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sikeston34m
RC-Monster Brushless
 
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Join Date: Sep 2007
10.04.2008, 09:57 AM

Excellant Work! I may wind up doing this with a spare E Revo Chassis that I have here.

You're not going to be satisfied with the top speed of the 4s2p A123 cells using the 4.3:1 gearing.

I plugged your values into Brian's Estimator. Here's how it looks.

Differential Ratio: 4.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 13.2
Motor KV: 515
Tire Diameter (inches): 4.3
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1 : 1
Total Ratio: 4.3 : 1
Tire Circumference (inches): 13.51 inches (343.12 mm)
Total Motor Speed: 6798 RPM
Vehicle Speed: 20.22 mph (32.49 km/h)
Estimated Adjusted Speed: 20 mph (32 km/h) - 2% loss
Effective KV Value: 515

This setup will not cog at all. Expect everything to run VERY cool. It will top out instantly and you're gonna be surprised how quiet it runs.

Here's yet another setup. Using the 3.3:1 gearing and 6S Lipo. Your motor will handle 6S. If you notice, now things are getting quite speedy. This will be ALOT harder on the drive train and alot harder to control. I'm not sure if those stock center drives will hold up to this, but here goes.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 22.2
Motor KV: 515
Tire Diameter (inches): 4.3
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1 : 1
Total Ratio: 3.30769 : 1
Tire Circumference (inches): 13.51 inches (343.12 mm)
Total Motor Speed: 11433 RPM
Vehicle Speed: 44.22 mph (71.03 km/h)
Estimated Adjusted Speed: 42 mph (67 km/h) - 6% loss
Effective KV Value: 515

Here's the all out setup that I will be doing. Let's swap motors now. This is running the 4120/14. How about the V3 Mamba Monster to power this? We can program it to be easier on the drive train. But here it is, the all out setup IMO.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 22.2
Motor KV: 660
Tire Diameter (inches): 4.3
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1 : 1
Total Ratio: 3.30769 : 1
Tire Circumference (inches): 13.51 inches (343.12 mm)
Total Motor Speed: 14652 RPM
Vehicle Speed: 56.67 mph (91.03 km/h)
Estimated Adjusted Speed: 52 mph (84 km/h) - 8% loss
Effective KV Value: 660

Top Speed seems faster. Using the 4.3:1 gearing on 6S, I was almost keeping up with interstate traffic (sideroad) with 5.75 tall tires. The Phaltline tires.

On 6S, we should keep on eye on temps until we get a feel for what it's gonna do.


I'm curious as to what your vehicle weight will be? I think my Revo Conversion is a little heavy.
   
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