12-03-2012, 09:06 PM
ok guys . i have the katana with a 5055 outrunner 700kv motor 1500W, CONTINUAL 75AMP CURRENT RATING . running 6s 3000mah , battery pack , 13 x6 lightwood prop . 85 AMP ESC . the model fully loaded weighs 2.6kg (5.7lb)
therefore formula at 3.3 v per cell =19.8v x 75 =1485 watts /5.7LB = 260 WATTS per pound !!!
i'm using a 13x6 lightwood prop.
the motor suggests 12x6 to 12x12 . the esc has a max loading burst of 100amps .
is there anything wrong / or out of spec here .
upon testing today with a fully charged 6s 3000 x20c battery , at 50% continual throttle , the esc started limiting current at 2min 30sec . and rpm became erratic . ESC WAS ABOUT 70 DEGREES C .
BATTERY WAS WARM , AND MOTOR WAS WARM TO HOT .
tested battery it was down to 3.92 volts per cell .
charged battery again
this time 35% throttle tied up to post , for 3 minutes . then 2x 10 second 3/4 throttle bursts, then at 4 minutes a 10 second full throttle burst , then back to 35% throttle till 5 minutes and 2x 3/4 throttle bursts . at 5 min 30 sec , tried full throttle and rpm did not increase much back to 30% throttle till 6 min 30 second mark still flyable at 30% throttle . i cut out there .
battery , motor and esc were all on the warm to hot . tested battery each cell was 3.8 volts . i'm aware the prop will unload a lot in the air compared to a static test . so all should be good .
does this make sense to anyone . with the throttle fully open with a 13x8 prop . this model pulled 100 amps . it now has a 13 x6 on it , and i fear it will over heat given a bit of high rpm flying .
however full throttle on this plane wouldnt be for the faint hearted . it will hover at 1/2 throttle .
this seems to be somewhere in the ball park .
question , what if i wanted to run a 1400kv motor for this plane , or a 280 kv motor, or an 8s battery . here lies my confusion !!!!!!
any input welcome .
ok my question really relates to amps . if i ran a 5s on this set up i would have 217watts/lb a 6s, 260watts/lb . if i had an 8s , what would happen ?
therefore formula at 3.3 v per cell =19.8v x 75 =1485 watts /5.7LB = 260 WATTS per pound !!!
i'm using a 13x6 lightwood prop.
the motor suggests 12x6 to 12x12 . the esc has a max loading burst of 100amps .
is there anything wrong / or out of spec here .
upon testing today with a fully charged 6s 3000 x20c battery , at 50% continual throttle , the esc started limiting current at 2min 30sec . and rpm became erratic . ESC WAS ABOUT 70 DEGREES C .
BATTERY WAS WARM , AND MOTOR WAS WARM TO HOT .
tested battery it was down to 3.92 volts per cell .
charged battery again
this time 35% throttle tied up to post , for 3 minutes . then 2x 10 second 3/4 throttle bursts, then at 4 minutes a 10 second full throttle burst , then back to 35% throttle till 5 minutes and 2x 3/4 throttle bursts . at 5 min 30 sec , tried full throttle and rpm did not increase much back to 30% throttle till 6 min 30 second mark still flyable at 30% throttle . i cut out there .
battery , motor and esc were all on the warm to hot . tested battery each cell was 3.8 volts . i'm aware the prop will unload a lot in the air compared to a static test . so all should be good .
does this make sense to anyone . with the throttle fully open with a 13x8 prop . this model pulled 100 amps . it now has a 13 x6 on it , and i fear it will over heat given a bit of high rpm flying .
however full throttle on this plane wouldnt be for the faint hearted . it will hover at 1/2 throttle .
this seems to be somewhere in the ball park .
question , what if i wanted to run a 1400kv motor for this plane , or a 280 kv motor, or an 8s battery . here lies my confusion !!!!!!
any input welcome .
ok my question really relates to amps . if i ran a 5s on this set up i would have 217watts/lb a 6s, 260watts/lb . if i had an 8s , what would happen ?
patience !! paaatience !! paaaaaatience paaaaaaatieeence dooooohhhh !!!
DANGER WIFE CAN READ FORUMS . love you darling . sig changed .