Speed Calculator

[squeeforever]

What I would do is have the values you said, like weight, desired voltage, tire size, etc, but I would also have a thing were you can choose your car or truck from a list, like you have the motors.

[BrianG]

Squee; I was thinking about doing that, but what effect would the truck type have? Depending on how people make their setups, materials used, cell-type, etc, weight can vary quite a bit for the same truck. Therefore, I would think weight alone would be more accurate since that's what the motor "sees" as the load.

Believe me, I'm not trying to shoot down your suggestion, I just need to able to do this programmatically and accurately.

[squeeforever]

Yea, I understand. Perhaps you could have a thing to were they can select whether its an onroad or offroad vehical? That could have alot to do with motor selection. Like a 380C vs. 540.

[BrianG]

That sounds valid! Now, I gotta figure out exactly what/how much effect it will have and how to apply it in choosing the motor. Ugg, this is getting complex!

[coolhandcountry]

Originally Posted by BrianG

That sounds valid! Now, I gotta figure out exactly what/how much effect it will have and how to apply it in choosing the motor. Ugg, this is getting complex!

I know you can handle it brian. :018: I have faith in you. You can do it.

[sjcrss]

do you think you can add LIPO info into the battery section along with the cell voltage as well.....

[Nick]

Does these seem right? Seems close, just wondering what other people think.

Nice tool by the way!

[Nick]

When I put 72t spur, it decreases the speed. Wouldn't higher gearing increase it?

[BrianG]

sjcrss: What do you mean? There is a dropdown for the number of cells and another for the cell voltage which covers the various voltage ranges of both NiXX and LiPo.

Nick:
Thanks!

That theoretical speed looks about right for the values you entered, but I bet you got a warning for that RPM! 6s is a wee bit hot IMO, but if it works for you, then have fun. At that voltage and motor wind, current consumption must be quite high?

Also increasing the tooth count on the spur gear makes it geared lower so it won't go as fast, but have more power. Increasing the pinion is probably what you're thinking of.

[Nick]

I'm wondering if you should factor weight in it? I just put a Mamba 7700 in what would be my E-Maxx and it says 85mph. :P

I'll get a Venom speed meter and maybe feedback to see how accurate it is. Will be nice to know.

[BrianG]

Nick: This is exactly why I'm going to factor weight in the motor selector calculator. Someone could even enter in the kv for a regular mamba system (which has a high kv) and the numbers on paper would look impressive even though real-world results would be disappointing to say the least! Too bad most motors don't specify the torque rating...

I started work on the new version last night. While I'm at it, I totally restructured the layout to have each seperate section in its own web page (using frames). There was just too many lines of code for easy editing. It's not close to ready yet, but for those wanting to see the progress, I will have the beta version uploaded here.

I figure the best way to handle the weight factor is to suggest the motor size by weight, and then the wind/kv by voltage used. I'm thinking of using this as a guidline for weight:

0-2 lbs = 380 can size (regular Mamba system?)
3-5 lbs = 540 "S" can size
6-9 lbs = 540 "L" can size
9-15 lbs = 540 "XL" size
13+ = 540 "XXL" can size or something like the 22xx LMT series.

How does this look?

[sjcrss]

ok..thanks...the new version is looking real good.....what programming format are you writing this in...just wondering cause Im taking programming classes at this time......

[Nick]

It's Javascript and HTML (DHTML).

I found a typo by the way, when I put 7XL motor and put it over RPM the Message says it's a 6XL. :)

Look forward to seeing it updated.

[BrianG]

Originally Posted by Nick

I found a typo by the way, when I put 7XL motor and put it over RPM the Message says it's a 6XL. :)

Fixed in both the regular and beta versions... Actually, the recommended rpm displayed in the warning box was wrong as well. Was simply an issue with array indexing.

[BrianG]

I'm working on the motor selector and have some questions. I need to group all the 540 can motors by S, L, XL, and XXL size.

Would the Lehner Basics be considered S size?
Would the Lehner Basics XL be considered L size?
Would both the LMT 1940 and 1950 be considered XL size? Or is the 1940 more L size and the 1950 XL size?

Argg! LMT has too many sizes! Better question:
Where do the following motors fall in the S, L, XL (and maybe XXL) size rating?
1920 S?
1930 L?
1940 XL?
1950 XXL?