There are a few helicopters to the rear of this enclosed areas but I think these are actually C-2 Greyhounds. Notice the engine housings on wing stubs on either side of the fuselage. The teardrop shape in the top of some may be the antenna mount for the E-2 Hawkeye variant.
They are Sikorsky CH-37s. with a few CH-34s in the back row. In 1970 there were several of these at Coleman AAF in Manheim, Germany. I was there for 14 months and saw one fly. The CH-37 was the piston-engine forerunner of the turbine CH-53s and CH-54s. The big P&W radials used on 37s and 34s sounded incredibly loud and macho.
http://www.pimaair.org/Acftdatapics/Sikorsky%20CH-37%20090.jpg