Assuming:
- L/D 40:1 850 pound Sailplane (in my case Genesis 2)
- Cluster of (3) currently available EDF Units producing combined ~60
pounds STATIC THRUST (AFTER taking into account loss of efficiency do
to close clustering of intake ducts)
- Battery capacity for ~10 minutes full power .. no reserve
- 2,500ft Paved Runway .. No Tailwind 
- Sailplane pre-positioned on runway (not taxied to runway)
- Goal altitude of ~1,500ft AGL
I should have added: "Starting from 1,000ft MSL"
Curt -95