I found it exhaust speed during 90* turn very quickly. Maybe my technique is wrong. Can one of T7 pilots available on this forum explain RL behavior and technique and how it differs from PMDG model (if it does)? PMDG T7 tend to stop in the middle of turn, and if I add power a little bit, I experience a steep and abrupt acceleration.

...well, friction at least.  Sorry, this is the enginerd in my coming out.  Drag at 15-20 notes is virtually zero (drag increases as a square of speed).  Further, drage depends on cross sectional area (primarily), so you could stack those 3 wheels in each bogey right behind each other and the drag is very near a single tire due to the cross section the air sees being equal. 

 

The loss from wheels is due to friction between the tire and the ground, as well as the tire and it's bearing on the strut.  For tires, this can get lumped in to a phrase "rolling resistance".  This also includes the angular momentum each tire sees.  This absolutely increases with each tire.

 

Sorry, I try not to pick on words normally and you're absolutely right about the concept.  I see many aviation folks (professional and sim) talk in words of drag for anything that slows them down, even if it's a wheel on the ground at 5 kts where drag effectively is non-existent.

 

I understand. Rolling resistance would have been better. Though i believe FSX's ground friction equation is a lot different to real world friction and the way it deals with aircraft models so my point remains (if i'm right about the way it works!).