[Off-Topic]
The guys who fly below 20A aren’t looking for speed,
- they fly without duct,
- they use a large wing like the RL optimised front Wing or a Gong Rise XL (@jeffM) or Veloce (thinner so lower drag but a bit more difficult at the beginning). A high aspect windsurf wing would do the job too.
- they use an optimized prop like the Flying Rodeo one or a customized 10usd cut down Yamaha clone (184mm to 130ish) like JeffM