Hi

Thanks for your enquiry

RCV have tested a number of APC 3 and 4-bladed propellers and would recommend the following sizes
3-bladed - 15x13W : 15.75x13
4-bladed - 15.5x12
All of these prop sizes are available from APC.

After looking at your photo, it is possible that Solo props (http://www.soloprops.com/) would have a suitable prop for your requirements. These have an adjustable pitch.

I hope this helps, however if you have any more queries, please do not hesitate to contact me

Best regards
Laurenne