntiArf's Avatar
Just put together a 20mm EDF using the 8mm Blade heli motor BLH3327 and a 6 blade cut down EDF30 rotor. Ran it up on a pretty much discharged 2s at 18W without getting too hot. I like this little motor so far, after using it in the 21.5mm EDF Jet Provost. The fan on 3 blades was a bit unloaded at 21.5mm, where the 20mm setup seems a bit better so far with 6 blades. Now to decide what to build around it, if all goes well. I know you did a bit of experimenting with the motor, but I think it would be worth building a fan for one. I could see a 15mm on 3s.
Oct 03, 2021, 04:08 AM
Team30 Micro EDF
NitroCharged's Avatar
Thread OP
I'll definitely get that inrunner in something in the near future. I wonder how a 5 blade prop chopped down like the 3 and 4 bladers I use would go.... better order some!


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