KV and runtimes - Page 2 - RC-Monster Forums

BrianG · 04.13.2009, 10:49 AM

True, using large tires, gearing for silly speed, or any other parameter that is not typical will change things.

It's too bad there wasn't something where you could plug in your vehicle and some other parameters and it would pick the proper motor for the job.

lincpimp · 04.13.2009, 10:55 AM

Quote:

Originally Posted by BrianG

True, using large tires, gearing for silly speed, or any other parameter that is not typical will change things.

It's too bad there wasn't something where you could plug in your vehicle and some other parameters and it would pick the proper motor for the job.

Maybe you need to whip something up that would do that....

BrianG · 04.13.2009, 11:00 AM

Nah, too complex. There are just too many variables to consider.

crazyjr · 04.13.2009, 11:14 AM

I lean towards the lower kv if i can, because as BrianG said it gives headroom for higher voltage, but also headroom if you miss the gearing. I have been running a neu 1515/2.5d/f (1600kv, i think) for a year with 20/51 and 5s lipo, I don't think i can get it hot even with a heating pad. I don't think it's even broke 110*F on any run

Arct1k · 04.13.2009, 11:16 AM

Quote:

Originally Posted by BrianG

Nah, too complex. There are just too many variables to consider.

Yeah I'm not sure Brian's coding skills are up to aything that complex - you'd have to come up with load factors and a multi dimensional selection algorithm.

Just think of the data inputs that would be required - I think we ask to much of Brian. ;)

BrianG · 04.13.2009, 11:49 AM

Quote:

Originally Posted by Arct1k

Yeah I'm not sure Brian's coding skills are up to aything that complex - you'd have to come up with load factors and a multi dimensional selection algorithm.

Just think of the data inputs that would be required - I think we ask to much of Brian. ;)

yeah, just thinking of sorting a multi-dimensional array gives me a headache.

snellemin · 04.13.2009, 12:00 PM

How about just a simple power to weight ratio to come up with a "decent" motor. This is how I select motors.

Arct1k · 04.13.2009, 12:07 PM

Brian I was able to find a few articles that might be of help ;)

http://www.aspfree.com/c/a/ASP/How-t...nsional-Array/

BrianG · 04.13.2009, 12:40 PM

Quote:

Originally Posted by snellemin

How about just a simple power to weight ratio to come up with a "decent" motor. This is how I select motors.

Don't forget about speed. Speed and weight are the most decisive factors in choosing a motor IMO.

Quote:

Originally Posted by Arct1k

Brian I was able to find a few articles that might be of help ;)

http://www.aspfree.com/c/a/ASP/How-t...nsional-Array/

1: Those are VB solutions. I HATE vb; utter crap.

2: Not all browsers support VB on the client-side!

3: Did I mention I hate VB?

4: Umm.... let's just say ASP is not a viable solution given the facts.

5: And just to be clear, I hate VB.

_paralyzed_ · 04.13.2009, 12:43 PM

VB and fans

Arct1k · 04.13.2009, 12:47 PM

Jeeze dude - There is always fortran 77...

http://www.physics.nau.edu/~bowman/P...10_arrays.html

BrianG · 04.13.2009, 12:51 PM

That's right! If I could put the things I hate into a bucket and blow them up, it would be the following (in no particular order):

- Fans (for RC use only - fine to keep stationary objects and me cool

)
- VB
- The ex
- People driving while talking on their cell-phone. Arrggg, gets me mad just typing that!
- Old (>65) drivers. Most are totally oblivious to anything around them.
- And, just in case I forgot someone; pretty much anyone who pisses me off on a regular basis.

BrianG · 04.13.2009, 12:52 PM

Quote:

Originally Posted by Arct1k

Jeeze dude - There is always fortran 77...

http://www.physics.nau.edu/~bowman/P...10_arrays.html

Fortran, eh? Let me step back into my time machine...

scarletboa · 04.13.2009, 05:13 PM

Quote:

Originally Posted by BrianG

That's right! If I could put the things I hate into a bucket and blow them up, it would be the following (in no particular order):

- Fans (for RC use only - fine to keep stationary objects and me cool

)
- VB
- The ex
- People driving while talking on their cell-phone. Arrggg, gets me mad just typing that!
- Old (>65) drivers. Most are totally oblivious to anything around them.
- And, just in case I forgot someone; pretty much anyone who pisses me off on a regular basis.

what do you have against fans in r/c vehicles? is it because they get messed up when bashing or racing in dirt?

BrianG · 04.13.2009, 05:28 PM

Quote:

Originally Posted by scarletboa

what do you have against fans in r/c vehicles? is it because they get messed up when bashing or racing in dirt?

That's one reason, but I'll list them all:

1: Short lifespan due to dirt/debris and environment.

2: Added wiring complexity.

3: Shorter runtime and more weight (albeit not much).

4: Poor subsitute for a proper motor/ESC. If things get hot where you need a fan to remain operational, chances are there is something wrong with the setup (needs larger motor and/or ESC, or different gearing).

5: If you rely on the fan to keep temps in check, what happens when it fails and you don't realize it? 'Cause you know it will fail...

However, if you have a good setup that runs just warm under normal use, and just use fans for extra cooling, that's ok I guess. I just like simple, and additional fans goes against that.