primary difference is deadband. Ever notice in years past, futaba had servos as "92" and "91" with the "92" versions being classified for helis,..i.e. 9155/9255. The difference was deadband. Same with the car servos. I'm actually using servos that are called "car" servos now,..but far less expensive than most would think are OK. both my E5S (600 on 6S) and E5SS (715 on 12s) are using Futaba 3470SV's on the swash, using 8V output from BEC. Torque and speed are fine, they're sbus2 so if I actually wanted to change deadband or anything else they're capable, and at $45 ea from tower, I could just keep spares around if I wanted to. They're 3/4 ounce lighter than common "heli" servos also. If more torque was needed (which it isn't), the 9470 could be another choice, but they're $100 ea. I do work at Hobbico, the Futaba importer, but I pay for equipment also, it's not free,.. and I think these are the best value. Matt flew my machines at triple tree in september and loved the setups.
Support guys tell me that deadband is the primary difference. On planes you must have much wider deadband or the surfaces will sit on the ground and flutter. Helis and cars need far less. Unfortunately there isn't a super inexpensive superfast servo in the lineup, so standard heli tail servo must be used for the tail to work well.
Usual caveats apply,.. Futaba doesn't call these "heli" servos, and you use them on a heli at your own risk,.. but my experience is positive.
