Oz Report

Leading Edge Vortices

Bats do it, bees do it, ....

http://www.nytimes.com/2008/03/04/science/04angi.html

In the latest issue of the journal Science, Anders Hedenstrom of Lund University in Sweden and his colleagues report that when a nectar-eating bat hovers in midair to sip liquid sugar, the mammal’s sharp-edged flexible wings generate the same sort of precision whirlwind lift detected recently in studies of insect flight.  As the bat curls its membranous flappers in and out three times per second, a series of tiny cyclones form at the leading edge of each wing.  The result?  Even as gravity plucks at its heels, the bat’s homegrown tornadoes suck it back up toward Oz.

Other researchers have demonstrated that insects like honeybees and dragonflies rely on such leading-edge vortices to supply the major part of their lift, particularly during a hover or slow cruise.  The new work shows that considerably heavier animals than insects can rally the power of quick-changing or “unsteady” aerodynamic tactics in their quest to stay high.  The star of the current study, the Pallas’s long-tongued bat of Latin America, weighs maybe 12 grams, 120 times greater than the average bee.  The researchers predict that hummingbirds will also be shown to have twister-tipped wings.

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Eating your own Dog Food

A real world test for my SeeYou program and FS. (Mt Borah, Manilla)

This last week I had the opportunity to compete, put out the Oz Report, assist with the scoring (after setting up the scoring system and computer), and test my scoring system against the FS scoring system that is being supported by CIVL.  This was as much a real world test for my program (it has been used in about half a dozen competitions, and of course, tested there) as it was for the FS program (which has been beta tested in France in 2007).  Of course, I was eager to run them side by side to see if there were any differences.  And doing this in real time while pilots wanted their scores, and wanted them correct was quite a challenge for me and for Stein-Tore, the FS author who is in Norway (or Sweden).

Stein-Tore and I had many email conversations as we ran into discrepancies and I learned how to run his program.  Having two programs looking at the same data (and it was a chore just getting the data (track logs) to match) and comparing them with RACE (another hurtle) was the kind of process you need to stamp out those nasty subtle bugs.

You can find the FS program here: http://ozreport.com/12.033#0

You can find the latest version of my program here: http://ozreport.com/forum/viewtopic.php?p=51049#51049

We found a bug in my program which became evident on an unusual day when many pilots who made goal didn't get any speed points.  This hasn't seemed to have had much effect on previous competitions scored with my program.  We also found a bug in FS that incorrectly allocated the distance points if you didn't make goal, giving you too few.  Those bugs have been corrected now and both programs should give almost the same results.  I say almost because there are still very subtle differences (like, I think difference earth models).  The differences are too minor to worry about now.

FS is an excellent free program (mine is free also, but you need to purchase SeeYou) and very well written.  It is fun to use.  Check it out.

My SeeYou program is also a hoot and scorekeepers love using it.  Both programs require that you have your Garmin USB drivers and USB/serial port drivers up to date.

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Evidence-based medicine

I was going to write this story before my more major crash (Mt. Borah, Manilla)

Conrad Lotten is again the hero of this story.

On Wednesday I blew a launch on the north launch at Mt.  Borah.  I did something very similar what you saw in the video of my launch on the west side later in the day.  Likely I took two or three steps with the glider horizontal then let the glider nose come up.  Also I launched on a flat slope with no cliff (until later) into no wind or wind from the side.

In this incident I suffered from cuts and and scratches.  The glider suffered from a broken down tube, a bent downtube, and scruffs to the nose cone:

Click on above for high resolution shots.  Thanks to Billo.

The picture above of the bandage has a story.  This was the cut, a bit deep, a flap of skin that had to be cut off.  The first thing we did was rinse the scrapes and cuts in lots of water.  Conrad says the best thing that you can do for a cut or scrape is thoroughly rinse in in lots and lots of tap water.  Doctors used to use sterilized water, but tap water turned out to be better because you used much more of it and the point was to get out the dirt and other bad particles.  So the more the better.  Thoroughly flush the wound.

We put betadine on the cuts, but Conrad said this was useless, that it killed the good with the bad.  The ointments and anti infection agents didn't do anything useful.  It's the original cleaning that counts to stop infection.

The next step was to get a bandage that kept the cut moist so that the skin could grow back quickly.  Conrad went to the chemist and found OpSite post operative dressings.  They required that I shave my leg around the wound in order to get them to stick to skin instead of hair.

This was a deeper wound than just a surface scratch, so the idea is that skin cells have a much easier time growing in areas where they are no continually dried out.  I wanted a bunch of skin to grow back as quickly as possible.  It is working.

I've had no infection on any of the wounds.  The OpSite bandage stays on as long as I like.  In fact there is no need to change the dressing, Conrad states.  Better not to disturb the skin as it grows back.  I can take a shower with the bandage and it stays attached to the skin.

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New Australian Distance Record

Jonny goes 517 km (321 miles) for the world foot launched distance record (Beechmont, QLD, Australia)

On Wednesday morning Jonny launched early from Beechmont on an excellent day and beat his previous Australian distance record of 500 km, flying 517 km (321 miles) landing 40 km west of Roma, QLD,  past Muckadilla.  He should be back in Beechmont at 2 AM, and be ready to go again on Thursday as it looks like a better day.

While we were in Manilla on Saturday it looked like Monday through Wednesday would be good (and we couldn't see Thursday).  Jonny headed back from Manilla right away on Sunday to get ready to go.  Wednesday was the first good day.

Two weeks ago I flew with Jonny at Beechmont and it was great because he is a guy who wants to go big and is willing to go early.  There are very few guys who are made like this.  I've known Jonny since he was eight years old and it is great to have someone around who has this attitude.

On Wednesday we were driving north from Manilla to Brisbane though Toowoomba.  It was blue until we got near the small town of Texas were I began to see very scattered and very high cu's, the highest cu's I'd seen in Australia this year.  Right away I thought it looked like Jonny might be in the air.  I was feeling bad because I couldn't be with him, on launch at least.

There were more and more clouds as we got to Toowoomba, but Jonny would have been far to the west of these by 4 Pm as we entered Toowoomba.  By the time we got into Brisbane we had received an SMS from Vicki Cain at Moyes.  As Belinda was writing her back, Jonny called as soon as he got into cell phone voice range.

This is a world record for a foot launched (mountain launched)  hang glider (flex or rigid).

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