the short-span d.iic prototype had been further refined and with a narrower chord upper and lower wing, using the göttingen 180 airfoil. one wing was slightly longer than the other to counter the p-factor of its huge four-blade propeller. the port panels outboard of the struts were in length, while those on the starboard side were long. the performance improved noticeably in top speed and in climb rate over the d.iii. an order for this model, now known as the d.iv, was placed in march 1918 and additional orders were placed as the qualities of the design became known. aircraft started reaching operational units in august but of the 280 ordered only 123 were completed by the end of the war, about half of those reaching operational units.