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Renovating burnt motors, stripped servos and LiPos

earthsciteach

Moderator
Moderator
#1
I find myself with a few motors that are burned up, a few stripped, but otherwise functional servos and several LiPos that have a broken connection somewhere between cells or balance leads. Do any of you take the time to try to refurbish these items?

Motors: I tried rewinding a motor once, but it instantly fried. I know it is doable, have seen the youtube vids, but need to figure it out. My biggest unknown is what gauge of winding wire to use and where to get it. Any advice?


Servos: They all seem to strip at the same gear. Can I buy replacements? I'm using mostly Tower Pro 9g servos.

LiPos: I have at least 3 new LiPos that simply have a bad connection somewhere. Does anyone dissect these and repair?

I'm getting kind of bored with flying lately and am entertaining myself with this, at the moments. I'm also converting a chuck glider to a 3 channel sailplane and adding a tow connection to my HZ SC to fight the doldrums I seem to be in.
 

jetpackninja

More combat please...
Mentor
#2
I've only used the radio crap wire for my rewinds. I've smoke a couple right off the bat but the third one worked like a charm. There is a thread on RC Groups devoted to such things. I suspect most people just buy new ones. The FC2812 motors that I rewind are only six bucks new ;) Guys that do this kind of thing swear by these guys for the wire source: http://www.gobrushless.com/shop/index.php?app=ccp0&ns=catshow&ref=magnet+wire
There's a thread over on RC Groups devoted to rewinding and a spreadsheet somewhere that tells you what wire, how many turns etc to get so many KV. If I can find it I'll send it along.

Are you talking about the blue 9g TP servos? If so they are identical to the HXT-900 servos that HK sells.
Replacement gear sets are here:
http://www.hobbyking.com/hobbyking/store/__4950__HXT900_Replacement_Gear_Set.html
It's not a big job. Haven't done it on the HXT-900's but did it on a set of HS55.
Probably not really worth the effort considering the low cost of the servos.

I have replaced repaired the balance tabs on a few lipos but haven't ever taken apart the cells. It can be done, carefully of course, but at that point my lipos just get cut ion half and tossed in the trash :)

I'm getting kind of bored with flying lately
Buy a Harley
 

earthsciteach

Moderator
Moderator
#3
A Harley, sadly, is in a different universe than my budget affords! I think I found my problem, though. Flying around without a goal or purpose is kind of boring. I think me and my art teacher flying friend need to focus on getting our combat wings in the air. I am feeling the need for some destruction.
 

jetpackninja

More combat please...
Mentor
#4
Now you are talking my language :)

A few good combat hits can really do wonders for your attitude.
This time of year when the hits don't come every weekend is challenging.
I'd hoped to do a few build projects this winter but just haven't managed to get excited about it.
Helping my son with his CTH Albatross trainer but other than that just can't seem to get fired up.
Maybe if I get started on another Grim I'll get fired up again :)
 

jetpackninja

More combat please...
Mentor
#5
One of our guys when asked what combat is all about said:
"Combat is the glue that holds the universe together. Without it we would all die!"~Ryan, Plane Insane RC

I hope your art teacher friend shows you some good smackage
 

pgerts

Old age member
Mentor
#7
Seems that you got all answers from Jetpack.
Be careful with the LiPos.
Stripping the cover is easy but get the glass fiber tape before you start. Cant find it today at HK but i buy my tape at the lokal hardware store - used to tape steel tubes together for transportation aso.
I also have alu-solder and a good solder iron. Like with connectors you cant heat the battery so the iron must be hi capacity and the contact time very short.

Winding wires are normally found at an electric shop where you can leave you big motor for rewinding. They do normally have all gauges of enameled wires - even the thinnest. Honestly i have never had a motor that expensive that the time and effort made rewinding meaningful, but i have repaired some where the wire was broke close to the winding.
 

Ak Flyer

Fly the wings off
Mentor
#8
I haven't had any success with motors once the windings go. Never felt it worth the risk to mess with lipos since the turnigy's are so cheap. I do understand the boredom of flying laps over and over again. Start making challenges with your friends.
Simple things like a short landing contest are a blast. Make a line on the ground or place a streamer down or something and see who can land the closest to the line without touching down before it. Have hover contests, knife edge, see who can fly inverted the longest or lowest etc. You would be surprised what your super cub is capable of when you start pushing it. Float flying, set up a limbo type deal with a streamer and see if you can fly under it, or get crazy and put two up a couple feet apart and see if you fly in between without cutting either one. Get into 3D flight. I highly recommend the Hobbyking Hawk 3D. I love mine and the whole thing can be done for under 60 bucks. Then there's always helis. Of course, if you partake in any of these ideas, share the pics and videos.
 

Ak Flyer

Fly the wings off
Mentor
#10

jetpackninja

More combat please...
Mentor
#11
right on AK!
ding ding ding ding on the mg90s servos. I get them from hobbypartz or hobbyking. They are cheap and work great.

Teach- I use the mg90s almost exclusively in my combat planes. In my 36 inch wings I think we have only had one failure.
I've even used them in my 55 inch wings but managed to strip a few. If you saw some of the things that they survived before they failed... Amazing little servos for the price!
The deal at Grayson looks like a good deal. I ought to have them spec out a few other combat parts...