Why The Engines That Flew On Saturn V Rocket Look Different In Museums
Video from the channel Scott Manley about Saturn V, linked on its Above Ten Thousand entry. Duration: 6:28. Language: English. Video type: Documentary.
What it's about
Scott Manley explains why the F-1 engines seen in footage of Saturn V launches appear covered in hammered sheet metal, while the examples on display in museums show all their piping.
Historical context
The question arose with the release of the Apollo 11 IMAX documentary, whose shots of the base of the rocket show the engines up close. During testing, engineers were concerned about the heat radiated by the engines onto each other, especially onto the central one. They were also concerned about a flight effect: as the vehicle gains altitude and speed, the low pressure behind the shock wave draws the exhaust back toward the engines and along the side of the vehicle. It's a phenomenon also observed on the Space Shuttle.
Key facts
The protection consisted of two layers of Inconel sheet separated by an asbestos insulator. It wasn't installed by the engine manufacturer or fitted when the stage was assembled, but at the Vehicle Assembly Building during stacking, requiring about 800 to 1,000 man-hours of work. It's already visible on Apollo 4, the first Saturn V launch. That's why museum F-1s don't have it. Manley adds that the film Apollo 13 shows the engines without it, while First Man does depict it.