Originally Posted by Zeetwentyeight
I have an E-Flite Apprentice S 15E and I have an E-Flite Power 25 870Kv motor that I'd like to install in it. I was looking at a 45 amp Eflite ESC to run with the motor. Would this be a good setup? Also, what would be a good prop size be with a setup like this? Currently I am running the stock setup (15 brushless motor, 30 amp ESC, 11x8 prop with a 3300mah 25c 3S LiPo. I know NOTHING about electronics, prop matching to power setup a or anything so any help with these questions would be great! Thanks in advance!
Take a look at one of those computer programs for this purpose. I use www.motocalc.com
, free for 30 days, then $39.
Enter your models wingspan, wing area, weight with receiver/servos. Then select the E-Flite 25 motor, and 3300 Mah 3S LiPo battery. Select a prop range from 10-6 to 13-8.
Motocalc will spit out a whole slew of prop sizes from 10-6, 10-7, 10-8, 11-6, 11-7 and so on. First click on the 10-6 prop selection, and look at "Opinions". Move to the other prop sizes and so on.
Keep an eye on the maximum Amps and Watts predictions. Motocalc isn't exact, but will get you pretty close to the final prop selection.
I ran the numbers and found that an APC-E (Electric Prop) would be pretty close, pulling 43 Amps, 350 Watts, and turning the prop at around 7400 RPM. Rate of climb is predicted to be around 1500 Feet Per Minute.
Note that this is a foamie model with a flat bottom wing. So, do be careful about overpowering your model and a possible catastrophic failure of your wing or similar during violent acrobatics.
Since this is your first go-around with electric power, IMHO, it would be wise to purchase one of those wattmeters to measure the amps/watts actually pulled by your electric motor. These electric motors are DUMB! They will happily turn over a way to big prop, with fantastic performance. Until the magic smoke comes out of the motor/ESC/battery pack!