June 18, 2012 update. I had a gorgeous summer evening with free time, and no passengers, so I used the opportunity to practice hammerhead turns. (my original post below, describes how I stumbled into this.) It was super FUN, and inspiring more confidence in my plane.
I climbed to 10,000 feet, and found 2 tiny side-by-side clouds as my reference. From a cruise speed of 135 to 145 knots, I would pull sharply up, but never reaching vertical. I’d estimate I’d reach about 15 degrees away from vertical, and watching airspeed dropping. I found that starting my sharp turn left or right at around 100 knots worked quite well. I gradually learned that at first, that I was being too timid with the ailerons for turning and relying on the rudder too much. But once I became quite aggressive with sharp turns of the yoke/ailerons at 100 knots, plus rudder to stay coordinated, I could swing the plane very quickly around from pointing up, to pointing down. Then it was just a matter of pulling strongly back on the yoke to bring the nose level again.
So I did about 30 of these turns, and if I wasn’t in a hurry to pull out of the dive, enjoying the sensations, then I’d end up losing about 200 feet from where I started. But if I was really aggressive on the aileron turns and very fast hard pull-out, there were a few times when I ended up leveling off at 10,000 feet again, not losing any altitude. But I think my ultimate lesson is, never do this at 200 feet above a mountain valley.
A few interesting things happen during these turns. Every loose item in the plane, like maps, car keys, sunglasses, etc, will be floating in mid air and end up in the back seats. ( But nothing went further back into the tail region). Most turns are finishing with airspeed around stall speed of 55 knots, but only once did I hear the stall warning sound, and never did it feel like a stall. I always felt the wings were flying and responding, every time, all the time. During the pull-out from the dive back to level flight, airspeed is increasing from the white range into the mid green range, and ending at around 135 knots. Never getting too fast or near the yellow speed range. The reversal of direction to 180 degrees of start, was nearly perfect every time, so I never had any hint of spin or spiral dive. And sometimes I was very aggressive with the rudder, sometimes perfectly coordinated, sometimes lagging with rudder uncoordinated from the ailerons, which only slowed my turn, but never caused any control problems, as long as I was determined to “turn” the plane. (Ie, I never tried any foolish “stall the plane while pointing vertically upward”.)
Those 2 little clouds were my visual reference. I was going back and forth between them, beside them actually. I’d cruise past the near cloud, and when I reach the far cloud, pull vertically up, turn, and I’d see the same cloud on the way down, REMARKABLY near to the same spot where I began going up. My pull-out from the dive would put me 200 feet below that cloud most times, and by the time finished pull-out and regain back to 10,000 feet and cruise speed, parallel to the 2nd cloud, it was time to repeat once again. So, WOW, you can absolutely turn around in a very short turning radius with this technique.
A few more observations. The GPS units get confused for a few seconds and tell the G500 unit that GPS is lost and shows a warning that I must fly by “dead reckoning.” Once, the engine monitor voice annunciator said a warning about something, like oil pressure or something, but I wasn’t paying attention to it. I had FULL gas tanks at the start, so I think that prevented gas and air from moving around a lot in the tanks, and I’d recommend full tanks to others who want to try this. After all, gas flow in this plane is gravity-based. OH, I’ll also mention that I was never fiddling with the throttle. It was always at cruise power.
May 14, 2012. I was in the right-hand seat, and my daughter in the left seat. We were finishing up an hour-long session of practicing her skills on a wonderful day of crosswinds. We ended up discussing box canyon turns, and that’s when I finished up by demonstrating a hammerhead turn. (This was in the context of talking about being in a canyon, and converting forward speed into altitude.) I didn’t know it’s true name until later on (from Google), but it was basically exactly like the diagrams show. From level flight at 120 Knots, I pulled the nose sharply upward, slowing rapidly and applying flaps. When speed reached 80 Knots, I began a sharp left turn, which was complete by the speed of 50. My plane stalls around 55, so it must have stalled briefly without my noticing, but by then, my nose was pointing down to the ground, gaining speed again, for a nice pullout, going in the opposite direction.
I found a youtube video of an acrobatic plane, demonstrating the hammerhead turn. Obviously my expedition didn’t go vertically upward like the Yak does. But the video nicely illustrates the very short turn radius it provides, and the exciting phase when the plane is accelerating straight down towards the ground.
Now that I know how, I think I’ll practice this some more, pay attention to all the details. ( Oh, and you can bet, I’ve reviewed spin recovery procedures! )
