Hello to all, New member to the squawk. Was curious if anyone has knowledge on if the 70mm 4S Freewing 3000kv EDF will hold up paired with a ZTW Mantis 85a ESC, running a 6S cell? Plan on putting them in a 70mm Yak 130. Any input is appreciated.
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I'm not able to do the exact calculations at the moment, but a quick reckoning tells me that on 6 cells the motor will be trying to spin the fan at >75k rpm!... :Scared:
that's 6 cells at 4.2V fully charged = 25.2V
A 3000kv motor on 25.2V = 75600 rpm
I don't know the exact figure, but the max rpm for the fan is likely to be in the 50-55k range -
I was figuring it would be an extreme upper range. Not sure if the thing would hold together for long either. I'm sure the ESC can handle the draw as the 6 blades always draw less than the 12's but don't need to find out at the cost of a new plane either. May try a bench test and figure the 50K rpm range and adjust throttle throw/travel so it can only peak at that 50k range. I may also try it with a 5S pack and get some comparison rpm and draw readings too. Thanks for the reply MeadowhayComment
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I'd expect about a 7 second fan lifespan on 6S
Its a question of if the fan throws the blades or the motor melts down first.
BTW... limiting throttle to avoid overheating the motor due to excess watts doesn't work.FF gliders and rubber power since 1966, CL 1970-1990, RC since 1975.
current planes from 1/2 oz to 22 lbsComment
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Silly question on my part, but if you got 6s batteries, why didn't you get the off-the-shelf version of the Yak?Originally posted by Atesvn View PostComment
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The way I look at batteries is the cell number is the octane and the mAh is the gallons, What he's trying to do is the equivalent of putting JP7(the fuel that the SR-71 uses) into a Ford Pinto.Originally posted by fhhuber View PostComment
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