Off the Wall Monster Electric.
12-01-2003, 04:15 AM
#1
Senior Member
Thread Starter
My Feedback: (3)
Join Date: Nov 2002
Location: Mary Esther, Florida, FL
Posts: 20,205
Likes: 0
Received 14 Likes
on
13 Posts
Off the Wall Monster Electric.
Got a note from another user, asking for advice on multi-motor electrics:
On the multi-motor, using electric there should be no worries about loss of a motor in flight, that consideration is eliminated. Bothers will be component selection, control, and installation.
Taking the monster first. It is actually simpler than the tri-motor.
Just got another note – he specifies 550 can motors, LiPo batteries, and 18.5 pounds target weight. At that weight it will work. Holding the motors to 13A at 12v we have our 50 watts/pound. Using the “War Emergency” rating of 15A/motor we almost get to 60 w/lb.
Since the motors and batteries are specified that leaves only the circuit and ESC units to pick.
Just picking easy numbers that are close, we want 960 watts, and 12 volt multiples.
Considering the batteries first, if we run the system with parallel motors we have to have 80 amps at 12 volts from the batteries. Not practical.
If we set the system as three series pairs of motors we can run at 24 volts, the battery current then is 40A, better, and we can use three ESC units at 14 amps each. Except for the battery current this would be fine.
Then we could have two sets of three motors wired in series, and wire the batteries for 36 volts. This cuts us to 27 Amps on the batteries, and using two ESCs that’s 14 Amps each.
The last way is to have all the motors in series, and the batteries wired for 72 volts. This, of course, will only draw 14 Amps.
My pick is three pairs. Running 24 volts at 14 Amps is within the capabilities of the Astro 217D ESC, and I’ve had very good service from them. Actually, one 217D could drive four of the motors, but not all six. Going to a higher voltage or higher current leads to much more expensive units, three 217D will cost about $150.
Opinions from anyone else?
The three motor plane is going to wait for my comments, too late now.
Bill.
WR,
I am pretty sure that I am in need of your expertise..........I have two multi-engine systems that I need some help with.....one is on a 144 inch Daimler-Benz Project Aircraft...electric, 4 pulling and 2 pushing, and the other is independent control for 3 electric motors, one with reverse........I am going to use a 9Z WCII for these, and need some expert advice.......
Hope that you can help me..
I am pretty sure that I am in need of your expertise..........I have two multi-engine systems that I need some help with.....one is on a 144 inch Daimler-Benz Project Aircraft...electric, 4 pulling and 2 pushing, and the other is independent control for 3 electric motors, one with reverse........I am going to use a 9Z WCII for these, and need some expert advice.......
Hope that you can help me..
Taking the monster first. It is actually simpler than the tri-motor.
Just got another note – he specifies 550 can motors, LiPo batteries, and 18.5 pounds target weight. At that weight it will work. Holding the motors to 13A at 12v we have our 50 watts/pound. Using the “War Emergency” rating of 15A/motor we almost get to 60 w/lb.
Since the motors and batteries are specified that leaves only the circuit and ESC units to pick.
Just picking easy numbers that are close, we want 960 watts, and 12 volt multiples.
Considering the batteries first, if we run the system with parallel motors we have to have 80 amps at 12 volts from the batteries. Not practical.
If we set the system as three series pairs of motors we can run at 24 volts, the battery current then is 40A, better, and we can use three ESC units at 14 amps each. Except for the battery current this would be fine.
Then we could have two sets of three motors wired in series, and wire the batteries for 36 volts. This cuts us to 27 Amps on the batteries, and using two ESCs that’s 14 Amps each.
The last way is to have all the motors in series, and the batteries wired for 72 volts. This, of course, will only draw 14 Amps.
My pick is three pairs. Running 24 volts at 14 Amps is within the capabilities of the Astro 217D ESC, and I’ve had very good service from them. Actually, one 217D could drive four of the motors, but not all six. Going to a higher voltage or higher current leads to much more expensive units, three 217D will cost about $150.
Opinions from anyone else?
The three motor plane is going to wait for my comments, too late now.
Bill.
