Quick Foilsim check. At 9 foot span, 1.2 foot chord, 5.5 degrees AoA the lift is just a hair over 10 lbs at 17 to 18 mph. Lift coefficient at this speed being a safe 1.16. If you're lanching into a 5 mph headwind that's only 13 mph we need from our brawny linebacker.

Time to start the shot put throwing trials...

Note too that it's not just about actually throwing the darn thing. The successful launch will still only occur if the arm guides the model such that the fuselage leaves the hand at a low angle of difference to the line of travel. In other words if it's launched with a strong bank angle or traveling belly first with the wing beyond the stall angle then bad things will follow before the pilot can correct them. Power with accuracy from the launcher is a must for that critical first second following the release.