Yes, I did check the resistance on both of Hacker motors and here is the data:
B40 12S w/4.4:1 Resistance: 0.0213 Ohm
B50 12S w/ 6.7:1 Resistance: 0.0129 Ohm
B40 motor has more resistance, both 12 turns short motors and B50 has 2.39A idle current compared to 1.47A B40 has.
My calculations show 1.6Kg (about 50 ounces) thrust while pulling 28A, with max 40Amps it will be probably around 2Kg.
So, even at 28A glider should have enough thrust doing 50 km/H (way above stalling speed). At least I feel comfortable with those numbers.
I definitely will post my report on performance results. It's almost a week wait until all parts arrive (some of them from Taiwan) so I can put everything together.
I also really re-thinking my servo KST choice and a lean towards ordering MKS servos for flaps and ailerons. KST can be used on some less expensive projects.
Thanks for your conversation and notes!