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Old Nov 15, 2001, 09:47 PM
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San Diego, CA. USA
Joined Nov 2000
585 Posts
How many flights before a S400 starts to go downhill?

I push my S400 motors pretty hard. Zagi motors, not necessarily on Zagi. I run them pretty much full throttle on 8x1400 AE's. Good circulation, they don't get very hot. 13A peak, 16000 RPM at beginning, 5.5x4 prop. It's seems that after 25 flights it doesn't have the zip it used to. Is this possible or should I be looking for another problem (ie battery)? (And I do keep it oiled).
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Old Nov 16, 2001, 05:32 AM
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f2racer's Avatar
MA
Joined Sep 2001
248 Posts
I believe that the 380 in a Zagi should be something like $5 at a LHS. You may want to just swap in a new one and try. It's probably unlikely that the motor went bad in only 25 flights. I'd take a look at how your battery pack is doing. Have you discharged the cells (to .8-.9v per cell) recently? You're running NiCDs that may develop memory if you don't discharge every 6-10 charges. Memory will cause the battery not to charge to it's peak capacity which will cause the performance degradation that you mentioned. From what I understand discharging too often is also detrimental to batteries.
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Old Nov 16, 2001, 05:51 AM
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United Kingdom, Bracknell
Joined Nov 2000
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Yup, I prop all my 6V S400s to about 13A static and am flying one that is nearly 2 years old. Maybe performance has degraded slightly, but if so I haven't noticed. In fact I have never even oiled the bearings

As F2 said, could be a problem with your pack(s). But very quick/cheap/easy to replace the motor anyway to rule that out - you may have got a bad one.
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Old Nov 16, 2001, 09:05 AM
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San Diego, CA. USA
Joined Nov 2000
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ok, I'm going to pay a little attention to my batteries. I charge them at home, sometimes the night before. I do slow charge them periodically, but I think they need to be pumped up at the field. This motor was really running well not too long ago. Thanks
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Old Sep 23, 2007, 09:33 PM
Next time I'll ARTF...
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Canberra, Australia (Southside)
Joined Feb 2004
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6.5x3 DD, 7x600AE ... in a 1.6m light thermal glider - about 6 years stirling service... people still ask what brushless motor I have installed to get it to climb so nicely.
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Old Sep 23, 2007, 10:09 PM
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United States, MI, Roseville
Joined Dec 2000
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The practical limit on the typical "S400" can motor is about 10 amps. Figuring 10% or so reduction unload in the air, I wouldn't pull more than 11 amps on the ground.
I have been using these motors since '96 or so, and with a water break-in they run pretty good for about 25-30 flights before the magnets begin to degrade from heat, and the armatures need cleaning (not worth the trouble).
On 3 cells, the 7.2 volt motor with a 5/5 or 5.5 /4.5 will provide long service. Using the 6 volt type with 3 cells will result in short motor life, even with cooling. It's just asking too much from a $3.00 motor.

This study is pretty close to my experience: http://www.image-maker.demon.co.uk/pages/spd_400.html
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Old Sep 24, 2007, 04:10 AM
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United Kingdom, Bracknell
Joined Nov 2000
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Wow, a 6 year old thread springs to life again!

Well I still have the same 6V S400s in my Twin Star, they still pull about 13A each on full throttle (with 8 sub C cells), and I've never touched them since I fitted them in August 2001. Only maintenance has been to lube the gearboxes.

And the S400 in my even older Pico Jet was still running perfectly when I replaced it with a spare Graupner 480L.
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Old Sep 24, 2007, 07:06 AM
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East Anglia, UK
Joined Sep 2002
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I run em at around 7-9A static, less in the air, on 3s LIPO and they simply don't degrade at all.

Ultimately the brushes will wear after a few hours flying time I suppose.


I put a drop of 3 in 1 on the bushes every 6 months or so.
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Old Sep 24, 2007, 07:49 AM
Next time I'll ARTF...
glydr's Avatar
Canberra, Australia (Southside)
Joined Feb 2004
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Quote:
Originally Posted by Bill Glover
Wow, a 6 year old thread springs to life again!
My mistake! It came through my RSS feed today (I do not know why) so I thought it was a recent question... I was glad to find someone who still uses brushed motors! The fleet is mainly brushless - however 4 regularly used aircraft use brushed motors (and even nicads )

Now we can let the thread go back into the deep realms of RCG archives...
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Old Sep 24, 2007, 09:16 AM
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United Kingdom, Bracknell
Joined Nov 2000
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Quote:
Originally Posted by glydr
My mistake! It came through my RSS feed today (I do not know why) so I thought it was a recent question... I was glad to find someone who still uses brushed motors! The fleet is mainly brushless - however 4 regularly used aircraft use brushed motors (and even nicads )

Now we can let the thread go back into the deep realms of RCG archives...
No worries! There will probably be pages of posts now

I tend to use brushless for new models, but with Li packs getting better and better motor efficiency isn't quite as important as it used to be ... IMHO.

I also have models with nicd packs!

Actually my most efficient indoor models used brushed motors (albeit coreless ones), with Li Ion packs. I comfortably get a whole evening's flying from a single charge.
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