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BrianG · 04.24.2008, 10:06 AM

The majority of your HP and torque will be at take-off and possible at the upper end of the speed range where drag is the greatest. Depending on how high you have to gear up, I would expect more current than 100A even on 12s considering the weight of your vehicle. Some of the lighter cars are pulling over 100A. How about using a Castle HV-110? They are actually underrated and should be more like a HV-130. And Castle may be willing to add an extra FET PCB to get it up to something like HV-170 level. Or, their hydro HV-240 would be possible if you replace the cooling tubes with actual heatsinks.

Also, while dual motors increase output significantly, the output probably won't be exactly double because of the slight parameter tolerances; one motor may be spinning slightly lower than the other and/or ESCs may not be outputting the exact same throttle level as the other. I would use one larger motor instead. Weight will be reduced and setup will be simplified. A 1527 1.5d or 1y (kv around 1300) on 12s should be plenty.

Something else you want to look at is if you can get the gearing needed to reach that speed with the spur/pinion, tires, voltage, motor kv, etc you have. Since your vehicle will be so heavy, what about using a two speed? If using a single speed, the motor may have a hard time to pull that weight geared so tall (more of an issue with a single motor). The only thing I'm wondering is the tires breaking loose on shift.

At the start of my project, a couple hi-speed "veterans" chimed in. While their vehicles were small and light, they said aerodynamics plays a VERY big role. The idea is the make the body as aerodynamic as possible (this includes covering turbulent areas like under the car, around suspension components, and around the tires), while providing adequate downforce (but not too much) to keep it planted. Hence, the funny looking body styles. I have a Porsche body I'll be using for playing around, but am planning to make a homemade lexan/plexi body similar to the typical "airplane" looking ones for the high speed runs.

	(#55)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	04.24.2008, 10:06 AM The majority of your HP and torque will be at take-off and possible at the upper end of the speed range where drag is the greatest. Depending on how high you have to gear up, I would expect more current than 100A even on 12s considering the weight of your vehicle. Some of the lighter cars are pulling over 100A. How about using a Castle HV-110? They are actually underrated and should be more like a HV-130. And Castle may be willing to add an extra FET PCB to get it up to something like HV-170 level. Or, their hydro HV-240 would be possible if you replace the cooling tubes with actual heatsinks. Also, while dual motors increase output significantly, the output probably won't be exactly double because of the slight parameter tolerances; one motor may be spinning slightly lower than the other and/or ESCs may not be outputting the exact same throttle level as the other. I would use one larger motor instead. Weight will be reduced and setup will be simplified. A 1527 1.5d or 1y (kv around 1300) on 12s should be plenty. Something else you want to look at is if you can get the gearing needed to reach that speed with the spur/pinion, tires, voltage, motor kv, etc you have. Since your vehicle will be so heavy, what about using a two speed? If using a single speed, the motor may have a hard time to pull that weight geared so tall (more of an issue with a single motor). The only thing I'm wondering is the tires breaking loose on shift. At the start of my project, a couple hi-speed "veterans" chimed in. While their vehicles were small and light, they said aerodynamics plays a VERY big role. The idea is the make the body as aerodynamic as possible (this includes covering turbulent areas like under the car, around suspension components, and around the tires), while providing adequate downforce (but not too much) to keep it planted. Hence, the funny looking body styles. I have a Porsche body I'll be using for playing around, but am planning to make a homemade lexan/plexi body similar to the typical "airplane" looking ones for the high speed runs.