Is the ASW-27B still being made?

At 16:35 14 May 2013, wrote:

It strikes me the right answer for sailplanes is a front electric
sustainer=
powered by a very small battery and fuel cell.=20

I like your thinking John. Fuel cells also produce water (useful for
hydration) and heat (useful for socks). If you choose a direct ethanol
version you would also have a ready supply of hooch for when you eventually
land out and need a drink!

Jim

On Tuesday, May 14, 2013 10:35:52 AM UTC-6, wrote:

It strikes me the right answer for sailplanes is a front electric sustainer powered by a very small battery and fuel cell.

Gliders need light weight. Batteries are all sorts of things but they are not light weight.

It depends on the energy density of the chemistry (in Mega Joules/kg.)
Lead-acid: .17 mJ/kg.
Lithium Ion: 0.72-0.875 mJ/kg
lithium-Air: 9.0 mJ/kg.
Hydrogen-air fuel cell: 97 mJ/kg
IC engine w/fuel: Typically 9 mJ/kg

Lithium-air looks promising. Hydrogen-air fuel cells have proven to have long endurance in aircraft propulsion systems. Lithium batteries can deliver a huge surge of power for takeoff. A "range-extender" fuel cell/lithium battery hybrid looks interesting for electric vehicles but in a glider...?

Jet engines are cool, light, and start easily (I gather)

Unless you have a wet start.