Speed Calculator

Originally Posted by BrianG

- max cell count
- max current
- power limit
- if it runs on 12v
- if it runs on 120v AC
- whether you can adjust the CC/CV threshold
- efficiency
- any other noteworthy features.

It's OK if you don't know the efficiency (the code assumes 80% as a ballpark figure if it isn't known). This value is not something commonly given, I just happened to measure it on my EOS 7i a while back.

Thanks in advance! You'll be contributing to a good cause. :)

ok i will help as far as i can, i mite ask ???'s to how i figure out the stuff lol... but tomrow, everyone here is sleeping, and i and going to bed soon lol

but from what i know

the ps it comes with is 15.8 volts i THINK i need to double cheack

it says on the box 10 amp ac/dc charger, so idk.. cant say if it runs on 12 volts as i dont have anything to run it with other then the ps it comes with... 120 ac, idk, what ever voltage in the us is is what its going to always be at... need to have her on and look around for the others... and idk what or how to cheack alot of this as i never cared lol, so if u could help when i need to then that id be great!

[BrianG]

That's OK. I just went to the MRC website and got the data. They didn't list the power limit, but since the included power supply delivers 10A at 15v (150w), I assumed a 120w power limit since they probably figured in a 25% margin, not to mention charger efficiency. If this is incorrect, someone can let me know...

k good lol now i cant screw up sumthin LOL

[BrianG]

Fixed...

[jnev]

Great. Thanks Brian for adding the 989. Really appreciate it.

[seth556]

I was working on something like this minus all the extra features. Now I'm thinking I might have the basic calculations and then add extra stuff to find roll center and all that dealing with the car setup.

Heres the project page. http://sourceforge.net/projects/rc-gear

[Finnster]

Hi Brian, great work BTW. One small request, could you please add the 51T spur to the drop down menu? It has all the revo spurs, and this would be convient when comparing between the Emaxx/strobe tranny and the stock Revo. Thanks!

[BrianG]

***RC***: No problem. :)

Originally Posted by seth556

I was working on something like this minus all the extra features. Now I'm thinking I might have the basic calculations and then add extra stuff to find roll center and all that dealing with the car setup.

Heres the project page. http://sourceforge.net/projects/rc-gear

I think I've seen that before - nice job!

If you want to borrow any data from my web version, feel free. Most of the data and common functions are in the "library.js" file, which is called in all the pages. I'm sure you know how to get the file, but I can also send it to you. Each data array has comments to describe what the various values are.

Originally Posted by Finnster

Hi Brian, great work BTW. One small request, could you please add the 51T spur to the drop down menu? It has all the revo spurs, and this would be convient when comparing between the Emaxx/strobe tranny and the stock Revo. Thanks!

Done! Also added the pitch in the spur list and fixed a small bug (does not affect calculated output - just a user-interface thing).

[seth556]

I think I've seen that before - nice job!

If you want to borrow any data from my web version, feel free. Most of the data and common functions are in the "library.js" file, which is called in all the pages. I'm sure you know how to get the file, but I can also send it to you. Each data array has comments to describe what the various values are.

I think I will. It'll be a lot easier than trying to find all the ratios on my own.

Dang, you have 76 error messages?!?!?!

[jhautz]

Hey Brian!!! Your a Mod!!! Nice job Man. When did that happen??? I just noticed.

Congrats Dude!

[captain harlock]

Last weekend I made a drag race with my SuperMaxx( 1950/10, 149.18 controller, 6s Ev020 packs and 20 pinion: 36 spur in a Slipperential) against an electric powered 1/10 touring car with a very fast LRP brushless system with only 6 sub-c cells and I was very close behind it and never were able to pass it?!!!!

I used your speed estimator, Brian, and it gave me a 46-47mph speedrun while I was hoping for 50-55mph.

I think the Slipperential's gear ratio is a bit high.

What do you think? should I get a centerdiff?

u arent going to beat that touring car man, there whicked fast with bl no matter what bl is in it and batts.............but cd, u already got one in the slippy dont u? or whats would be different? sorry, idk so dont be harsh

[BrianG]

From what I've seen, the slipperential tends to create a low gear ratio. To get more speed, try using smaller spur, larger pinion, higher voltage, higher kv motor, and/or bigger tires.

And don't forget, once the calculator gets past ~45mph, wind resistance plays a BIG role in actual speed (depending on vehicle).

[captain harlock]

Originally Posted by BrianG

From what I've seen, the slipperential tends to create a low gear ratio. To get more speed, try using smaller spur, larger pinion, higher voltage, higher kv motor, and/or bigger tires.

And don't forget, once the calculator gets past ~45mph, wind resistance plays a BIG role in actual speed (depending on vehicle).

Your suggestion is a bit hard to make since it'll cost money.

I believe a direct drive ( cd-pinion) would help alot.

Promod once ran a Lehner XL1600 with 6s lipos in his truck with a centerdiff and it made a nice 50mph for him.

I'm 100% sure the problem is with the slipperential( it's for racing).

ultimately i think your fighting a loosing battle because his car has more top speed potential than yours... but if you want to try... i think i saw a 24t pinion in the rc-monster store... theoretically that will give you a 20% increase in top speed and its quite cheap compared to getting a whole new motor... if you still have your emax tranny, you can slap that back in there for the race as well, that should theoretically give you another 20%