On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

It's a mystery to me why some people think you can "get away with" so much more in old gliders than in those great big heavy clumsy glass ones.

Somewhere in this thread I saw a statement that you could safely turn back from 150 ft in an old glider (which I agree with), but you're a dead man if you try it below 300 ft in glass.

The differences that govern such a thing just aren't that big!

Let's look at some numbers for weight and wing area of typical training gliders (from Wikipedia):

ASK13: 290 kg, 17.5 m^2
Blanik L13: 292 kg, 19.15 m^2

PW6: 360 kg, 15.3 m^2
ASK21: 360 kg, 17.95 m^2
Puchacz: 368 kg, 18.16 m^2
Janus: 365 kg, 17.3 m^2

G103: 390 kg, 17.9 m^2
Duo Discus: 410 kg, 16.4 m^2
DG1000: 415 kg, 17.5 m^2

There's not a lot of difference in the wing areas, with individual variations bigger than the generational differences.

Yes, the glass ones weigh a bit more. How much more?

Someone flying solo in an ASK21 is at about the same all up weight as someone in a ASK13 with a smaller than average instructor in the back seat.

Someone flying solo in a DG1000 is at about the same all up weight as someone in a ASK13 with a largish instructor in the back seat.

We expect students to be able to cope with the flying characteristic differences between having an instructor and not having one -- and to cope with that difference on their first time flying alone!