Pioneer aviation engineer (1889–1972) who developed the first four-engine airplane and the first modern helicopter to be put into widespread use. Vintage matte-finish 5.25 x 4 photo of one of Sikorsky’s amphibious planes, signed in fountain pen, “I. Sikorsky.” Several blocks of toning over image and signature, and mounting remnants to reverse, otherwise fine condition. RRAuction COA.