Speed Calculator

[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).

[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]

The slipperential has a centerdiff, indeed, but it's not directly connected to the pinion. I want to make a direct connection between the pinion and the centerdiff to increase speed a bit.

[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%

[BrianG]

New addition to the calculator. This might be hard to explain, but I'll try.

On several pages, there are images that change depending on the options listed. These images are made up of smaller images put together like a puzzle. As such, you can't simply post a direct link to any image since it would only be one piece of the puzzle.

So, each page that has images like this, there is a new button called "Get Picture". When clicked, a help window will pop up with a link that you can post in the forum so other can see it.

For example, on the "Lipo Wiring" page, the first section shows how a pack is built, but defaults to a 1s1p pack. If someone wanted to post a picture of what a 4s2p pack looks like, they just click the "Get Picture" button, and then copy the section in blue into a link on this page. Like this:

Link to see a 4s2p pack.

Hopefully this will be useful. :)

[BrianG]

Added differential ratio for HPI Hellfire...

[Serum]

somehow I saw this coming.. :)

[BrianG]

Actually, I did it for you and Mike since you said you both got one. :)

Seriously, it's kind of an odd ratio. A 42T ring gear? But I actually counted the teeth and verified it. Figured it was oddball enough to add it.

[Patrick]

BrianG, thanks for making the speed calculator. I use it all the time. Half the time I'm on rcmonster I have the calculator open as well, so when people say they X motor on X voltage with X gearing in X vehicle, I can quickly put that into the speed calculator to get an idea of what speeds where talking about.
I also use it to quickly check what kv all the different motors are, since I can't remember all of them. It's a lot quicker than looking for specs on a manufacturers website. If it's not too much of a pain would you please be able to add a few more of the neu 15 series motors, mainly the lower kv ones, since neu are the hardest for me to remember and theres the less of the neu's on there than most other brands.
If it takes too long don't worry, but if you do then, thanks.

[BrianG]

Cool! I'm glad you found it useful!

I guess I could add the other 15xx motors. :) I just have the ones I did simply because those are the ones Mike stocks.

EDIT: Added all the 1512 and 1515 data...

[Patrick]

Oh, he can special order the other ones as well though can't he?