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Help! Flite test power pack c.

kilroy07

Well-known member
#2
A 2200 3cell ought to do the trick for most of the standard planes and is the "workhorse/standard" battery, around 1300-1500 if you want to go a bit lighter/smaller (personally, I wouldn't go below 25C discharge rate.)
 

The Hangar

Well-known member
#4
What airplane will it be for? I typically run on 3s 1000 mah in my simple cub and simple scout, and a 1500 mah 3s in my spitfireand Edge 540.
 

chris398mx

Well-known member
#7
I bought one of the new Radial C packs and a 4S battery recommended for the FT-P47. The power pack comes with 10x4.5 props. The problem is my motor is getting pretty hot and I am flying a generally 50% throttle with short burst once in a while. Did Flite TEST make a poor recommendation for 4S and prop size? Should i be running a smaller prop with this set up? If so, what prop would work good with the 4S batteries? Thanks for any help you guys or gals can recommend.
 

The Hangar

Well-known member
#8
I bought one of the new Radial C packs and a 4S battery recommended for the FT-P47. The power pack comes with 10x4.5 props. The problem is my motor is getting pretty hot and I am flying a generally 50% throttle with short burst once in a while. Did Flite TEST make a poor recommendation for 4S and prop size? Should i be running a smaller prop with this set up? If so, what prop would work good with the 4S batteries? Thanks for any help you guys or gals can recommend.
Hmm, that’s strange, and if it’s a problem on flitetest’s end, that’s pretty disappointing. Maybe try a 9 inch prop...
 

FDS

Well-known member
#9
@chris398mx If you look at the motor specs I suspect that it’s designed to run a 10” prop at 3s. You are spinning a big pitchy prop faster, which will increase the load a lot. You want a 9x3 prop on 4s I suspect.
 
#10
I bought one of the new Radial C packs and a 4S battery recommended for the FT-P47. The power pack comes with 10x4.5 props. The problem is my motor is getting pretty hot and I am flying a generally 50% throttle with short burst once in a while. Did Flite TEST make a poor recommendation for 4S and prop size? Should i be running a smaller prop with this set up? If so, what prop would work good with the 4S batteries? Thanks for any help you guys or gals can recommend.
I would suggest measuring the power with a watt meter.
 

BATTLEAXE

Well-known member
#13
I bought one of the new Radial C packs and a 4S battery recommended for the FT-P47. The power pack comes with 10x4.5 props. The problem is my motor is getting pretty hot and I am flying a generally 50% throttle with short burst once in a while. Did Flite TEST make a poor recommendation for 4S and prop size? Should i be running a smaller prop with this set up? If so, what prop would work good with the 4S batteries? Thanks for any help you guys or gals can recommend.
Generally it is a 50/50 split between radius and pitch when it comes to prop selection. The P-47 with the radial C pack is great with a 9x6 on 3s, which is pretty standard for any other warbird, but the P-47 is heavier so you can gain a significant rpm advantage out of the 4s, almost 4700 rpm actually. This allows for a smaller radius prop, (less spinning mass, less effort for the motor, less heat generated). Pitch can decrease as well because now you motor will spin faster, (less pitch, less drag, less effort, less heat generated again). Given the size and weight of the plane a 9" prop should be sufficient at a 4" pitch will be plenty, but remember getting those faster RPM's at the high end will cost in wattage which means a higher amp draw. If you are using the 35 amp ESC I would be concerned about that getting hot too. I run a 9x6 primarily in most planes on 3s and there are times when my 40 amp ESC gets warm, not to hot to touch but does raise concern, same with the battery sometimes. If i was to run a 4s on the same 9x6, I would want the safety factor of a 60 amp ESC just to stay in parameters.

I bet the 10x45 pushes a lot of air on a 4s run up test doesn't it? Probably wants to pull the plane right out of your hands. If it was a smaller more profiled plane like the Spit or the Mustang on 4s, you could even go down to an 8x5 or 8x6 to get really good efficiency, torque and speed. Let me know how it turns out. Curious in Canada lol