stunthanger.com
Electric Stunt => Gettin all AMP'ed up! => Topic started by: RC Storick on February 16, 2013, 05:48:07 PM
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I bought 2 E-flight power 25 motors. I flew one in my Viper and it was using 89% of 4s 3300 batteries. So I bought the 4S 4000. Of which seem to be heavy to me. Well I called Wil Hubin tonight and we talked E=I/r crap and he figured out my problem. The problem was that I have 2 1250 KV motors and I and suppose to have 850 KV motors (thats what I get for buying from my local hobby shop). Boy do I have a lot to learn. The planes are the same but the rigmarole is something else. I sure hope its as good as everyone is saying.
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Ouch! Hang in there guy maybe the hobby shop will allow an exchange. Just remember, we have over 75 years of glow engine experience to draw from but only 10 years? of electric setups to do the same.
Bob
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What Bob said. You spent a lifetime learning how to make internal combustion engines sit up and beg; now you're trying to spin up on electrics in one season. Clearly it can be done -- but think about all the little bits and pieces of wisdom you know about IC engines and consider that it'll take a bit of time to learn the equivalent electric lore.
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I bought 2 E-flight power 25 motors. I flew one in my Viper and it was using 89% of 4s 3300 batteries. So I bought the 4S 4000. Of which seem to be heavy to me. Well I called Wil Hubin tonight and we talked E=I/r crap and he figured out my problem. The problem was that I have 2 1250 KV motors and I and suppose to have 850 KV motors (thats what I get for buying from my local hobby shop). Boy do I have a lot to learn. The planes are the same but the rigmarole is something else. I sure hope its as good as everyone is saying.
Robert,, what you have are the motors eflight designed for RC pylon racing,, ( which I do)
Private message me and maybe I can help you out,,, at least in getting rid of these motors,,
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With a nickname like Sparky ... how can you say you aren't suited to E-Stunt?
Sounds like this just would have been a costly boo-boo, save for friends like Mark!
hang tight!
Dean
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Update I only have 1 1270KV motor so the 840 is in the plane.
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This is why for my first electric I am copying other's successful setups. I'll branch out after I really understand the system. Until then, I'll listen to the guys that are already successful with it.
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This is why for my first electric I am copying other's successful setups. I'll branch out after I really understand the system. Until then, I'll listen to the guys that are already successful with it.
SParky got caught in one of the really diffucult situations,, the Eflight .25 is made two ways, and the ONLY difference is the NMPRA EF-1 sticker on the 1270 KV motor,, heck the guy at the hobby shop is probably the one who screwed up
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It is exceptionally easy to change a motor's velocity constant (what we call kV in the modeling world). All it takes is to wind the motor with more turns of thinner wire (for a lower kV) or fewer turns of thicker wire (for a higher kV). The result is a motor that behaves almost exactly as before, but with some of the parameters scaled by the change in the number of turns.
This sort of thing is done all the time with industrial motors. It's common to see a motor data sheet that has one set of graphs for power and efficiency, then this humongous chart listing a dozen different parameters for a dozen different winding arrangements.
So its not at all surprising that a model motor manufacturer should offer the same basic motor with different winding arrangements.
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The e 25 is actually 870 kv that we use...got 4 of them in 5 different airplanes at or near 58 oz flying weight ..tp45c 2700 mah 4s 14 volt (10 oz) battery uses `1600 mah to do the pattern with a 12.6 epusher apc. at 9600 rpm...214 flights on one airplane without any problems.i got tons of batteries and all my 4s 3300 batterys weigh 12.5 to 14.0 ounces...way too heavy for my airplanes.Don't be discouraged the fun is in flying these things....