JS4 has a retractable electric motor instead of FES and it can self launch.

“The JS4 will be available with the jet sustainer system as well as the new electric self-launch motor option which retracts into the fuselage for low-drag ultimate performance.“

Getting some extra mileage out of all that fuselage and wing work on the JS3. I’m guessing the electric motor might go in the JS3 as well unless the flap mixer gets in the way since it’s otherwise the same fuselage. They had been talking FES previously as an option for the JS3.

All that leaves is a high-performance two-seater - unless they want to try to crack the trainer market.

Admirable efforts.

Andy Blackburn