I flew 1/4 scale planes years ago and after getting back into the hobby I wanted to fly the large gas planes. The first things I bought was a new DA50, some radio equipment and a 110" civilian type plane. My question is why do we have 7.4 batteries when it seems most components need to be regulated to 6 volt? Why are servos claiming 350+ torque when you need to regulate the receiver back? The DA50 ignition must also be regulated. I hope I don't appear to be on a rant but am just wondering why I was sold these batteries if they are needing another $100 thrown at them (regulator) to make them usable. I'm sure my inexperience is showing through and thanks in advance for your replies.

Well you gotta understand the discharge curve of the batteries, lipo family of batteries hold a higher voltage at discharge better than NiCads or Nickle metal.
now if you regulate to 6. Volts on the receiver, and 5 volts on the ignition but recharge at 7.1 volts on the battery you've got a cushion there.
look at a smart fly board when get to more than 1 servo on a control surface

Interesting question.

First, there's plenty of HV rated servos and most ignitions made today (not counting your DA 50 which has been around a while) will take a straight 2S LiPo.

Now back to your issue. You're talking about a "civilian plane", thats open ended, what sort of plane is it and what type of flying are you planning? Nothing running a 50cc engine really needs the expense, complexity, or weight of a SmartFly board IMO but they are nice.

In reality, you probably should have been suggested to use A123 batteries with a simple and inexpensive voltage drop down for your ignition. WrongWay RC sells voltage drops for both Lipo (dual diode) and A123 (single diode) inline voltage drops that work perfectly on ignition systems that can't take HV. That won't help you with your servos though, and you haven't mentioned which servos you purchased.

HV setups have their place, but unless you're doing cutting edge 3D on a plane with large surfaces, and are in the upper 10 percent of pilot ability (i'm not by far! ), its really not necessary.

They do it so that you can get the higher power if you want it. You don't have to go up to 7.2v if you don't need the torque and speed, but if you do you have it. So those servos allow for a lightweight and compact servo installation with tons of power. The cost is having to use regulators. But I can't imagine a 1/4 scale plane that requires 350 oz in servos. My 50cc Extra 300 doesn't even need that, not even on the rudder. So a 6v setup should be fine. There are 2 routes you can go with that. The first is to choose a more robust main battery to run your electronics and then use a BEC (an absolute must to prevent interference) to run the ignition, and the second is to use separate batteries for both. The advantage for the first is simplicity in charging and maybe a tiny weight savings. The advantage to the second is that a failure in your ignition, BEC, or wiring for the ignition won't also shut down your control system. I'm a fan of keeping them separate personally, but both ways work.

Thanks guys. I did overbuy thinking I would progress into more of an aerobatic or even a warbird later on. I do have an IBEC on the ignition. I talked to a tech from one of the major radio manufacturers and he said I could probably get by without a regulator on the receiver but it was not what they advise. Why take those chances? He also said by the end of the year there will be receivers made for high voltage out also. I'm learning but it is slow. Local hobby shops have never sold any gas engines or high voltage stuff. They are very little help. Thanks again for your help.