Complex sentence: The Air Force also had new-build aircraft from the end of the production line, they were designated SE.161R and had Gnome-Rhône 14R engines with distinctive four-bladed propellers.
Split into simpler sentences: The Air Force also had newly built aircraft from the end of the production line. Designated SE.161R, they had Gnome-Rhône 14R engines with distinctive four-bladed propellers.