Monday, April 23, 2018

A couple of test flights

Over the past week, I did two test flights with two different CFI friends in Cessna 172s. The goal was to use the Airball system (V3 board, Raspberry Pi display) in a "real" flight setting and see what the CFIs reaction was, and how they thought it would help them teach.

CFI #1

This CFI was like, ok, this is great but what does it do? :) He noted that he usually teaches attitude flying. I replied, well, think of all the times when your attitude is not a good indication of your AoA. This lit a fire in his brain.....

The first thing he did was to completely botch a stall recovery, where he pointed the nose down at the ground, "panicked" that he ground was coming up at him, then pulled up again. And there we were, with the nose pointed down towards terra firma yet the AoA was right down in the stall region. Hah!

Next he proceeded to do a steep turn. And this was definitely within utility category limits and non-aerobatic, but it was steep. My jowls felt like they were going to sag down into my lap. And lo and behold, a "fat" airball that "sagged" down to a high AoA, which if we were not careful could lead to an accelerated stall. Hah!

He also tried some more commercial maneuvers including wingovers (half of a lazy-8) and noted that it was interesting to see the yaw in the maneuver very clearly displayed, without having to look down at the laggy, slow inclinometer ball.

We also did some more regular things like slow flight and stalls, and observed how the ball changed position.

CFI #2

This CFI is all about teaching AoA, and was quite happy to finally have an instrument that visualizes it. Thus enthused, we launched for a jaunt.

We spent a long time trying stuff out with the AoA monitor. He came up with the idea of using the ╬▒REF marker (the split circle) to mark a given flight condition, then try variations from that. This was brilliant and allowed us to figure out, for example, how the AoA changed when flaps were deployed, or observe the phugoid oscillation of the airplane if we pulled up flaps without trimming. We spent a long time messing around with the flaps and observing their effect on AoA and theorizing about what was going on.

Overall, he was excited about the possibilities and planned to try it out with some of his students.

On our return from this flight, something happened that is worthy of its own blog posting. Stay tuned....

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