Quote:
Originally Posted by NG[_2_]
Really, if you look at patterns that people actually fly, there is not so much difference in philosophy as you think. I challenge everybody to download log files from your airport, or contest, plot them, and see what they look like. Some base legs have long straight segments between sharp turns, some are merely connected gentle turns from downwind to final, but we all end up in the same place, on a controlled glide path and airspeed, safely aligned with the runway. The only thing that is confusing to students is authoritarian pronouncements of single and often incorrect ways to fly it. For example, nobody really flies downwind with a 45 degree lookdown angle to the runway, that would put them 800' away at 800 AGL, with no hope of flying a controlled base leg. Even the author of that silly guideline doesn't fly that close, if you look at his igc files at competitions. Most people fly downwind 2000-2500 away from the runway, which is more like a 20 degree lookdown angle. Do the math, look at what you actually fly, look at what other people fly. For example, see http://noss.ws/temp/patterns.jpg for a sampling of patterns a dozen or so experienced pilots flew and logged on OLC in varying conditions at the same location on the same runway. |
Now this part is true and very believable. I have seen this and when I look at traces from others at my gliderport they are definitely twice as wide (or wider) than I fly for my pattern. As previously mentioned, being an ex USAF guy, and used to using angles to set up patterns for bomb deliveries, I did try to do exactly what the books say, and at 1000 feet entering down wind I'd try to be at a 45 degree look down. By my 'rough' calculations (trig and all that), that means I'm on downwind 1000 feet away from the runway. Aint no one else at our glider port that close...
I then check air brakes and leave them out in order to start getting down and aim to hit abeam my touchdown point at a 30 degree look down angle (from texts, 500' alt abeam touch down point, and trig again). That position, rolling off downwind into a 25 degree bank rocks you nicely around to final with a continuous not too hard turn, plenty of correction, easy to see wind effect, roll out 1/4 mile aligned with runway, simple.
I'm not sure who came up with the angles, but they either do not understand trig, or did not do the calculations and compared them to suggested altitudes at each point. As mentioned, since I see almost no one else running down downwind at 1000 feet off set from the runway (and usually at 2000') I'm pretty sure no one else is using that 45 degree look down number.