The topic under discussion: How do you determine the wind direction on the ground when there is no windsock?
From: "Leo Jones" <malvernhill@hotmail.com>
Subject: XC landings
Ok, here's my 2c worth.
Probably more than anything else when I fly XC I worry about what the wind is doing on the ground, and I know I'm not alone.
The first thing is obvious - use all your sense of observation to continually monitor wind direction whilst still plenty high. You know, smoke, dust, wind lines on water, trees, long grass etc. I once ascertained wind direction when it was light by watching geese land on a pond, figuring they would land into wind. It worked, the wind was the opposite direction to what I would have thought - my buddy didn't see the geese and pounded downwind! However since then I have observed waterfowl land downwind!
Second, if the wind is more than 10 mph you won't have much problem determining its direction - it's obvious that you are moving much faster over the ground in one direction. A GPS certainly helps too, but as Kevin points out, it's not a good idea to get fixed on looking at this when you are getting down to decision height.
Smoke bombs are great, when they work. I have used 5. Of these 3 were duds! They are also expensive, extremely messy (the orange powder leaks out everywhere) and dangerous to store in your harness, or anywhere else useful come to that! They can definitely start a fire, and right now with half the West ablaze, it would be pretty dumb to use them except over bare ground.
Streamers can be useful. The cardboard thingy's with the bog paper inside, that crop dusters' use, work quite well. Day-Glo streamer tape rolled around a short piece of dowel and stored inside a film canister works well. Make sure that it is AT LEAST 20 - 30 ft long though, or it'll just end up in a heap. Make one end an obvious different color, and ensure that whatever you attach it to is light enough not to zoom down (ending up in a heap), heavy enough so it reaches the ground before you do, and firmly attached to the tape. Roll it up and put the last bit under the roll and then leave the end sticking out of the canister. Then you just yank it out, hold onto the end until it's unrolled, and drop from about 150-200ft. If there's any significant wind you should be able to tell - if it lands in a heap, well then just land the best way you can. Upslope is always a good idea, come in fast though.
In light winds though, you stand a better chance of making a good landing, if your approach, setup, and general landing technique is good, than by trying to guess and correct for switchy winds. I have seen pilots pile in trying to make low turns to "follow the streamer" when if they had just kept the wings level and airspeed under control they would likely have made a good landing crosswind or even downwind. If your wings are not level, and you are running out of airspeed, and you’re turning, then you are probably going to whack anyway. A good aggressive landing technique can easily balance out a light tailwind or crosswind.
Even so, if you fly XC, you are going to land downwind sooner or later. It goes with the territory. It's unlikely that you will land SERIOUSLY downwind, I mean if the wind is strong enough to be life threatening in a downwind landing then it'll be obvious. If you ride horses you are gonna fall off.
LJ
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From: robndi@flytandem.com
Subject: Re: XC Landing
Hi everyone,
My old faithful regarding the wind (assuming that anything more than about 5 or 7 mph will be obvious) is to fly directly toward a power (telephone) pole at about 500' agl. Important: Make a mental note of the initial heading while flying toward the pole. I do this to a pole on the "suspected but not verified yet" upwind side of the LZ. They are usually abundant since the local convenience store where I will be waiting my ride surely needs power to keep their beer cold. But any pole near or on the side of the LZ will work.
Now, as you are in the last 2 seconds to arrive directly above the pole where it is like an arrow about to be pointing directly at you, you roll the glider to a nice 30 or so degree bank. Then perform a constant airspeed, constant bank 360. When you are down to the last 2 seconds of performing a complete 360 arriving at EXACTLY the same initial heading (remember the heading you noted in the last paragraph?), note the instant you are arriving at that heading (pay attention here... concentrate on your HEADING and constant turning rate). At the split second you arrive exactly back at the initial heading, glance down at the pole and your drift will have the top of the pole pointing into the wind. But only look down for a moment to get the pole tilt data then concentrate again on constant turning and your heading. To help me do this I look down only with my eyes and keep my head and body fairly still. My mind will be saying something like: "3... 2... 1... look" This truly a shifty eyed way to get wind direction.
You should continue the circling at a constant rate and bank angle and each time around for about 3 circles verify the pole's top position as you pass the initial heading each time. Don't roll out each time but continue to stay turning and drifting. If the air is kick ass you should just work the lift and not land yet :)
By the time you get down to about 200' agl you should have completed about 3 circles all adding up to info on the wind direction. The top of the pole will be pointing further and further into the wind. You have drifted toward the downwind side and all that's left is the last downwind base and final into the field.
I've used it many times and it makes for a fun mental game as well as bringing great safety benefits.
Then all that's left is to get a beer from the store to reward yourself on a great flight and well planned approach.
Rob