Could I recommend a visit to this site?
CHIRP
Pprune has a distinguished remit in aviation but this could be another channel to advise what you experienced and learnt.
The venturi effect over a missing fuel cap can empty a tank in short order with certain airfoil designs. My airfoil - USA 35-B created enough suction to evacuate over 100 litres in less than a minute after a fuel cap with a locking tab at full engagement and a cover flap with a slightly worn wing head stud dzus simultaneously failed on a short irregular runway.
Your airfoil - possibly the NACA 652-415 might be kinder with regard to this issue but a Chirp report could be helpful to the flying community at large.