Originally Posted by
jester_s1
If a servo makes enough torque at 4.8v to operate the control surface it is attached to, then there isn't a problem using 4.8v. But it has become standard practice with RC planes to use 6v for two reasons. First, it lets us use a little bit lower end servo and still get the torque we need. Second, it prevents the aforementioned brownouts.
Okay, I get it that 6 volts is "standard practice". I just can't agree with J.Dunker's statement about always using 6+ volt packs. IF the only servos that will work for a given application are rated at 4.8 volts, to use 6 volts will burn them out in a very short amount of time. The way I see it, there is a big difference between having a bit of power in reserve and just carrying extra power just to have it. Does a Kadet really need 6 or 7.2 volts to fly well? In a word, NO. They were designed back in the day of 4.8 volts and S-48 servos. HELL, my first plane, a Kadet Jr, was built using 4.8 volts powering three S-19 servos and even that was considered overkill for a 48" trainer. The Kadets haven't changed, only the radio gear and batteries used to control them. Even in the Kadet Sr kit assembly instructions, it lists this Airtronics servo:
94102 Precision Heavy Duty Bushed Standard 50oz-in at 4.8 volts, .22 second transit time for 60 degrees
If that's what was listed when the kit was first kitted, why do I need to use a 6 volt pack now? It wasn't needed back then so why the change? Is it because it's needed or just because it's there to satisfy those that think they need, to quote Tim Allen, "MORE POWER"?