In October 1914 Siemens started design of four-engined aircraft similar to that of Sikorsky in Russia. As entirely new venture company sponsored designs by two Steffen brothers leading to giants R.I-VII of 1915-1917.
The then relatively low engine power required lightest construction. This in turn required precision and caution, especially when landing – where such giant wooden aircraft were extra-sensitive. Many crashed.
All Aero 