Saturday, June 07, 2008

Air work and ground work

Today's flying pretty well matched the forecast: weak lift, 2 knots, not going very high. There was probably an inversion at 5000' MSL or so, but the air was clear enough you could not see the inversion from the ground. Barometric pressure was low, and winds were light. I found a couple of thermals, never got much above release altitude. No heavy sink, some weak lift late in the flight, probably not convergence because it was localized and not spread out. (See, I remembered the possibility of a shear line!)

The PW5 is grounded, so I took a solo flight in a Blanik, the new one that I've only flown once before. (The other time was a dual flight.) I played with it a little bit, because last time I flew it it seemed to want to roll left. Well, this time when I released the stick and did not adjust with rudder, it tracked nicely straight ahead. After a while it did drop a wing, but it was very gentle and randomly chose left and right. So I would conclude that there is no problem.

I did notice that I could not trim it back far enough to stabilize at Minimum Sink speed, which is 42 knots. I also noticed it's a very quiet ship! And in this one, I was feeling the bump of lift well before the varios indicated any.

Usually in a Blanik, in weak lift, it's helpful to pull out the flaps about halfway. This expands the wing area, producing more lift, without dropping them down, which would add drag. Often this makes the difference between "zero sink" and usable lift. Today it did not seem to help. So I tried not pulling them out even halfway... still did not seem to help. I wonder if there's some difference with the flaps? Something to try again in this ship.

The PW5 needs its annual inspection, and we thought our local A&P was going to do it today. We usually do whatever minor disassembly is needed to make the A&P's job easier, and in the case of the PW5 that means removing the "seat pan". I'm one of the most frequent fliers of it, so I was designated. I've never seen it disassembled, but it turned out to be pretty easy: remove 22 screws and wrangle it out. He never returned, so the PW5 remains in pieces for now. I did get a chance to look at how the control stick mechanism works.

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