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By pike
#399836
I'm flying again after a 3-year layoff. I was mostly flying and landing at low altitude (Quest in Fl.). Now I'm in the mountains and flying at 10,000. I flew yesterday and had a good breeze into the launch. The take-off and flight went well, but the landing sucked. I busted a down tube. I'm an H-3 with plenty of landings but I need any advice you would offer on landing in thin air. LZ is at 9000 ft. Thanks in advance. (BTW, hi to the gang at Quest from "Guitar George")
#399839
I'd suggest what is referred to as a Stabilized Approach when we fly those things with wheels and propellers, with one change.

https://www.faasafety.gov/files/gslac/c ... oncept.pdf

The change would be a much higher speed. Speed is your friend! No low altitude turns, you want a long straight final. The one big thing for me when landing at altitude (or the equivalent density altitude) was pretty much ignoring ground speed. You're coming in like the space shuttle and if you wait for the ground speed to look "familiar" you're gonna whack. Listen to the glider and flare on "feel" instead of speed and will be well.

An afternoon on the training hill reminding yourself of what a perfect landing is like isn't a bad idea either.
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By AIRTHUG
#399843
pike wrote: Fri Aug 04, 2017 12:45 pm I'm flying again after a 3-year layoff.
How can you be sure your crash wasn't due to the above, rather than the density altitude? Lack of currency can be costly!
pike wrote: Fri Aug 04, 2017 12:45 pmI need any advice you would offer on landing in thin air.
This isn't specific to landing in thin air... but really solid technique works everywhere. Dense sea-level air (and usually a nice breeze too) just lets imperfect execution appear to work just fine. It works 'till it doesn't... like high altitude and light or no wind.

Give this a glance: http://freeflightadvice.com/flare-physics/

Cheers,
RV
#399845
Hard to offer any relevant advice without actually watching your landing.

Overall however, the biggest problem I see in pilots' landings, especially at higher elevations, is fear of flaring. Fear of flaring begins with slowing the glider down too much until you have your arms extended, your body almost prone and the wing out ahead of you. There is no arm extension left with which to flare, and any flare you have will only push the glider further out ahead of you.

When landing, come in with extra speed, keep your knees as close to the basetube as comfortably possible. Allow the glider to naturally slow down without either pushing out or pulling in - this way you'll feel when it wants to stall. When it's time to flare, you can't be tentative - even if it looks like the ground a going past in a blur beneath you. Extend your whole body and try to punch the sky. Once you've done that DON'T LOOK DOWN! Looking down and trying to reach the ground with your feet just undoes all of your flare and lets the glider nose back down. Flare and HOLD IT. No glider in the world will climb out more than a few feet with it's nose pointed straight up.
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By dbotos
#399852
Keeping eyes up is a good way to avoid getting tricked by your ground speed. I'm sure most of us know the phenomenon from traveling on the highway - looking forward in the direction of travel doesn't seem like you're going all that fast, but look 90 degrees out the side window and things zip by in a blur.

I've also found that keeping eyes up helps me have a better sense of altitude while landing.

Loose grip helps for being able to feel the glider as it bleeds off speed approaching the flare window. I call it the hula-hoop grip because you encirle the tube with your hand but leave a little extra room, like a hula hoop around someone's waist.

For thin air, you can think of it like this: to generate lift, you need air molecules pushing up on your wings at a certain rate. If the air is thinner (less air molecules in a given volume), you need to move faster through that volume to encounter air molecules at the same rate as you would in denser air.
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By pike
#399854
Thanks to all, good reading. Gee, you mean a 3 year lay off degrades your flying skills???? LOL Aparently so. Thanks Guys for the help. I appreciate it.
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By red
#399855
pike wrote: Fri Aug 04, 2017 12:45 pmI'm flying again after a 3-year layoff. I was mostly flying and landing at low altitude (Quest in Fl.). Now I'm in the mountains and flying at 10,000. I need any advice you would offer on landing in thin air. LZ is at 9000 ft. Thanks in advance. (BTW, hi to the gang at Quest from "Guitar George")
Pike,

After a lot of flying at 5000' (1,5km) LZs, when I went back to sea level, my first flare was a surprise. Everything looked and felt right, but my flare took me to an instant five yards (meters) high. At my old LZs, this would have resulted in a Richter-scale whack, but in the thick air, my big glider just parachuted down nicely. Since you are going the other way (landing at higher LZs), I would say that you should flare a bit early (as compared to your lower landings), and very abruptly. There will be much less chance of "ballooning" up in the thinner air than you may expect.

Also, don't be shy about using oxygen there, before anybody local does, until your body has had a few months to adapt to the lower level of oxygen at your altitude. Headaches, dizziness, nausea, or any loss of mental focus means that you need oxygen immediately, and do not fly without it then. Watch this guy, calling the "Four of Spades."

https://www.youtube.com/watch?v=UN3W4d-5RPo

You will not be able to feel a lack of oxygen, until it gets serious.
#399856
Advice I'd like to add is to be prepared to run during landing.

No-step landings are great but landing at higher altitudes is going to require running more often than not. Especially without much headwind.

Watch birds, dust, and/or whatever and meditate on the physics of what needs to be accomplished and do it.
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By jlatorre
#399875
When I was regularly taking off at 10,000' in the Sandias, we used to use a rule of thumb that each thousand feet of altitude was equal to a one mph downwind. So a dead-air takeoff or landing at 5000' was equivalent to a 5 mph tailwind at sea level. A dead-air takeoff or landing at 5000' would be equivalent to a 10 mph downwind at sea level. I had the opportunity to test this when I went east for a vacation, and took off in a 10 mph downwind at Oregon Ridge in Maryland. It felt just like a no-wind takeoff at Sandia Crest.
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By pike
#399938
Thanks again for the tips guys. The O2 won't be an issue as we have lived out here at 7500' for 3 years. We skied 65 days last winter so we are routinely at altitude. The top of the mountain is 11,000'. I've been doing a mental review of my landing. I waited too long to flare (not enough speed) and I pushed out on the frame instead of up. Mel over in Albuquerque fixed my down tube for me and is re-packing my chute. I'm going back over and will spend some time on the training hills with him to get my landings tuned up again.
Thanks
George