Ok. Well, consider this: Electric flight is already somewhat complex as compared to glow. You have at least 3 controls (Rudder, Elevator, Throttle) and in some cases four (Aileron). Add a receiver, an ESC, an electric motor, the battery pack, and you have the barest minimum setup for electric flight. This is a conversion. The OP said "Gas to Electric" but then said "40 size" so we are talking glow, not gas. Just a minor point, but I just wanted to clear that up.
Anyway, in this case, since we're talking about a 40 size conversion to electric, I will assume a fourth servo for the aileron. These servos are not micro servos, they are at least standard service servos, similar to an Airtronics 94102Z or Futaba S3003, both are standard, bushing type servos. As for the Futaba, the manufacturer recommends the following:
This servo can produce high-current draw from your batteries. If using NiMH or NiCd batteries, make sure they are capable of delivering sufficient amps.
I will assume the same is true for the Airtronics, or Hitec, or any other servo in that class.
For this very reason, I would recommend a separate battery with an ESC without BEC (not necessary so why pay extra for it). The OP stated he has a 600mah and an 1100 mah 4.8 v receiver battery. This is the way I would definitely go. Forget the LiPo and regulator for the receiver... redundant, ie. unnecessary, and adds unnecessary complexity. It, the LiPo, is needed for the ESC and motor.
Make your weight measurements (see below) separately, once with the 600 mah and once with the 1100 mah. I would go with the 1100mah, but I am the type that likes the warm-fuzzy with having just a bit more available.
Be sure to do the math to insure that the motor/esc/LiPo pack are sufficient for the weight of that airframe it is going in. Weigh it with everything intended for flight, or if the motor/esc/battery pack have not yet been purchased, use the numbers provided by the manufacturer, weigh the airframe, add the weight of the p ower plant, then do the math to see if the power is sufficient. If not, well, move up to a higher power and re-do the math. At some point, you will find the right combination for safe flight.
Make sure to include the receiver battery in the equation.
Use this guideline in selecting the proper power for that conversion:
1. Power can be measured in watts. For example: 1 horsepower = 746 watts
2. You determine watts by multiplying ‘volts’ times ‘amps’. Example: 10 volts x 10 amps = 100 watts
Volts x Amps = Watts
3. You can determine the power requirements of a model based on the ‘Input Watts Per Pound’ guidelines found below, using the flying weight of the model (with battery):
50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
70-90 watts per pound; Trainer and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models
4. Determine the Input Watts Per Pound required to achieve the desired level of performance:
Example:
Model: E-flite Brio 10 ARF
Estimated Flying Weight w/Battery: 2.1 lbs
Desired Level of Performance: 150-200+ watts per pound; Unlimited performance 3D and aerobatics
2.1 lbs x 150 watts per pound = 315 Input Watts of total power (minimum) required to achieve the desired performance
5. Determine a suitable motor based on the model’s power requirements.
Basic algegra.. [X(]
: you have 11.1 volts (nominal) for a 3 cell Lipo, say 110 watts per pound for sport flying, say 7 pounds = 770 watts. The math says that you will have a current draw of 69.4 amps.
So, this conversion will need a sufficient battery for 70 amps maximum draw and a motor that will give you the right power, 770 watts.
CGr.