Monday, August 24, 2009

"Gonna do some spins?"

We don't usually wear parachutes in our two-place Blanik trainers. So when we do, everyone we meet seems to ask, "Gonna do some spins?" Yep, that's what was on our agenda today. I'm working with an instructor to finish up training flights required for my Commercial and Instructor practical tests. One of the requirements is "...instructional proficiency in stall awareness, spin entry, spins, and spin recovery procedures...". Technically you don't need to wear parachutes when doing spins with an instructor, but we all think it's a good idea!

We took a 4200' AGL tow and were careful about doing clearing turns because we knew two other gliders were in the area. We also made sure we were well clear of the Victor airway that runs south of the airport - you can't do aerobatics within 4NM of an airway. We were able to do four spins and recoveries and still had a few hundred feet before reaching 1500' AGL, the minimum altitude for completing aerobatic maneuvers.

For three of the spins, I entered with the traditional method: pulling up into an obvious stall before using full rudder. For one of them, I did a more subtle spin entry that should be really useful in training students. I just slowed down to stall speed and kicked full rudder, much like what would happen in a too-slow approach with a skidding turn. In this case the nose was not in an obviously high attitude, although of course my angle of attack was high to get the slow speed. A slow entry like this really shows how a spin could sneak up on you.

I noticed more G force when pulling out of some of these spins than I did on some previous solo spins. Maybe I was eager to complete the recovery with little loss of altitude, and pulled up a little aggressively?

I made sure to enter one of the spins to the right, since I had noticed I tended to do them to the left in the past. That's probably because I favor left turns in general. I read an article somewhere that explained that: we control the stick with our right hands, and it's easier to push across to the left than to pull to the right - it's just a more natural angle for your arm and wrist.

We didn't try to go soaring, because we had other ground school work to do that afternoon. For the landing, I worked on using the wind to my advantage on base and final legs. My altitude on base leg has been right for no-wind conditions, but sometimes I underestimate how much a headwind component is going to knock me back on final approach. In the middle of the base leg, my instructor pointed out that I was a little high, and I said that was intentional. I slipped it a bit and kept my glide path a little higher than I've been doing. And guess what: touchdown was right in the box, instead of a couple feet short as I sometimes do.

We glider pilots (at least in my club and at my location) are real sticklers for accurate landings. There's a line in the sand that you are not to touch down before. We judge every landing in relation to that line. And if you're trying to land to commercial requirements, you have to stop in just a few hundred feet, so you don't want to land much beyond that line or you use up too much stopping space. So there's a very narrow sweet spot about 10 feet long that we're aiming for. And that line is imaginary, between two cones. There used to be a chalk line, but it's long since worn away. So you're using your peripheral vision and quick glances left and right to estimate your approach over that line. Very tricky to get just right! But it means you learn to put the ship down where you want it, within 10 feet or so. That came in very handy when I landed out at Olancha, where the dirt strip had a few bushes here and there.

1 comment:

smiss said...

Hi Roger, interesting comments re spin training. When I was doing ab-initio in NZ I was taught spins the stall and boot rudder way, but since doing additional training in Australia, my instructors have used a method that starts from an assumed under-banked, over-ruddered slow speed turn, such that a low-hours pilot might get into near the ground.

Generally the instructor puts the glider into a gentle banked turn at slowish speed, then feeds in more rudder and as speed slows and wing drops, he feeds in more aileron to try to lift the low wing until the spin develops, then it's over to me to recover.

I think the latter method has helped me understand the danger signs near the ground.