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I Learned About Flying From That: My First Solo and My First Loop
While I was doing the 360-degree turn I realized that it was essentially the same as a loop but on a different axis (horizontal vs. vertical), with the exception, of course, that gravity was a constant in the 360-degree turn, whereas in the loop it was a positive during half of the maneuver and a negative during the other half. My college physics classes taught that centrifugal force is a force from the center outward and is a constant, but gravity is a factor that could not be ignored. When you swing a bucket of water in a circle in a vertical axis, the centrifugal force has to be sufficient to overcome the pull of gravity on the top of the circle. My thinking at this point was that in performing a loop, you just had to have enough speed and be in a tight enough circle so that the resultant centrifugal force would be more than equal to the force of gravity, consequently keeping the net force always outward. This would not be a problem on the bottom half of the loop, but it would be critical on the top.
Next came the calculation: The normal cruise speed of a PT-19 is about 105 mph. I made the assumption that if I could get the airspeed to 145 to 150 mph, pull the stick back into a steep climb position and keep it there, sooner or later I would be upside down — in the top of the loop — where the centrifugal force would be slightly more than the pull of gravity, thus keeping everything from falling (just like the water in the bucket at the top of the circle). At that point, if I continued to hold the stick back, the nose of the airplane would start pointing downward and the force of gravity would start to increase the speed to the point that the throttle setting would have to be reduced to avoid going too fast — the goal being 105 mph at the bottom of the loop (the starting point). In my mind, I thought it should work.
I thought more about it overnight, and the next day I decided to try it. I was flying solo about 30 miles from Cimarron Field. It was a cloudless sunny day. I climbed to 8,000 feet and got myself oriented to a north heading. I pushed the stick forward, the nose went down and the airspeed soon reached 150 mph. I pulled the stick back, the nose came up and the airspeed dropped — 140 … 130 … 120 … 110. I kept the stick pulled back. At 105 mph I appeared to be upside down and heading south. The airspeed started increasing. I kept the stick back and started reducing the throttle setting. The airspeed increased to 110 … 120 … 130. I reduced the throttle setting even more. At 135 mph I was starting to level out at 7,000 feet and was heading north. I reduced the back pressure on the stick and was soon flying straight and level at 105 mph. The loop was complete — just as I had calculated in my mind, thanks to my physics studies.
I never told my flight instructor about the event. I was too afraid that he would not have approved of my little scientific experiment. Now I’m 90 years old, and when I look back at the stunt, I realize how stupid and ill advised it was. Had my mental calculations been only slightly in error and the airspeed at the top of the loop been less than the airplane’s stall speed — and I had no idea what the stall speed of an upside-down PT-19 was — the airplane could have potentially flipped into an inverted spin. Such an event is difficult — sometimes impossible — to recover from, even for an experienced aerobatic pilot, much less for someone who had absolutely no aerobatic training at all.
I guess therein lies the reason that pilots in training for combat missions are always young 21- or 22-year-olds and not 50- or 60-year-olds. Combat missions are always dangerous, and young guys are more likely to ignore the hazards and “go for it,” whereas older pilots tend to be more cautious and unwilling to take the chances the mission requires.