Top-hinged composite wing--similar to Integral.
Fairly thick sellotape-type stuff---used for temporary repairs to greenhouse glass,etc.
Stick to ail,cover rest of surface with talc to de-stick the rest, fold into gap. Choose a width to close the gap at full deflection,plus around 5mm extra---not too much more, or it can jam in the gap whilst closing. Run a small bead of cyano along the joint for added security .