I was drifting one of the facetmobile discussions with my sailplane delusions and decided to continue the dialogue here.
1: Span loading or wingspan length divided by total weight is a good predictor of glide angle.
2: Wing loading or wing projected area divided by total weight is a good predictor of stall speed.
Most competition sailplanes are designed to maximize the first element at perhaps some expense to the second.
But not all. As @Victor Bravo has mentioned, some standouts include Marske’s Monarch, Sandlin’s gliders, and I’d go ahead and include all the successful single surface hang gliders out there like the Wills Wing Falcon series, Moyes Malibu, etc.
Here the idea is to minimize sink rate, and to do this, they sacrifice some of idea 1: above in favor of idea 2: Make a glider with as much area as you can get away with the weight.
I was thinking of ways you could take this idea up even a little more. I think the ultimate example would be a paraglider, whose weight is negligible. That said, my design interest lies with rigid structure and aerodynamic control.
As I’ve been building my Sandlin Goat derivative, my mind has strayed frequently to the idea of a flying plank glider, à la Backstrom, but built like a Sandlin goat. I know a tailless design has performance drawbacks, but maybe for this soaring mission it doesn’t matter as much? The subtraction of the weight of the tail could make for an interesting decrease in wing loading and commensurate sink rate reduction. If you kept the 36 foot span, your span loading could possibly also improve. If you added more chord, you could add a lot of area to further reduce wing loading and make the aircraft less sensitive to CG placement.
1: Span loading or wingspan length divided by total weight is a good predictor of glide angle.
2: Wing loading or wing projected area divided by total weight is a good predictor of stall speed.
Most competition sailplanes are designed to maximize the first element at perhaps some expense to the second.
But not all. As @Victor Bravo has mentioned, some standouts include Marske’s Monarch, Sandlin’s gliders, and I’d go ahead and include all the successful single surface hang gliders out there like the Wills Wing Falcon series, Moyes Malibu, etc.
Here the idea is to minimize sink rate, and to do this, they sacrifice some of idea 1: above in favor of idea 2: Make a glider with as much area as you can get away with the weight.
I was thinking of ways you could take this idea up even a little more. I think the ultimate example would be a paraglider, whose weight is negligible. That said, my design interest lies with rigid structure and aerodynamic control.
As I’ve been building my Sandlin Goat derivative, my mind has strayed frequently to the idea of a flying plank glider, à la Backstrom, but built like a Sandlin goat. I know a tailless design has performance drawbacks, but maybe for this soaring mission it doesn’t matter as much? The subtraction of the weight of the tail could make for an interesting decrease in wing loading and commensurate sink rate reduction. If you kept the 36 foot span, your span loading could possibly also improve. If you added more chord, you could add a lot of area to further reduce wing loading and make the aircraft less sensitive to CG placement.
