Roger wrote:
Eric, can you explain span loading as opposed to wing loading?

Span loading = weight/span. I don't have a good technical reference for
it, but it accounts for aspect ratio effects to some extent. Consider
two gliders with the same wing area and weight, giving them the same
wing loading. The one with the higher aspect ratio, and consequently
lower span loading because the span is greater, will thermal better.
It's weight could be increased until they climbed the same, but it would
now have a higher wing loading and cruise better.

I mentioned it because it seemed likely you were thinking of 15 meter
ships flying around empty in the weak winter conditions at about 7.5
lbs/sq ft, and wondering how an 18 meter glider could possibly keep up
at 8.5 lbs/sq.

On Oct 21, 8:13 pm, Eric Greenwell wrote:
Roger wrote:
Eric, some places fly all year and if the pilot is 200 - 250 lbs the
wing loading in a motor glider is near max.Have you considered a sustainer glider instead of a self-launcher? That
removes 100 pounds or so. I've found my 18 meter glider climbs as well
as a typical 15 meter glider that has less wing loading. Span loading is
an important number, so don't go just by wing loading.

In the winter this means
the non-engine folks have a much easier time staying aloft, and the
motor glider in on the ground watching the pure gliders having fun.Start the engine, climb a bit, and go back to soaring. You will be able
to do cross-country flights on the days the unpowered folk don't dare
leave the field. The engine is your portable towplane, and even in weak
conditions you might find, as I have, that you don't need it as much as
you thought you would.

Starting the engine might be the of competition or badge flight, but
it's not the end of the flight or the fun. A few of my most memorable
flights involved weak conditions and low cloud bases, but I had good
soaring flights because I knew it wasn't going to end in a retrieve. Not
that retrieves can't be fun, but after 20 years of them before I got the
motorglider, my wife and I aren't missing them much!

To the 26E, 808 list I'd add the Antares, and the Apis and Silent
gliders (electric and gas versions). Lots more choices today than 10
years ago.

--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation websitewww.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" atwww.motorglider.org



--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org