I flew a Decathlon this week, rebuilt, very tidy, zero engine, zero prop etc, 150hp motor.
With 2 up (185lbs/190lbs), 2/3rds full tanks, OAT 85 f, 25/25, 70 mph, why were we only getting 3 - 500 fpm ROC ?
I admit when we levelled, it gathered it's skirts and we were doing 120 quite quickly...