Posted by: quienessupa | December 30, 2008

Hang Gliding in our Arctic subzero cold fronts – Part 1

wing over snow

2 cold blasts lately brought a chance to experience familiar places for the first time. 

1degree driving to LZ

12/14/08, a group of ‘adventurous’ HG/PG pilots met in the Lookout LZ in a frigid 2 degrees F.  There was potential for the wind to pick up enough for some ridge lift.  But how much did we need?

PGs on snow and limp windsock in background

I was curious to see how much extra punch the phat air would have.  Since we’re used to 75 degree air, this subzero air must have more mass (per volume) and take less velocity to keep us aloft.  At least I was hoping that this extreme temp would make it more noticeable.  See reference at bottom, but landing at 5,600 ft, at -6 degrees F means the adjusted altitude density is about 2,400 ft!  That’s like landing in Big Spring, TX.  75 degree air at 5,600ft has an alt density of about 8,200ft.  So, comparing this cold flying to “usual” flying here, we’re at air densities roughly one mile lower!  “Relatively”, we were landing in sea level style air, a nice treat.   But the interesting part would be whether or not there’s a noticeable difference in wind velocity necessary to keep us up flying…   The below picture is my battons several inches below the surface.

battons in snow

The roads were snowpacked and I remember doing a perfect powerslide from the highway and off to the parking lot backwards. 

snow setup

We were out there in that cold for a good 5 hours and the cold air coming in didn’t warm up past 5 degrees all day. 

Kiernan Launch2

Kiernan launching (above pic) 

A true sledder is probably 4 minutes or less, but my flight was 11 minutes, along with probably most of us.  Then there was Andy in his Poison (PG) who taunted us, staying up for 1.5 hours in what he thought might be heat coming off Clear Creek.  Never above launch really, but he was in the zone.  Bad Ass flight Andy.. In his tracklog (below), look how each pass is just BARELY above the previous… that’s light lift!  That’s where he was the entire flight!

Andys flight

My face was feeling strange in the 11 minutes at 23mph.  The 6030 had to be turned on for a while before it did anything but beep, but eventually it’s screen readout came to life, which is impressive!  Another push of cold had just come in when I launched and clouds started forming above me and around and the Coors plant’s steam went from a normal plume to creating it’s own cloud that engulfed launch with the smell of cooking barley or hops…mmm 

My tracklog below is showing 200ft too high:

GE flight

The ice-crystals sparkled in the sun and reminded me of being at cloudbase in the summer at 17,999ft flying from Dinosaur.  I think I might have soared if I was on that 225 falcon I used to have. 

Kiernan Launch1

Kiernan launching from virgin powder…  My launch was SHIITY.  I didn’t realize the snow had drifted below me and as I took the first few steps, the transition from jog to run never happened b/c the snow got too deep and I pretty much fell and pushed out so the glider would do the work.  Phat air might have saved me there!  The Sport 2 took me out of the snow but as I got 4-6 feet up and away she reminded me gently with a good amount of bar pressure that she needed airspeed or else.  So she kinda took a little dive w/o my consent and we were even.  The back of my harness filled up with enough snow for Frosty’s head so I shook it out in the air.

Coors Steam

Above, the Coors plant is working on my beer.  This is before that steam turned into a cloud that engulfed us!  I broke down in the cold and realized I was getting pretty tired.  And subsequently cold.  But I went back up for another go potentially.  Since the HG took so long to hike up in the snow again and the set up is kinda hard with things disappearing in the snow, I got ready to go and it started blowing down the hill and the day was over.  Dude, so it’s about 5 below zero and I’ve just set up my glider, gotten tired and cold and the wind’s blowing more and more down the hill.  That was bummerish.  I owe Kiernan big time for waiting and helping me walk my glider down the snowy hill. 

blow down windsock driving down

It was -8 degrees when I got in the truck to leave (above pic).  The haze in the background is visible moisture coming off a reservoir several miles NE. 

Below Picture, notice how the Coors Plant steam is way more pronounced at -8 degrees, than the earlier picture:

coors steam -8

In the severe cold, the different smoke stacks around created their own low clouds that would make a bump in the strong inversion.  Also, we talked about how the Coors plant looked like ample lift to soar in, but we couldn’t glide that far.  The soaring that Andy did was in light wind(2-5?).  He used every bit of the bubbles coming up the windward hill, just enough to keep it up.  It’s hard to say how much of our flights were extended by heavy air ridge lift, or the bubbles of instability that would come thru.  I’ll just rest my case for now, until we get another cold event.  Need a smidge more wind. 

It took a couple hours at home by the fire before my bones stopped radiating cold!

 

Reference:

JJ pointed out this website to calculate ‘altitude’ density:  http://wahiduddin.net/calc/calc_da.htm

Local discussion here:  http://rmhpa.org/messageboard/viewtopic.php?t=2240


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