Please help me complete this combo
03-11-2004, 03:46 PM
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Please help me complete this combo
I just bought a Graupner 480 race 7.2v motor.
(I already have a Graupnner Speed 400 6v motor and was hoping to use some of the same stuff if possible)
I have 2 NiMh battery packs, an 8-cell 650 2/3 AA and a NiMh 8-cell 1100 (cells are a little bigger than the other)
I have electric props: 6x4, 8x6 and 9x6 and a gearbox (2-1, 2.5-1, 3-1).
To run the motor direct drive, which prop would I use and with what kind and size ESC?
To run the motor geared, which prop with what kind and size ESC? I can gear 2-1, 2.5-1, and 3-1.
Hope this isn't too confusing. Thanks.
Beeza
(I already have a Graupnner Speed 400 6v motor and was hoping to use some of the same stuff if possible)
I have 2 NiMh battery packs, an 8-cell 650 2/3 AA and a NiMh 8-cell 1100 (cells are a little bigger than the other)
I have electric props: 6x4, 8x6 and 9x6 and a gearbox (2-1, 2.5-1, 3-1).
To run the motor direct drive, which prop would I use and with what kind and size ESC?
To run the motor geared, which prop with what kind and size ESC? I can gear 2-1, 2.5-1, and 3-1.
Hope this isn't too confusing. Thanks.
Beeza
03-11-2004, 05:09 PM
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RE: Please help me complete this combo
Beeza,
There are so many combinations that it is difficult to answer your questions. If you will go to this web page:
http://brantuas.com/ezcalc/dma.asp
and plug in your numbers it will give you a wealth of information.
Later;
D.W.
There are so many combinations that it is difficult to answer your questions. If you will go to this web page:
http://brantuas.com/ezcalc/dma.asp
and plug in your numbers it will give you a wealth of information.
Later;
D.W.
03-12-2004, 08:49 AM
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RE: Please help me complete this combo
The problem is, unless you know what you're looking for, you can plug numbers in all day long and they'll look fine. Yeah, a Speed 480 7.2V Race direct drive to a 9x6 prop on an 8-cell KAN650 pack will draw 47 Amps. Looks fine to me... Except, that combination would probably start a fire, if it worked at all.
What you're trying to do is pair things up such that you don't exceed the capabilities of any one part. To do that, you need to know the maximum capabilities of each component, specifically the maximum current each piece can handle comfortably. How do you figure that out? Well, sometimes it's specified by the manufacturer and vendor, as in the case of equipment specifically made for R/C like LiPoly batteries and brushless motors. When you're adapting things from industrial and consumer applications, you have to rely on the people that came before you and figured it all out through testing. Both the cells you're using and the motor were originally designed for consumer products or industrial applications.
I just happen to know that KAN650 cells top out at around 10 Amps. Your typical 1100mAh NiMH will top out anywhere from 12 to 15 Amps. The motor I'm a little fuzzy on. I want to say 15 Amps, but don't hold me to that figure.
With this information you can now plug numbers into P-Calc and see what comes up. FWIW, the KAN650 pack shouldn't even be considered. For a direct drive combo using what you have, the 1100mAh NiMH pack, and 6x4 prop.
What you're trying to do is pair things up such that you don't exceed the capabilities of any one part. To do that, you need to know the maximum capabilities of each component, specifically the maximum current each piece can handle comfortably. How do you figure that out? Well, sometimes it's specified by the manufacturer and vendor, as in the case of equipment specifically made for R/C like LiPoly batteries and brushless motors. When you're adapting things from industrial and consumer applications, you have to rely on the people that came before you and figured it all out through testing. Both the cells you're using and the motor were originally designed for consumer products or industrial applications.
I just happen to know that KAN650 cells top out at around 10 Amps. Your typical 1100mAh NiMH will top out anywhere from 12 to 15 Amps. The motor I'm a little fuzzy on. I want to say 15 Amps, but don't hold me to that figure.
With this information you can now plug numbers into P-Calc and see what comes up. FWIW, the KAN650 pack shouldn't even be considered. For a direct drive combo using what you have, the 1100mAh NiMH pack, and 6x4 prop.
