RE: 4120 vs 4130: Your project experience
Magna,
Here's something else you should consider.
Since you're attempting to reuse the 18 - 20 3300 mAh cell pack, the AXI 4210/14 is only rated for up to 16 cells which narrows your choice to the 4120/18 (rated to 20 cells) or the 4130 series motors which are rated for up to 30 cells.
This is purely subjective but I would look at it this way. If the plane calls for a 40 - 50 glow, the 4120/18 (in your case) is comparable, however, a plane that calls for a 60 - 90 glow will suggest a 4130 AXI. Again, this is subjective and depends on several variables. In my experience, I have found myself confused at times. Worse yet, if you ask 10 people the same question, you sometimes get 10 different answers.
The AXI's are good motors. I have a 4120/14 in my 8 lbs, 81" Proctor Antic with a 950 Square Inch wing area and it flies every bit as good as it did with a 60 glow engine.
Good luck on your choice.