40G? I doubt it. And even a 180 mph capable R/C pylon racer slows his model for the turns. You couldn't do a 40G turn because the control surfaces would stall and the plane would side-slip because of the plane's inertia in the direction of travel. Something would rip off first. Dive bombers found that if they forgot the dive brakes they would pull up and the plane would keep going down but at a nose level attitude (wings stalled) until they pancaked in with their bomb.

Here's a FAA report on G forces during maneuvers.

http://www.faa.gov/library/reports/m...ia/AM72-28.pdf

a 70º pull-out "blackout" maneuver puts 6 G's on a pilot. A "tight level turn" (like a pylon) is 8g.