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Old December 21st 16, 05:28 AM posted to rec.aviation.soaring
Steve Leonard[_2_]
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Default Wing loading vs Span

On Tuesday, December 20, 2016 at 9:00:38 PM UTC-6, wrote:
On Tuesday, December 20, 2016 at 4:04:59 PM UTC-5, Jonathan St. Cloud wrote:
In days of old the phrase was "Nothing beats wing span". Now it seems as if these short wing "open" birds, i.e., JS1C are beating the long wing birds. Rarely even see a 23 meter bird in the open class. Having almost half my glider time in the open class I miss the long beautiful wings and at the end of a dying day a 6.2 pound wing loading.

https://www.youtube.com/watch?v=tt9VfoN2kTA&t=44s

Never having flown a 21 meter bird, but I cannot imagine they are as efficient at dolphin flying as a bird with more span.

So the question is, does span still beat wing loading or does 21 meters at 12 pounds beat 26.5 meters at 9.2 pounds? I realize there are many assumptions and variables, but damnit I miss the beauty of the long wings.


Just my opinion after about 300 hours racing a Nimbus 3 at 25.5 meters and about 9 psf. If the day is good, you can't keep up on a head to head run if you have more span but less wing loading. But, if you make some decisions better then them, you can for a race. You don't have a significant edge in mass, so Kinetic Energy is not significantly different. You have more wetted area, and lower wing loading, so in strong stuff, they can probably keep right up on the pull ups while dolphin flying. And out-glide you on the run.

When it gets weak, we all get light. I can get down to about 7.2, they can get down to about the same. You gain a span loading advantage, so maybe a bit on climb. But, I find the Nimbus handles worse dry than wet, so my climb doesn't go up as much as I would hope when I get light. Then, when you leave the thermal, you feel like you are a feather.

20 years newer aerodynamics does make a difference. But, like you, Jonathan, I do love span. To quote Platypus: "There is no Substitute for Span. Well, there is. It is called talent. But, you can buy span." So, I bought 25.5 meters of it. And I love every minute of flying it!

Steve Leonard
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