A heavy-lift helicopter was a military aircraft used by Diamond Dogs in 1984.
Background and features
The heavy-lift helicopter possessed a long fuselage, what appeared to be four engines (similar to the UTH-66 Blackfoot), six rotor blades, and four tail rotor blades. While the UTH-66 Blackfoot remained the Diamond Dogs' all-purpose helicopter, the heavy-lift helicopter was seen carrying heavy loads (such as Metal Gear Sahelanthropus) that the UTH-66 could not. The length and width of the fuselage gave the indication it could be also used to ferry a large amount of personnel as well in its bay.
The first time the helicopter was seen used was when ferrying Metal Gear Sahelanthropus's body to the R&D Platform of Mother Base shortly after Snake's victory over the Metal Gear and the death of Skull Face. Despite the helicopter's apparent capabilities, four were needed to haul the Metal Gear to the platform while still straining under the weight.
Kingdom of the Flies
The helicopter was used again by Diamond Dogs during the Kingdom of the Flies incident, once again hauling Sahelanthropus's body. This time, however, due to the damage inflicted on the Metal Gear, it was carried in parts by separate helicopters, apparently with much more ease than carrying the entire mecha.
Behind the scenes
The unidentified helicopter is first seen at the conclusion of Chapter 31 in Metal Gear Solid V: The Phantom Pain, and was set to appear in "Kingdom of the Flies." It was not given a name in the game itself, unlike the UTH-66 Blackfoot and the HP-48 Krokodil.
The helicopter seems to be a cross between the CH-47 Chinook and the HH-53 "Jolly Green Giant" helicopters, taking the forward fuselage and length from the CH-47 and the engines and tail rotor system from the HH-53.