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power 25 brushless can i use a 11x7 prop?

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Old 01-16-2011, 05:26 AM
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Default power 25 brushless can i use a 11x7 prop?

im wondering because the lowest recommended prop range is 11x8 i have a new 11x7 and would like to try it out. please help i dont know how to calculate the watts/its pulling tho i have a power meter but need help on exactly how to determine if the prop/battery i have are a good choice for the motor
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Old 01-16-2011, 05:45 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

I have a couple of these motors and they are quite flexible. The worst that can happen is that you will not be using all the power the motor can produce. Also, use the top cell count (4?).

I don't knw what you mean by a "power meter." If it's a newer generation of a whatt Meter or what's up meter, then it should read all the parameters and retain them for you to read until you disconnect the battery. It will not give you rpm, but it wil tell youthe highest ad maybe the average amp draw. As long as you don't exceed the max continuous amps for the motor you fine. then it's a question of whether or not it will fly your plane.

You should downwload "DriveCalc." a free and excellent predictor program. You will have to play with it for a while, but it's really worth it in the end.
Walt
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Old 01-16-2011, 09:57 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

Here is a calculator for motor prop battery combos. It works pretty well.

http://www.s4a.ch/eflight/motorcalc_e.htm

If you are talking about a Monster power 25, you can use the Eflite motors for the calculator.

With a 3s 2500mah battery, 11X7 prop pulls 26.2 amps 273 watts with 58 ounces of thrust. If that is enough trust to fly your plane then the 11X7 will work. If not you will have to try a larger prop.

Spend some time with the calculator and see what you can come up with. I have a Monster Power 46 and the 60. I spent a lot of time there just trying different props, batteries to see what change had what effect.


Buzz.

P.S. After you figure out what prop you want to run, then use you watt meter to make sure you do not pull to many amps for your motor ESC.
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Old 01-16-2011, 10:09 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

i have the mentor epts from efite im currently running the power 25 and 40 amp esc, it just says recommended prop range 11x8-14x6, what am i looking for when i put the different props in the calculator, do i need to look at thrust or current draw? the motor says ideal for models needing up to 600 watts, i dont know how to calculate this
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Old 01-16-2011, 11:50 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

Watts= amps you read on the meter multiplied by the voltage from the batteries. This motor will produce the best power on a 4s lipo (20C or higher) and an APC 11x7e using at least a 50A esc. Use at least a 2200mAH 20C lipo because the current this motor will pull is @45A at full throttle and your battery must be rated to handle a constant 45-50Amps. I use a Castle Creations Phoenix ICE 50 lite ESC with my Power 25. This is enough power to fly a 2kg (4.5lbs) plane about 60mph. I get 7 minutes flying using a 4s 2650 20C. This setup is good for @ 78 oz thrust and will give verticle climbs on a 60 oz model.

- WL
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Old 01-16-2011, 11:58 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

Ok when you say multiply the watts to the voltage you mean 11.1 or what the current voltage at the time is?
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Old 01-16-2011, 12:09 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

Using your 40A ESC you might not be able to use an 11x7 prop unless that ESC can handle more than 40A for a few more seconds, then it should work because you'll not be flying full power all the time, unless you want to fly like a rocket. Another choice would be a 3S lipo and an APC 13x6.5e . Better thrust but less speed. The 4.5lb plane would fly about 50mph but would be cruising for about 10 minutes on a 3S 2650mAH 20C LiPo battery.

- WL
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Old 01-16-2011, 12:10 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

The voltage at the time you're reading amps.
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Old 01-16-2011, 12:20 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

The 4s setup should show about 12.8 volts under a 44A load .... so 12.8v x 44a = 563.2 watts. A freshly charged battery will have higher voltages at first but slowly drop as it drains. Set the ESC low-voltage cut-off at 3.2volts per cell
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Old 01-16-2011, 01:21 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

i currently have the stock set up 3s 3200 with the 40 amp esc and power 25 motor, im trying to figure out whats the best prop to use as far as power, i have 11x7,12x8 and a 13x6.5
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Old 01-16-2011, 02:16 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

The 12x8 I find to stall and not produce as much thrust during take offs because the prop can't bite into the airstream going that slowly in the air. That apc 13x6.5e will be the best for a 3s pack.
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Old 01-16-2011, 02:21 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

when you increase diameter do the rpms increase or decrease? or does it take effect the pitch as well?
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Old 01-16-2011, 03:08 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

The 13x6.5 prop will be the best and create the maximum safe loads using 3s packs. The RPMs will drop as you increase both the pitch and diameter. Go up in diameter means go down in pitch. A 12x6 will draw about the same load as a 11x7 or a 13x5. The way to choose the right one is based on type of model.... a light weight sleek racer would use a smaller diameter but aggressive pitch... like a 10x9 on this motor. A heavy and big trainer would use the 13x6.5 or even a 14x5.
-WL
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Old 07-31-2012, 06:09 AM
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Default RE: power 25 brushless can i use a 11x7 prop?


Quote:
ORIGINAL: Waterlogged

The 13x6.5 prop will be the best and create the maximum safe loads using 3s packs. The RPMs will drop as you increase both the pitch and diameter. Go up in diameter means go down in pitch. A 12x6 will draw about the same load as a 11x7 or a 13x5. The way to choose the right one is based on type of model.... a light weight sleek racer would use a smaller diameter but aggressive pitch... like a 10x9 on this motor. A heavy and big trainer would use the 13x6.5 or even a 14x5.
-WL

I have this motor and am too looking for more performance than the stock prop. I haven't tried the 13x6.5 but do have the 12x6.5. What makes you think the 13 diamter would be the best? Just curious as I don't actaully have a lot of experience with electric setups I am also just using 3200 20C batteries.
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Old 08-01-2012, 08:53 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

Which airplane are you powering with this motor?
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Old 08-01-2012, 08:59 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

i'm putting it into a GP Sequence (no, not looking to compete with it so a EP 25 is fine for me).
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Old 09-16-2012, 03:45 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

If you already have the props then fly and see which you like the best. The more monitoring you can do the better. A watt meter would be good to test amp draw on the bench. Keep an eye on your speed controller and motor. Next will be performance when you are flying and flight times.
A 11x6 from the different maker are not all the same. So testing is your best solution.
Strat with the motors manufacture recommendations and test from there.
I have some 12x10's that I run on my Power 25. It is on a spitfire.

Good luck and happy flying.
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Old 09-16-2012, 04:46 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

Are you using the 12x10 on 3S or 4S. THANKS,RACJ
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Old 09-28-2012, 09:50 PM
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Default RE: power 25 brushless can i use a 11x7 prop?

There are at least two E-Flite power 25 variants with different KV ratings.


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Old 10-12-2012, 06:08 AM
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Default RE: power 25 brushless can i use a 11x7 prop?

I am running 3 cells in the Spitfire.
I have an SU-26 that will have 4 cells, but it hasn't flown yet.
I took the summer off because of the heat here in TX.
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