My rebuttal, “VALUE OF URT,” is on the IAC website, here. That article includes links to several incidents that support my argument, and to several videos on my YouTube channel that illustrate key points.
I also addressed URT in an article in the November 2017 issue of AOPA Flight Training magazine: The Right Formula.
I recently escaped the gray skies over Seattle and made a quick visit to Boulder City, NV to fly the Extra 300L. Here’s video of one aerobatic session, a warmup to help me reset my personal G-tolerance and practice several basic aerobatic maneuvers.
Every pilot learns that a wing can stall “in any attitude and at any airspeed.”
But it’s difficult to demonstrate that principle in a typical training aircraft. This video of an exercise that I do with my stall/spin/upset recovery students shows the value of training in an aerobatic aircraft.
I fly a basic loop, but at several points during the maneuver, I intentionally increase the angle of attack by pulling back abruptly on the stick. Each time I pull, the angle of attack quickly reaches the critical angle of attack, and the airplane shudders in an accelerated stall, regardless of the airplane’s airspeed or pitch attitude relative to the horizon.
In other words, you can change the airplane’s attitude (and its angle of attack) almost instantly, but changing its flight path requires more time. That difference between the attitude and the flight path is angle of attack, and when that angle exceeds the wing’s critical angle of attack, the wing stalls.
It’s also helpful to remember that a loop is just a vertical turn. The same principle applies when you bank the wings and turn an airplane in the horizontal plane. If you pull back on the yoke or stick during a turn, you increase the angle of attack. Pull back too aggressively, and the wing will reach its critical angle of attack and stall, regardless of the indicated airspeed.
I do the exercise below with my stall/spin/upset students to simulate the disorienting effect of a wake-turbulence encounter. We perform 1-1/2 aileron rolls to inverted and then push and roll to recover to normal upright flight. The exercise is confusing at first, and the nose always drops well below the horizon during the “upset.” It’s a great way to help pilots understand what could happen if they were caught in a wintip vortex.
Wake turbulence caused by wingtip vortices is major hazard to small aircraft.
I have collected short excerpts from a recent aerobatic flight near Seattle, WA to demonstrate a few basic aerobatic maneuvers. Each video shows the maneuver first from the left wingtip and then from my perspective in the rear cockpit of the Extra 300L.
Here are highlights from an early summer aerobatic ride in the Extra 300L east of Seattle.
The passenger from Switzerland enjoyed the view of the “Cascade Alps” east of Seattle as we flew through a series of aileron rolls; loops, half-Cuban 8s; big, lazy barrel rolls; slow rolls; hammerheads, and a little inverted flight.