The Mega 16/15/x series are great motors, but, they are intended to be primarily used direct drive. This helps keep the weight and complexity. This is also why they come in winds from 2-8 turns so you can design your optimal system.
Keep in mind that there are grey areas in the design philosophy that allow for flexibility like gearing. I think that you are on the right track with your 16/15/4 choice.
I have only used the Mega motors in direct drive applications.
My Wattage Extra 330L uses the following combination:
- Mega 16/15/7 direct drive brushless motor
- AeroNaut 10x7 black carbon prop
- RTF @ 24.5oz with
- 8-HECELLs or 500AR cells, 15amps @ 6100 RPMs, 100 W, 6.0oz pack
An 8-cell, CP1300 pack provided, 19amps @ 7000 RPMs but the 10.6oz pack increases the RTF weight to 29.1oz.
I have a new Lithium pack that I will test soon. The 3s3p pack is made from the new Kokam 340SHC cells. It has a 1020mAh capacity and can deliver 20amps continuous but it weighs only 3oz!
My little Extra will be RTF at only 21.5oz and it already has awesome vertical runs!
You can see pictures about half way down my
Aerobatics page.
My other Mega application is the 100mph ProJeti using a 16/15/3 motor.
Details are at the bottom of my
Wings page.
Good luck!