10 acres = 4ha
So a square block would be 200mx200m
Sunfish IIRC has been building one of these:
STOL CH 750 light sport utility airplane from Zenith Aircraft Company - the ultimate short take-off and landing sport kitplane - Sport Pilot Ready
Assume they are the same as the related Savannah and the reverse of a light 172 ie TO from a tennis court but landing 100m over 50ft you'd better be perfect every time.