54 MPH E-Maxx

[HiAmplidude]

A single C50 13L on 24 cells pulled one of my heavy, all-aluminum, extended E-Maxx's to 54 MPH a couple days ago (tested by 12-channel WAAS GPS)

Yes, dreams can come true, and one of those insane motors is looking for a loving home here:
http://66.93.220.59/rcnuts/for_sale.htm

[Performance RC]

How much for the B50 8S and HAcher Master car ESC? Make a deal. Will these two work together? Can I run 14 cells on the ESC?

[HiAmplidude]

The prices are on the site I linked in the original post. You may have to hit "refresh", there, to get the latest list of available parts.

No, you don't wanna run 14 cells on any ESC with the B50 8S on the other end. That motor spins a mind-boggling 4613 RPM/V and intense current consumption. Anything over 10 cells is really asking for trouble, although I have successfully run 12 cells on that setup with lots of attention to cooling for both motor and controller, and very heavy gauge wire throughout.

The 8S is still one of my all-time favorite motors. It turns a light car into a rocket and also has the grunt torque to bring an E-Maxx drive train to its knees.

[TrinityGuy21]

How fast will a e-maxx go with a C50 Hacker with the Master Car Sport. Also, what does 13L mean? Also how many cells can my Master Car Sport handle?

[DualBL]

no, 13L means its a 13 turn, and is a L which basicly means "Large"

with B50's, there's S, L, and XL
with the C50's, I'm pretty sure it goes C50, C50L, and C50XL

-Nick

[TrinityGuy21]

It doesn't say, HiAmp what is the C50 Hacker Maxx Motor, compared to? Like a 10 turn? I want to be able to SMOKE them. They have xxx's, b4 and a xxx-4. Can my Master Car Sport speed controller handle 14-cells?

[OptimaMan]

Hey trinityguy, you really can't compare the brushless with a 10 turn motor. A brushless on 12 cells, can easily produce over 400 watts without getting damaged at all. You definitely can't say that about a 10 turn brushed 540 motor.

It's not about how fast a motor spins that is most important. Afterall, a motor that spins 100000 rpm with low torque isn't all that good. Nor is a big fatty that only goes 10,000 rpm. A Honda S2000 engine revs like crazy, but it doesn't have as much power as a 350.

The most important figure for a motor is power output and efficiency. Any motor can produce a ton of power at like 50% efficiency, but that's not what you want. You want a setup that uses up the juice so that all the battery energy is converted to motion and not lost as heat.

For fast emaxxes, do you want to go fast in a straight line for 1 minute or do you want to race for 5 or 10 minutes? How many cells do you wanna run with? You have to know these answers before you can really pick your motor.

My experience for motors is this... if you want a nice 10 minute bashing run with decent speed, get a 550 sized or so bl with around 3000 rpm/volt. Top speed with 12 cells and 15/72 gearing is only in the mid 20's, but the motor is running at around 90 percent efficiency.

If you want a motor for 5 minute racing, get a motor around 4000 rpm/volt with 12 cells. You'll be screaming down the straightaways at mid 30's mph, and breaking parts left and right, but you'll be fast.

If you want max speed, get the biggest motor, put enough cells on it so that the motor will spin at the redline, and gear it appropriately - that doesn't mean the biggest pinion gear.

BUT, what good is an emaxx that goes over 40 mph? You can only go back and forth in a straight line while burning up batteries, controllers, and rolling at every turn and the batteries last less then 3-4 minutes!!!

-OptimaMan

[HiAmplidude]

Originally posted by OptimaMan
BUT, what good is an emaxx that goes over 40 mph? You can only go back and forth in a straight line while burning up batteries, controllers, and rolling at every turn and the batteries last less then 3-4 minutes!!!

-OptimaMan

OptimaMan, good post, I agree with much of what you posted. Particularly the 3000 RPM/V on 12 cell "rule-of-thumb" that E-Maxx runners should start with, in general.

However, I have built 40+ MPH E-Maxxes that can run well over 10 minutes, and are tuned for agility. They would be unapposed by a long margin at our indoor track.

It has a lot to do with the motor. A small Lehner Basic series motor at around 3000 RPM/V will have to work three times as hard as a larger Lehner 1930 series motor at around 3000 RPM/V. This "work" results in high current-draw, which smokes speed controllers and bubbles cheap batteries, while the big 1930 motor is still running strong 10 minutes later...

You're absolutely right about not being able to hang a tight turn at 40 MPH, but I don't know of any RC car that can do that well. As long as it turns well at the speeds you *need* it to turn well at, it's kinda' cool to know you have over 30 MPH in your pocket, incase you ever wanna pull it out.

Hey, I'm completely with you that the actual investment value isn't necessarily there... Depends on the mental stability of the person. hehehe