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Apprentice with 4s and power 15 what prop?

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Old 09-13-2011, 10:49 PM
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Default Apprentice with 4s and power 15 what prop?

Hi,

I have the Eflite Apprentice and am running 50Amp ESP with a real power 15 not the standard one that comes in the kit. So i just got me a pulse XT 25e and am running 4cell 4000mAh batteries, id like to stock up an a few of these batteries so if i could run the same battery in both the planes would be handy and yes they just fit

So from my limited understandng of the electrics changing to a 4 cell will up my RPM which in turn will cause the motor to draw more watts prehaps exeeding the motors capacity and burning it out hence my need for a less aggressive prop. (Correct?)

So without a watt meter im hoping someone has run a similar setup on the power 15 with 4 cell batteries and can tell me what prop i should be using?

Thanks

Marcel
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Old 09-14-2011, 07:07 AM
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Default RE: Apprentice with 4s and power 15 what prop?

You ought to be OK running a 10x6 on 4S. However, I strongly recommend using a wattmeter to verify your current draw. You want to be around 34 amps or less according to their specs. Without a wattmeter, a 9x5 might be a better starting point to avoid excess heating.

Here's a DriveCalc run with a motor closely matching the Power 15's weight and Kv on an APC 10x7E. Good luck with the upgrade.

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Old 09-15-2011, 09:51 PM
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Default RE: Apprentice with 4s and power 15 what prop?

Thanks Tim! Will try a 9x5 to start with. Guess if I'm going to get serious about this hobby i should invest in a watt meter anyways.
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Old 10-22-2011, 06:59 AM
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Default RE: Apprentice with 4s and power 15 what prop?

If you are going to run RTF or buy exactly what the mfg recommends then you don't need a wattmeter. But if you start mixing motors, ESC, props and batteries, then a wattmeter is mandatory.  

I have shown members of our club why they are burning up ESC, destroying batteries, etc.  Usually they have too much prop or too little battery and they start burning things up.  Sometimes they take a set-up intended for a 2S battery and they go to 3S.   WOW, look at the jump in power!   WOW, look at the cool smoke coming out of the plane.  

Get a wattmeter and make sure you know what is going on.
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Old 11-18-2011, 09:45 AM
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Default RE: Apprentice with 4s and power 15 what prop?

The apprentice is big plane, n with my last one i had a rimfire .15, 45amp esc and ran masterairscrew's 3 bladed 11*8 prop n was more then enough tractor n speed with it...running a little 9*5 will most likely burn out your motor and or esc...i would run an 11*8x3 or even a 12*6 dual blade..
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Old 11-21-2011, 04:59 PM
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Default RE: Apprentice with 4s and power 15 what prop?

running a little 9*5 will most likely burn out your motor and or esc

Why? A small prop will draw fewer amps, so the motor and ESC will run cooler... okay it might not generate enough thrust to fly the plane, but it can't harm the motor or ESC if you under-prop it!
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