Using larger motor and run time is longer??
02-18-2004, 10:53 PM
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Using larger motor and run time is longer??
I have been flying a Littlest Stick converted to electric power. The motor, esc, and battey pack is from a skyvector parkflyer. I know this parkflyer is not very good but the flight system works fine in this small plane. I really like it because I have almost nothing invested in it,just spare parts .
I wanted to give it more power so I installed a 6 volt 280 motor and Wingo prop. The battery is a 6 volt 600 mah NiMH. I'm not sure of the stock motor size but it is used on the small parkflyers like the E-Gull from readytoflyfun.com
The smaller motor ran for 10 minutes and the new speed 280 will run well over 12 minutes on this battery. I put the wingo prop on the smaller motor once and it ran for only 8 minutes and really got hot but it did have great power with it. So I know it takes more power to turn this prop. I'm not sure if I gained any power with the 280 motor, the prop doesn't really turn up that fast but I'm not sure
My question is, why is the larger motor and prop running longer than the smaller motor and prop? Is it that much more efficient?
Thanks , Lynn
I wanted to give it more power so I installed a 6 volt 280 motor and Wingo prop. The battery is a 6 volt 600 mah NiMH. I'm not sure of the stock motor size but it is used on the small parkflyers like the E-Gull from readytoflyfun.com
The smaller motor ran for 10 minutes and the new speed 280 will run well over 12 minutes on this battery. I put the wingo prop on the smaller motor once and it ran for only 8 minutes and really got hot but it did have great power with it. So I know it takes more power to turn this prop. I'm not sure if I gained any power with the 280 motor, the prop doesn't really turn up that fast but I'm not sure
My question is, why is the larger motor and prop running longer than the smaller motor and prop? Is it that much more efficient?
Thanks , Lynn
02-19-2004, 08:24 AM
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RE: Using larger motor and run time is longer??
Thank you for demonstrating on of the major misconceptions of electric power.
The power does not come from the motor. Swapping a motor out for a bigger one doesn't necessarily mean you'll get more power. If you do, it's just dumb luck. It could go either way, and in most cases, you end up with LESS power.
Power comes from the battery in the form of Volts and Amps. Volts are controlled by the number of cells in the battery, and Amps are controlled by the characteristics of the motor, and the load put on the motor.
In your case, you didn't change the battery or the load. You changed the characteristics of the motor. The motor you chose is not as "hot" as the motor it replaced. That is to say, it doesn't turn as fast on a given voltage. Because it's not trying to turn the propeller as fast, it's not drawing as many Amps, so your flight times are longer.
As you've found out, physical size is not an indication of how much power a motor will produce. It's generally an indication of how much power it can HANDLE, but not necessarily. To make use of a motor's potential, you have to choose the right battery and propeller for that specific motor. Using the battery and propeller off a completely different motor MIGHT work, but usually, you end up with less power, or you burn the motor out by overloading it.
I suspect your stock motor is a "180" type. It's about the same length as the 280, except it has flat sides, right?
The power does not come from the motor. Swapping a motor out for a bigger one doesn't necessarily mean you'll get more power. If you do, it's just dumb luck. It could go either way, and in most cases, you end up with LESS power.
Power comes from the battery in the form of Volts and Amps. Volts are controlled by the number of cells in the battery, and Amps are controlled by the characteristics of the motor, and the load put on the motor.
In your case, you didn't change the battery or the load. You changed the characteristics of the motor. The motor you chose is not as "hot" as the motor it replaced. That is to say, it doesn't turn as fast on a given voltage. Because it's not trying to turn the propeller as fast, it's not drawing as many Amps, so your flight times are longer.
As you've found out, physical size is not an indication of how much power a motor will produce. It's generally an indication of how much power it can HANDLE, but not necessarily. To make use of a motor's potential, you have to choose the right battery and propeller for that specific motor. Using the battery and propeller off a completely different motor MIGHT work, but usually, you end up with less power, or you burn the motor out by overloading it.
I suspect your stock motor is a "180" type. It's about the same length as the 280, except it has flat sides, right?
02-19-2004, 05:56 PM
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RE: Using larger motor and run time is longer??
Yes, the original motor was a 180 with the flat sides. I ordered a 6 volt GR6328-280 motor because that is the battery voltage I had. I also used a Wingo prop because that is what Hobby Lobby uses on their 280 powered planes. Now I notice they use a 7 cell battery with 720 mah on those planes.My battery is just 5 cells. I guess this 6 volt motor is really low power, but it does not overheat with the Wingo prop. Also I have noticed that the speed control does not turn the motor on until the lever is moved halfway. I was thinking that it may not be getting full power.
the specs on the motor are: GR6328
12watts ,6.0volts, free rpm 14.2K, load rpm 8K, prop 6x4,4amps ,thrust 3 oz
thanks, Lynn
Edit: I just flew the plane late this afternoon and it flew great. There was a strong breeze from the south and it climbed to 100 ft in a flash. Keep in mind this is a 8 oz plane with a 19.75 inch wingspan.It had enough power to pull through the wind and not get carried away downwind.It would almost hover into the wind and go like heck downwind.
So I guess the 280 motor is doing a fine job and its not a bad combination after all.
the specs on the motor are: GR6328
12watts ,6.0volts, free rpm 14.2K, load rpm 8K, prop 6x4,4amps ,thrust 3 oz
thanks, Lynn
Edit: I just flew the plane late this afternoon and it flew great. There was a strong breeze from the south and it climbed to 100 ft in a flash. Keep in mind this is a 8 oz plane with a 19.75 inch wingspan.It had enough power to pull through the wind and not get carried away downwind.It would almost hover into the wind and go like heck downwind.
So I guess the 280 motor is doing a fine job and its not a bad combination after all.
02-20-2004, 08:11 AM
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RE: Using larger motor and run time is longer??
If it works, don't knock it, right? Right!
The voltage rating on these inexpensive can motors is their industrial/commercial rating. That's the voltage they should be run at for maximum life expectancy. Since the motors are cheap, we don't care about maximum life. We want maximum power, so it's not uncommon to run a "6 Volt" motor on 7.2V, 8.4V or 9.6V (or more commonly, 6 cells, 7 cells, or 8 cells)
The voltage rating on these inexpensive can motors is their industrial/commercial rating. That's the voltage they should be run at for maximum life expectancy. Since the motors are cheap, we don't care about maximum life. We want maximum power, so it's not uncommon to run a "6 Volt" motor on 7.2V, 8.4V or 9.6V (or more commonly, 6 cells, 7 cells, or 8 cells)
