motocalc or???

[rmoore7167]

Im just getting into electrics. Ive read periodically that there is programs to calculate flight times, proper motors, props etc. Can anyone lead me to a decent program?

One other question on batteries. can I use 3 cell lipoly on brushed motors? someone at hobby store told me i couldnt.

thanks

[Hydro Junkie]

Can't say on the program, but as for the batteries and a brushed motor, did (s)he say why? Unless I'm WAY OUTDATED on electrical/electronics systems, a battery is a storage medium for DC power and nothing more. Granted, the various types use different ways of storing the charge, but they still just hold the charge. Does anyone have any reason that I'm not aware of, as I'm curious on this too

[Dave Robelen]

Hi,
The only reason that running three li-poly cells with a brushed motor would be a problem is the ratings of the ESC used. It has nothing to do with the motor. Many of the current ESC's are rated for a maximumof 8 cells (9.6V), and hooking one of these to three li-poly's could run the voltage up to 12V or so. The problem has to do with how much voltage the BEC circuit can drop as it provides 5V power to the receiver and servos. All of the voltage over 5V is converted into heat, and when the temp gets too high, you lose power to the R/C gear. I am told that it will come back when things cool down, but why take the risk?
If any manufacturer is making 12V ESC's, it would be either Castle Creations or FMA Direct. The folks building the brushless ESC circuits were quicker to provide for the extra voltage, quite a few of them can handle a three cell li-poly pack.
Cheers, Dave

[roger111]

Try this link, its a little confusing but, it's for what you are asking.

http://brantuas.com/ezcalc/dma1.asp