Training Tip: Load versus load factor
Student Pilot A is practicing a 360-degree steep turn, working hard to maintain sufficient back-elevator pressure to keep the trainer at a constant altitude while watching for the outside visual reference to reappear in the windscreen.
Student Pilot B, back at the flight school, is pondering a load-factor chart in a flight training text, working hard to grasp the idea that the load being supported by the airplane’s wing in a steep turn is greater than the aircraft’s total weight.
Unfortunately for Student Pilot A, the steep turn has wandered on that chart a bit as he strayed from the 45 degrees of bank required for this performance maneuver by the Private Pilot—Airplane Airman Certification Standards.
Fortunately, his ability to sense the increased load factor as the overbanking tendency brought the aircraft close to a 60-degree bank angle, and his ability to notice the quickening rate of turn, cued the student to ease up on the bank angle, and reduce pitch to keep the turn level. (Lowering pitch, or angle of attack, was necessary because the total load imposed on the banked wing was being reduced.)
Student A also was mindful of something Student B, down on the ground, has just encountered in the textbook (while seated on a sofa, at 1G): “Load factors become significant to both flight performance and load on wing structure as the bank increases beyond approximately 45°.”
In the airplane, the practical significance of this information is inescapable: Load factor increases to 2 Gs at 60 degrees of bank, then increases rapidly to 5.76 Gs at 80 degrees of bank—but any load factor beyond 3.8 positive Gs would put a normal-category aircraft at risk of excessive structural stress.
The best safeguard against overstressing the airframe is to make sure to fly the maneuver at or below maneuvering speed (VA), which you can regard as “the maximum speed at which an airplane may be stalled safely.”
Flying the maneuver at the “manufacturer’s recommended airspeed or, if not stated, a safe airspeed not to exceed VA” also is a skill required when performing the maneuver on your private pilot practical test.
Many student pilots think steep turns are one of the most fun training maneuvers. Is it a favorite of yours? Share your thoughts at AOPAHangar.com
