I have returned to the hobby after many years of absence and I now have a 4 star 60 which utilizes a Y harness for dual servos for the ailerons. I have seen a plane at our flying field which utilizes 4 servos on a Y harness for ailerons. I am not aware that when you buy a servo or receiver that manufacturers specify the limits on the current pulled per channel on a receiver or the current requirements of a particular servo. I have asked this questionat my club and the answer that I got was that the current requirements are so small that it does not matter but this does not satisfy my curiosity. Can someone give me a more definitive answer?Thanks</p>

From what I have read the connectors are more the problem. They are rated at 3A. The reciever buss will carry more than we need to worry about. The loads on the servos are usually momentary. It is more important to have enough battery capacity to prevent brownouts. Even 72Mhz will drop out on low voltage. It just resets faster than we can see. I have run up to a 33% system with just the recever, but I used two batteries. There were plenty of 40% planes run on Y harnesses from the recievers with no problems. The discussion about power started when digital servos were introduced. They used more power so people went to two batteries with still one reciever. Some folks used two recievers to spread the load out and give some redundancy on the larger more expensive airframes. Eventually someone designed a power buss system so then everyone thought they needed one because it was for sale. It is hard to quantify amp loads because the load is contnually shifting in flight.

Not to argue the 4 servos on y-harness or current /voltage used, my experience has been to use a 5 cell pack for 6v. and all shall be fine. Yes, y's are ok but separet servo for each aileron best. Never have I ever seen 4 servos on ailerons. This might be so on a bipe?

Bigger airplanes can use 4 aileron servos......I would set mine up on dual channels with a Y to a pair of servos one on each wing and of course the other Y to the other pair of servos...that way if you lost a channel or a servo you still have some aileron left......
I have a bipe with 4 servos.....some of my flyin buds have 40 % monoplanes with 4 servos they don't have a problem with current...most of us are flying with Li-ion batteries and voltage regulators..or smart flys that allow 7.4 V for high voltage servos but 6V for the receiver...
As far as current draw...it won't be a steady draw but will vary with the load and amount of travel requested on the control surface