On Tuesday, 13 November 2018 22:17:59 UTC, Duster wrote:
Unclear, but see LAK's Facebook page and Martin's posts. On one account there's a LAK17C-FES which implies a non-self launching version that is "totally" different than the 17B-FES. What do you call a self-launching front engine glider? FESL (front engine self launcher)? One reply by LAK to the Facebook fight review (which reads like an ad) was "Big" when answering a question about what mods they made to the wing. Together, one might envision the 17C has a new wing (more than a twist) with an option for an FES or FESL, the latter having a larger propeller, more power packs and increased ground clearance. Only guesses meant to tease us? Maybe John will share what he knows about pricing?

FES as an acronym has been retrofitted for self-launch as well now, see their website now http://www.front-electric-sustainer.com/
"FES is efficient and innovative Front Electric Self-launch / Self-sustainer propulsion system for powered sailplanes,"
I believe the difference is 'just' another battery pack and a bigger prop.